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Here
are some answers to our most frequently asked
questions. We hope you find this a helpful resource,
but don't hesitate to Contact
Us if you need more information!
Q. What products/companies do you represent?
A. We are very selective about the companies and
products we represent, because of our commitment
to quality and customer satisfaction. We are committed
to helping you find the right equipment for your
needs. We area regional provider for each company
we represent, which means a more direct and personal
contact for your sales and service needs. Take
a look at our products page for all the details.
Q.
What makes a fire pump different from other kinds
of pumps?
A. Although Aurora fire pumps are nearly identical
in appearance to their 410 and 420 horizontal
split-case pumps, they differ in a few subtle
ways that make them more suitable for use as Listed
Fire Pumps. First, they meet the stringent requirements
of MFPA Pamphlet 20, Underwriters Laboratories
and Factory Mutual Research Corporation for reliability
and unfailing service under the most difficult
and demanding circumstances. This fact alone should
speak well for Aurora's product quality and premium
design features. Fire pumps are required to produce
specific flow rates (GPM) and pressures of 40
PSI or greater. Further, the above mentioned agencies
advise that the pumps should produce at least
65% of that pressure at 150% of the rated flow-and
all the while operating at a 15 foot lift condition.
The performance curves must be such that the shut-off
head, or "churn," is from 101% to 140% of the
rated head, depending upon the agency's definition
of the term. Aurora's fire pumps are not offered
for fire pump service unless they meet all agencies'
requirements. Beyond performance characteristics,
Aurora fire pumps are carefully scrutinized by
both U.L. and F.M. for reliability and long life
through analysis of their design and construction.
Casing integrity, for example, must be suitable
to withstand a hydrostatic test of three times
the maximum operating pressure without bursting!
Aurora's compact and well-engineered design allows
us to satisfy this specification with many of
our 410 and 420 models. Engineering calculations
for bearing life, bolt stress, shaft deflection,
and shear stress must also be submitted to U.L.
and F.M. and must fall within conservative limits
to ensure utmost reliability. Again, the superior
design of Aurora's split-case line comes through
with flying colors. Finally, after all the preliminary
requirements have been met, the pump is ready
for final certification testing to be witnessed
by representatives from U.L. and F.M. Performance
tests will require that several impeller diameters
will be demonstrated satisfactorily, including
the minimum and maximum, and several in between.
Q.
What is the typical lead time for a fire pump?
A. The control panels can ship out in a week or
two if desired, but often are held back to ship
with the fire pumps. Typical lead times run 5-8
weeks from release of an order; however, Aurora
has a Red Hot Quick Ship program for their fire
pumps which can produce fire pumps in three, two,
or sometimes even one week!
Q. Is there a market for used fire pumps?
A. No. Due to the liability encountered in fire
pump installations, there are not many trustworthy
people who would be willing to risk putting used
equipment in a new system.
Q. What is the easiest way of determining pump
rotation?
A. For a horizontal split-case fire pump, if you
are sitting on the motor facing the fire pump,
from this vantage point a pump is right-hand,
or clock-wise, if the suction is coming from the
right and the discharge is heading toward the
left. The opposite is true for left-handed, or
counter-clockwise rotation.
Q.
Can I get a single phase fire pump?
A. Yes, provided that the motor HP does not exceed
15, and the job site voltage is 230 volt. The
motors on these units are not currently Listed
for fire protection, but the control panels on
the fire pumps are. Cost increases are moderate.
Q.
How are engines and motors sized for fire pumps?
A. Motors and engines supplied with Aurora fire
pumps are sized according to NFPA 20, and designed
to operate on any point of the pump curve without
exceeding the motor nameplate service factor,
or engine size (see NFPA 20, 6-5.2.1). This means
that the fire pump can flow more than 150% without
damaging the motor or engine. Sizing only to 150%
of rating is a short-cut, and is not the intent
of NFPA 20. All Aurora motors and engines are
sized to the intent of NFPA 20.
Q. Can I use a flow meter loop as a substitute
for a test header?
A. A flow meter loop is often practical where
flowing excessive water through standard U.L.
Playpipe nozzles is inconvenient; however, when
using a closed flow meter loop around a fire pump,
you may be testing the pumps hydraulic performance,
but you are NOT testing the water supply, which
is a critical component of the fire pump system.
If there is an obstruction to the water supply,
this will not be evident with a flow meter loop,
but will certainly be exposed by testing a fire
pump with hoses and Playpipes. On an initial start-up
of a fire pump system, we always insist on flowing
water through the system to ensure the integrity
of the entire system.
Q.
I heard you no longer need a relief valve on diesel
fire pumps. Is that true?
A.
Not in all cases! The answer to this question
depends on the highest expected job site suction
pressure available, and the specific pumps churn
pressure. If the sum of those numbers, multiplied
by 1.21 exceeds the system component rating (which
is typically 175 psi for standard fittings) the
YES, you DO need a main relief valve. Or you can
upgrade your fittings to a higher rating.
Q.
Do I need to worry about NPSH in fire pump applications?
A. Rarely. NPSH (net positive suction head) is
an important consideration in industrial applications,
such as boiler feed or hot water pumps. With fire
pumps, however, you are dealing with cold water,
which uses all of atmospheric pressure to your
advantage. Fire pumps need a "flooded suction,"
where the water arrives to the pump impeller through
gravity. You need this to guarantee a pump prime
100% of the time, so that when you have a fire,
your pump operates! You cannot get a fire pump
without a foot valve, or some artificial means
for priming.
Q.
When do I need a pressure recorder in a fire pump
panel?
A. On all diesel applications, and on all Factory
Mutual electric fire pump applications.
Q.
When will you answer more questions on this FAQ
page?
A. We will add them as issues arise, but please
call us with your questions!
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