demand exceeds the capacity of one pump, both pumps shall operate.
Provide a pneumatic tank and "NO-FLOW" shut-down controls. Provide
emergency power.
7.
DOMESTIC HOT WATER SYSTEMS
7.1
Buildings Housing Patients, Research Buildings, and Ambulatory
Care:
A.
Entire Building: Provide duplex shell and steam coil central
water heaters with the capacity of generating the flow demand
at 60 degrees C (140 degrees F) with each heater sized to
supply 75% of demand. However, the heater discharge
temperature shall be set at 54 degrees C (130 degrees F).
Provide a water temperature alarm system on heater discharge,
or where water enters the piping system. Temperature limit
stop of type T/P combination temperature and pressure
balancing valves shall be set at 40 degrees C (105 degrees F)
at shower head. Use recirculating system.
B.
Dietetic Equipment: Provide duplex shell and steam coil
booster heaters to generate the flow demand at 60 degrees C
(140 degree F) with each heater sized to supply 50% of demand.
Use recirculating system.
C.
Hydrotherapy Equipment: Provide simplex shell and steam coil
booster heater to generate 60 degrees C (140 degrees F) at
point of use.
D.
Exceptions:
1.
A multi-unit heater system may be used for hospitals. With
one heater down, the remaining heaters shall provide 75%
of total demand.
2.
Dietetic and hydrotherapy equipment located near hospital
heaters may be served by these heaters, in lieu of
separate heaters.
7.2
Laundries: Laundry equipment heaters are designed and provided by
separate contract (VA will furnish and install in conjunction with
laundry equipment). The remainder of a laundry building shall be
served with a simplex heater as described in Paragraph 7.3.
7.3
Other Buildings: Provide simplex shell and steam coil electrical
or gas central heater with the capacity of generating the flow
demand at 60 degrees C (140 degrees F). However, heater discharge
shall be 54 degrees C (130 degrees F). Consider Legionnaires
disease, energy consumption and initial cost when selecting a
circulating system.
7.4
Therapeutic Pool: See Article, THERAPEUTIC POOL EQUIPMENT.
7.5
Size each heater based on modified Hunter's Curve (Hot and Cold
Water Section, ASHRAE GUIDE AND DATA BOOK) and fixture unit count
indicated in Article, PLUMBING FIXTURE SCHEDULES. Special
equipment demands such as dishwashers, sterilizers, and laboratory
glass washers must be added to the water heater load.
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