International Building Code Illustrated Handbook 2015 International Code Council

This chapter provides specific detailed regulations for those types of buildings and uses that have very unique characteristics. The uses in Chapter 4, though encompassing only a very small fraction of the uses commonly encountered, require special consideration. Some of the provisions address conditions that could occur in various occupancy classifications such as covered and open mall buildings, high-rise buildings, and underground buildings. Concerns associated with motor-vehicle-related uses, hazardous occupancies, and institutional uses are specifically addressed. Special elements within a building, such as stages, platforms, motion picture projection rooms, and atriums, are also regulated by Chapter 4.

In all cases it should be remembered that the provisions found in Chapter 4 deal in a more detailed manner with uses and occupancies also addressed elsewhere in the code. Some of the provisions in this chapter may be more restrictive than the general requirements of the code, whereas others may be less restrictive. The general rules found in other areas of the International Building Code® (IBC®) will govern unless modifications from this chapter are utilized.

Section 402 Covered Mall and Open Mall Buildings

Provisions for covered mall and open mall buildings included in the IBC set forth specific code requirements for a specific building type. Provisions in this section only apply to covered and open mall buildings having a height of not more than three levels at any one point and not more than three stories above grade plane. Furthermore, the provisions are only those that are considered to be unique to covered and open mall buildings. For those features that are not unique, the general provisions of the code apply. Covered and open mall buildings that comply in all respects with other provisions of the code are not required to comply with these provisions. It should be noted that foyers and lobbies of office buildings, hotels, and apartment buildings should not be considered covered or open mall buildings. An example of an open mall and associated buildings is shown in Figure 402-1.

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Figure 402-1 Open mall.

402.1.1 Open space. The special provisions of Section 402 are applicable only where the entire building, including the anchor buildings and attached parking structures, are surrounded by permanent open space at least 60 feet (18,288 mm) in width and the anchor buildings are no more than three stories in height above grade plane. See Figure 402-2. The allowance provided in the exception to Section 402.1.1 for reduced open space surrounding covered mall buildings, including their associated parking garages and anchor stores, is consistent with that for other unlimited area buildings as permitted by Section 507 since a covered mall building contains similar characteristics of those buildings. The reduction in required open space is not permitted where the covered mall building or anchor stores include Group E, H, I, or R occupancies. Where a building is considered an open mall building, the required permanent open space is regulated based on the open mall building perimeter line as described in Section 402.1.2.

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Figure 402-2 Covered mall building.

402.1.2 Open mall building perimeter line. It is necessary that a perimeter line for an open mall building be established in order to apply various requirements in Section 402. The line creates the boundary of the tenant spaces, service areas, pedestrian paths, and similar spaces that make up the open mall building, but does not include any anchor buildings or parking garages. An example is shown in Figure 402-3.

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Figure 402-3 Open mall building perimeter line.

402.4 Construction. Where covered and open mall buildings are constructed of other than Type V construction, they may be of unlimited area. Associated anchor buildings of Type I, II, III, or IV construction may also have unlimited floor area provided they are no more than three stories in height above grade plane. For those anchor buildings exceeding three stories, the general height and area limitations of Chapter 5 are applicable, including appropriate increases for frontage and the presence of an automatic sprinkler system. In all cases, the minimum type of construction required for any open or enclosed parking garage is that mandated by Section 406.

Tenant spaces must be separated from each other by fire partitions complying with Section 708. In addition to protecting one tenant from the activities of a neighbor, the tenant separation requirements for malls are also intended to assist in the goal of restricting fire to the area of origin. There is no requirement, however, for the separation of tenant spaces from the mall itself.

As a general rule, the anchor building is viewed as a separate building from the covered mall building. Therefore, a fire wall must be used to provide the necessary fire-resistive separation. However, only a fire barrier is required where the anchor building is no more than three stories in height and its use is consistent with one of those identified in the definition of “Covered mall building” in Section 202. Although some type of 2-hour fire-resistance-rated separation is mandated between an anchor building and the mall, openings in such a separation typically need no fire-protection rating. Anchor buildings, other than Group R-1 sleeping units, constructed of Type I or II noncombustible construction may have unprotected openings into the mall.

Under the concept of covered and open mall buildings, there is no requirement for a fire separation between tenant spaces and the mall. Similarly, the food court needs no separation between tenant spaces and the mall. The hazards presented by an attached parking garage, however, must be addressed through the separation provided by a minimum 2-hour fire-resistance-rated fire barrier.

402.5 Automatic sprinkler system. An automatic fire-sprinkler system is the primary means of fire protection for a covered mall building. The system is required throughout all portions of the covered mall building other than open parking garages. Additionally, the code requires a standpipe system in accordance with Section 905. Because of the reliance placed on the sprinkler system, this section requires the following additional safeguards:

1. The code requires that the sprinkler system be complete and operative throughout all of the covered mall building before occupancy of any of the tenant spaces. In those areas that are unoccupied, an alternative protection method may be approved by the building official.

2. The mall and the tenant spaces shall be protected by separate sprinkler systems, except that the code will permit spaces to be supplied by the same system as the mall, provided they can be independently controlled.

Sprinkler protection is also required for open mall buildings. This protection must extend to beneath any exterior circulation balconies located adjacent to the open mall.

402.6.1 Interior finish. The interior finish requirements for tenant spaces and anchor buildings are regulated for interior finishes based on their specific occupancy classification in accordance with Section 803.11. The common areas, including the mall and exits, are to have wall and ceiling finishes that have a minimum Class B flame spread rating.

402.6.2 Kiosks. Kiosks and similar structures, both temporary and permanent in nature, are regulated for construction materials and fire protection owing to their presence in an established egress path. Such structures shall be noncombustible or constructed of fire-retardant-treated wood, complying foam plastics, or complying aluminum composite materials. Active fire protection is provided by required fire suppression and detection devices. Kiosks are also limited in size, and their relationship to other kiosks is regulated. Multiple kiosks can be grouped together, provided their total area does not exceed 300 square feet (28 m²). At that point, a separation of at least 20 feet (6,096 mm) is required from another kiosk or grouping of kiosks.

402.6.4 Plastic signs. In this section, the IBC limits plastic panels and plastic signs because they are within an exitway (the mall) and they are combustible (even though of approved plastic). It is important to note that the percentage of wall covered is based on the area common to each single tenant space. Thus, for a tenant space whose common wall with the mall is 60 feet (18,288 mm) wide and 11 feet (3,353 mm) high, the total area is 660 square feet (61.3 m²). As the code permits 20 percent of that area to be of plastic panels or signs, the sum of all of the plastic signs and panels on the common wall is limited to 132 square feet (12.3 m²). Figure 402-4 illustrates the code limitations for plastic signs and panels.

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Figure 402-4 Limitations for plastic signs and panels in malls.

This section also requires that the use of foam plastic in signs be based on testing in accordance with UL 1975, Fire Tests for Foamed Plastics Used for Decorative Purposes, or NFPA 289, Standard Method of Fire Test for Individual Fuel Packages.

402.7.2 Smoke control. A smoke-control system need not be provided for a covered mall building unless an atrium is provided that connects three stories of the building. In covered mall buildings of one or two stories, no smoke-control system is required. In addition, a smoke-control system is not required for an open mall building due to the lack of a roof over the mall area. The minimum 20-foot (6,096-mm) width mandated for an open mall, extending from the floor to the roof, provides an equivalent level of protection as a smoke-control system in the maintenance of a tenable environment in the mall area.

402.8 Means of egress. One of the significant areas in which the provisions for covered mall and open mall buildings differ from the general provisions applied to the majority of buildings is the means of egress. Issues such as occupant load determination and travel distance are modified specifically in this section owing to the unique features of a covered or open mall building. It is important to remember that where this section conflicts with the general requirements of the code in Chapter 10, the provisions of this section are applicable.

402.8.1 Mall width. With its added life-safety systems, the mall may be considered a corridor without meeting the width requirements of Section 1005.1 when the mall complies with the conditions of this section as depicted in Figure 402-5. In this case, the code requires that the minimum mall width be 20 feet (6,096 mm), and this typical cross section shows that the minimum required width may be divided so that a clear width of 10 feet (3,048 mm) is provided separately on each side of any kiosks, vending machines, benches, displays, etc., contained in the mall. In addition, food court seating in the mall would have to be located so as not to encroach upon any required mall width. Understandably, the mall width shall also accommodate the occupant load immediately tributary thereto.

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Figure 402-5 Mall width requirements.

402.8.2 Determination of occupant load. The determination of the occupant load and minimum required number of exits can be divided into two areas:

1. Tenant spaces.

2. The covered or open mall building.

The maximum occupant load of any individual tenant space is determined in a manner consistent with its use as regulated by Chapter 10. Means of egress requirements for individual tenant spaces are to be based on the occupant load as typically determined. Figure 402-6 depicts the method for determination of the occupant load in a tenant space having a retail area, a storage room, an office, and a bathroom. Although the total tenant space contains 1,500 square feet (139.3 m²) of floor area, each individual use has a designated occupant load based on the appropriate factor from Table 1004.1.2. In this example, the occupant load would be calculated at 44.

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Figure 402-6 Occupant load and means of egress from tenant space.

Not only must the occupant load be determined for each individual tenant space, but the occupant load for the entire covered or open mall building must also be determined. It is highly unlikely that all tenant spaces will be fully occupied at the same time in a covered or open mall building. Therefore, a different method is used to determine the number of occupants from which to base the means of egress from the mall itself. This occupant load is to be determined based on the gross leasable area of the covered or open mall building, excluding any anchor buildings and those tenant spaces having an independent means of egress, with the occupant-load factor determined by the following formula:

Occupant-load factor = (0.00007) (gross leasable area) + 25

As a result, the net effect is that the total occupant load computed for the covered or open mall building will be something less than the summation of the occupant loads previously determined for each individual tenant space.

The occupant-load factor used for egress purposes shall not exceed 50, nor is it ever required to be less than 30. Where there is a food court provided within the covered or open mall building, the occupant load of the food court is to be added to the occupant load of the covered or open mall building as previously calculated in order to determine the total occupant load.

In utilizing several examples, assume a building contains 600,000 square feet (55,740 m²) of gross leasable area. The occupant-load factor, when calculated, would be 67. However, a factor of 50 would be used in determining an occupant load of 12,000. Should a food court be present that seats 600 occupants, the occupant load of 12,000 would be increased accordingly. Where a covered mall building contains 100,000 square feet (9,290 m²) of gross leasable area, the occupant-load factor would be 32. A factor of 32 would then be used to calculate the occupant load of the covered mall building, which would be 3,125 occupants. As the provision is applied to a smaller covered mall building, an occupant-load factor of 30 will be used when the gross leasable area of the covered mall building is less than 71,500 (6,642.3 m²) square feet. As a final note, because anchor buildings are not considered a part of a covered mall building, their occupant load shall not be included in computing the total number of occupants for the mall.

402.8.3 Number of means of egress. Figure 402-6 also depicts the requirements of Section 402.4.2 for the determination of the number of means of egress from the tenant space. Based on an occupant load of 44, the provisions of Chapter 10 would require only one means of egress from this tenant space. Therefore, the number of means of egress complies with the code. However, if the distance, x, exceeds 75 feet (22,860 mm), two means of egress would be required even though the occupant load is less than 50.

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Figure 402-7 Arrangement of exits.

402.8.4 Arrangements of means of egress. The provisions of this section are unique to the covered mall building and are depicted in Figure 402-7. The limitations described in this section encompass a large number of occupants, and this section prevents those occupants from having to traverse long portions of the mall to reach a means of egress. The provisions also prevent the overcrowding of the mall, such as if a large number of patrons from these uses were to be discharged into the mall at the same time and some distance from a means of egress. An open mall building is addressed a bit differently in that assembly occupancies located within the perimeter line are permitted to have their main exit open at any point into the open mall.

In securing the intent of Section 402, the provisions of Section 402.8.4 establish the requirement that means of egress for anchor buildings shall be provided independently from the mall exit system. Furthermore, the mall shall not egress through the anchor buildings. Moreover, the termination of a mall at an anchor building where no other means of egress has been provided except through the anchor buildings shall be considered to be a dead end, which is limited in accordance with Section 402.8.6.

402.8.5 Distance to exits. Figure 402-8 depicts the multifaceted provisions of this section as it relates to a covered mall building as follows:

1. The first case is illustrated for travel within the tenant space and includes the provisions applicable to tenant spaces A and B. For tenant space A, the diagram depicts the application of the code for a tenant space with a closed front with only a swinging exit door to the mall. The entrance to the mall would be the point at which occupants from the tenant space pass through the exit door from the tenant space to the mall.

Tenant space B represents the condition for an open storefront using a security grille instead of a standard exit door. The entrance to the mall in this case is the point at which occupants of the tenant space pass by an imaginary plane that is common to both the tenant space and the pedestrian mall. The location of the assumed required clear exit width along the open front of tenant space B may be placed at any point along the front, and its location would depend only on that which would render the least-restrictive application of the provisions.

For either tenant space A or B, the code permits the travel distance within the tenant space to the entrance to the mall to be a maximum of 200 feet (60,960 mm).

2. After the occupants exit from a tenant space into the mall, the code permits another 200 feet (60,960 mm) of exit travel distance to one of the exit elements described in Section 202. This travel limitation also applies to all other locations in the mall where occupants may be located when an exiting condition occurs.

It can be seen from this discussion, plus the perusal of Figure 402-8, that the travel distances permitted for a covered mall building are generally more liberal than those permitted by Section 1017.2. This liberalized and increased travel distance is based on the rationale that travel within a mall will be within an area where special fire protection features are provided.

3. Another limitation of these provisions regarding travel distance within covered mall buildings is also illustrated by Figure 402-8. In this instance, if the path of travel is through a secondary exit from tenant space B to an exit (in this case an exit passageway), travel distance is not limited once the exit is reached.

4. In the case of exiting via the corridor as depicted for tenant space A, the total travel distance is limited to 200 feet (60,960 mm). This limitation is based on the consideration that a corridor does not offer as much protection as either an exit (such as an exit passageway) or the mall.

For an open mall building, travel from an individual tenant space to the mall is addressed in the same manner as for a covered mall building. Once the open mall is reached, travel to the perimeter line is then regulated.

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Figure 402-8 Travel distance.

402.8.6 Access to exits. This section uses the same approach as does Chapter 10 of requiring that the means of egress be arranged so that the occupants may go in either direction to a separate exit. However, in this section the dead end is measured in a manner similar to that of Exception 3 of Section 1020.4. Figure 402-9 shows the manner in which dead-end conditions are measured and limited.

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Figure 402-9 Dead-end mall criteria.

Regardless of the occupant load served, the minimum width of an exit passageway or corridor from a mall is to be 66 inches (1,676 mm). The exit passageway shown in Figure 402-10 must be at least 66 inches (1,676 mm) wide. The main entrances shown in the same figure are not subject to this requirement insofar as the exit width limitations of Section 1005.1 will most often require a greater exit width.

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Figure 402-10 Exit passageway width.

Another exiting provision that is unique to a covered or open mall building regards exit passageway enclosures. Section 402.8.7 allows mechanical and electrical equipment rooms, building service areas, and service elevators to open directly into exit passageways, provided the minimum 1-hour fire-resistance-rated separation is maintained.

402.8.8 Security grilles and doors. Quite often, mall tenants wish to have the dividing plane between the mall and the tenant space completely open during business hours. Horizontal sliding or vertical security grilles or doors are usually placed across this opening. This section permits their use, provided they do not detract from safe exiting from the tenant space into the mall. To secure that intent, the code requires four limitations outlined in this section.

Section 403 High-Rise Buildings

This section encompasses special life-safety requirements for high-rise buildings. The comparatively good fire record notwithstanding, particularly in office buildings, fires in high-rise buildings have prompted government at all levels to develop special regulations concerning life safety in high-rise buildings. The potential for disaster that is due to the large number of occupants in high-rise buildings has resulted in the provisions included in this section.

The high-rise building is characterized by several features:

1. It is impractical, if not impossible, to completely evacuate the building within a reasonable period of time.

2. Prompt rescue will be difficult, and the probability of fighting a fire in upper stories from the exterior will be low.

3. High-rise buildings are occupied by large numbers of people, and in certain occupancies the occupants may be asleep during an emergency.

4. A potential exists for stack effect. The stack effect can result in the distribution of smoke and other products of combustion throughout the height of a high-rise building during a fire.

The provisions in this section are designed to account for the features described above.

403.1 Applicability. Although a high-rise building can be defined in accordance with the special features just described, the IBC elects to define a high-rise building in Section 202 as one having one or more floors used for human occupancy located more than 75 feet (22,860 mm) above the lowest level of fire department vehicle access.

This section identifies those types of buildings and structures to which the provisions for high-rise buildings do not apply. Included in this group of structures are aircraft-traffic control towers, open parking garages, portions of buildings containing Group A-5 occupancies, special industrial occupancies, and buildings housing specific Group H-1, H-2, and H-3 occupancies.

403.2 Construction. Primarily because a sprinklered high-rise building is provided with an increased level of fire protection supervision and control, the IBC permits certain modifications of the code requirements, which are sometimes referred to as trade-offs. The trade-offs for construction type are considered to be justified on the basis that the sprinkler system, although a mechanical system, is highly reliable because of the provisions that require supervisory initiating devices and water-flow initiating devices for every floor. In addition, a secondary on-site supply of water is mandated for those high-rise buildings subject to a moderate to high level of seismic risk.

This section permits some degree of reduction in the required fire-resistance ratings of building elements required to be protected on account of type of construction. In the evaluation of the maximum allowable height and area permitted for the building, the original construction type would remain applicable.

In addition to the reductions permitted for building elements identified in Table 601 based on the building’s type of construction, the fire-resistance rating of shaft enclosures may be reduced to 1 hour where sprinklers are installed within the shafts at the top and at alternative floor levels.

The reduction in fire-resistance ratings is not applicable in all cases. In all high-rise buildings of Type IA construction, the 3-hour rating for structural columns supporting floors must be maintained. The critical role of columns in the structural integrity of a high-rise structure during fire conditions mandates that their fire resistance not be lessened. For buildings that exceed 420 feet (128 m) in height, no reduction to the required fire resistance of any building elements is permitted. In addition, the required vertical shaft protection cannot be reduced from the general 2-hour requirement. The increased risk of catastrophic damage associated with these very tall buildings requires an increased level of fire resistance.

403.3 Automatic sprinkler system. The automatic fire-sprinkler system required by Section 403.3 must be completely reliable, as must the other life-safety systems. As part of that reliability effort, a high-rise building must be provided with a secondary water supply where required by Section 403.3.3. In Seismic Design Category C, D, E, or F, an on-site automatic secondary water supply shall be provided, with a supply of water equal to the hydraulically calculated sprinkler design demand, including the hose stream requirement, for a duration of at least 30 minutes. As fires can (and do) break out as a result of earthquake damage to the various mechanical systems within a building, it is imperative that the reliability of the sprinkler system be such that any resulting fires can be automatically extinguished.

403.4 Emergency systems. Among the more important life-safety features required by the code are the alarm and communications systems required by this section. Where it is expected that people will be unable to evacuate the building, it is imperative that they be informed as to the nature of any emergency that may break out, as well as the proper action to take to exit to a safe place of refuge. Furthermore, a system is necessary in most cases to provide for communication between the fire officer in charge at the scene and the fire fighters throughout the building. Section 911 provides details of the required fire command center utilized by the fire department to coordinate fire suppression and rescue operations.

In order to provide for efficient and reliable communications among fire fighters, police officers, medical personnel, and other emergency responders, an emergency responder radio communications system must be installed in all high-rise buildings. The details for such systems are established in Section 510 of the International Fire Code® (IFC®). IFC Section 510.4.1 specifies that acceptable radio coverage is satisfied when 95 percent of all areas on each floor of the building meet the signal strength requirements in Sections 510.4.1.1 and 510.4.1.2 for signals transmitted into and out of a building.

In addition, one of the fire department’s duties during a fire event is to expel the smoke after the fire has occurred. Three methods for smoke exhaust are available: through natural means, through the use of mechanical air-handling equipment, or through an equivalency approach. Where the method of natural ventilation is used for the removal of smoke, openable windows or panels are required to be distributed around the perimeter of each floor level. The fire departments can open the appropriate windows as necessary and provide pressurization through the use of fans. The use of fixed tempered glass panels is also acceptable if they are not coated in a manner that will modify the natural breaking characteristics of the glass. Where mechanical air-handling equipment is used for smoke removal purposes, the building’s HVAC system is equipped with appropriate dampers at each floor that are arranged in a manner that will stop the recirculation of air through the use of 100 percent fresh air intake and outside exhaust. The panel for controlling this system is to be located in the building’s fire command center. In addition, the building official has the authority to approve any other means of smoke removal provided it accomplishes the intended goal of the prescriptive mechanical or natural ventilation approaches described by the code. See Figure 403-1. It must be noted that this smoke exhaust system is for fire department use only and is not intended to be a part of the occupant-related life-safety systems placed in high-rise buildings.

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Figure 403-1 Smoke removal.

Furthering the intent of the IBC that life-safety systems in high-rise buildings be highly reliable, the code requires that the power supply to the life-safety systems be regulated by the appropriate provisions of NFPA 70, more specifically, Articles 700 and 701. The basis of the reliability is that the building’s power be automatically transferable to a standby or emergency power system in the event of the failure of the normal power supply. Those standby power loads required by the code include power and lighting for the fire command center, ventilation and automatic fire detection equipment for smokeproof enclosures, and elevators.

The code further requires that lighting for exit signs, means of egress illumination, and elevator car lighting be automatically transferable to an emergency power system capable of operation within 10 seconds of the failure of the normal power supply. Additionally, all emergency voice/alarm communications systems, automatic fire detection systems, fire alarm systems, and electrically powered fire pumps are to be provided with emergency power.

403.5.1 Remoteness of interior exit stairways. The general requirements for separation of exit or exit access doorways as established in Sections 1007.1.1 and 1007.1.2 are supplemented in this section by adding a minimum required separation distance between the enclosures for interior exit stairways. In addition to maintaining a minimum separation between the doors to the enclosures of one-third the length of the overall diagonal dimension of the area served, the interior exit stairways must be located at least 30 feet (9,144 mm) apart or not less than one-fourth the diagonal dimension, whichever is less. See Figure 403-2. If three or more interior exit stairway enclosures are mandated, at least two of the enclosures must be separated as indicated.

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Figure 403-2 Remoteness of exit enclosures.

403.5.2 Additional exit stairway. During a fire that requires a full evacuation of a building of extensive height, the fire-fighting operations will reduce the capacity of the egress system. The extended period of time needed to fully evacuate a very tall building means that people will still be evacuating while full fire-fighting operations are taking place. Sound high-rise fire-fighting doctrine provides that the fire department take control of one stair, the one most appropriate to the circumstances of the given fire condition. This can result in a significant reduction in egress capacity of the stairway system. For example, in order to conduct suppression activities in a building with two required stairs of the same width, one-half of the exit capacity is unavailable while the building is still being evacuated. An additional stair is required so that egress capacity will be maintained through the time that full evacuation is complete.

It is important to note that this additional stair is not required to be a dedicated fire department stair. The fire department should be able to choose the stair that is most appropriate for the actual fire event. As a result, it will be necessary for emergency responders to manage evacuation flow to the available stairs.

The application of this requirement is limited to only those buildings over 420 feet (128 m) in height. In addition, it does not apply to Group R-2 occupancies due to the limited occupant load of such uses. In determining if the required egress width is provided by the stairway system, it must be assumed that the widest of the stairways is the one that is unavailable for means of egress travel. The remaining stairways must be sized to accommodate the total required egress width. The additional stairway’s sole purpose is to provide additional egress capacity. Therefore, other means of egress design issues, such as travel distance and exit separation, are not regulated. See Application Example 403-1.

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Application Example 403-1

The additional exit stairway is not required where occupant evacuation elevators are provided in accordance with Section 3008. The availability of elevators for evacuation purposes provides for a reasonable alternative to an additional stairway.

403.5.3 Stairway door operation. In those cases where it is impractical to totally evacuate the occupants from the building through the stairway system, it must be possible to move the occupants to different floors of the building that are safe by way of the stairway system. For this to happen, the doors to the interior exit stairway enclosures must either be unlocked or be designed for automatic unlocking from the fire command station.

The IBC further requires that a telephone or other two-way communication system (such as a two-way system with speaker and microphone) be located at every fifth floor in each required stair enclosure for those cases where the stair enclosure doors are to be locked. Moreover, the code requires that this communication system be connected to an approved station that is constantly attended. Thus, anyone trapped in the stairway during a nonfire emergency may call for help without traversing more than two levels. In the case of office buildings and apartment houses, the attended station may be considered the office of the building as long as the office has continuous attendance by responsible individuals who are familiar with the life-safety systems. For hotel buildings, the most likely choice for the attendance station will probably be the hotel telephone operators, and, again, they must be trained to assist the persons trapped within the stair enclosure.

403.5.4 Smokeproof enclosures. Those interior exit stairway enclosures in a high-rise building that serve floor levels located more than 75 feet (22,860 mm) above the lowest level of fire department vehicle access must be designed as smokeproof enclosures. Exit stairways that do not serve floors above the height indicated are not regulated by this section. Section 1023.10 regulates the access, extension, and termination relating to the utilization of smokeproof enclosures and pressurized stairways as a part of the means of egress system. Section 909.20 provides the construction and ventilation criteria for smokeproof enclosures, as well as establishing stair pressurization as an acceptable alternative.

403.5.5 Luminous egress path markings. In high-rise buildings, increased visibility for travel on stairways and through exit passageways is important due to the extreme conditions that may be encountered under emergency conditions. The use of photoluminescent or self-illuminating materials to delineate the exit path is required in high-rise buildings housing Group A, B, E, I, M, and R-1 occupancies. Specific requirements related to these egress path markings are set forth in Section 1025 and include the regulation of striping on steps, landings, and handrails; perimeter demarcation lines on the floor and walls, including their transition; acceptable materials; and illumination periods. An example of such markings is shown in Figure 403-3.

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Figure 403-3 Luminous egress path markings.

403.6 Elevators. In order to facilitate the rapid deployment of fire fighters, at least two fire service access elevators are required in high-rise buildings that have an occupied floor more than 120 feet (36,576 mm) above the lowest level of fire department vehicle access. Usable by fire fighters and other emergency responders, the specific requirements for the elevators are set forth in Section 3007. There are a number of key features that allow fire fighters to use the elevator for safely accessing an area of a building that may be involved in a fire. A complying lobby is required adjacent to the elevator hoistway opening, creating a protected area from which to stage operations. Access to standpipe hose valves is required, as are two-way communication features. A single fire service access elevator is permitted in the unlikely situation where a building regulated by this section has only one elevator.

The mandate for multiple fire service access elevators is based on information that indicates at least two elevators are necessary for firefighting activities in high-rise buildings. In addition, past experience has shown that on many occasions elevators are not available due to shutdowns for various reasons, including problems in operation, routine maintenance, modernization programs, and EMS operations in the building prior to firefighter arrival. A minimum of two fire service elevators provided with all of the benefits afforded to such elevators better ensures that there will be a fire service access elevator available for the fire fighters’ use in the performance of their duties.

A more comprehensive discussion of the requirements for fire service access elevators is found in the analysis of Section 3007.

The use of elevators as an evacuation element for occupants of a high-rise building is possible provided the elevators are in compliance with the requirements established in Section 3008. The controls and safeguards provided in Section 3008 create a suitable environment to allow complying elevators to be used for occupant self-evacuation purposes. The presence of such elevators does not reduce the general means of egress requirements established in Chapter 10; however, the additional exit stairway mandated for very tall high-rise buildings by Section 403.5.2 is no longer required. It is important to note that the installation of occupant evacuation elevators in high-rise buildings is not mandated by the code; however, such elevators are permitted for use for occupant self-evacuation and may be utilized as an alternative to the additional stairway requirement.

Section 404 Atriums

This section was developed to fill a need for code provisions applicable to the trends in the architectural design of buildings where the designer makes use of an atrium. Prior to the early 1980s, building codes did not provide for atriums, and, moreover, atriums were prohibited because of the requirements for protection of vertical openings. They were, however, permitted on an individual basis, usually under the provisions in the administrative sections of the code permitting alternative designs and alternative methods of construction. The general concept of alternative protection is to provide for both the equivalence of an open court and at the same time provide protection somewhat equivalent to shaft protection to prevent products of combustion from being spread throughout the building via the atrium.

An atrium is considered “an opening connecting two or more stories other than enclosed stairways, elevators, hoistways, escalators, plumbing, electrical, air-conditioning or other equipment, which is closed at the top and not defined as a mall.” This section permits large unprotected vertical openings through floors without the need for a shaft enclosure or other means of vertical opening protection. The use of atriums is permitted in all buildings other than those classified as Group H occupancies.

Note that most cases where two floors are open to each other do not create atrium conditions. That is because Section 712.1.9 permits two stories to be open to each other where six conditions are met. The atrium provisions are typically only utilized for open two-story spaces where they cannot fully comply with the conditions of Section 712.1.9 and are too large to qualify as a mezzanine as permitted by Section 712.1.11. Addressed in Section 712.1.7, the atrium provisions are provided only as one of many applications addressed in Section 712.1 for the protection of vertical openings.

404.3 Automatic sprinkler protection. One of the basic requirements for atriums is that the building be provided with an automatic sprinkler system throughout. Two exceptions modify this general requirement. Those areas of the building adjacent to or above the atrium are not required to be sprinklered if appropriately separated from the atrium. This separation must consist of minimum 2-hour fire barriers, horizontal assemblies, or both. In addition, sprinkler protection is not required at an atrium ceiling located more than 55 feet (16,764 mm) above the atrium floor.

404.5 Smoke control. Another major component of the life-safety system for a building containing an atrium is the required smoke-control system. The design of the smoke-control system is to be in accordance with Section 909. Although the exhaust method is typically used as the means of accomplishing smoke control, the code would not prohibit the use of the airflow or pressurization methods where shown to be suitable. One of these methods is often used where the ceiling height makes it difficult to maintain the smoke layer at least 6 feet (1,829 mm) above the floor of the means of egress.

Applicable in other than Group I-2 and Group I-1, Condition 2 occupancies, an exception eliminates the requirement for smoke control in those atriums that connect only two stories. However, as previously addressed, most situations where two floors are open to each other are not regulated under the provisions of Section 404. Typically, Section 712.1.9 is utilized to permit an opening between two floor levels without requiring compliance with any of the atrium provisions.

404.6 Enclosure of atriums. With some exceptions, an enclosure separation is required between the atrium and the remainder of the building. See Figure 404-1. The basic requirement is for a 1-hour fire-resistance-rated fire barrier with openings protected in accordance with Tables 716.5 and 716.6. This degree of enclosure, in addition to the other special conditions of Section 404, is intended to provide protection somewhat equivalent to the otherwise mandated shaft protection. Two alternative methods of atrium separation are described in the exception. The special sprinkler-wetted glass enclosure as depicted in Figure 404-2 provides a prescriptive method of achieving equivalency. In addition, the separation may consist of a ¾-hour-rated glass-block wall assembly.

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Figure 404-1 Atrium enclosure.

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Figure 404-2 Glass protection.

The separation between adjacent spaces and the atrium may be omitted on a maximum of any three floor levels, provided the remaining floor levels are separated as provided in this section. In computing the atrium volume for the design of the smoke-control system, the volume of such open spaces shall be included.

Section 405 Underground Buildings

Structures that have floor levels well below ground level, and thus significantly below the level of access and egress from the exterior, present special hazards to both the building occupants and fire personnel. Much like high-rise buildings, underground buildings can create difficult egress conditions as well as pose many problems for the fire department in their rescue and suppression activities. Fundamental to the protection features of this type of building are the requirements for Type I noncombustible construction and the installation of an automatic sprinkler system. A standpipe system is also required. For clarification, only the underground portion of the structure needs to be of Type I construction, and only those floor levels at the highest discharge level and below need to be sprinklered. See Figure 405-1.

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Figure 405-1 Underground buildings.

The basic criterion for consideration as an underground building is that a floor level used for human occupancy be located more than 30 feet (9,144 mm) below the finished floor of the lowest level of exit discharge. Exempted from the requirements of Section 405 are sprinklered dwellings; parking garages having fire suppression systems; fixed guideway transit systems such as subways; stadiums, arenas, and similar assembly uses; those buildings where only a very limited amount of floor area would qualify by the definition; and mechanical spaces that are typically unoccupied.

A valuable concept in fire protection is utilized in the provisions for underground buildings that extend even deeper into the ground. Where an occupied floor level is located more than 60 feet (18,288 mm) below the finished floor of the lowest level of exit discharge, at least two compartments of approximately equal size must be created. The compartmentation must extend throughout the underground portion of the structure, up to and including the highest level of exit discharge. The separation between the two areas is intended to allow for horizontal egress travel to a refuge area if necessary, while also permitting the use of the compartment as a staging area for fire-suppression activities. A smoke barrier is required as the separation element, with door openings also protected in a manner to restrict smoke leakage. Other openings and penetrations are strictly limited. Air supply and exhaust systems, where provided, must be independent of the other compartments. Where the underground portion of the building is served by elevators, each compartment must have access to at least one elevator. An elevator lobby, enclosed by a smoke barrier, may be used to allow a single elevator to serve more than one compartment. Doors into the elevator lobby shall be gasketed, have a drop sill, and be automatic closing by smoke detection. See Figure 405-2.

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Figure 405-2 Compartmentation of underground buildings.

Smoke control is also an important part of the overall fire-protection package. By limiting the spread of smoke to only the originating area of the fire, the remainder of the underground building should be provided with acceptable egress paths. Each compartment shall be provided with its own smoke-control system. A manual fire-alarm system and complying communications system is also an integral part of the fire- and life-safety concept for underground buildings.

Stairways serving the floor levels of an underground building that are more than 30 feet (9,144 mm) below the discharge level are to be smokeproof enclosures, with at least two means of egress from each floor level. If multiple compartments are formed, each compartment must have at least one exit, with a second egress path available into an adjoining compartment. It is mandatory that multiple exits be provided within enclosures designed to resist the penetration of smoke.

Both standby and emergency power shall be provided to specific loads identified by this section. See the discussion of Section 403.4.

Section 406 Motor-Vehicle-Related Occupancies

Although uncommon, fire hazards related to motor vehicles are a concern, particularly where associated with other occupancies. The code regulates occupancies containing motor vehicles, whether they be parked, under repair, or being fueled. The hazards are primarily related to the fuel in the vehicles, as the overall fire loading related to vehicle occupancies is typically quite low.

406.3 Private garages and carports. Although uncommon, fire hazards related to motor vehicle parking are a concern. Where the amount of floor area devoted to vehicle parking is relatively small, the code recognizes the limited hazard level by establishing a limited set of safeguards. In addition to the scope established by the definition of “private garage,” the maximum floor area per Group U garage is established at 1,000 square feet. Multiple Group U garages are permitted in the same building provided such garages are separated by minimum 1-hour fire barriers, with a maximum aggregate area per building based on the allowable building area provisions of Sections 503 and 506. Figure 406-1 illustrates an example of multiple garages located in a single building.

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Figure 406-1 Private garage floor area limits.

406.4 Public parking garages. Public parking garages, which are simply those garages that are not considered as private garages based on the limitations of Section 406.3 and definition of “private garage” in Section 202, will fall into one of two categories, either open or enclosed. The special characteristics of each type of parking structure are addressed in Sections 406.5 and 406.6. This section addresses the general requirements for public parking garages, whether they be open or enclosed.

There are fundamentally two types of parking garages regulated by the IBC—private garages and public garages. Although there is no specific definition for either private garage or public garage, the basis for both classifications is Section 406.3 addressing private garages and carports. Those parking structures that fall outside of the scope of Section 406.3 or the private garage definition in Chapter 2 are considered as public parking garages. The primary difference between private and public garages is typically the size of the facility, rather than the use. Strictly limited in permissible height and area, private parking garages serve only a specific tenant or building. It is important to note that there is no implication that public parking garages must be open to the public, as they are only considered public in comparison to private garages. A public parking garage is then further characterized as one of two types, either an enclosed parking garage or an open parking garage, and regulated accordingly.

To allow access to the garage to other than high-profile vehicles, the clear height of each level is to be at least 7 feet (2,134 mm). Note that the minimum height of the means of egress system is 7 feet, 6 inches (2,286 mm), based on the general provisions of Section 1003.2. However, Exception 7 to Section 1003.2 allows the clear height to be reduced to 7 feet (2,134 mm) in those areas of parking garages used for vehicular and pedestrian traffic.

Guards must also be provided in accordance with the general provisions of Section 1015. In addition, all parking areas more than 12 inches (305 mm) above adjacent levels shall be provided with vehicle barriers at the ends of parking spaces and drive lanes. The height of the vehicle barriers cannot be less than 2 feet, 9 inches (835 mm). Where the parking garage is connected directly to a room containing a fuel-fired appliance, a vestibule is mandated to separate the two spaces. This provides at least two doorways to isolate the equipment from the vehicle area. The vestibule is not necessary where the appliance ignition sources are placed at least 18 inches (457 mm) above the floor. The International Mechanical Code® (IMC®) and/or International Fuel Gas Code® (IFGC®) should also be consulted for those requirements regulating the installation of mechanical equipment within parking garages.

406.5 Open parking garages. Studies and tests of fires in open parking garages have shown that, in addition to a low fire loading, the potential for a large fire is exceedingly remote. Based on this data, the IBC establishes special provisions for open parking garages in this section, which in general are less restrictive than those for enclosed parking structures addressed in Section 406.6. The key is that the open parking garage is well ventilated naturally, and as a result, the products of combustion dissipate rapidly and do not contribute to the spread of fire.

To secure the proper amount of openness, the code, as illustrated in Figure 406-2, specifies the following:

1. The building must have openings on at least two sides.

2. The openings must be uniformly distributed along each side.

3. The area of openings in the exterior walls on any given tier must be at least equal to 20 percent of the wall area of the total perimeter of each tier.

4. Unless the required openings are uniformly distributed over two opposing sides of the building, the aggregate length of openings considered to provide natural ventilation shall constitute a minimum of 40 percent of the wall length of the perimeter of that tier.

5. The area of openings in the interior walls must be at least 20 percent of the area of the interior walls with openings uniformly distributed.

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Figure 406-2 Open parking garages.

There are situations where the required openings of open parking garages are located below the surrounding grade. Section 406.5.2.1 mandates that a clear horizontal space be provided adjacent to the garage’s exterior openings that allows for adequate air movement through the opening. The dimensional requirements are based on the provisions of Section 1203.5.1.2, which addresses openings below grade when such openings are used for the required natural ventilation of a building’s occupied spaces. Where openings in the exterior wall of an open parking garage are located below grade level, some degree of clear space must be provided at the exterior of the openings. As the distance of the openings below the adjoining ground increases, the minimum required exterior clear space also increases proportionately. The horizontal clear space dimension, measured perpendicular to the exterior wall opening, must be at least one and one-half times the distance between the bottom of the opening and the average adjoining ground level above. The extent of the required clear space allows for adequate exterior open space to meet the intent and dynamics of natural ventilation requirements for open parking garages. See Figure 406-3.

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Figure 406-3 Parking garage openings below grade.

As a general rule, the maximum allowable height and area of open parking garages is calculated in the same manner as for other buildings. Classified as a Group S-2 occupancy, the provisions of Chapter 5 would apply. However, where the open parking garage contains no uses other than the parking of private motor vehicles, the specific size limitations of Table 406.5.4 and Section 406.5.5 take effect. Because the potential fire severity of an open parking structure used solely for vehicle parking is extremely low, the code permits area and height limitations in excess of those for other Group S-2 occupancies. For example, a stand-alone open parking garage of Type IIB construction would be permitted a floor area of 50,000 square feet (4,645 m²) per tier based on Table 406.5.4, with a height limit of eight tiers for a ramp-access garage. For such an open parking garage exceeding three stories in height, the total area of the multistory building is not limited to three times that for a one-story building, as is required by Section 506.2.3, but rather can be computed as the permitted area per tier times the number of tiers. Therefore, in the example just given, the total area permitted would be 400,000 square feet (37,160 m²) for a stand-alone Type IIB open parking garage. The maximum height in tiers has been limited somewhat arbitrarily by the code, based on the length of time it would take for fire-department personnel to reach the top of the structure for fire-suppression purposes.

The area and height increases above the tabular limits listed in Table 406.5.4 for single-use open parking garages are those outlined in Section 406.5.5, and are basically keyed to the provision of more natural ventilation area than the minimum required by the code. For unlimited-area buildings permitted by this section, see Figure 406-4.

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Figure 406-4 Unlimited area open parking garages.

In the classification of a Group S-2 parking structure as an open parking garage, the code identifies the following prohibitions:

1. There shall be no automobile repair work performed in the building.

2. There shall be no parking of buses, trucks, or similar vehicles.

3. There shall be no partial or complete closing of the required exterior wall openings by tarpaulins or by any other means.

4. There shall be no dispensing of fuel.

The intent of these limitations is to further ensure low fire loading, low possibility of fire spread, and natural cross ventilation.

406.6 Enclosed parking garages. Any vehicle parking garage that does not meet the criteria of an open parking garage or a Group U private garage is to be regulated under the general provisions for a Group S-2 occupancy. Tables 504.3, 504.4, and 506.2, along with any applicable height and area increases, will limit the height and floor area of an enclosed parking garage, with an allowance for use of the roof for parking purposes. Ventilation of an enclosed parking garage must be provided in accordance with the IMC.

406.7 Motor-fuel-dispensing facilities. Because most of the hazards involved with a fuel-dispensing operation are due to the storage and dispensing of flammable liquids, the majority of regulations are addressed by the IFC. The primary provisions of this section apply to canopies that are placed over the fueling areas for the purpose of customer convenience. Because of the potential exposure of gasoline and vehicle fires during fuel-dispensing operations, the canopies and supports over pumps are required by this section to be of noncombustible construction or, alternatively, constructed of fire-retardant-treated wood, complying heavy-timber members, or be of 1-hour fire-resistance-rated combustible construction. Occasionally, combustible materials may be used in or on a canopy under limited conditions. The allowance for approved plastic panels installed in canopies over motor-vehicle pumps is intended to isolate the combustible plastic materials from other buildings so that if the materials become ignited, they will not present an exposure problem to other buildings.

To avoid damage to vehicles and canopies, the height of canopies must not be less than 13 feet, 6 inches (4,115 mm). The 13-foot, 6-inch (4,115-mm) dimension should provide adequate clearance for recreational vehicles.

406.8 Repair garages. In the IFC, a repair garage is defined as any building or portion thereof that is used to service or repair motor vehicles. The potential exists for a moderate fire hazard that is due to the presence of various combustible and flammable liquids such as solvents, cleaning products, and gasoline. During repair operations, it is also not uncommon for ignition sources to be present. It is this combination that creates the highest level of hazards that are addressed by Section 406.8. Classified as Group S-1 occupancies, special concerns for repair garages are primarily regulated through the IFC.

The presence of a repair garage in a building with different types of uses is addressed no differently than other mixed-occupancy conditions. The provisions of Section 508.1 are applicable, allowing the option of using the accessory occupancies, nonseparated occupancies, or separated occupancies method for addressing the multiple occupancy groups in the building.

Garages used for the repair of vehicles powered by nonodorized gases, such as hydrogen and nonodorized liquid natural gas, are to be provided with a listed or approved flammable-gas-detection system. The design of the gas-detection system will provide for activation of the safeguards at the point where the level of flammable gas exceeds 25 percent of the lower explosive limit. At this point, the system must initiate audible and visual alarm signals in the garage, deactivate the garage’s heating systems, and activate any mechanical ventilation interlocked with gas detection. Similar functions should take place where there is a failure of the detection system.

Section 407 Group I-2

In institutional occupancies, particularly those classified as Group I-2, it is important to balance the fire-safety concerns with the functional concerns of the health-care operations. This section modifies the general code provisions in an effort to achieve such a balance.

407.2 Corridors continuity and separation. Corridors are intended to provide a direct egress path adequately separated from hazards in adjoining spaces. However, in hospitals, nursing homes, and other Group I-2 occupancies, a number of necessary modifications are provided to facilitate the primary functioning of these types of health-care facilities. These modifications recognize the special needs of these occupancies to provide the most efficient and effective health-care services. See Figure 407-1.

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Figure 407-1 Corridors in Group I-2 occupancies.

In order to provide appropriate waiting spaces for visitors, Section 407.2.1 allows such waiting spaces to be unseparated from the corridors. One reason for this is to permit the waiting areas and similar spaces to be so located as to permit direct visual supervision by health-care facility staff. In exchange for the elimination of the corridor separation, certain conditions are imposed on the location of such waiting spaces. Although the scoping language only includes waiting areas and similar spaces, the primary criteria limiting those spaces that can be open to a corridor are identified in Item 1. Health-care facilities will often create alcoves adjacent to the corridor for the temporary storage of medical supplies, linen carts, food carts, etc., that are necessary to the daily functions of the facility. Without the alcoves, the corridors would be obstructed by these uses. Therefore, the code makes an allowance for such spaces. Allowances are also made for areas associated with the treatment of mental-health patients. Provided the areas are under continuous supervision by facility staff, they may be open to the corridor where six conditions are met.

Similarly, Section 407.2.2 makes provisions for the location of clerical stations and similar spaces necessary for doctors’ and nurses’ charting and communications in positions that need not be separated from the corridors. Essentially, these special-use areas are permitted to be located in the corridor. When this arrangement occurs, however, it is necessary that the construction surrounding the clerical station be as that required for corridors.

In nursing home environments, residents are encouraged to spend time outside of their rooms. By providing a variety of shared living spaces open to the circulation/means-of-egress system, socialization and interaction are encouraged. Further, being able to preview activities that are occurring helps to encourage joining and allows reluctant participants to join at their own pace. Finally, a more open plan allows staff to more easily monitor residents throughout the day. For these reasons, it is important that the physical separation of shared resident spaces from corridors be eliminated. The conditions established in Section 407.2.5, some of which are represented in Figure 407-2, provide the means for recognizing the benefits of openness while also maintaining an appropriate level of egress protection.

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Figure 407-2 Group I-2 shared living space.

Another allowance for eliminating the separation between a corridor and surrounding spaces addresses areas with cooking facilities. A part of the desired group environment is also a functioning kitchen that can also serve as the hearth of the nursing home. Instead of a large, centralized, institutional kitchen where all meals are prepared and delivered to a central dining room of the resident’s room, the new “household model” nursing home uses decentralized kitchens and small dining areas to create and focus the feeling of home. Allowing kitchens that serve a small, defined group of residents to be open to common spaces and corridors is viewed as critically important to enhancing the feeling and memories of home for older adults. Figure 407-3 identifies several of the 13 conditions set forth in Section 407.2.6 that must be met where this alternative approach is utilized.

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Figure 407-3 Group I-2 domestic cooking facilities.

407.3 Corridor wall construction. Walls enclosing corridors and other spaces permitted by Section 407.2 to be open into corridors are intended to provide a relatively smoke-free environment during the relocation of patients during a fire emergency. Therefore, such walls must be constructed in accordance with the provisions of Section 710 as smoke partitions. The walls may extend either tight to the floor or roof deck above, or extend tight to the ceiling, provided the ceiling is also constructed to limit smoke transfer.

Corridor doors protecting those spaces adjacent to the corridor are not required to have a fire-protection rating, nor are they required to be self-closing assemblies. They must, however, be able to limit the transfer of smoke through the opening but need not be tested for air leakage under UL 1784. One of the most controversial issues relative to the arrangement of health-care facilities such as hospitals and nursing homes is the matter of the installation of door closers on doors to patient sleeping rooms. The health-care industry has long believed it is more important to the proper delivery of health-care services that the doors to patient rooms not be self-closing and therefore constantly closed. In recognition of this special need, self-closing or automatic-closing devices are not required on corridor doors. Positive latching is required, however, and roller latches are not considered acceptable latching hardware. Where positive latching is not desired, typically where sliding doors are installed at patient or treatment rooms, the common corridor arrangement cannot be utilized. In such instances, the spaces could be designed as care suites under the provisions of Section 407.4.4. Corridor-type configurations within such suites are not subject to the requirements of Section 407.3.

Locking devices may be arranged so that they are readily operable from the patient-room side and are readily operable by the facility staff from the opposite side. This special arrangement permits keys or other limited access methods to be utilized for the care recipient rooms. However, egress from the care recipient rooms shall be unrestricted unless such rooms are in mental-health facilities.

407.4.4 Group I-2 care suites. Special means of egress provisions are provided for care suites in Group I-2 occupancies. The definition of “care suite” in Section 202 identifies the scope of such special provisions. The concept of suites recognizes those arrangements where staff must have more supervision of patients in specific treatment and sleeping rooms. Therefore, the general means of egress requirements are not appropriate under such conditions. The special allowances for suites are not intended to apply to day rooms or business functions of the health-care facility.

407.5 Smoke barriers. Evacuation of a building such as a hospital or nursing home is a virtual impossibility in the event of a fire, particularly in multistory structures. Horizontal evacuation, on the other hand, is possible with a properly trained staff. As a result, the code makes provisions for horizontal compartmentation as illustrated in Figure 407-4, so that if necessary, care recipients can be moved from one compartment to another. This intent is secured by this section wherein, under most conditions, each story of a Group I-2 occupancy is required to be divided into at least two approximately equal compartments by a smoke barrier constructed in accordance with Section 709. Limited by floor area and travel distance, each compartment shall be sized to permit the housing of patients from adjoining smoke compartments. It is expected that in multistory buildings, the floor construction also provides for smoke compartmentation vertically. As such, the concept of smoke resistance must be considered relative to vertical openings and penetrations, including interior exit stairways and shaft enclosures.

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Figure 407-4 Hospital compartmentation.

407.9 Secured yards. It is not uncommon that a secured exterior area or yard be provided for Group I-2 occupancies, particularly where the facility specializes in the treatment of mental disabilities such as Alzheimer’s disease. Where such fencing and locked gates prohibit the continuation of the exit discharge to the public way, the use of safe dispersal areas is acceptable. To adequately provide for temporary refuge, the safe dispersal area must be sized to accommodate the occupant load of the egress system it serves. In all cases, the entire dispersal area must be located at least 50 feet (15,240 mm) from the building.

Section 408 Group I-3

The concerns for both security and fire safety must be balanced when it comes to Group I-3 detention facilities. Special consideration must be given to the secured areas without sacrificing an unreasonable degree of fire and life safety for the occupants. This section addresses the unique conditions that occur in these types of buildings.

Section 408.3 modifies the general requirements for the means of egress found in Chapter 10. A major difference is the allowance for glazing in the doors and walls of required exit stairways, provided a number of conditions are met. As would be expected, the most dramatic variation from the general requirements has to do with the locking hardware. The requirements vary based on the nature of the detention occupancy. Reference must occasionally be made to the occupancy conditions of Section 308.5 to determine the appropriate egress criteria.

Similar to the provisions of Section 407 for Group I-2 occupancies, smoke compartments must be created where the occupant load per story is 50 or more. Additionally, regardless of occupant load, floor levels utilized as sleeping areas must be divided into a minimum of two compartments. More than two smoke compartments may be necessary on any floor level where the dictated travel distances cannot be provided or where the occupant load of the compartment is excessive. No more than 200 occupants can be assigned to a single compartment. The refuge area must be sized to accommodate the total number of residents that may be contained within the compartment. Independent egress is needed from each compartment so that it is not necessary to travel back into the compartment where travel originated.

An important feature of the Group I-3 provisions is the allowance for multiple levels of residential housing to be open to each other without an enclosure. Through the safeguards provided, it is possible to provide increased security by opening up the multiple housing areas to a single common area where visual supervision is more easily accomplished. It is important that independent egress to an exit be provided from each level. The limit of 23 feet (7,010 mm) between the lowest and highest floor levels, as well as the required egress directly out of each story, provides additional qualifications that must be met in order to eliminate the required vertical enclosure protection.

As an additional allowance for security purposes, the fire-protection rating is not required for security glazing installed in 1-hour fire barriers, fire partitions, and smoke barriers that may be present. Rather, equivalent protection is provided through compliance with four specific conditions addressing the glazing and its frame. The use of security glazing is necessary in such facilities to track and contain inmate movement for the protection of other inmates and administrative personnel. Three of the most common types of fire separations are addressed: fire barriers, fire partitions, and smoke barriers. The allowance is not applicable to fire walls, nor is it permissible where the fire separation wall has a required fire-resistance rating of more than 1 hour. The conditions imposed on the security glazing limit the area of each individual glazed panel, mandate sprinkler protection that will wet the entire glazing surface on both sides, regulate the gasketed frame for deflection, and prohibit the installation of obstructions between the sprinklers and the glazing.

Section 409 Motion-Picture Projection Rooms

Prior to the 1970s, building codes addressed the subject of motion picture projection rooms based on the hazard of the cellulose nitrate film being used at that time. Actually, production of cellulose nitrate film ceased around 1950, although its use continued thereafter. In fact, even today, some cellulose nitrate film is used at film festivals and special occasions requiring the projection of historically significant films that are still imprinted on cellulose nitrate film. Where this type of film continues to be utilized or stored, it will be regulated under the provisions of NFPA 40. Although the provisions in the codes since 1970 are based on the use of safety film, some of the protection requirements for cellulose nitrate film have been retained in the present requirements, such as ventilation requirements for the projection room.

The intent of the current provisions regulating motion picture projection rooms is to provide safety to the occupants of a theater from the hazards consequent on the light source where electric arc, xenon, or other light-source projection equipment is used. Although not used to any extent today, electric-arc projection lamps emit hazardous radiation. Xenon lamps, which have been highly prevalent as projection lamps, emit ozone. As a result, the provisions of Section 409 are based on the lamps used for projection of the film rather than the type of film to be used, as long as the film is not nitrate based.

The provisions intend to isolate the projection room so that it does not present a danger to the theater audience. As the room is designed for the projection of safety film, there is no intent to provide a special fire-resistive enclosure, and fire protection of openings between the projection room and the auditorium is not required. However, due to the projection lamps, it is the intent of the code to provide an emission-tight separation so that any opening should be sealed with glass or other approved material such that emissions from the projection lamps will not contaminate the auditorium.

Section 410 Stages, Platforms, and Technical Production Areas

The provisions in Section 410 are continuously reviewed in an attempt to bring the code requirements in line with the present methods and technologies regarding the use of stages and platforms, as well as related accessory and support areas. Although the basic provisions for life safety have remained essentially unchanged over the years, occasional modifications have been made that are due to the need to accommodate state-of-the-art performances.

410.2 Definitions. Although the definitions listed in this section are complete and reasonably understandable, there are terms unique to the performing arts that are not generally understood, such as fly gallery, gridiron, and pinrail, which fall under the general term “technical production area.” The distinctions between the definitions of a stage and a platform are also very important because of the specific requirements for each. The primary difference between a stage and a platform is the presence of overhead hanging curtains, drops, scenery, and other stage effects. The amount of combustible materials associated with a stage is typically greater than that for a platform. Thus, the fire-severity potential is much higher.

410.3 Stages. An assembly occupancy considered among the most hazardous is a Group A-1 containing a large occupant load and a performance stage. The hazard created by the stage is the presence of combustibles in the form of hanging curtains, drops, leg drops, scenery, etc., which in the past have been the source of ignition for disastrous fires in theaters. Modern stages also have an increased hazard from special effects such as pyrotechnics, utilized in so-called spectaculars.

Where the stage height exceeds 50 feet (15,240 mm), the fire hazard is even greater because the fly area that is usually above the stage is a large blind space containing combustible materials that have a fuel load considerably greater than that normally associated with an assembly occupancy. Many of the construction requirements for stages are depicted in Figure 410-1.

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Figure 410-1 Stages.

410.3.1 Stage construction. In addition to the features shown in Figure 410-1, any stage may have a finished floor of wood, provided construction of the stage floor or deck is in compliance with this section. As the area above and at the sides of stages can be filled with combustible materials that can be moved both vertically and horizontally, such as curtains, drops, leg drops, scenery, and other stage effects, the code requires that such stages be constructed of the same materials as required for floors for the type of construction of the building and separated from the balance of the building.

410.3.4 Proscenium wall. Where the stage height exceeds 50 feet (15,240 mm), measured from the lowest point on the stage floor to the highest point of the roof or floor deck above, a proscenium wall must be provided. The proscenium wall is intended by the IBC to provide a complete fire separation between the stage and the auditorium. Extending from the foundation continuously to the roof, the wall is to have a minimum fire-resistance rating of 2 hours.

410.3.5 Proscenium curtain. Because the opening in the proscenium wall described in Section 410.3.4 is too large to protect with any usual type of fire assembly, the code requires that it be protected with a fire-resistive fire curtain or water curtain. Where a fire curtain is installed, it must comply with the provisions for fire-safety curtains set forth in NFPA 80 Fire Doors and Other Opening Protectives. A fire curtain or water curtain is not required where a complying smoke-control system or natural ventilation is provided. Horizontal sliding doors may also be used to provide the required separation provided they a have a minimum 1-hour fire protection rating.

The purpose of the proscenium curtain protection is to provide occupants with additional time to exit the assembly seating area if there is a fire in the stage area. With the benefits afforded by an engineered smoke-control system or natural ventilation, the occupants should be equally or better protected from the hazards of fire than with a proscenium curtain or water curtain. By providing a performance-based alternative to a proscenium curtain, more design options are available where the use of fire-safety curtains is considered impractical or causes obstructions of the production. It is important to note that the elimination of the proscenium curtain is not permitted if the smoke-protected seating provisions of Section 1029.6.2 are being utilized, for example, a decrease in the required egress widths of the assembly seating area.

The requirement for a complying fire curtain is triggered solely by the proscenium wall provisions of Section 410.3.4. Where a proscenium wall is fire-resistance rated for a different purpose, such as a bearing wall in a Type IB building, the fire curtain is not required.

410.3.7 Stage ventilation. The Iroquois Theater fire in 1903 was directly responsible for the requirement for automatic vents in the roofs of theater stages. Because of the presence of large amounts of combustible materials, excessive quantities of smoke will accumulate in and above the stage area unless it is automatically vented or removed by a smoke-control system. The removal of smoke is necessary for fire fighting as well as the prevention of panic by drawing off the smoke so that it will not infiltrate the theater auditorium.

The maximum floor area of stages that is permitted without the installation of venting is 1,000 square feet (93 m²). The stage area to be considered includes the performance area and adjacent backstage and support areas not separated from the performance area by fire-resistance-rated construction. In addition, stages must be equipped with smoke-removal equipment or roof vents where they are greater than 50 feet (15,240 mm) in height. If either of these two conditions exist, stage ventilation is required. The detailed requirements for smoke vents in the IBC are intended to provide reliability and a reasonable assurance that after many years of operation the vents will operate when needed.

410.4 Platform construction. Materials used in the construction of permanent platforms must be consistent with those materials permitted based on the building’s type of construction. Therefore, in noncombustible buildings, the platforms must be of noncombustible construction. However, in buildings of Type I, II, and IV construction, the use of fire-retardant-treated wood is permitted where all of the following conditions are met:

1. The platform is limited in height to 30 inches (762 mm) above the floor.

2. The floor area of the platform does not exceed one-third the floor area of the room in which it is located.

3. The platform does not exceed 3,000 square feet (279 m²) in floor area.

In those situations where the concealed area below the platform is to be used for storage or any purpose other than equipment, wiring, or plumbing, the floor construction of the platform is to be fire-resistance rated for a minimum of 1 hour. Otherwise, no protection of the platform floor is necessary.

As it is often impractical to construct temporary platforms of fire-resistive materials, the code permits temporary platforms to be constructed of any materials, but restricts the use below the platform to that of electrical wiring or plumbing to operate platform equipment. Therefore, no storage of any kind is permitted beneath temporary platforms, because of the potential for a fire to start and spread undetected.

410.5 Dressing and appurtenant rooms. Not only must a stage exceeding 50 feet (15,240 mm) in height be separated from the adjoining seating area by a minimum 2-hour fire-resistance-rated proscenium wall, but such a separation is also required between the stage and all other portions of the building, including all related backstage areas. Dressing rooms, property rooms, workshops, storage rooms, and all other areas must be separated from the stage with minimum 2-hour fire-resistance-rated fire barriers and/or horizontal assemblies, and all openings must be appropriately protected. A minimum 1-hour fire-resistance-rated separation is required where the stage height does not exceed 50 feet (15,240 mm).

In addition to their required fire separation from the stage, dressing rooms and all other related backstage areas must be separated from each other. One-hour fire-resistance-rated fire barriers and/or horizontal assemblies, along with opening protectives, satisfy the minimum requirements. The hazards caused by the significant fire loading that occurs in conjunction with stages are greatly reduced through the use of compartments.

410.7 Automatic sprinkler system. One of the special areas mentioned in Table 903.2.11.6 that requires a suppression system is stages. The general requirement mandates the sprinklering of not only the stage area but also all support and backstage areas serving the stage. An automatic sprinkler system is an effective tool in limiting the exposure of a fire to the area of origin. Sprinklers are not required for a stage having both a small floor area and a low roof height. Under such conditions, the amount of combustibles in the stage area is typically very limited.

Section 411 Special Amusement Buildings

Amusement buildings are usually classified as Group A occupancies but should be classified as Group B where the occupant load is less than 50. The major factors contributing to the loss of life in fires within amusement buildings have been the failure to detect and extinguish the fire in its incipient stage, the ignition of synthetic foam materials and subsequent fire and smoke spread, and the difficulty of escape. Provisions for the detection of fires, the illumination of the exit path, and the sprinklering of the structures are required to protect the occupants in such structures. However, amusement buildings or portions thereof without walls or a roof are not required to comply with this section, provided they are designed to prevent smoke from accumulating in the assembly areas. Approved smoke-detection and alarm systems are also required in amusement buildings. A provision of Section 411.7 is that on the activation of the system as described, an approved directional exit-marking system shall activate in those areas where the configuration of the space is such as to disguise the path and make the egress route not readily apparent.

Section 412 Aircraft-Related Occupancies

Because of the unique nature of occupancies related to aircraft manufacture, repair, storage, and even flight control, provisions have been developed to address the special conditions that may exist. Although the various uses fall into different occupancy classifications, they all have one thing in common—they are related to aircraft. Additional requirements related directly to aviation facilities are found in Chapter 20 of the IFC.

412.3 Airport-traffic control towers. These provisions are intended to reconcile the differences between the life-safety needs of air-traffic control towers and the life-safety requirements in the body of the code. The life and property loss in these towers has been very small even though they have not complied completely with all of the code requirements in the past. In developing these provisions, consideration was given to the inherent qualities of the use, which makes the general requirements of the IBC inappropriate. For example, air-traffic control personnel are required to undergo medical examinations to ensure they are of sound body and mind. Recognition was also given to the life-safety record of these uses and specific limitations, which are imposed on the allowable size, type of construction, etc. The provisions also require automatic fire-detection systems.

412.4 Aircraft hangar. Aircraft hangars are intended to be classified as Group S-1 occupancies. All aircraft hangars are to be located at least 30 feet (9,144 mm) from any public way or lot line, providing adequate spatial separation for neighboring areas. It should be noted that the measurement is taken to the nearest point of any public way, not to the centerline as typically applied. Otherwise, their exterior walls must have a minimum 2-hour fire-resistance rating. Because of the concerns about below-grade spaces under any facility where flammable and combustible liquids are commonly present, the code requires the hangar floor over a basement to be liquid and air tight with absolutely no openings. Floor surfaces must also be sloped to allow for drainage of any liquid spills.

412.4.6 Fire suppression. In order to minimize the fire hazards associated with aircraft hangars, fire suppression is required based on the criteria of Table 412.4.6. The table determines the hangar classification (Group I, II, or III) to which the fire suppression must be designed in accordance with NFPA 409, Aircraft Hangars. The classification is based on the hangar’s type of construction and fire area size. Fire area size is based on the aggregate floor area bounded by specified fire separation elements that have a fire-resistance rating in accordance with Section 707.3.10. For the purposes of hangar classification, ancillary uses located within the fire area are not required to be included in the fire area size provided they are separated from the aircraft serving area by minimum 1-hour fire barriers. See Figure 412-1.

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Figure 412-1 Aircraft hanger fire area.

412.6 Aircraft paint hangars. The hazards involved with the application of flammable paint or other liquids cause aircraft painting operations to be highly regulated. Where the quantities of flammable liquids exceed the exempt quantities listed in Table 307.1(1), such hangars are classified as Group H-2 occupancies. They must be built of noncombustible construction, provided with fire suppression per NFPA 409, and ventilated in the manner prescribed by the IMC. Where the amount of flammable liquids within the hangar does not exceed the maximum allowable quantities set forth in Table 307.1(1), the classification is most appropriately a Group S-1 occupancy, and the provisions of this section do not apply.

412.7 Aircraft manufacturing facilities. The traditional travel distance limitations have always been considered somewhat problematic for expansive aircraft manufacturing facilities without incorporating exit passageways or horizontal exits into the building’s means of egress system. Due to the compartmentalized nature of horizontal exits, they do not lend themselves to aircraft production processes or movement of the completely assembled aircraft. For similar reasons, exit passageways are generally installed below the floor of the manufacturing level. The use of underground passageways during a fire event or other emergency in such a large, high-volume space is widely viewed as generally contrary to human nature. Once aware of an event, employees typically evacuate the building instinctively at the level with which they are most familiar. It is also relatively common for occupants to want to move away from the point of origin of a fire due to a person’s sensory awareness within the entire open space. Given the fact that occupants sense safety as they move away from a fire incident, it is counterintuitive to enter an underground area unless as a final resort.

In spite of these observations, it is important that it can be demonstrated that such large-volume spaces are able to provide a tenable environment for the evacuation or relocation of building occupants. The increased travel allowances established in Table 412.7 are supported by smoke and temperature fire modeling conducted using the National Institute of Standards and Technology Fire Dynamics Simulator computer program. Results of the fire modeling activity, based on conservative assumptions, were used to establish the maximum travel distances provided.

The travel distance allowances for aircraft manufacturing facilities are therefore based on a combination of building features: the minimum height from the finished floor to the bottom of the ceiling, roof slab, or roof deck above; and the contiguous floor area of the aircraft manufacturing facility having the indicated height.

Ancillary spaces within or adjacent to the manufacturing area are permitted to egress through the manufacturing area having a minimum height as established by Table 412.7. The portion of travel within the ancillary spaces is limited to the general travel distances set forth in Table 1017.2 based upon the occupancy classification of the ancillary space. The overall travel distance cannot exceed the distance indicated in Table 412.7.

412.8 Heliports and helistops. Helistops are differentiated from heliports by the presence of refueling facilities, maintenance operations, and repair and storage of the helicopters; thus, helistops pose similar hazards to those posed by aircraft repair hangars. The minimum size of a helicopter landing area is addressed, as are requirements for construction features and egress. Where heliports and helistops are constructed in compliance with the provisions of this section, they may be erected on buildings regulated by this code.

Section 413 Combustible Storage

Any occupancy group containing high-piled stock or rack storage is subject to the provisions of the IFC as well as the IBC. Chapter 32 of the IFC regulates combustible storage based on a variety of conditions, including the type of commodities stored, as well as the height and method of storage and the size of the storage area.

This section also specifically addresses any concealed spaces within buildings, including attics and under-floor spaces, that are used for the storage of combustible material. Where combustible storage occurs in areas typically considered unoccupiable, the storage areas are to be separated from the remainder of the building by 1-hour fire-resistance-rated construction on the storage side. The protective membrane need only be applied on the storage side insofar as the location of the hazard has been identified as the storage area only. Openings are to be protected with self-closing door assemblies that are either of noncombustible construction or are a minimum 1¾-inch (45-mm) solid wood. This separation is not necessary in Group R-3 and U occupancies. In addition, those combustible storage areas protected with sprinkler systems need not be separated. The provisions are not intended to apply to those storage rooms that are constructed and regulated as usable spaces within the building.

Section 414 Hazardous Materials

Figure 414-1 outlines the process for determining the code requirements that are a function of the quantities of hazardous materials stored or used. The outline is useful for both design and review. To begin, one must determine the hazardous processes and materials involved in a given occupancy and gain a thorough understanding of the operations taking place. Once the hazardous processes and materials have been identified, it is necessary to classify the materials based on the categories used by the code.

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Figure 414-1 Code approach to hazardous materials.

Section 414.1.3 provides the means for the building official to acquire outside technical assistance to assist in the review of a project. Such assistance is often critical in assuring that appropriate decisions are made.

Classifying materials is a subjective science, requiring judgment decisions by an expert familiar with the characteristics of a particular material to categorize it within the categories used by the IBC and IFC. Accordingly, material classifications must be determined by qualified individuals, such as industrial hygienists, chemists, or fire-protection engineers. Though some jurisdictions employ individuals qualified to make these determinations, most jurisdictions rely on outside experts acceptable to the jurisdiction to submit a report detailing classifications compatible with the system used by the code.

Often, a permit applicant will attempt to submit a cadre of Material Safety Data Sheets (MSDSs) as a means of identifying material classifications. Though these may contain the information necessary to determine the proper classification, they do not normally contain a complete designation of classifications that is compatible with the system used by the IBC. Therefore, MSDSs are not normally acceptable as a sole means of providing material classifications to a jurisdiction. The building official should understand that it is not the responsibility of the jurisdiction to provide classifications for hazardous materials. Rather, it is the responsibility of the permit applicant to provide material classification information. In this way, potential liability of the jurisdiction for improper classification of materials is avoided.

In the classification system used by the International Codes®, hazardous materials are generally divided into two major categories, physical and health hazards, and 12 subcategories, as follows:

Physical Hazards

Explosives and fireworks

Combustible dusts and fibers

Flammable and combustible liquids

Flammable solids and gases

Organic peroxides

Oxidizers

Pyrophoric materials

Unstable (reactive) materials

Water-reactive materials

Cryogenic liquids

Health Hazards

Highly toxic and toxic materials

Corrosives

414.1.3 Information required. A report is required to allow the building department to evaluate the presence of hazardous materials within the proposed building based on the criteria established by the IBC. Since Tables 307.1(1) and 307.1(2) are critical in the evaluation of buildings containing hazardous materials, information is needed in order to properly utilize the tables. Such information must include the maximum expected quantities of each material in use and/or storage conditions, those fire-protection features that are to be in place, and any use of control areas for isolation of the materials. The submission of a technical report is necessary to allow the jurisdiction to perform a code compliance evaluation. The requirement for a technical report gives jurisdictions the benefit of expert opinions provided by knowledgeable persons in the particular hazard field of concern. Technical reports are required to be prepared by an individual, firm, or corporation acceptable to the jurisdiction, and must be provided without charge to the jurisdiction. Where the quantities of hazardous materials are such that a Group H occupancy is warranted, floor plans must be submitted to the building official identifying the locations of hazardous contents and processes.

414.2 Control areas. As addressed previously in the discussion of Section 307, areas in a building that are designated to contain the maximum allowable quantities of hazardous materials in use, storage, dispensing, or handling are considered control areas. At a minimum, 1-hour fire barriers shall be used to separate control areas from each other. Where required by Table 414.2.2 for the fourth story above grade plane and all stories above, a minimum 2-hour fire-resistance rating is required for such fire barriers. Openings in fire barriers are to be protected in accordance with Section 716. As a general rule, all floor construction that forms the boundaries of control areas is to have a minimum 2-hour fire-resistance rating. Building elements structurally supporting the 2-hour floor construction shall have an equivalent fire-resistance rating. There is an allowance for those two-story and three-story sprinklered buildings that are primarily of 1-hour fire-resistive construction (Types IIA, IIIA, and VA), which permits 1-hour floor construction of the control area and the supporting construction. It is apparent that a considerable level of fire separation must be achieved in order to increase the quantity of hazardous materials in non–Group H buildings. An example of this provision is illustrated in Figure 414-2.

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Figure 414-2 Control areas.

414.5.1 Explosion control. Table 414.5.1 indicates, based on material, the explosion control methods that must be provided where hazardous materials exceed the allowable quantities specified in Table 307.1(1). Explosion control is also required in any structure, room, or space occupied for purposes involving explosion hazards. Once some type of explosion control is required, Section 911 of the IFC must be referenced to identify the details for controlling explosion hazards.

414.5.3 Spill control, drainage, and containment. The intent of this section is the prevention of the accidental spread of hazardous material releases to locations outside of containment areas. Applicable to rooms, buildings, or areas used for the storage of both solid and liquid hazardous materials, the specifics for spill control, drainage, and containment are contained in the IFC.

414.6.1 Weather protection. In order to be considered outside storage or use in the application of the IFC, hazardous material storage or use areas must be primarily open to the exterior. If it is necessary to shelter such areas for weather protection purposes, the enclosure and its location are limited by the following requirements:

1. No more than one side of the perimeter of the area may be obstructed by enclosing walls and structural supports unless the total obstructed perimeter is limited to 25 percent of the structure’s total perimeter.

2. The minimum clearance between the structure and neighboring buildings, lot lines, or public ways shall be equivalent to that required for outside storage or use areas without weather protection.

3. Unless increased by the provisions of Section 506, the maximum area of the overhead structure shall be 1,500 square feet (140 m²).

4. The structure must be constructed of approved noncombustible materials.

Section 415 Groups H-1, H-2, H-3, H-4, and H-5

The provisions of this section apply to those buildings and structures where hazardous materials are stored or used in amounts exceeding the maximum allowable quantities identified in Section 307. Applied in concert with the IFC, the requirements address the concerns presented by the high level of hazard as compared to other uses. For a further discussion, see the commentary on Section 414.

415.6 Fire separation distance. This section provides regulations that limit the locations on a lot for Group H occupancies and establish minimum percentages of perimeter walls of Group H occupancies required to be located on the building exterior. Based on the specific Group H occupancy involved, the building must be set back a minimum distance from lot lines, as shown in Figure 415-1. As illustrated in Figure 415-2, the distance is measured from the walls enclosing the high-hazard occupancy to the lot lines, including those on a public way. An exception to this method of measurement occurs where two buildings are on the same site and an assumed imaginary line is placed between them under the provisions of Section 705.3. In such a situation, the assumed line is to be ignored in the application of this section. The specific provisions in this section also require that Group H-2 and H-3 occupancies included in mixed-use buildings have 25 percent of the perimeter wall of the Group H occupancy on the exterior of the building. The access capability for fire personnel is greatly enhanced where the hazardous conditions are located in such a manner that allows for exterior fire-fighting operations. Exceptions are provided for smaller, liquid use, dispensing, and mixing rooms; liquid storage rooms; and spray booths. See Figure 415-3. It should be noted that where a detached building, required by Table 415.6.2, is located on the lot in accordance with this section, wall construction and opening protection is not regulated based on location on the lot. A minimum fire separation distance of 50 feet (15,240 mm) is required for such buildings. Therefore, the exterior wall and opening requirements of Table 602 have no application.

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Figure 415-1 Location on property for the detached buildings.

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Figure 415-2 Location on property for mixed occupancies that include a Group H-2 occupancy.

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Figure 415-3 Perimeter wall on exterior.

415.7 Special provisions for Group H-1 occupancies. Because of the extreme hazard presented by Group H-1 occupancies, this section requires that such occupancies be used for no other purpose. Roofs are required to be of lightweight construction so that, in case of an explosion, they will rapidly vent with minimum destruction to the building. In addition, thermal insulation is sometimes required to prevent heat-sensitive materials from reaching decomposition temperatures.

This section also requires that Group H-1 occupancies that contain materials possessing health hazards in amounts exceeding the maximum allowable quantities for health-hazard materials in Table 307.1(2) also meet the requirements for Group H-4 occupancies. This provision is parallel to Section 307.8, which requires multiple hazards classified in more than one Group H occupancy to conform to the code for each of the occupancies classified.

415.8 Special provisions for Group H-2 and H-3 occupancies. Group H-2 and H-3 occupancies containing large quantities of the more dangerous types of physical hazard materials are considered to present unusual fire or explosion hazards that warrant a separate and distinct occupancy in a detached building used for no other purpose, similar to the requirements for a Group H-1 occupancy. The threshold quantities for requiring detached Group H-2 and H-3 occupancies are set forth in Table 415.6.2.

This section also requires water-reactive materials to be protected from water penetration or liquid leakage. Fire-protection piping is allowed in such areas in recognition of both the integrity of fire-protection system installations and the need to protect water-reactive materials from exposure fires.

415.9 Group H-2. Both this section and the IFC are to be used in the regulation of buildings containing the following hazardous materials operations:

1. Flammable and combustible liquids

2. Liquefied petroleum gas distribution facilities

3. Dry cleaning plants

The hazards presented in these operations, through the storage, use, handling, processing, or transporting of hazardous materials, are unique enough to require special provisions, both in this section and in the IFC. The regulations of buildings in which materials that produce combustible dusts are stored or handled are further established in Section 426.

415.10 Groups H-3 and H-4. This section identifies several specific issues in Group H-3 and H-4 occupancies. Group H gas rooms shall be isolated from other areas of the building by minimum 1-hour fire barriers and/or horizontal assemblies. Highly toxic solids and liquids must also be separated from other hazardous material storage by fire barriers and/or horizontal assemblies having a minimum 1-hour fire-resistance rating, unless the highly toxic materials are stored in approved hazardous material storage cabinets. A related provision requires liquid-tight noncombustible floor construction in areas used for the storage of corrosive liquids and highly toxic or toxic materials.

415.11 Group H-5. The Group H-5 occupancy category was created to standardize regulations for semiconductor manufacturing facilities. This section provides the specific regulations for these occupancies. The Group H-5 category requires engineering and fire-safety controls that reduce the overall hazard of the occupancy to a level thought to be equivalent to a moderate-hazard Group B occupancy. Accordingly, the areas permitted for Group H-5 occupancies are the same as those for Group B occupancies.

The code requires that special ventilation systems be installed in fabrication areas that will prevent explosive fuel-to-air mixtures from developing. The ventilation system must be connected to an emergency power system. Furthermore, buildings containing Group H-5 occupancies are required to be protected throughout by an automatic fire-sprinkler system and fire and emergency alarm systems. Fire and emergency alarm systems are intended to be separate and distinct systems, with the emergency alarm system providing a signal for emergencies other than fire. This section also provides requirements for piping and tubing that transport hazardous materials that allow piping to be located in exit corridors and above other occupancies subject to numerous, stringent protection criteria. The provisions for Group H-5 occupancies are correlated with companion provisions in Chapter 27 of the IFC.

Table 415.6.2—Detached Building Required. This table establishes the threshold quantities of hazardous materials requiring detached buildings. Once the quantities listed in the table are exceeded, a detached building is required. The limitations placed on detached buildings required by Table 415.6.2 and classified as Group H-2 or H-3 are essentially the same as those applied to H-1 occupancies. The applicability of the table is based solely on the total quantity of material present. The material can be in use, in storage, or both. See Application Example 415-1.

GIVEN: A manufacturing operation requires up to 300 pounds of a Class 3 water reactive (in use).

DETERMINE: The maximum amount of the Class 3 material that can be stored in the building without detached storage being required.

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Otherwise, a single-occupancy Group H-2 detached building is required.

Application Example 415-1

Section 416 Application of Flammable Finishes

This section applies to those buildings used for the spraying of flammable finishes such as paints, varnishes, and lacquers. In addition, Chapter 24 of the IFC contains extensive requirements for these types of operations. The IFC addresses a variety of spraying arrangements, each of which is specifically defined and regulated. These include spray rooms, spray booths, spraying space, and limited spraying space. The IBC provides limited construction provisions only for those arrangements determined to be spray rooms, as well as ventilation and surfacing requirements for all spraying spaces. An automatic fire-extinguishing system is mandated for all areas where the application of flammable finishes occurs, including all spray, dip, and immersing spaces, and storage rooms.

The occupancy classification of buildings, rooms, and spaces utilized for flammable finish application is not specifically addressed. Certainly, where the quantity of hazardous materials exceeds the maximum amounts established by Table 307.1(1) or 307.1(2), a Group H classification is warranted. However, where the maximum amounts are not exceeded, the analysis would be no different than that for other types of uses. In a manufacturing building, a Group F-1 occupancy classification would be appropriate. Spraying operations within a vehicle repair garage would most likely be considered part of the Group S-1 classification. A spray room, designed and constructed to house the spraying of flammable finishes, must be adequately separated from the remainder of the building. The enclosure must consist of fire barriers, horizontal assemblies, or both, each having a minimum fire-resistance rating of 1 hour. Spraying rooms must be frequently cleaned; thus, all of the interior surfaces must be smooth and easily maintained. The smooth surfaces also allow for the free passage of air in order to maintain efficient ventilation. The room construction must also be tight in order to eliminate the passage of residues from the room, which should be easily accomplished because of the fire separation required. Spraying spaces not separately enclosed shall be provided with noncombustible spray curtains to restrict the spread of vapors.

Section 417 Drying Rooms

Where the manufacturing process requires the use of a drying room or dry kiln, the room or kiln containing the drying operations must be of noncombustible construction. It must also be constructed in conformance with the specific and general provisions of the code as they relate to the special type of operations, processes, and materials that are involved. Clearance between combustible contents that are placed in the dryer and any overhead heating pipes must be at least 2 inches (51 mm). In addition, methods are addressed to insulate high-temperature dryers from adjacent combustible materials.

Section 418 Organic Coatings

Defined in Section 202 of the IFC, organic coatings are those compounds that are applied for the purpose of obtaining a finish that is protective, durable, and decorative. Used to protect structures, equipment, and similar items, organic coatings provide a surface finish that resists the effects of harsh weather. The concern for occupancies where organic coatings are manufactured or stored is based primarily on the presence of flammable vapors. As such, this type of use is highly controlled, by both the IBC and the IFC.

The manufacturing of organic coatings creates a high probability that flammable vapors will be present. Therefore, buildings where such materials are manufactured shall be without basements or pits because of the heavier-than-air nature of the vapors. In addition, no other occupancies are permitted in buildings used for the manufacture of organic coatings. The processing of flammable or heat-sensitive material must be done in a noncombustible or detached structure. Tank storage of flammable and combustible liquids inside a building must also be located above grade. In order to isolate the various hazard areas, the storage tank area must be separated from the remainder of the processing areas by minimum 2-hour fire barriers and/or horizontal assemblies. Because of the extreme hazards involved with nitrocellulose storage, it must also be separated by 2-hour fire-resistance-rated fire barriers and/or horizontal assemblies, or preferably located on a detached pad or in a separate structure.

Section 419 Live/Work Units

An increasingly popular concept of building use combines a residential unit with a small business activity. Residential live/work units typically include a dwelling unit along with some public service business, such as an artist’s studio, coffee shop, or chiropractor’s office. There may be a small number of employees working within the residence and the public is able to enter the work area of the unit to acquire service. Live/work units are a throwback to 1900-era community planning where residents could walk to all of the needed services within their neighborhood. These types of units began to re-emerge in the 1990s through a development style known as “Traditional Neighborhood Design.” More recently, adaptive reuse of many older urban structures in city centers incorporated the same live/work tools to provide a variety of residential unit types. Provisions specifically addressing live/work units recognize the uniqueness of this type of use.

By definition, a “live/work unit” is primarily residential in nature but has a sizable portion of the space devoted to nonresidential activities. Often service-related in nature, the nonresidential portion is limited in several respects. The unit itself, including both the residential and nonresidential portions, is limited to 3,000 square feet (279 m²) in total floor area. In addition, the nonresidential activities cannot take up more than 50 percent of the unit’s total floor area. The portion dedicated to nonresidential use must be located on the first floor of the unit, or where applicable, on the unit’s main floor level. In addition to the unit’s residents, a limit of five workers or employees is permitted at any one time. An overview of the limitations is shown in Figure 419-1.

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Figure 419-1 Live/work unit.

The occupancy classification of a live/work unit is Group R-2 based upon the primary use of the unit. Although differing uses are typically classified based on the characteristics of the varying uses involved and considered as mixed-occupancy conditions, in this case a single classification is considered acceptable. The potential hazards created due to the nonresidential uses are addressed through the special requirements of Section 419 that are to be applied in addition to those required due to the Group R-2 classification. Since live/work units are regulated as single-occupancy conditions, the provisions of Section 508 for mixed-occupancy buildings do not apply. In addition to the other limitations on use of a live/work unit, significant storage uses and those activities involving hazardous materials are prohibited. The increased fire load found in many storage uses is not considered in the live/work provisions, nor is the potential physical or health hazard that is due to the use or storage of hazardous materials. A very small amount of storage is permitted if it is deemed to be accessory to the nonresidential use.

Even though a live/work unit is classified as a Group R-2 occupancy, there are several issues where the residential and nonresidential portions are regulated independently. Structural floor loading conditions, accessibility features, and ventilation rates are all to be based on the individual function of each space within the unit, as are the design of the means of egress and the determination of required plumbing facility. In all other cases, the provisions applicable to a Group R-2 occupancy are to be applied to the entire live/work unit.

Section 420 Groups I-1, R-1, R-2, R-3, and R-4

In residential-type uses, it is important that any fire conditions created in one of the dwelling units or sleeping units does not spread quickly to any of the other units. As residential fires are the most common of fire incidents, it is critical that neighboring units be isolated from the unit of fire origin. The need for an adequate level of fire resistance is enhanced because of the lack of immediate awareness of fire conditions when the building’s occupants are sleeping. The provisions are applicable to hotels and other Group R-1 occupancies, apartment buildings, dormitories, fraternity and sorority houses, and other types of Group R-2 occupancies, and between dwelling units of a Group R-3 two-family dwelling. Sleeping units and dwelling units of a supervised residential care facility classified as Groups R-4 and I-1 must also be provided with such fire-resistive separations.

Where dwelling units or sleeping units are adjacent to each other horizontally, the minimum required separation is a fire partition. The wall serving as a fire partition is regulated by Section 708 and typically must have a minimum 1-hour fire-resistance rating. A reduction to a ½-hour fire partition is permitted under the special conditions set forth in Exception 2 of Section 708.3. Where dwelling or sleeping units are located on multiple floors of a building, they must be separated from each other with minimum 1-hour fire-resistance-rated horizontal assemblies as described in Section 711. An allowance for a ½-hour reduction, similar to that permitted for fire partitions, is also available under specified conditions.

In addition to the required separation between adjoining units, dwelling units and sleeping units must also be separated by complying fire partitions and/or horizontal assemblies from other adjacent occupancies. Applicable in mixed-use buildings, this requirement takes precedence over the allowances in Sections 508.2 and 508.3 for accessory occupancies and nonseparated occupancies, respectively. Even in those cases where the mixed-occupancy provisions of Section 508.2 or 508.3 are applied, the separation requirements of Section 420 must be followed. In those cases where the separated occupancy provisions of Section 508.4 are utilized, the more restrictive fire-resistive rating is applied.

It should be noted that the separation of dwelling units and sleeping units from other types of spaces in the building appears to only apply if those spaces are of a different occupancy than that of the residential units. For example, a separation is not required between a Group R-1 sleeping unit in a hotel and the adjacent hotel lobby if the lobby is classified as a portion of the Group R-1 occupancy. However, it would seem that the intent of this section suggests that a separation be provided in order to isolate each individual dwelling unit or sleeping unit, regardless of the classification of the adjacent space. See Figure 420-1.

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Figure 420-1 Separation of dwelling units and sleeping units.

Section 422 Ambulatory Care Facilities

Ambulatory care facilities, often referred to as ambulatory surgery centers or day surgery centers, are defined in Chapter 2 as a building or portion of a building “used to provide medical, surgical, psychiatric, nursing or similar care on a less than 24-hour basis to individuals who are rendered incapable of self-preservation by the services provided.” Classified as Group B occupancies, such facilities are generally regarded as moderate in hazard level due to their office-like conditions. However, additional hazards are typically present due to the presence of individuals who are temporarily rendered incapable of self-preservation due to the application of nerve blocks, sedation, or anesthesia. While the occupants may walk in and walk out the same day with a quick recovery time after surgery, there is a period of time where a potentially large number of people could require physical assistance in case of an emergency that would require evacuation or relocation.

Although classified as a Group B occupancy in the same manner as an outpatient clinic or other health-care office, an ambulatory care facility poses distinctly different hazards to life and fire safety, such as:

• Patients incapable of self-preservation require rescue by other occupants or emergency responders.

• Medical staff must stabilize the patient prior to evacuation, possibly resulting in delayed staff evacuation.

• Use of oxidizing medical gases such as oxygen and nitrous oxide.

• Potential for surgical fires.

As a result of the increased hazard level, additional safeguards have been put in place. Smoke compartments must be provided in larger facilities, and the installation of fire-protection systems is typically mandated. See Figure 422-1.

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Figure 422-1 Ambulatory care facility.

Any story containing ambulatory care facilities having more than 10,000 square feet (929 m²) of floor area must be subdivided into at least two smoke compartments by smoke barriers in accordance with Section 709. The limit on compartment size of 22,500 square feet (2,092 m²) may require that three or more smoke compartments be provided. Additional compartments may also be required due to travel distance limitations. Any point within a smoke compartment must be no more than 200 feet (60,960 mm) in travel distance from a smoke barrier door. Each smoke compartment must be large enough to allow for 30 square feet (2.8 m²) of refuge area for each nonambulatory patient. In addition, at least one means of egress must be available from each smoke compartment without the need to return back through the original compartment. Fire-safety evacuation plans must be provided where smoke compartments are mandated. The plans are intended to address the defend-in-place philosophy for emergency response as defined in Section 202 and regulated by Sections 404 and 408 of the IFC

As a general rule, Group B occupancies do not require a sprinkler system based solely on their occupancy classification. However, Section 903.2.2 mandates that a Group B ambulatory care facility be provided with an automatic sprinkler system when either of the following conditions exist at any time:

• Four or more care recipients are incapable of self-preservation, or

• One or more care recipients who are incapable of self-preservation are located at other than the level of exit discharge.

The extent of the sprinkler protection is detailed in Section 903.2.2. In addition, the fire alarm requirements are more stringent than those of other Group B occupancies. Section 907.2.2 requires the installation of a manual fire alarm system in all Group B fire areas containing an ambulatory health-care facility. The manual fire alarm boxes are not required if the building is fully sprinklered and the occupant notification appliances activate upon sprinkler water flow.

Section 423 Storm Shelters

ICC-500, ICC/NSSA Standard on the Design and Construction of Storm Shelters, establishes minimum requirements for structures and spaces designated as hurricane, tornado, or combination shelters. The standard addresses the design of such shelters from the perspective of the structural requirements for high wind conditions, and addresses minimum requirements for the interior environment during a storm event.

Scoping provisions mandate the construction of complying storm shelters in critical emergency operations facilities where such facilities are located in geographical areas where the shelter design wind speed is at its highest 250 miles per hour. This geographical area, which includes most of the Interior Plains region of the United States, is identified in detail in Figure 304.2(1) of ICC 500. Critical facilities, such as emergency operations centers, fire and police stations, and buildings with similar functions, are essential for the delivery of vital services or the protection of a community. It is important to protect the occupants of such critical facilities struck by tornadoes, as well as to maintain continuity of operations for those facilities. Emergency operations facilities, as well as police and fire rescue facilities, are crucial to disaster response because an interruption in their operation as a result of building equipment failure may prevent rescue operations, evacuation, assistance delivery, or general maintenance of law and order, which can have serious consequences for the community after a storm event.

Most Group E educational occupancies must also be provided with complying storm shelters under the same criteria. Due to unpredictable and often very short tornado warning time, there are many high-wind events where it is unfeasible to evacuate school buildings. Therefore, it is very important that refuge areas be provided that are capable of providing a near-absolute level of protection for the vulnerable individuals.

Section 424 Children’s Play Structures

Play structures for children’s activities were regulated for some time by the IBC only where such structures were located within covered mall buildings. The primary concern, consistent with that of other structures located within a covered mall building, was the combustibility of such play structures. Due to the potential fire hazards associated with children’s play structures, the regulations are now applicable where such structures are located within any building regulated by the IBC, regardless of occupancy classification.

Children’s play structures must be constructed of noncombustible materials or, as an option if combustible, must comply with the appropriate criteria established in Section 424. Such alternative methods include the use of fire-retardant-treated wood, textiles complying with the designated flame propagation performance criteria, and plastics exhibiting an established maximum peak rate of heat release.

KEY POINTS

• Special uses such as covered and open mall buildings, atriums, high-rise buildings, underground buildings, and parking garages are so unique in the type of hazards presented that specialized regulations are provided in the IBC.

• A covered mall building or open mall building consists of various tenants and occupants, as well as the common pedestrian area that provides access to the tenant spaces.

• For those features that are not unique to a covered or open mall building, the general provisions of the code apply.

• The means of egress provisions for a covered or open mall building are typically more liberal than those for other buildings.

• High-rise buildings are characterized by the difficulty of evacuation or rescue of the building occupants, the difficulty of fire-fighting operations from the exterior, high occupant loads, and potential for stack effect.

• There are a number of provisions for high-rise buildings that are less restrictive than the general requirements, including the reduction in fire resistance for certain building elements.

• The special allowance for a reduction in construction type is not applicable to any high-rise building exceeding 420 feet (128 m) in height.

• Smoke detection, alarm systems, and communications systems are important characteristics of a high-rise building.

• Occupant egress and evacuation, as well as fire department access, are addressed in high-rise buildings through provisions for stairway enclosure remoteness, an additional stairway, luminous egress path markings, fire service access elevators, and occupant evacuation elevators.

• The use of the atrium provisions is typically limited to those multistory applications where compliance with the other vertical opening applications established in Section 712.1 is not possible.

• Buildings containing atriums, high-rise buildings, covered mall buildings, and open mall buildings must be provided with automatic sprinkler systems throughout.

• Another component of the life-safety system for a building containing an atrium is a required smoke-control system.

• An underground building is regulated in a manner similar to that for a high-rise building, as the means of egress and fire department access concerns are similarly extensive.

• Fundamental to the protection features for an underground building are the requirements for Type I construction for the underground portion and the installation of an automatic sprinkler system.

• Private garages and carports are regulated to a limited degree based on the hazards associated with the parking of motor vehicles.

• Special provisions for open parking garages are typically less restrictive than those for enclosed parking structures because of the natural ventilation that is available.

• In Group I-2 and I-3 occupancies, the functional concerns of the health-care operations must be balanced with the fire-safety concerns.

• Stages exceeding 50 feet (15,240 mm) in height present additional risks that are due to the expected presence of high combustible loading such as curtains, scenery, and other stage effects.

• Under-floor areas and attic spaces used for the storage of combustible materials must be isolated from other portions of the building with fire-resistance-rated construction.

• Hazardous materials that are used or stored in any quantity are subject to regulation by Sections 307 and 414, and the IFC.

• An increase in the maximum allowable quantities of hazardous materials in a building not classified as Group H is permitted through the proper use of control areas.

• Group H occupancies are highly regulated because of the hazardous processes and materials involved in such occupancies.

• Special provisions are applicable to the construction, installation, and use of buildings for the spraying of flammable finishes in painting, varnishing, and staining operations.

• Special allowances and conditions are applicable to live/work units where a dwelling unit or sleeping unit includes a significant amount of nonresidential use operated by the tenant.

• Dwelling units and sleeping units must be separated from each other and from other portions of the building through the use of fire partitions and/or horizontal assemblies.

• Health-care offices where care is provided to individuals who are rendered incapable of self-preservation are considered to be ambulatory care facilities.

• Storm shelters, constructed in accordance with ICC-500, are required in critical emergency operations facilities and most Group E occupancies.

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