Fire Protection

Fire poses the greatest risk of sudden catastrophic loss during construction activities in existing buildings. Just one of the numerous examples is the 1985 Harrison Court fire in Philadelphia, in which a blocklong National Register warehouse building undergoing rehabilitation burned to the ground (see cover photo). The fire was caused by sparks from cutting torches that were being used during selective interior demolition work.

To address the threat of loss of life and property during construction operations, the National Fire Protection Association (NFPA) publishes NFPA 241: Safeguarding Building Construction and Demolition Operations, most recently reissued in 1989(1). Although written to provide fire protection procedures for all types of building construction activities, including new construction, NFPA 241 should be a reference standard in any selective demolition specification, and a foundation for addressing fire safety on building rehabilitation sites. Additional guidance is available in NFPA 914: Rehabilitation and Adaptive Reuse of Historic Structures. When these are utilized as reference standards, the historic building owner should obtain and enforce their recommendations (see figure 1).

The building owner and design professional should also review fire protection measures and fire fighting methods that are permitted by the standard but may be insensitive to the protection of historic finishes. Such measures and procedures should be clearly sited as "prohibited" in the specifications or construction agreement.

According to NFPA, 60 % of the fire losses to buildings under construction were caused by the following:

Figure 1. The spontaneous combustion of cloth rags that had been used in applying a common finishing wax caused over $1 million damage to a historic government office building in 1991. Remains of the trash can where the rags had been stored overnight is indicated by the fireman's notepad. After the cause of the fire was determined, a standard specification provision was developed for future contracts requiring the contractor to remove all material contaminated with finishing products from the site at the end of the day.

1) portable heating equipment (25%);
2) cutting, welding, and plumbers' torches (20%); and,
3) matches and smoking (15%) .

In addition to these three causes cited by NFPA, for historic buildings there is a fourth major cause-the use of heat devices to remove paint. They share a common characteristic: they are all caused by contractor operations on the site. For these reasons, full adherence to the project specifications is needed to reduce, or eliminate, these causes of fire.

Temporary Heat

During the normal operation of a building, the heating plant-boiler or warm air furnace-is placed at a remote location (usually in a fire-rated room); set in a stationary position; equipped with a fresh air supply and non-combustible exhaust flue; and supplied with fuel piped from a remote oil bank or by a natural gas pipe brought into the building. In the case of construction projects involving historic buildings, temporary heating devices are frequently utilized. These devices are inherently dangerous because they are portable and often unstable; have movable and nearby fuel tanks; and often exhaust into the space being heated.

Electric temporary heaters are considered the safest temporary heating devices, but require heavy conductors and power supplies which are not always available at desired locations when temporary heat is needed. As a result, these are generally not used. One alternative is a propane heater, which is safer and cleaner in operation than the oil-fired temporary heating unit, and has greater output and portability than the electric heater. Oil-fired temporary heaters should be avoided unless they can be vented directly to the building's exterior, or be placed in a completely open space of a building that is of non-combustible construction.

Cutting, Welding, and
Plumbers' Torches

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