CHAPTER
33
SAFEGUARDS DURING CONSTRUCTION
Section 3302 Construction Safeguards
Section 3306 Protection of Pedestrians
Section 3307 Protection of Adjoining Property
Section 3308 Temporary Use of Streets, Alleys, and Public Property
Section 3309 Fire Extinguishers
This chapter deals with safety practices during the construction process, as well as the protection of property, both public and private, adjacent to the construction site. Included in the provisions are requirements addressing site work; protection of pedestrians; and temporary use of streets, alleys, and public property. Special issues relating to fire extinguishers, exits, standpipes, and automatic sprinkler systems are also addressed.
Section 3302 Construction Safeguards
Where an existing building continues to be occupied during the process of remodeling or constructing an addition, it is very important that the life- and fire-safety features of the building continue to be in place. Required exits shall be maintained, the strength of structural elements shall not be diminished, fire-protection devices are to remain in working condition, and sanitary facilities shall be fully functional. These features must be maintained at all times during any remodeling, alterations, repairs, or additions to the building under consideration. Obviously, there will be times when the specific protective feature is the element or device being altered or repaired. In this case, an equivalent method shall be provided to safeguard the occupants. Chapter 33 of the International Fire Code® (IFC®) is referenced for fire safety during construction, as well as for demolition as stated in Section 3303.7.
Section 3303 Demolition
As the work of demolishing a building is subject to so many variations and so many different hazards, the International Building Code® (IBC®) authorizes the building official to require the submission of plans and a complete schedule of the demolition. Under certain circumstances, pedestrian protection may be required during the demolition process. Such protection shall be provided in compliance with other provisions of Chapter 33. For some multilevel buildings, and for certain types of demolition operations, it may also be necessary to temporarily close the street. Once the structure has been demolished, any resulting excavation is to be filled consistent with the existing grade, or in any other manner in conformance with the ordinances of the jurisdiction.
Section 3304 Site Work
The provisions in Section 3304.1 for excavations and fills are intended to apply to the specific area where the building or structure will be located. This section is not intended to address massive grading on a site. For those requirements, one would turn to Section 1804, as well as any local grading ordinance that might be in effect. To prevent decay and to eliminate an avenue of entrance for termites and other insects, the code requires that the area of the site occupied by the building be free of all stumps, roots, and any loose or casual lumber. Typically applicable in the construction of wood-framed structures, the requirements also address wood forms that have been used in placing concrete, as well as any loose or casual wood that might be in direct contact with the ground under the building.
The IBC limits the slopes for permanent fills or cut slopes for permanent excavations for structures to two units horizontal in one unit vertical (50-percent slope). Although steeper-cut slopes are permitted where substantiating data are submitted, the limitation on filled slopes of two units horizontal in one unit vertical (50-percent slope) is an absolute limitation, and filled slopes may not be steeper. Although cut slopes into natural soils may be excavated with a slope steeper than 50 percent, depending on the nature of the soil materials and the density, the code reasons that fill slopes must not be steeper than 50 percent to cover unprecedented circumstances such as heavy rains creating overly saturated soils or, in the case of seismic activity, vibration of the soils during an earthquake causing failures of steep-filled slopes.
Understandably, the code requires that fill or surcharge loads should not be placed adjacent to an existing building or structure unless the existing building or structure is structurally capable of resisting the additional loads caused by the fills or surcharge. See Figure 3304-1. Alternatively, the existing building can be strengthened in order to resist the additional loading.
Figure 3304-1 Surcharge load on adjacent building.
The code requires that existing footings or foundations that may be affected by an excavation be adequately underpinned or otherwise protected. This concerns excavations on the same lot and under the control of the same individual who has control of the existing buildings. For obvious reasons, it is the intent of the code that excavations in close proximity to an existing footing shall not be made unless proper protective measures are taken for the existing building. These measures may involve underpinning of the existing foundations, or shoring and bracing of the excavations, so that the existing building foundations will not settle or lose lateral support.
Where the excavation is for a new building foundation and the new footing is at an elevation below, but within reasonably close proximity to, an existing foundation, underpinning is the usual procedure to protect the existing foundation. If the existing footing is for a structure that creates a horizontal thrust, the means of providing lateral support may take the form of a buttressed retaining wall designed to resist the lateral thrust of the existing foundation.
Where buildings are to be supported by fills, the code requires that the fills be placed in accordance with accepted engineering practice. Thus, fills utilized for the support of buildings must be designed by a geotechnical engineer (soils engineer) utilizing the principles of geotechnical engineering so as to provide a proper and adequate foundation for the structure above, and one that will limit settlements to tolerable levels. In order to verify the adequacy of the geotechnical design of the fills, the IBC permits the building official to ask for a soil investigation report outlining the geotechnical design of the fill materials, as well as a report of the satisfactory placement of the fill.
Section 3306 Protection of Pedestrians
Both Section 3306 and Chapter 32 regulate the use of public streets and sidewalks. Section 3306 provides those general regulations and criteria for the temporary use of public property, which are generally found to apply to most jurisdictions.
As the nature and philosophy of each jurisdiction varies, so do the regulations each promulgates regarding the use of public property and, in particular, the use of streets and sidewalks. Adjacent property owners have rights of access to their property. The public street also provides access for public services such as fire and police protection, street sweeping and maintenance, street lighting, trash pickup, and other services provided by the jurisdiction or its contractors. Utilities serving adjacent property also use the public street for access.
Pedestrians must be protected from the potential hazards that exist during construction or demolition operations adjacent to the public way. The type of protection depends on the type of operation being conducted. For example, an excavation directly adjacent to a pedestrian path would necessitate a minimum of a construction railing along the side facing the excavation. It is also possible that a barrier would be required. Where the pedestrian path extends into the public street, a construction railing is required on the street side of the walkway to protect the pedestrians from vehicular traffic. Table 3306.1 provides the criteria for determining whether or not additional protection is required, depending on the height and proximity of the construction operations to the pedestrian walkway. The level of protection mandated by the table is shown in Figure 3306-1. Depending on these various parameters, the protection required will vary from none or merely a construction railing, to a barrier or covered walkway.
Figure 3306-1 Pedestrian protection.
3306.2 Walkways. A public jurisdiction provides sidewalks and streets for the free passage of vehicular and pedestrian traffic. In the case of pedestrian traffic, the usual procedure is to provide a sidewalk on each side of the street. Therefore, when construction or demolition operations are conducted on property adjacent to the sidewalk, the code requires a walkway at least 4 feet (1,219 mm) wide be maintained in front of the building site for pedestrian use. However, in those cases where pedestrian traffic is unusually light, the jurisdiction may authorize the fencing and closing of the sidewalk to pedestrian use. The walking surface, in addition to being durable, must be in compliance with the accessibility provisions of Chapter 11. The walkway shall also be designed to support all imposed loads, with a minimum design live load of 150 pounds per square foot (7.2 kN/m2).
3306.3 Directional barricades. Where the temporary walkway used for pedestrian travel around a construction or demolition site extends into the street, it is critical that a sufficient barrier be provided to direct vehicular traffic away from the walkway. The construction of the barrier is to be large enough to ensure that motorists will easily and quickly identify the revised traffic path.
3306.4 Construction railings. The code only requires an open-type guardrail 3 feet, 6 inches (1,067 mm) in height where a construction railing is required. The intent of the railing is to direct pedestrians as they travel adjacent to construction areas, as well as to provide a very limited degree of protection. Where access must be further regulated, such as adjacent to an excavation, additional provisions must be applied. It is incumbent that the jurisdiction adequately protect pedestrians from the hazards associated with construction or demolition work.
3306.5 Barriers. The intent of the code is that a barrier, where required, be solid and sturdy enough to prevent impacts from construction operations from penetrating the barrier and injuring passing pedestrians. Because of this intent, the code also requires that the barrier be at least 8 feet (2,438 mm) in height and extend along the entire length of the building site. Although the IBC requires openings in the barrier to be protected by doors that are normally kept closed, the code does not intend to prevent the use of small viewports at eye level so that passing pedestrians may stop and view the construction operations if they wish.
To provide a reasonable level of protection from the construction operations, barriers are to be designed to resist loads as required in Chapter 16. As an option, specific construction procedures are outlined in Section 3306.6. The procedures address the size and spacing of studs as well as the size and span limitations for wood structural panels used in the barrier.
3306.7 Covered walkways. A covered walkway is required for the same reasons as a protective barrier—to prevent falling objects from endangering passing pedestrians. Therefore, the code requires that the design be such that the roof and supporting structure is capable of preventing falling objects from breaking through. With a minimum required clear height of 8 feet (2,438 mm) measured from the floor surface to the canopy overhead, the covered walkway must be adequately illuminated at all times. Pedestrians using walkways adjacent to building sites where construction or demolition operations are taking place have every right to safe passage and to be protected from falling debris and other hazards of construction operations. Furthermore, they should not be subjected to the indignities of dirt, water, and other foreign material sifting through leaks in the canopy.
Because a covered walkway is intended to protect pedestrians against construction operations, including demolition, the canopy structure should be structurally designed to serve that purpose. Thus, the code provides two means for the design of the canopy:
1. A structural design to withstand the actual loads to which it will be subjected, provided the design live load is not less than 150 pounds per square foot (7.18 kN/m2).
2. A prescriptive design in accordance with this section of the code where the covered walkway will not be subjected to a live load greater than 150 pounds per square foot (7.18 kN/m2).
The exception provides for a permissive design based on a live load of 75 pounds per square foot (3.56 kN/m2) for the covered walkway where the construction operation is limited to the erection of a new, small, light-frame building not more than two stories above grade plane.
3306.9 Adjacent to excavations. Where a site excavation occurs within 5 feet (1,524 mm) of the street lot line, it must be enclosed with a barrier not less than 6 feet (1,829 mm) in height. The barrier must be constructed to resist the wind pressures specified in Chapter 16, but need not meet the general barrier requirements of Section 3306.6. The building official also has the authority to require a barrier around excavations in those cases where the excavation is more than 5 feet (1,524 mm) from the street lot line. Because of the potential liability involved, it is probable that most excavations of considerable size or hazard would be enclosed by a complying barrier.
Section 3307 Protection of Adjoining Property
It is critically important that during construction, remodeling, or demolition work, any adjoining public or private property be protected from damage. Essentially, all portions of the neighboring structure must be protected from damage, including footings, foundations, exterior or party walls, chimneys, skylights, roofs, and other building elements. In addition, water run-off must be controlled to prevent erosion. Although there are no specific requirements laid out in the IBC for the level of protection required, the intent of the protection is based on common-law precepts, such as that of lateral support where it comes to footings and foundations. Over the years, common law and, more recently, statute law have established the requirements for lateral support. That is, the owner of a piece of real property shall be entitled to the lateral support of the property by adjacent property. Responsible practice would also dictate a satisfactory level of protection for other portions of the adjacent site and building during the construction process.
Where excavation work is to be performed, the person responsible for such work shall notify the owners of any adjoining buildings. The written notice, to be delivered no less than 10 days prior to the initiation of the excavation work, shall indicate that excavation work is to take place and that protection of the adjoining buildings should be considered. Appropriate action should be taken where access to an adjoining site or building is desired in order to provide the proper protective measures.
Section 3308 Temporary Use of Streets, Alleys, and Public Property
It is important that access to essential facilities be maintained where construction materials and equipment are temporarily stored on public property. Obstructions shall not block access to such fire protection features as standpipes, fire hydrants, or alarm boxes, as well as any catch basins or manholes that might be present. In regard to maintaining safe and effective vehicular traffic in the area where construction materials and equipment are stored, such materials or equipment must be located at least 20 feet (6,096 mm) from the street intersection, or otherwise located where sight lines are not obstructed.
Section 3309 Fire Extinguishers
It is quite common for combustible debris and waste materials to accumulate in and around a building under construction. Therefore, at least one approved portable fire extinguisher sized for at least ordinary hazard and complying with Section 906 of the IFC is to be provided at every stairway on all floor levels where combustible material has accumulated. In addition to those extinguishers required within the building, every storage shed and construction shed shall also contain an approved fire extinguisher. Additional extinguishers may be required by the building official where any special or unique hazards exist, such as the presence of flammable or combustible liquids.
Section 3310 Means of Egress
Once a building under construction reaches a considerable height, deemed to be 50 feet (15,240 mm) or four stories by the IBC, there is a need to provide at least one stairway that is available and usable for egress purposes. The temporary stairway shall be adequately illuminated during those times where there are occupants who may need to utilize the stairway. A temporary stairway need not be provided where there is at least one permanent stairway that is maintained and usable as the construction progresses. Where an existing building exceeding 50 feet (15,240 mm) in height is undergoing an alteration, at least one lighted stairway must continue to be available.
Section 3311 Standpipes
For those buildings required to have a permanent standpipe system per Section 905.3.1, during construction operations a standpipe system must also be installed before the construction height exceeds 40 feet (12,192 mm) above the lowest level of fire department access. As construction continues to proceed upward, the standpipes shall also be extended in a timely manner. A standpipe shall always be available within one floor of the highest point of construction having secured decking or flooring. During construction operations, the amount of combustible materials from concrete forms, scaffolding, plastic and canvas tarpaulins, and other materials are prevalent not only throughout the building, but throughout the construction site itself. Thus, in many cases, the standpipe system provides the only source of water for fire-fighting operations.
A minimum of one standpipe is required, with hose connections to be located in accessible areas adjacent to usable stairs. The standpipes may be either temporary or permanent, but in all cases shall meet the minimum requirements of Section 905 for capacity, outlets, and materials. The water supply may also be either temporary or permanent, as long as it is available at the first sign of combustible material accumulation.
KEY POINTS
• Where an existing building continues to be occupied during the process of remodeling or constructing an addition, it is very important that the life- and fire-safety features of the building continue to be in place.
• Once a structure has been demolished, any resulting excavation is to be filled, consistent with the existing grade.
• The code requires that fills or surcharge loads not be placed adjacent to an existing building unless the existing building is structurally capable of resisting the additional loads caused by the fills or surcharge.
• Pedestrians must be protected from the potential hazards that exist during construction or demolition operations adjacent to the public way.
• Depending on various conditions, required pedestrian protection varies from none, to merely a construction railing, to a barrier, to a covered walkway.
• During construction, remodeling, or demolition work, any adjoining public or private property must be protected from damage.