9
Fire-Protection Systems
As we have seen in Chapter 7, the code recognizes the effectiveness of active fire-protection systems. The provision of an automatic sprinkler system allows trade-offs with passive fire-resistance in numerous sections of the code. The code also requires that active systems be provided in buildings above a certain height and above certain occupancy loadings. Thus the code recognizes the efficacy of active systems in concert with passive fire-protection to provide a balanced approach to fire and life safety for building occupants.
Active systems, especially fire sprinklers, are very effective but subject to interruption of water supplies unless emergency water sources with backup pressure systems are provided. At the same time, passive systems are subject to failure due to construction defects, poor maintenance, remodeling, failure of attachments, and damage from building movement or building use. The designer should consider the integration of both passive and active systems while developing the building design. The best designs do not rely on just one set of systems to provide fire protection but use an overall holistic approach to provide maximum protection.
We will touch on those active systems that integrate most effectively with passive fire-resistive strategies. The primary systems considered are fire sprinklers, smoke-control systems, and smoke and heat vents. These systems respond to hazards with defined actions designed to suppress fires or provide for occupant safety and egress. Other systems—fire alarms, fire extinguishers, and standpipe systems—provide notification for egress or auxiliary firefighting capabilities for the fire service. The code requires their presence for certain occupancies but does not allow balancing their use with alternate design considerations. The systems that interact with design decisions, especially fire sprinkler systems, are the ones discussed here.
The design and installation of automatic sprinkler systems is typically governed by rules developed by the National Fire Protection Association and promulgated as NFPA 13. An automatic sprinkler system is designed to respond to a fire when the sprinkler heads are activated by a fire or by heat. The systems are designed to function without intervention by the building occupants to cause their operation. The history of fire sprinklers as fire-suppression devices has been a good one, and they have been required under a greater range of circumstances in each new edition of model codes.
Residential sprinkler systems may be installed under the provisions of NFPA 13D or 13R, which are subsets of the provisions of NFPA 13. These may be acceptable as sprinkler systems in specific instances, but the code does not recognize these as fully equivalent to NFPA 13 systems for the trade-offs contained in exceptions or reductions unless they are specifically allowed. See the requirements for Group R occupancies for allowable uses for these sprinkler-system classes.
When reading sections of the code that refer to Chapter 9, the designer should go to the section referred to in Chapter 9 to verify which type of sprinkler system is required by the IBC. These systems are described in § 903.3. This is where the code draws distinctions between NFPA 13, 13D, 13R and alternative sprinkler systems. Do not assume that all automatic sprinkler systems are per NFPA 13 without referring to Chapter 9.
Fire-protection systems consist of:
- Detection systems that sense heat, fire, or smoke (particles of combustion) and activate an appropriate alarm.
- Alarm systems that alert occupants of an emergency in a building by the sense of hearing, sight, or, in some cases, touch, as by such things as vibrations.
- Automatic fire-extinguishing or sprinkler systems that are activated by heat from a fire and discharge either an approved fire-extinguishing agent or water over the fire area in order to extinguish or control a fire.
- Automatic sprinkler systems that consist of underground and overhead piping from a suitable water supply, to which automatic sprinklers are attached in a regular pattern designed to provide even coverage for water discharge. Upon activation by heat from a fire, the systems discharge water over the fire area.
A fire-protection system may also include equipment to control or manage smoke and combustion products of a fire.
Various occupancies are required to have automatic sprinkler systems by § 903. These requirements are based on several factors:
- Occupancy type
- Occupant load
- Area of occupied space
- Locations not providing ready egress or ready fire-department access
The requirements are listed by occupancy group. Carefully note that an automatic sprinkler system may be required:
Note also that the increases for building heights and areas allowed in Chapter 5 for provision of sprinkler systems apply only when those systems are installed throughout a building.
In addition to the requirements contained in § 903.2, Table 903.2.11.6 is a useful cross reference for sprinkler requirements contained in other code chapters.
Automatic Sprinkler Systems
Group A: § 903.2.1 requires that when any of the conditions listed on this and the following page exist, an automatic sprinkler system be installed:
Note that for any of the Group A occupancies on this and the facing page, any one of the specified conditions triggers the requirement for sprinklers. The requirements include:
- A-1: Throughout a floor containing an A-1 occupancy when one of the following conditions exist:
Group B: There are increasing numbers of “ambulatory care facilities,” which are usually classified as B occupancies. The sprinkler provisions in § 902.2.2 are based on the use description of ambulatory care, not on the occupancy classification. Sprinklers are required on the entire floor where there are more than four care recipients incapable of self-preservation on the level of exit discharge, or when one or more such persons are located at other than the level of exit discharge. When there are incapacitated care recipients above the level of exit discharge, then the floors supporting that level must also be sprinklered.
Any one of the specified conditions below triggers the requirement for sprinklers in Group A occupancies:
- A-2: Throughout a floor containing an A-2 occupancy when one
of the following conditions exist:
- The fire area exceeds 5,000 sf (465 m2).
- The fire area has an occupant load of 100 or more.
- The fire area is located on a floor other than the level of exit discharge.
- A-3: Throughout a floor containing an A-3 occupancy when one
of the following conditions exist:
- The fire area exceeds 12,000 sf (1115 m2).
- The fire area has an occupant load of 300 or more.
- The fire area is located on a floor other than the level of exit discharge.
- A-4: Throughout a floor containing an A-4 occupancy when one
of the following conditions exist:
- The fire area exceeds 12,000 sf (1115 m2).
- The fire area has an occupant load of 300 or more.
- The fire area is located on a floor other than the level of exit discharge.
- A-5: A sprinkler system is to be provided in concession stands, retail areas, press boxes, and other accessory use areas larger than 1,000 sf (93 m2) in A-5 occupancies, such as outdoor stadiums.
- Where merchandise is stored in high-piled or rack storage, sprinklers shall be provided at those areas per the International Fire Code
- Group S-1: § 903.2.9 requires an automatic sprinkler
system throughout all buildings where:
- Where S-1 occupancies are used as repair garages, § 903.2.9.1 requires an automatic sprinkler system thoughout the building when:
- The fire area containing the repair garage exceeds 10,000 sf (929 m2) and the building is two or more stories above grade plane; or
- The S-1 fire area containing a repair garage in a building no more than one story above grade plane exceeds 12,000 sf (1115 m2); or
- The repair garage service area is located in a basement; or
- There is an S-1 fire area used for the commercial repair of trucks or buses and the fire area exceeds 5,000 sf (464 m2).
- Group S-2: § 903.2.10 requires an automatic sprinkler
system throughout buildings with enclosed S-2 occupancies that
are:
- Excepted are enclosed parking garages under Group R-3 occupancies. Note that this exception also includes the requirement that the area of the garage be less than or equal to 12,000 sf (1115 m2).
§ 903.2.11.1 requires that in buildings other than U occupancies, sprinklers are required at floors below grade or with limited firefighting access. Any floor area exceeding 1,500 sf (139.4 m2) must be provided with one type or the other of exterior wall openings noted to the right, or automatic sprinklers must be provided for the story.
- § 903.2.11.2: Trash and linen chutes merit special sprinkler
protection. They typically occur in residential buildings where
people sleep. They are also accessible for use by occupants and
thus may not be maintained in a safe condition by users. Therefore
sprinklers are to be provided in addition to the passive protection
provided by shaft enclosures and fire-rated rooms separating the
chutes from circulation spaces and adjacent uses.
- § 903.2.11.3 requires that automatic fire sprinklers be
installed throughout buildings having an occupied floor with 30 or
more occupants located 55' (16 764) or more above the lowest level
of fire-department vehicle access. Thus, any building higher than a
mid-rise structure is to be sprinklered, even if not considered a
high-rise building per § 403.
- Per § 903.3.1.2.1, sprinkler
protection is to be provided for exterior balconies of dwelling
units and sleeping units where either of the following conditions
exists:
- The building is of Type V construction, provided that there is a roof or deck above.
- Exterior balconies, decks, and ground
floor patios of dwelling units and sleeping units are of
unprotected combustible construction in accordance with §
705.2.3.1, Exception 3.
- Per § 903.3.1.2.3, attic fire
protection must be provided under certain conditions:
Standpipe Systems
§ 905 contains the requirements for the installation of standpipe systems. Standpipes are permanent pipes rising through a building that provide hose connections for use in interior fire-fighting. Standpipes are designated as Class I, II, or III per the definitions in Chapter 2, based on the hose connections they furnish.
Standpipe types are classified as either wet or dry and automatic or manual. Dry standpipes contain air that is displaced by water when they are put to use. Wet standpipes contain water at all times. The use of these is often determined by location. For example, dry standpipes can be on open landings in cold climates, where the water in wet standpipes would freeze.
Standpipe classifications for automatic standpipes presume that the water supply for the standpipe can meet the system demand. Manual standpipes depend on additional pressure and water supply to meet the demand. Hooking up a fire-department pumper truck to the standpipe typically provides such additional supply.
Standpipes are often referred to as fire risers, a term also applied to vertical fire-sprinkler supply lines. Avoid confusion in language by determining to which pipes the term applies.
Standpipes are permitted to be combined with automatic sprinkler systems. Thus a single riser pipe may supply both the sprinkler system and the hose connections. However, such a single pipe will be larger in diameter than two separate pipes, since it must meet the demand of both the sprinkler and hose connection systems. Typically the systems are combined, since a single riser, even if somewhat larger in diameter, is easier to locate in the building than two such risers.
Required Installations
Triggers for standpipe requirements have different thresholds depending on building height, occupancy type, provision of sprinklers, and building area.
Class III Standpipes Required
Exceptions to § 905.3.1 are:
- Class I standpipes are allowed in buildings that are fully sprinklered per § 903.3.1.1 or § 903.3.1.2.
- Class I manual standpipes are allowed in open parking garages where the highest floor is not more than 150' (45 720) above the lowest level of fire-department access.
- Class I manual dry standpipes are allowed in open parking garages subject to freezing as long as the standpipes meet spacing and location criteria per § 905.5.
- Class I standpipes are allowed in basements that have automatic sprinklers.
- Determining the lowest level of fire department access does not require consideration of recessed loading docks for four or fewer vehicles and topographic conditions that make fire department vehicle access impractical or impossible.
§ 905.3.4 requires Class III wet standpipes be provided at stages larger than 1,000 sf (93 m2) in area, with 1½'' (38) and 2½'' (64) hose connections located on each side of the stage. If there is an automatic sprinkler system a 1½'' (38) hose connection is to be provided. § 905.3.4.1 requires a hose cabinet or rack and the hose to be equipped with an adjustable fog nozzle.
Class I Standpipes Required
§ 905.3.2 requires that Class I automatic wet standpipes be provided in nonsprinklered Group-A occupancies having an occupant load of more than 1,000 people. This is not required for open-air seating spaces without enclosed spaces.
§ 905.3.3 requires standpipes be provided in covered and open mall buildings and any building connected to them where otherwise required in § 905.3.1. This translates into requirements for Class I standpipes located per § 905.4 as illustrated to the left. When other types of standpipes are not required by § 905.3.1, Class I hose connections are to be located:
It is to be presumed that these requirements are supplementary and complementary with those for malls contained in § 905.4.
§ 905.3.5 requires Class I automatic wet or manual wet standpipes be provided in all underground buildings.
Standpipe Locations
Locations are described for hose connections for the various standpipe classes. Class III standpipes, having components of both other classes, must comply with both sets of regulations.
Class I Standpipe Hose Connections
§ 905.4 requires Class I standpipe hose connections be provided at the following locations:
When risers and laterals of Class I standpipes are not located in an enclosed stairway or pressurized enclosure, § 905.4.1 requires the piping to be protected by fire-resistant materials equal to those required in the building for vertical enclosures. Protection is not required for laterals in fully sprinklered buildings.
Class II Standpipe Hose Connections
Class III Standpipe Hose Connections
Class III standpipe hose connections, by definition, have both Class I and II hose connections. Therefore, § 905.6 refers back to § 905.4 for the location of Class I connections and to § 905.5 for the location of Class II hose connections. The laterals and risers are to be protected as for Class I systems per § 905.4.1. Where there is more than one Class III standpipe, they are to be hydraulically interconnected at the bottom.
In Group A-1 and A-2 occupancies having loads larger than 1,000 people, Class II hose connections are to be located:
- Class II standpipe laterals and risers do not require fire-resistance-rated protection.
- For light-hazard occupancies, the hose for Class II systems may be minimum 1'' (25.4) hose where approved by the building official.
Portable Fire Extinguishers
§ 906 is excerpted from sections contained in the International Fire Code. It is included in the IBC since the requirements have design implications for building planning. We will discuss the typical requirements for buildings without sprinkler systems or with conventional sprinkler systems. Note that per the Exception to § 906.1, buildings of Group R-2 occupancy have less extensive extinguisher requirements when each dwelling unit is provided with a fire extinguisher with a minimum 1-A:10-B:C rating. Note also that Table 906.1 contains a number of additonal requirements for portable fire extinguishers based on specific building operations.
Extinguishers are assumed to be available for use by building occupants who have little or no training in their use. They are intended as a first line of defense against a developing fire until trained firefighters can respond to the scene of the fire. The requirements are based on the type of fires anticipated; the extent of flammable materials, which determines the hazard-class; the size of the potential floor area in which a fire may occur; and the travel distance for a building occupant to get to an extinguisher's location.
Extinguishers are rated A, B, C, or D, depending on the type of fire they are designed to suppress. See the discussion at right for an explanation of their ratings. Their rating also gives an indication of the size of fire they are designed to fight. Many extinguishers have chemicals in them that are designed to respond to multiple types of fires. Thus, one will often see extinguishers noted as “2A-10B-C.” This extinguisher would be usable on ordinary combustibles, flammable liquids, or an electrical fire. The basic code requirements are determined by the expectation that fires will generally require Class A or B extinguishers. The requirements for Class C extinguishers, per § 906.3.3, are tied to those for Classes A and B. Class D extinguishers are related to the specific type of metals anticipated for use and their quantities. These specialized requirements are contained in the reference standard, NFPA 10.
The determination of the type of extinguishers required will be based on the anticipated use of the facility. These assumptions should be confirmed with the AHJ early in the design process to set extinguisher spacing and size criteria. We interpret the requirements for mulitple-class extinguishers to be complementary. Thus, for multiple-class extinguishers, the most stringent requirements for extinguisher spacing will apply for multiple classifications.
- Class A extinguishers are intended for use with “ordinary
combustibles,” such as wood or paper. Water is the primary
extinguishing agent.
- Class B extinguishers are intended for use with spilled
flammable liguids, such as grease, oil, or gasoline, in shallow
depths. The extinguishing agents are designed to smother the fire
and not spread the burning liquid.
- Class C extinguishers are intended for use in electrical fires.
The extinguishing agent is designed to be non-conductive so as not
to spread the influence of an energized conductor on the fire.
- Class D extinguishers are intended for use on flammable metals and are often specific for the type of metal in question. There is no picture designator for Class D extinguishers. These extinguishers generally have no multipurpose rating for use on other types of fires.
Fire Extinguisher Size and Spacing
Fire-Alarm and Detection Systems
Fire alarms are audible and visual devices to alert occupants and responders of emergencies. Detectors are automatic devices that usually sound an audible and visual alarm to alert occupants and also trigger other responses in systems such as sprinklers, smoke-control systems, or HVAC controls. Systems to notify building occupants of an emergency can be either manually or automatically actuated.
The code requires differing types of alarms or detectors, and different levels of actuation in various occupancies and types of buildings. When buildings are sprinklered and the sprinklers connected to the alarm system, automatic heat detection is not required. Sprinklers are heat-actuated and thus are a type of heat detector themselves. Fire detectors are to be smoke detectors as well, except in areas like boiler rooms where products of combustion would tend to set off smoke detectors. In those rooms alternative types of fire detectors may be used. Alarms are to be per NFPA 72.
The code offers trade-offs between manual alarms and automatic detection systems under certain conditions. There are instances where having manual alarms may result in a large number of false alarms, so providing automatic detection may be a desirable alternative.
Detailed requirements are grouped by occupancy or use. The table on the following pages gives general requirements; it does not provide for every nuance of conditions.
| Section 907.2.x | Occupancy or Building Type | Occupant Load or Condition | Device Type | Exceptions | Notes |
| .1 .1.1 |
A A |
≥ 300 “due to assembly occupancy” or >100 above or below level of exit discharge ≥ 1,000 | Manual fire alarm Voice/alarm |
Not required if sprinklered & w/ water-flow alarm | E Assembly per Group E requirements; captioned systems for hearing impaired to be provided if required per § 1108.2.7.3 |
| .2 | B | ≥ 500, or > 100 occ. above/below exit discharge, or B ambulatory health facility | Manual fire alarm | Not required if sprinklered & w/ water-flow alarm | |
| .3 | E | > 50 >100 |
Manual fire alarm Voice/alarm |
Manual pull boxes are not required if all of a long criteria list for detection are met or if the building is fully sprinklered with automatic notification to a normally occupied location. | When installed, sprinklers & smoke detectors must interconnect to alarm system; system must accommodate communication between secure areas and a central location when the school is under lockdown conditions |
| .4 | F | ≥ 2 stories and > 500 occupants above/ below exit discharge | Manual fire alarm | Not required if sprinklered & w/ water-flow alarm | |
| .5 | H-5 and manufacturing of organic coatings | All | Manual fire alarm | Smoke detection required for toxic gas, peroxides, and oxidizers per International Fire Code | |
| .6 | All I | All | Manual fire alarm | Manual pull boxes not required at sleeping rooms if at staff stations in I-1 and I-2 occupancies | |
| .6.1 | I-1 | Corridors, habitable spaces | Auto smoke detection | In Condition 1, not required if fully sprinklered | Smoke alarms to be installed per § 907.2.11 |
| .6.2 | I-2 | Corridors in nursing homes and hospitals | Auto smoke detection and alarm activation per § 907.4 | Not required if smoke compartments containing rooms have smoke detectors or auto-closing doors | |
| .6.3 | I-3 | All | Manual fire alarm and auto smoke detection | Alarms to alert staff | |
| .6.3.3 | I-3 | Housing area | Smoke detectors | Alternate detector location and size limits for small groups | Not required for sleeping units with 4 or fewer occupants in sprinklered smoke compartments |
| .7 | M | ≥ 500 occupants on all floors, or > 100 above/below exit discharge | Manual fire alarm | Not required if a covered or open mall per § 402, or fully sprinklered & w/ water-flow alarm | When occupied, alarm may notify attended station that will activate voice/alarm system |
| .8 | R-1 | All | Manual fire alarm & auto fire detection | 1. No alarm if ≤ 2 stories with 1-hour separations and direct
exit 2. No alarm if sprinklered and local alarm and one manual pull box at approved location |
|
| .9 | R-2 | 1. 3 or more stories 2. Dwelling units > 1 level below exit discharge 3. > 16 dwelling units |
Manual fire-alarm system | 1. Not required if ≤ 2 stories with 1-hour separations and
direct exit 2. No manual alarm box if sprinklered and local alarm |
|
| .9.3 | R-2 | College and university buildings | Automatic smoke detection that activates occupant-notification system | Not required if there are no interior corridors, and sleeping rooms have direct exit access | At common, laundry, and storage areas, and interior corridors serving sleeping units. When required, the smoke detection devices are to be interconnected to the building fire alarm system |
| .10 | Single- and multiple-station smoke alarms | Listed Single- and multiple-station smoke alarms complying with UL 217 shall be installed in accordance with § 907.2.10.1 through § 907.2.10.7 and NFPA 72. | |||
| .10.1 | R-1 | 1. Sleeping areas 2. Every room in means of egress path 3. Each story in multistory units |
|||
| .10.2 | R-2, R-3, R-4, I -1 |
1. Near each separate sleeping area 2. In each sleeping room 3. In each story of dwelling units |
Not required in sleeping rooms of I-1 with smoke detectors in sleeping rooms as part of an automatic smoke detection system | ||
| .10.3 | To cut down on false alarms from cooking or from water vapor, the location of smoke alarms near cooking appliances and bathrooms is dependent on the type of smoke alarm (ionization or photoelectric) used. The location is to be per NFPA 72. | ||||
| .10.5 | Smoke-alarm interconnection | Where more than one smoke detector is required in dwelling or sleeping units the smoke alarms are to be intercon-nected such that the activation of one alarm will activate all the smoke alarms in the unit. Interconnection may be wire-less if listed system | |||
| .10.6 | Smoke-alarm power | From electrical source w/ battery backup in new construction; battery power OK in retrofit | |||
| .10.7 | Smoke-detection system is an unacceptable alternative to single-and multiple-smoke alarms | ||||
| .11 | Special amusement buildings | Automatic smoke detection | Alternates where smoke detectors will be activated by ambient conditions | Detection system sounds alarm at attended location | |
| .11.1, .11.2, .11.3 |
Special amusement buildings | System response (See notes at right) | 1. Illuminate means of egress with 1 foot-candle (11 lux)
minimum. 2. Stop sounds and distractions. 3. Activate exit markings. 4. Activate voice message. |
||
| .12 | High-rise buildings | Automatic smoke detection system per § 907.2.13.1, fire department communi-cation systems per § 907.2.13.2, and emergency voice/alarm communication systems per § 907.5.2.2 | |||
| .12.1 | High-rise buildings | Automatic smoke detection | |||
| .12.2 | High-rise buildings | Fire-department communication | Fire-department radios may be used in lieu of two-way communication when approved by the fire department. | Two-way fire-department communication per NFPA 72 from central command to elevators, elevator lobbies, emergency power rooms, fire-pump rooms, areas of refuge, and on each floor inside enclosed stairways | |
| .13 | Atrium connecting more than 2 stories | Smoke detection per § 907.5 by automatic alarm, fire flow, or manual alarm | Emergency voice/alarm system in Group A, E, or M occupancies per § 907.5.2.2 | ||
| .14 | High-piled combustible storage | Automatic smoke-detection system | Where required by International Fire Code | ||
| .15 | Aerosol storage uses | Manual fire alarm | When required by International Fire Code | ||
| .16 | Lumber, wood structural panel, & plywood veneer mills | Manual fire alarm | |||
| .17 | Underground buildings with smoke exhaust | Automatic smoke detectors | Similar conditions to high-rise buildings; also activation of smoke exhaust activates audible alarm in attended location | ||
| .18 | Underground buildings > 60' (18 288) below lowest exit discharge | Manual fire alarm | Emergency voice/alarm system per § 907.5.2.2 | ||
| .19 | Covered and open mall buildings > 50,000 sf (4645 m2) | Emergency voice/ alarm system per § 907.5.2.2 | System to be accessible to fire department | ||
| .20 | Residential aircraft hangars | Smoke alarm | Interconnected with sleeping-area smoke alarms | ||
| .21 | Airport control towers | Automatic smoke-detection system | Activates occupant notification system per § 907.5 | ||
| .22 | Battery rooms, lead-acid batteries, liquid capacity > 50 gal. (189.3 L) | Automatic smoke-detection system | |||
| .23 | Capacitor energy storage systems | Automatic smoke-detection system |
Emergency Voice/Alarm Communication
| § 907.5.2.2 | Device Type | Notes |
| Emergency voice/alarm communication system | Voice/alarm system per NFPA 72 Activation of detector, fire flow, or manual pull station will sound tone and activate alert instructions per International Fire Code at: 1. Elevator groups 2. Exit stairways 3. Each floor 4. Areas of refuge per this code In stadiums, arenas, and grandstands required to caption audible public announcements per § 1108.2.7.3, the emergency/voice alarm system is also to be captioned. |
Manual Alarm Boxes
§ 907.4.2 requires manual alarm boxes be located no more than 5' (1524) from the entrance to each exit. Travel distance to the nearest box is not to exceed 200' (60 960).
Visual Alarms
Visual alarms are to be provided in the following locations:
- Public and common areas
- Make provisions for visual alarms to be added in employee work areas.
- I-1 and R-1 sleeping accommodations per the quantities noted in Table 907.5.2.3.2.
- R-2 occupancies that are required by § 907 to have a fire-alarm system. (All dwelling units are required to be adaptable to accommodate visual alarm appliances per accessibility requirements of ICC/ANSI A117.1.)
Audible Alarms
Smoke-Control Systems
The purpose of smoke-control systems as stated in § 909 is to provide a tenable environment for the evacuation or relocation of occupants. The provisions are not intended for the preservation of contents, the timely restoration of operations, or for assistance in fire suppression or overhaul activities.
Smoke-control systems are classified as active fire-protection systems for our discussion in that they actively perform their basic function for life safety. They respond to fire not by their presence as barriers to fire or heat but by activating a sequence of operations to safeguard the building's occupants. These systems are referred to in the code as either of the active or passive type. This refers to whether the systems exhaust smoke through natural convection or by the use of mechanical ventilation. All smoke-control systems rely on automatic activation, whether the exhaust mechanisms are passive or active.
The systems are provided in certain building types such as malls or atriums to contain or evacuate smoke to allow building occupants to leave areas where smoke might hinder their egress. Buildings with smoke-control systems are typically those having large areas with interconnected air spaces where smoke cannot be contained by barriers but must be moved or exhausted for occupant protection. The design criteria for smoke-control systems require detailed calculations and modeling. They are almost invariably designed with the aid of a consultant experienced in design and construction of such systems.
§ 909.20 requires that smoke-proof enclosures required by § 1023.11 consist of an enclosed interior stairway accessed by way of an outside balcony or a ventilated vestibule. This requirement refers back to the requirements of § 403 and § 405 for high-rise buildings and underground buildings.
Smoke and Heat Removal
§ 910 covers the requirements for smoke and heat removal, which have functions similar to smoke-control systems. They typically use simpler technology to actively respond to fire conditions. Smoke and heat vents allow products of combustion or explosion to vent from the building and minimize the damage they can cause.
Smoke and heat vents are used in industrial and commercial occupancies where high-piled storage, manufacturing, or warehousing activities have high fuel loads or large quantities of hazardous materials. There is a potential for large catastrophic fires in such occupancies. The occupancy groups covered by this section are Group F-1 and S-1 occupancies larger than 50,000 sf (4645 m2) in undivided area as well as in buildings with high-piled combustible storage per § 3206.7 of the International Fire Code.
Smoke and heat vents are to operate automatically, either tied to sprinkler activation in sprinklered buildings or by response to heat in unsprinklered buildings. Engineered smoke-exhaust systems, similar in principle to a smoke-control system, may be substituted for prescriptive systems.
Under revisions to this code section, the design of mechanical smoke-removal systems is now allowed to be a designer's option without prior approval of the fire code official. Designers now have broader options to use active systems in lieu of the passive systems that have been in the code for many years. This is a significant and extensive change to this section that is beyond the scope of this introductory text.
Carbon Monoxide Detection
