Building owners and operators would ideally prefer to prevent fires from ever starting at their premises. Unfortunately, fires do happen. If a fire does occur, the aim is to reduce its impact on both the occupants and the property by containing it as soon as possible. As it stands, the current standards for building design include containment areas by the use of fire-rated construction methods and materials. Also called “compartmenting”, this approach adds another level of barriers in the building configuration. For example, the space occupied by the separation walls for a boiler room is enclosed within a larger compartment that further isolates the contained area from the rest of the building. The initial objective in achieving a fire-safe building is to prevent the ignition of materials. Primarily, this means separating ignition and heat sources from ignitable materials (fuels). Most building fires are started by an ignition source and ignitable material that have been brought into the building, not by any feature inherent to the building itself. Through codes, buildings are now designed with this in mind. Newer buildings will provide as much physical protection as possible to occupants during a fire, through containment and/or separation of occupied areas and egress paths. However, there are many older buildings where these features are not provided. Preventing the initiation of a fire in these buildings is critical as structural protection may be lacking.
The next key building element is protection, defined mainly as the use of the fire-rated barriers, fire doors and other features to provide protected egress. The concept behind protected egress is to create an envelope or continuous path of relative safety for the evacuation of occupants. The entire exit needs to be free of smoke, heat, combustion gases and other by-products of a fire to ensure safe and efficient evacuation. To accomplish this, codes require corridors and stairways in most occupancies to be of fire-rated construction materials and design. The doors between adjoining rooms must meet a specific fire-resistance rating and be equipped with automatic door closers. Fire-rated barriers include corridor walls, floors and ceiling. No penetrations or openings are allowed between the corridor space and adjoining rooms or other floors, except for the normally-closed doors between the corridors and/or rooms.The intent of the code is that as evacuation proceeds from occupied spaces to the exit way, and subsequently between each component of the exit path, the level of protection also should increase. The safety of the occupants hinges on the fact that all doors remain closed. Opening or leaving ajar even just one door could allow smoke and heat to enter the exit way and threaten evacuees. This could very quickly render the exit protection useless, making it impossible for people to reach a stairway and exit to safety. Stairways are an integral part of the protected egress and, as they provide a connection between floors, they must be constructed to have a much higher fire-resistance rating than corridors.
Despite the provisions of protection specified in the codes, walls with openings inherently have less fire resistance than unpierced walls. Fire doors are designed to protect an opening under normal conditions of use, which includes providing a clear space on both sides of the opening. When the opening is not in regular use and combustible material is piled against the door, window or shutter, the same level of designed protection cannot be expected. For this reason, combustible material should be kept well away from openings.
This article was contributed by Firepoint Inc, serving the GTA since 1997, developing fire department approved fire safety plans for newly constructed and existing buildings. Although every effort is made to ensure the accuracy, currency and completeness of the information, the bulletin publishers and authors do not guarantee, warrant, represent or undertake that the information provided is correct, accurate or current and shall not be liable for any loss, claim, or demand arising directly or indirectly from any use or reliance upon the bulletin information. Bulletin reproduction in whole or in part is prohibited without the written consent of Firepoint Inc. Copyright 2021 – All Rights Reserved. See www.firepoint.ca or call 905-874-9400.