The requirements contained in Division B – Part 3 of the National Building Code of Canada (NBC), and the provincial building codes based on this model building code, are predicated “on the assumption that firefighting capabilities are available in the event of a fire emergency”. These firefighting capabilities could be in the form of manual fire suppression (e.g. firefighter intervention) or automatic fire suppresion (e.g. automatic sprinkler protection). Both of these capabilities are reliant on the availability of a water supply for firefighting, which the building code addresses through the following requirement:
Every building shall be provided with an adequate water supply for firefighting.
NBC Sentence 3.2.5.7.(1)
This requirement can be broken down into two fundamental components: (1) the need to provide water and (2) to ensure there is enough of it.
What is a “water supply”?
This is essentially wherever and however water can be supplied to a building. The most common water supply in Canadian urban settings, where many Part 3 buildings are found, is a public or private water supply system. A service connection to this infrastructure provides water to the inside of a building while hydrants provide access to water outside of a building.
Other forms of a water supply could be in the form of artificial or natural water sources that are dedicated and/or maintained for the purposes of firefighting. These include water tanks, cisterns, ponds, rivers, and reservoirs.
What is “adequate”?
Adopted Standards
An internal fire suppression system, such as automatic sprinkler protection or a standpipe and hose system, is considered by the building code as fulfilling the requirement of Sentence 3.2.5.7.(1) for providing a water supply. This compliance is explictly acknowledged by certain building codes, such as the British Columbia Building Code (BCBC) and Vancouver Building By-law (VBBL).
Buildings that are sprinklered throughout with a sprinkler system conforming to Article 3.2.5.12. or have a standpipe system conforming to Article 3.2.5.8. to 3.2.5.10. are deemed to comply with Sentence (1).
BCBC Sentence 3.2.5.7.(2)
Building codes have adopted specific editions of standards for sprinkler systems (NFPA 13, NFPA 13R, NFPA 13D) or standpipe systems (NFPA 14) so that these systems are built in to the design and construction of the building. As the building code is concerned with the occupants of a building and the building itself, the referenced standards are in turn largely focused on internal firefighting for life safety and property protection and do not extend to manual firefighting intervention beyond what is captured within the standard. The standards contain specific requirements for hydraulic performance, installation, components and maintenance which provide adequacy.
Unadopted Standards
The explanatory material for Sentence 3.2.5.7.(1) in a number of provincial codes points to guides and standards that are not adopted or referenced as regulation, but could be used in determinining the adequacy of a water supply where internal fire suppression systems are not provided for a building.
There are also other commonly used guides in Canada that are neither adopted nor referenced by the building code regulations.
Insurance Services Office (ISO) – Needed Fire Flow
The ISO (not to be confused with the International Organization for Standardization) Needed Fire Flow method is referenced in the Appendix of the BCBC and VBBL. This method provides an estimated volumetric flow of water necessary to fight a structure fire, based on the following parameters of a given building:
- type of construction and effective area
- type of occupancy
- exposure hazard of adjacent buildings
- communication hazard with adjacent buildings
Although this method does not directly provide a quantitative volume of water that could be considered as an “adequate water supply”, the needed fire flow can be multiplied by a water flow duration to do so.
NFPA 1142 – Water Supplies for Suburban and Rural Fire Fighting
The NFPA 1142 (previously NFPA 1231) Standard on Water Supplies for Suburban and Rural Fire Fighting is the second method referenced in the Appendix of the BCBC and VBBL. This method establishes the minimum water supply necessary for structural firefighting purposes in those areas where it has been determined that there is no water or inadequate water for firefighting. This Standard is applicable only to suburban and rural areas (both of which are defined terms within the Standard) where the water infrastructure (i.e. municipal supply, hydrants) typically found in urban areas is either unreliable or not present. Similar to the ISO Needed Fire Flow method, the volume of water established by this method is based on the volume of a structure, its occupancy, and construction type.
American Water Works Association (AWWA) – Distribution System Requirements for Fire Protection
This guide is intended to assist in the civil (municipal) engineering design of a water distribution system that will also be used for fire protection, including how and where to install water mains and hydrants. The guide presents the following four methodologies to calculate the fire flow demands for a building:
- ISO Needed Fire Flow
- Iowa State University
- National Fire Academy Needed Fire Flow
- Illinois Institute of Technology Research Institute
It is failry uncommon for this guide to be used by building designers or Authorities Having Jurisdiction (AHJs) in determining the adequacy of a water supply, given the varying levels of accuracy in each calculation.
Office of the Fire Marshal (OFM) – Fire Protection Water Supply Guideline For Part 3 Of The OBC
Of the number of methodologies presented in the Appendix of the Ontario Building Code, the most detailed is the OFM Technical Guideline which itself is largely based on NFPA 1142. Consequently, the water supply determined by this guideline is based on the building size, occupancy, and construction type.
Fire Underwriter’s Survey (FUS) – Water Supply for Public Fire Protection in Canada
The FUS guideline is neither referenced nor adopted by any building code regulation, yet is prevalent in use across Canada. The FUS methodology uses water supply as one measure of risk for a municipal fire protection system and is typically found in municipal engineering design documents and zoning regulations. The estimated flow rate provides designers of water infrastructure an expected fire water demand, based on a theoretical building, that can be applied to distribution mains serving an area. The estimation does not provide a fire flow demand at the individual water supply connections of a building – the FUS calculation is intended only as a means for municipalities to assess their risk and the adequacy of the municipal water supply for fire fighting.
Who cares about adequacy?
The varying levels of empirical and theoretical estimates in determining adequacy for a firefighting water supply using these guides and standards is a result of the various stakeholders involved in preparing these documents and their considerations for risk and responsibility.
Designers and AHJs involved in the construction of a building are concerned with the safety of occupants and protection of adjacent buildings. These concerns are shared by the building code and referenced standards which have deemed a certain level of risk to be acceptable to a building and its occupants.
The fire service and offices of fire marshals are concerned with their level of preparedness to fight a structure fire involving a particular building. This is reflected through the use of the ISO NFF or NFPA 1142 methodologies. Other estimations based on empirical evidence and research are emerging, but have not yet replaced the rough estimations provided by the aforementioned methodologies.
Meanwhile, insurance underwriters are looking at the risk of and cost associated with a fire event involving a new municipal subdivision and its water supply system, which civil engineers are responsible for designing.
Why does this matter?
It is important to understand the intent and basis of each methodology that can be used to determine the adequacy of a firefighting water supply and apply each estimation accordingly.
For example, a building protected by an internal fire suppression system (e.g. NFPA 13) inherently meets the requirements of the building code. Applying an estimation intended for municipal water systems (e.g. FUS) as part of zoning regulations would be unecessary and inappropriate for the design of an individual, sprinklered building.
It would be similarly inappropriate to apply a methodology reliant on a municipal water supply system to a building located in a remote rural area, where the NFPA 1142 standard may be more relevant.
An adequate water supply for fire fighting is required for every building – remember what that means to you!
2 Responses
A very interesting read. Thank you for publishing this. I do however wish to point out a few concerns that I have with it. First, we definitely need to have better clarity on this subject in the Building Code. Second, you point to a number of unadopted standards. I think there needs to be a better understanding of each of these. A recent NRC study commissioned by the City of Ottawa reviewed a number of these standards and the FUS guidelines were the most used. ISO standard and its use may be more used in the US but also has a number of caveats with its us. Such as field verifications by ISO reps. Something not done in Canada. The NFPA 1142 and OFM standards do not apply to hydrant serviced areas. The AWWA standard talks about choosing a reputable standard only and then gives examples. This leads the FUS guidelines as the preferred method. This is important because the FUS guidelines deal with hydrant service areas and concerned about not just the building but prevention of exposure spread through the community. FUS guidelines lead to impacts on Dwelling and Community insurance gradings. FUS is the only way to go in my opinion.
Thanks for your thoughts Sean! I know that this is an extremely challenging one due to the lack of clarity in the Code, leading to every municipality and designer looking at it differently.
Do you know of any locations that require the FUS, or specific standards…or even have any advisory documentation? And are you able to share a link to the NRC study, I could add a section at the end of the post for additional reading material for anyone else digging into the subject.