This Article requires that an adequate water supply for firefighting is to be provided for every building. However, farm buildings of low human occupancy under the National Farm Building Code of Canada 1995 are exempted. The water supply requirements for interior fire suppression systems such as sprinkler systems and standpipe and hose systems are contained in other standards, for example, NFPA Standard 13, “Standard for the Installation of Sprinkler Systems”, and NFPA Standard 14, “Standard for the Installation of Standpipe and Hose Systems”. This Appendix note focuses only on water supplies that are considered essential to firefighting by fire department or other trained personnel using fire hoses.
Minimum requirements for water supply for firefighting are relevant mainly to building sites not serviced by municipal water supply systems. For building sites serviced by municipal water supply systems where the water supply duration is not a concern, water supply flow rates at minimum pressures would be the main focus of this Appendix note. However, where municipal water supply capacities are limited, it would be necessary for buildings to have on-site supplemental water supply.
An adequate water supply for firefighting should be an immediately available and accessible water supply with sufficient volume and/or flow to enable fire department personnel using fire hoses to control fire growth until the building is safely evacuated, prevent the fire from spreading to adjacent buildings, limit environmental impact of the fire, and provide a limited measure of property protection.
The sources of water supply for firefighting purposes may be natural or man-made. Natural sources may include ponds, lakes, rivers, streams, bays, creeks, springs, artesian wells, and irrigation canals. Man-made sources may include aboveground tanks, elevated gravity tanks, cisterns, swimming pools, wells, reservoirs, aqueducts, tankers, and hydrants served by a public or private water system. It is imperative that such sources of water be accessible to fire department equipment under all climate conditions.
The available water supply would allow arriving fire department personnel to use the water at their discretion when entering a burning building with hose lines. During the search and evacuation operation, hose streams may be needed for fire suppression to limit fire spread. The duration of the water supply should be sufficient to allow complete search and evacuation of the building. Once the search and rescue operations are complete, additional water may be required for exposure protection or fire suppression to limit property damage.
Fire departments serving remote or rural areas often have to respond to a fire with a transportable water supply of sufficient volume for approximately 5 to 10 minutes when using one or two 38 mm hose lines. This would provide minimal hose streams allowing immediate search and rescue operations in small buildings with simple layouts but limited fire suppression capabilities, especially if a fire is already well-established.
For larger more complex buildings, an on-site water supply for firefighting would be needed to provide an extended duration of hose stream use by the fire department to allow search and evacuation of the building, exposure protection and fire suppression. The volume of this on-site water supply would be dependent on the building size, construction, occupancy, exposure and environmental impact potential, and should be sufficient to allow at least 30 minutes of fire department hose stream use.
The recommendations of this Appendix note are predicated on prompt response by a well-equipped fire department using modern firefighting techniques, and buildings being evacuated in accordance with established building fire safety plans and fire department pre-fire plans. For buildings constructed in areas where fire department response is not expected at all or in a reasonable time, sprinkler protection should be considered to ensure safe evacuation.
Elementary and secondary schools usually have a record of well-established and practiced fire safety plans which would allow complete evacuations within 4 minutes. Because of this and the inherent high level of supervision in these buildings, a reduction of the water supply for firefighting may be considered. It is suggested that the level of reduction should be determined by the local enforcement authority based on the resources and response time of the fire department, and the size and complexity of the buildings.
When designing open, unheated reservoirs as sources of fire protection water, a 600 mm ice depth allowance should be included in the water volume calculations, except where local winter temperature conditions result in a greater ice depth (as typically found on local lakes or ponds). As well, make-up water supplies should be provided to maintain the design volumes, taking into account volume loss due to evaporation during drought periods.
1.
Buildings not Requiring an On-Site Water Supply
(a)
A building would not require an on-site water supply for firefighting if the building satisfies the criteria set out in Item 1(b) or Item 1(c) provided that:
(i)
the building is serviced by a municipal water supply system that satisfies Item 3(b), or
(ii)
the fire department can respond with a transportable water supply of sufficient quantity to allow them to conduct an effective search and evacuation of the building, determined on the basis of other guidelines or standards (such as, NFPA 1142, “Standard on Water Supplies for Suburban and Rural Fire Fighting”).
(b)
A building would not require an on-site water supply for firefighting where all of the following criteria are met:
(i)
the building area is 200 m
(ii)
the building height is 2 storeys or less,
(iii)
the building does not contain a care or detention occupancy,
(iv)
the building does not require a sprinkler system or a standpipe and hose system,
(v)
the limiting distance from the property line is at least 13 m if the building contains a high hazard industrial occupancy, and
(vi)
the building constitutes no significant environmental contamination potential due to fire.
(c)
A building that exceeds 200 m
2.
Sprinklered Buildings For sprinklered buildings, water supply additional to that required by the sprinkler systems should be provided for firefighting using fire hoses in accordance with the hose stream demands and water supply durations for different hazard classifications as specified in NFPA 13, “Installation of Sprinkler Systems”.
3.
Buildings Requiring On-Site Water Supply
(a)
Except for sprinklered buildings and as required by Items 3(c) and 3(e), buildings should have a supply of water available for firefighting purposes not less than the quantity derived from the following formula: Q = K • V • Stot where Q = minimum supply of water in litres K = water supply coefficient from Table 1 V = total building volume in cubic metres Stot = total of spatial coefficient values from property line exposures on all sides as obtained from the formula: Stot = 1.0 + [Sside1 + Sside2 + Sside3 +… etc.)] where S values are established from Figure 1, as modified by Items 3(d) and 3(f), and S need not exceed 2.0.
(b)
Water supply flow rates should not be less than that specified in Table 2. Where the water supply is from a municipal or industrial water supply system, the required flow rate should be available at a minimum pressure of 140 kPa.
(c)
The water supply as required in Item 3(a) should not be less than that needed to provide the minimum flow rate specified in Table 2 for a minimum duration of 30 minutes.
(d)
Where a masonry wall with a minimum fire-resistance rating of 2 h, and no unprotected openings is provided as an exterior wall, the spatial coefficient (Sside) for this side of the building may be considered equal to 0. This masonry wall should be provided with a minimum 150 mm parapet. Firewalls that divide a structure into two or more buildings may be given similar consideration when evaluating the exposure of the buildings to each other.
(e)
In elementary or secondary schools, the water supply determined in accordance with Items 3(a) and 3(b) may be reduced. The level of reduction to be applied would be at the discretion of the local enforcement authority, and should not exceed 30 percent.
(f)
The spatial coefficient Sside may be considered equal to 0 when the exposed building is on the same property and is less than 10 m
4.
Additions to Existing Buildings
(a)
Except as permitted in Items 4(b) and 4(c), additions to existing buildings should be provided with a water supply for firefighting as required in Items 3(a) to 3(e). Although under Part 11, Renovation, the required water supply is to be based only on the building volume of the addition, it is recommended that the entire building volume of the expanded facility be used to ensure complete evacuation and safety of all the occupants.
(b)
Buildings with new additions falling within any one of the following criteria would not require an additional water supply for firefighting where:
(i)
the expanded building complies with all the requirements of Item 1(a),
(ii)
the new addition does not exceed 100 m
(iii)
the new addition exceeds 100 m
(c)
Where a firewall is provided between the new addition and the existing building, the water supply for firefighting may be determined in accordance with Items 1(a) and 3(a), using only the building volume of the new addition.
Notes to Table 2:
(1) Q = KVStot as referenced in Paragraph 3(a)
Spatial Coefficient vs Exposure Distance
Further clarification of intent and sample problems and solutions are contained in the “Fire Protection Water Supply Guideline for Part 3 in the Ontario Building Code” (TG-03-1999). This guideline may be obtained through the Office of the Fire Marshal’s by contacting [email protected] or contact a Field Advisory Services adviser toll free at 1-800-565-1842.