When a building is built as new construction, it is relatively easy to control access to the site, and the people working at the site are primarily contractors outfitted with proper personal protective equipment (PPE), who are familiar with the hazards at a typical job site.
In the life of every building, the need for demolition and renovation will arise as a natural part of repurposing the building for different uses. When this occurs, the challenge is having an active construction project in the middle of an existing building that is occupied and in use.
This situation creates a unique set of challenges that must be fully evaluated to ensure safety to life and property from fire while the construction activities are in progress. Before any work begins, it is important to evaluate the exposures and controls in place for any new hazards generated by the construction work. NFPA 241 Standard for Safeguarding Construction, Alteration, and Demolition Operations (2013 Edition) provides guidance on the control of hazards that may be introduced during construction and renovation activities.
Often, the first action taken is to install a temporary enclosure made of fabric or plastic film to separate the occupied areas from the construction zone. It is important to verify that the materials utilized for the temporary barrier are either non-combustible or flame resistant, as confirmed through fire tests that show the material has low ”flame spread” and low “smoke developed” characteristics.
It is also important to evaluate how installation of the temporary enclosure affects egress paths in the facility for both the building occupants and the construction workers.
Life Safety
NFPA 101 Life Safety Code acknowledges that it may not be possible to meet every requirement in the Life Safety Code during construction/renovation in section 4.6.10 (2015 edition) shown below:
4.6.10.2* In buildings under construction, adequate escape facilities shall be maintained at all times for the use of construction workers. Escape facilities shall consist of doors, walkways, stairs, ramps, fire escapes, ladders, or other approved means or devices arranged in accordance with the general principles of the Code insofar as they can reasonably be applied to buildings under construction.
During the pre-project stage, before construction activities begin, each phase of construction should be evaluated to establish an Interim Life Safety Measures (ILSM) Plan which outlines the safety measures that will be put in place to protect the safety of occupants, visitors, and construction workers throughout each phase of the project.
A review of temporary construction barriers, exit signage, pathways to an egress point, emergency lighting, fire protection systems including smoke detectors, fire suppression, fire extinguishers, fire alarms systems, smoke barriers, emergency evacuation plans, and other features that contribute to the safety of occupants should be made to determine the impact of construction activities on life safety systems and egress from the facility during each phase of construction.
Adequate escape facilities should be maintained at all times for the use of occupants, including construction workers. Escape facilities consist of doors, walkways, stairs, ramps, fire escapes, ladders, or other approved means or devices arranged in accordance with the general principles of the Life Safety Code to the extent they can reasonably be applied to buildings under construction per Section 4.6.10 of NFPA 101 (2015 Edition).
Regular evaluation and revision of the Interim Life Safety Measures Plan should address the interim measures needed at each stage of construction as the project progresses.
Control of Ignition Sources
During construction activities, new sources of ignition are introduced and must be managed to reduce the potential for fire. Examples include hot work, temporary heating, smoking, temporary electrical and lighting, and roof installation activities that involve the use of torches, asphalt, and tar kettles.
Control of Combustibles
During construction activities, combustible loading can be increased due to staging of construction materials and equipment, the use of flammable or combustible liquids, and production of waste materials. This must be closely controlled to prevent continuity of combustibles that increases the fire hazard in the building and may exceed the capabilities of the existing sprinkler system.
Protection Features:
During construction activities it is important to keep existing detection and protection systems such as sprinkler systems, fire alarms systems, and fire hydrants in service, and to bring any new systems on-line as soon as possible. Having a pre-fire plan and maintaining access to the building for firefighting activities is also essential.
Conclusion
Recognizing the need to control ignition sources and combustibles during construction, and evaluating the impact of construction activities on life safety for building occupants, visitors, and construction workers are essential steps that should be taken to reduce the potential for loss of life or damage to property during construction activities.