American Fire Sprinkler Association
12750 Merit Dr., Suite 350 * Dallas TX 75251
Ph: (214) 349-5965 Fax: (214) 276-0908
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TECHNICAL UPDATE
AUGUST 11, 2010
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"When the pump is installed using a flow meter (closed loop) without a
test header and the other means for water flow is the roof manifold on
the standpipe, does the size of the test valve supply pipe have to
meet Table 4.26(a)? When is a test header a requirement?"
We have reviewed NFPA 20, 2010 Edition as the applicable standard. Our
informal interpretation is that you are only required to have a means
to flow test the pump.
A standard test header adjacent to the fire pump is not required and
the assigned pipe and component sizes dictated by Table 4.26 may not
apply. NFPA 20:4.20.1 indicates that a means to flow the pump shall be
provided. Additionally, A.4.20.1.2 talks about using standard test
headers, hydrants, or standpipe hose valves. Granted this section is
addressing restrictions on water discharge but it identifies other
means for performing a flow test. Although these valves are also
performing other functions, they still constitute a pump test valve
and the criteria from 4.20.3.4 apply. When the test valves are remote,
that being more than 15 ft, then the discharge pipe size from Table
4.26 can be increased one pipe size OR you can prove through hydraulic
calculations that the remote test valves are capable of flowing 150%
of the rated pump capacity (or the maximum available water per
20:4.20.3.4(2)(b) and 14.2.5.2.4. This calculation is then verified
as part of the acceptance testing per 14.2.5.2.3. Thus, as long as
your roof manifold for your standpipe will flow the required amount of
water required for the pump test, it is acceptable and can be called
your pump test header. In order to obtain the correct flow and
pressure at the top, you may need to use more than one roof manifold
or hose valves. Additionally there should be a gauge at the top of
the tallest and most remote riser to use in the verification process.
Even when you have proven the test via calculations, a flow test is
required to prove the pump performance. For a 1,000 gpm pump as an
example, use the most remote test site as No.1 flow point of 500 gpm,
and two other test points, No's 2 & 3, if available, of 250 gpm+ 250
gpm. Most likely the minimum standpipe size will be 4-in. When using
the standpipe to perform these tests, personnel safety is of the
utmost importance as well as possible damage by the outflow of the
water. The extra benefit of using standpipe roof manifolds is that you
can verify both the pump performance and the required top of riser
flow and pressure with one test. One last note is that there is an
error in the Notes attached to Table 4.26(a) Note (4) should reference
section 4.20.3.4 instead of 4.19.3.4, which doesn't exist.
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Technical Update is prepared by the Technical Services Dept. of the
AFSA: Roland Huggins, a PE registered in fire protection engineering,
Vice President of Engineering and Technical Services; Phill Brown, a
NICET IV certified automatic sprinkler technician and NFPA Certified
Fire Protection Specialist (CFPS) and Tom Wellen, a degreed fire
protection engineering technologist. This is provided with the
understanding that the AFSA assumes no liability for this opinion or
actions taken on it and they are not to be considered the official
position of the NFPA or its technical committees.
Copyright 2010, American Fire Sprinkler Association. All Rights
Reserved
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