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Needed Fire Flow

How Many Hydrants do you Need?

Needed fire flow is a requirement that is typically enforced during site plan approval.  Communities adopted procedures for determining how much water is needed during a fire emergency.

IFC 508.1 States:

An approved water supply capable of supplying the required fire flow for fire protection shall be provided to premises upon which facilities, buildings or portions of buildings are hereafter constructed or moved into or within the jurisdiction.

NFPA 1, 18.3.1 (2009 edition)

An approved water supply capable of supplying the required fire flow for fire protection shall be provided to all premises upon which facilities, buildings, or portions of buildings are hereafter constructed or moved into the jurisdiction.

If the community has adopted the appendix B and C of the IFC (Section 18.4 of NFPA 1), there are specific requirements on what the “required fire flow is.  The tables utilizes multiple variables to give the determined fire flow.  These variables include the construction type, size of the building, presence of an approved automatic sprinkler system, and available water.

In both the IFC and NFPA 1, the code allows users to provide alternative methods when adequate water systems are not provided.    Approved reservoirs, pressure tanks, elevated tanks, fire department tanker shuttles, or other approved systems capable of providing the required fire flow shall be permitted as long as they are acceptable to the Fire Code Official.

NFPA 1142, Standard for Water Supplies for  Suburban and Rural Firefighting.  The standard provides alternative methods in calculating the fire flow and design characteristics for dry-fire hydrants, water reservoir, and fire ponds.   These options are typically utilized when extending the water system is not an option.

The need for adequate fire flow is critical in fire suppression efforts.  When water systems are not properly sized, responding crews may not be able to provide water and extinguish the fire.

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{ 2 comments… add one }

  • arsnman4 April 5, 2009, 5:16 pm

    For anyone interested in learning how to calculate fire flow using various methods like ISO, NFPA 1142 or understanding how and why the IFC table uses the factors it does; The National Fire Academy has a free on-line course “Testing and Evaluation of Water Supplies for Fire Protection (Course Q128) available. Just create a free account and browse the catalog to find it. It can give you a better understanding on how to figure out what is needed for your local operational needs.

    http://www.nfaonline.dhs.gov/

  • Dan Taylor November 24, 2010, 2:20 pm

    The course has been changed to (Q218).

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