Special considerations for each step of a construction, renovation or demolition project.
Buildings of all types, while under construction, renovation or demolition, are both more susceptible to fire and at greater risk of the effects of fire. A wide variety of ignition sources increase the likelihood of fires starting. Concentrations of combustible materials, incomplete compartmentation and other passive systems, and unfinished fire protection systems allow fire to spread unimpeded. Wind conditions can increase the rapidity of fire spread.
This places at greater risk the workers occupying such buildings and the emergency responders that may be called upon to operate within or near them. Accident statistics and reports tell a tale of many construction workers being killed or maimed over the years by fires and explosions. In May 2008, 14 employees were injured in a natural gas explosion in a hotel under construction in California.1
In 2007, two firefighters were killed at a fire incident during the demolition of the Deutsche Bank Building in New York City.2
Typically, building and fire codes, such as those promulgated by the National Fire Protection Association (NFPA) and the International Code Council (ICC), contain comprehensive lists of the provisions that are to be followed during construction. However, being model standards or codes, they tend to focus more on the what, and give less attention to the who, how and when of implementation. This article presents protection and prevention features of different phases in construction, and discusses ways that the fire protection engineering profession may contribute to efficient and effective implementation of these features. See Figures 1-4.
An important concept affecting the efficiency of a project is the creation of lines of communication between the various stakeholders.
First, a fire protection engineer can serve as a liaison between disciplines. There is a network of fire safety-related interrelationships between structural fire protection; architectural layout; mechanical, HVACR and plumbing systems; fire suppression systems; electrical features; and fire alarm, detection and control systems. The fire protection engineer is in a unique position to understand how these items work together to achieve overall fire safety goals and thereby work to coordinate them.
The fire protection engineer can also consult with the owner on various concepts. One is the plan for partial occupancy if the owner expects to do this in stages. In some cases, the owner or their insurer will desire protection above and beyond what the fire and building codes require.
Two critical alliances that must be built early, and maintained through a projects life, are those that link the design team with both the code authorities and the emergency response organization in the projects jurisdiction. In some cases, this can be done with one alliance - when the code authority has the ability to speak for the responders within the same fire department or fire brigade. Certainly, the two roles are different - code authorities need to do enforcement, while the responders are in need of information for preincident planning.
Early and regular contact with code authorities can establish communication that is vital to efficient incorporation of code requirements, both those that address construction hazards and those that apply to the finished building. Jurisdictions frequently have amendments to the model codes. Both the base codes and local amendments can be interpreted to accommodate a wide array of sites and structures. The earlier the authoritys interpretations and expectations can be learned, the more efficiently the design and construction phases can proceed. This, in turn, translates into cost savings for the owner or developer and valuable time saved for all parties.
Emergency responders face significant challenges during a fire situation in any occupied building. They must deal with an extremely dynamic environment, with limited information on the fire, its byproducts and the building occupants. These challenges are compounded in a building under construction because the protection features and systems are constantly changing, as is the building itself. The more information they have at hand when an incident occurs, the better their decision-making can be, especially during a rapidly unfolding situation.
It is becoming more common to see fire protection engineers as members of design teams from the beginning of projects, especially large or unusual ones. A previously published article describes the benefits of utilizing fire protection engineers in the design process.3 As the complexity of a project increases, these benefits multiply. A number of federal agencies and local code authorities require fire protection engineering participation in projects above a certain threshold of size or complexity, especially those utilizing performance-based designs.
A basic function of the design team is to ensure that all fire protection features and systems required for the finished building are included in the design documents. Giving additional consideration during design to fire safety in all phases of construction will increase the safety of both construction workers and emergency responders.
The plans and specifications should reflect as much information as possible regarding the phasing of the features discussed in the following sections. Planning in advance can avoid conflicts. For example, the locations where hazardous materials will be stored and where unloading of construction materials will occur can be identified - and then this can be coordinated with the emergency access points, location of water supply and temporary connections. Advance consideration of these features can pay dividends later through more efficient and effective emergency operations.
It is also helpful to consider the stages in which a building will be constructed and occupied when designing the fire protection systems. In this manner, necessary items such as water lines, fire pumps and control panels can be located to support the various phases as well as the complete building. The owner may be in a position to provide early input, which would preclude conflicts.
Advance planning during design can also increase the safety of construction workers. Many fire-related construction worker injuries involve hazardous operations and materials. If the design documents indicate proper phasing and location of egress, extinguishers, hazardous operations and combustible storage, then it follows that the risks will decrease during operations such as welding or handling of flammable and combustible liquids.
Factors beyond the site or facility being designed can also be considered. This consideration could include how egress from adjoining occupied structures will remain clear during all phases of construction. For example, a typical, 4-foot (1.2 m) wide temporary pedestrian walkway might not suffice if more than two exit door(s) from an existing, occupied building discharge into it. The fire protection engineer can perform exit capacity calculations to determine the proper width of temporary egress routes.
Figure 5 shows a temporary walkway being constructed next to a construction site to serve an occupied building.
Permits must be obtained before the corresponding work begins. Early on, foundation and building permits will be required. Additional permits may be required for electrical, plumbing, gas, fire alarm, sprinkler and other fire protection systems. The fire protection engineer can assist the design team to prepare complete plans, specifications and shop drawings; submit required documentation; and navigate the permit system in a timely manner, especially if communication begins early with code authorities and emergency responders regarding key aspects of fire protection and prevention.
SITE WORK PHASE
By the time work begins at a construction site, a fire protection program should be in place, with a designated responsible program manager. The fire and building codes promulgated by the ICC and NFPA contain examples of program elements, including prefire plans; maintenance of fire protection devices and training on their use; hot work permits; system impairments; and temporary covers on fire protection devices. Other considerations include physical security features, guard service during nonworking hours and means for reporting fires or requesting emergency assistance.
Preincident plans, also known as prefire plans, are a compilation of information to assist emergency responders, including access, water supply, construction features, fire protection systems and special hazards. The fire protection engineer can be instrumental, with the building owners permission, in providing construction plans or shop drawings to the fire service. In some cases, these plans can be transmitted and stored electronically and then retrieved during response and operations through computer-aided dispatch systems.
Site visits by the public fire department or private fire brigade allow them to coordinate with the fire protection program manager to develop and update preincident plans. The more frequently responders visit the site, the better information they are likely to have when an incident occurs, thereby facilitating more accurate and rapid decision-making. In jurisdictions with career response agencies, different shifts would likely need to be accommodated for site visits. Volunteer response agencies would probably prefer evening or weekend site visits.
NFPA 241, Standard for Safeguarding Construction, Alteration, and Demolition Operations,4 calls for an on-site command post. This location contains plans, emergency information, communications, keys and other equipment for use by both emergency responders and the fire protection program manager.
As soon as site work commences, how to prevent fires and how they will be extinguished if they begin should be considered. Waste must be disposed of on a regular basis and must not be burned without the proper approvals and permits. Each storage shed or construction trailer should be located away from wildfire hazards or other occupied structures, and be provided with adequate fire extinguishers.
Figure 6 shows a fuel tank and fire extinguisher outside of a construction trailer.
Advance planning can ensure the timely provision of access and water supply for fire suppression. The water supply should preferably be the permanent water supply; however, temporarily stored water in sufficient quantity may be acceptable to code authorities in certain situations. Planning by the fire protection engineer and design team can minimize the need for temporary water supplies. Temporary or permanent roads made of all-weather material and of the appropriate width are essential for efficient access, as are key boxes for emergency perimeter access. Dead-end roads may need turnaround provisions for fire apparatus.
Adequate means of escape for all employees should be provided - both from any temporary buildings and from the site itself. Multiple exits from the site perimeter would be beneficial during large fire or hazardous materials situations that can obstruct a single exterior exit route.
INTRODUCTION OF HAZARDS
As each of the following hazards is introduced to the job site, proper precautions must be taken. Individual hazards may appear at different stages, i.e., some during site work, others at later stages.
- Open burning
- Motorized vehicles
- Materials subject to spontaneous ignition
- Welding and other hot work
- Temporary heating equipment
- Temporary electrical equipment
- Combustible formwork, scaffolding and other materials
- Flammable and combustible liquids
- Flammable gas
The fire protection engineer can help mitigate these hazards through planning and coordination. Assistance can continue through construction - in some cases helping to keep the lines of communication open between the fire protection program manager, the code authorities and the emergency responders.
Figure 7 shows welding at a building under renovation.
Labeling of hazards and permitting procedures are critical for the fire service. These issues emerged as significant in a 1988 incident in Missouri when a trailer containing explosive material detonated, killing six firefighters who were unaware of the presence of explosive materials.5 There can be a potential conflicting security concern of keeping extremely hazardous material locations unlabeled so as not to attract the attention of criminals and terrorists.
One hazard not currently addressed directly in the codes covering building design and construction is arson. This can be perpetrated by juveniles, disgruntled employees or radical groups. In recent years, extremist environmental groups have added arson to their arsenal. Early recognition of arson potential can be partially addressed by additional security.
As the structure is erected, provisions must be made for alerting all employees of an emergency, allowing them to escape the structure, and allowing responders to gain access and mitigate emergency situations. Proper planning by the fire protection engineer can help increase efficiency and decrease costs.
Material combustibility is another important consideration. Combustible formwork may not be allowed or may be limited to below a certain elevation or floor level. Temporary enclosures for heating or health hazard containment should employ noncombustible bracing or fire-retardant lumber, and any fabric or plastic used should be fire-retardant. Further, such enclosures must not obstruct exits and must be secured so that they do not contact ignition sources. Combustible enclosures were reportedly a factor in the Deutsche Bank Building tragedy in two ways: their flammability and obstruction of exits.6
At least one stair must be constructed as the building rises - for use by both exiting construction workers and entering emergency responders. Under NFPA 241, this begins when the building is over one story, and under the International Building Code (IBC), this begins at four stories or 50 feet (15 m).7 The stair must be lighted, and under NFPA 241, it must have identification signs. Fire extinguishers should be placed on each level at each stair. Planning ahead to use permanent stairs to meet this requirement should be more efficient and effective than using temporary stairs.
Functional standpipe systems are crucial in buildings under construction. Plans and specifications should indicate when a standpipe is required during construction. Under the IBC, the threshold is 40 feet (12 m) in height, while NFPA 241 leaves this to the code authorities. A single manual dry standpipe within the stair with one hose connection per floor may suffice, and must be raised and capped as construction progresses. The fire department connection must be marked and accessible. The International Fire Coderequires connections to be within 100 feet (30 m) of fire vehicle access.8 Signage can also include the highest floor served by the standpipe, but it must be kept current. The jurisdiction may require or request that the connection be outside the perimeter fence. The fire protection engineer can determine the requirements of the code authorities and the needs of the emergency responders, and specify both in the construction documents and shop drawings.
Figure 8 shows a fire department connection that is well-marked and accessible through an opening in a perimeter fence. However, the feed pipe may not be properly supported, and attached hose lines may contact sharp portions of the fence opening.
The availability of an elevator or hoist for fire service use may be required for very tall buildings when necessary for transporting hose and other equipment. The fire protection engineer should ask the jurisdiction at what point they would require this and how it should be phased in as the building rises.
Securing of construction materials on upper floors is not only a safety consideration for construction workers; this is also important to prevent materials from falling or being blown onto emergency responders during windy conditions. Likewise, protection of floor openings or edges will protect both construction workers and firefighters; the latter may operate with limited visibility.
Some jurisdictions require fire-fighter breathing air systems in tall buildings or long tunnels. In these locations, the requirement may be invoked during construction.
As the building tops off, roof operations become an issue from a fire safety standpoint. Codes contain specific procedures and protection for operations such as torch-applied roofing and tar kettles.
INTERIOR WORK AND BUILDING ENCLOSURE PHASE
As trade workers begin interior work, fire protection systems are installed. The fire protection engineer may be involved in the design, permit process and acceptance testing for alarm, detection, sprinkler, standpipe and other fire protection systems. Requests for information and clarification often must be fielded by fire protection engineers. Two areas of concern during construction are an impairment notification system and the prompt removal of temporary device covers that prevent damage during construction.
Before certain areas are concealed, inspections must take place, and the timing is important to prevent project delays. These items include fire-rated shafts, electrical work, sprinkler and standpipe hydrotests, fire-stopping and fire-proofing. The relationship built up between the design team, fire protection program manager, code authorities and responders could pay dividends as this work is coordinated.
Trash chutes should preferably be erected outside of the building. Interior chutes should be of noncombustible construction.
When the building exterior walls are in place, the required stairway must be enclosed. This protects construction workers and responders from smoke and heat that cannot vent readily. Phasing of construction must be done so that egress is not adversely impacted. Before exterior wall enclosure begins, whether the jurisdiction will allow the stairway to be enclosed on a floor-by-floor basis along with the exterior walls or whether the stairway must be fully enclosed first should be determined.
Towards the end of this phase, acceptance testing of systems is conducted. It is a good idea to invite emergency response agencies to witness the testing of systems with which they will interact (especially alarm detection and control). Alternatively, separate demonstrations could be conducted to educate emergency responders on the use of these systems - preferably prior to occupancy.
Ideally, occupancy will take place only after a building is fully complete with all protection features in place. However, the reality is that buildings are almost always occupied with punch list items that remain to be done, or portions are occupied while other sections remain unfinished or actively under construction.
Another opportunity for the fire protection engineer to assist is in determining the adequacy of the level of life safety when one or more fire protection features is not yet in place or is impaired. Usually, some additional protection should be in place to compensate for the missing or inoperative feature. One example of this is a fire watch during a fire alarm impairment. In the fire watch example, the qualifications of the persons performing the fire watch, their training, standard procedures and equipment should be considered, as well as any particular requirements of the code authorities.
Partial occupancy is almost always a reality in business or retail buildings subdivided into separate tenant occupancies, as well as in building addition projects. NFPA 241 calls for occupied areas and those undergoing construction or renovation to be separated by a one-hour fire-rated barrier with 3/4-hour fire-rated opening protectives; nonrated fixed barriers (not tarps) are permitted where sprinkler protection is installed. The sprinkler requirement applies to both sides of the barrier. However, some jurisdictions may make some allowances, such as delayed placement of suspended ceiling tiles on the construction side where no combustibles are stockpiled. Here the fire protection engineer can serve as a knowledgeable intermediary to ensure an adequate level of temporary protection.
Figure 9 shows the first floor of a building being finished that contains a few occupied assembly occupancies. Considerations include whether these occupancies have adequate egress capacity through the temporary construction barricades and walkways, whether the discharge areas are all clear, whether the alarm system in service and whether the fire department connections accessible.
Of particular concern is the occupancy of floors or areas above those still undergoing construction, renovation or tenant work. In buildings with required sprinkler protection, NFPA 241 precludes occupancy until all portions of the systems are completely installed and tested. However, this standard also allows occupancy of lower finished floors when work is incomplete on floors above, as long as the upper-level sprinkler systems have separate control valves and the occupied areas sprinkler system remains in service. Another consideration for partial occupancy situations is the completeness of work in all exit enclosures and in all discharge areas.
Alteration and renovation work conducted in buildings will have many of the same fire safety concerns as outlined above. In particular, means of egress, fire protection system maintenance, impairment notification, temporary protection measures and partial occupancy should be considered.
Many of the considerations during demolition work will generally be addressed in the reverse order of those for construction projects. Gas and electric service should be terminated where possible and labeled where remaining in service. Standpipes and stairs should be maintained as the building is brought down. Fire protection systems and fire barriers should remain in place and in service as long as possible (reportedly an inoperative standpipe system may have been a major factor in the fatal Deutsche Bank Building fire - in addition to the flammability of the temporary enclosures mentioned previously).
Unprotected openings in floors for any purpose should be avoided, including those for trash or debris removal. Special precautions are necessary with hazards such as oil-soaked floors or tanks that contained flammable or combustible liquids. Asbestos removal must be closely coordinated with code authorities and emergency responders.
Figure 10 shows a building under demolition.
The author thanks Jamie Barton, Assistant Fire Marshal, Gaithersburg City, MD, for reviewing this article.
Mat Chibbaro, P.E., is with the U.S. Occupational Safety and Health Administration.
2. http://topics.nytimes.com/top/reference/timestopics/subjects/d/deutsche_bank_ building_130_liberty_street_nyc/index.html
3. Bowman, A., Making an Impact: Fire Protection Engineers and the Design Process, Fire Protection Engineering, Winter 2003, pp. 8-13.
4. NFPA 241, Standard for Safeguarding Construction, Alteration, and Demolition Operations, National Fire Protection Association, Quincy, MA, 2009.
7. International Building Code, International Code Council, Washington, DC, 2009.
8. International Fire Code, International Code Council, Washington, DC, 2009.
All Photos Mat Chibbaro