06-06
3.7 SMOKE AND FIRE PROTECTION
See Supplement, Attachment No.1.
4. HEATING SYSTEMS:
4.1 GENERAL
As far as possible, hydronic hot water heating system(s) shall be
used to heat the space; and, if the building is on the grounds of the
medical center, the hot water shall be produced from the steam
available from the central boiler plant. The incoming steam pressure
shall be reduced to 30 PSIG by installing a suitable PRV station (VA
Standard Detail Nos. 15705-31 & 15705-32. Medium pressure steam (30
PSIG) shall be used for the steam preheat coils, steam to hot water
convertors, and humidifiers. If the use of the building steam from
the central boiler plant is not feasible due to elaborate and
cumbersome steam/condensate piping distribution layout, or due to
insufficient boiler capacity, dedicated hot water boilers shall be
used. The electric resistance heating shall not be used unless it is
proven cost effective.
4.2 SELECTION CRITERIA (HOT WATER HEATING)
The following criteria shall apply for sizing and selecting hot water
heating systems:
A. PUMPING CAPACITY (5.0 HP OR LESS): If the pumping capacity is equal
to or less than 5.0 HP, two convertors and pumps of 100% capacity
each shall be provided. One converter and pump shall act as standby.
B. PUMPING CAPACITY (LARGER THAN 5.0 HP): If the pumping capacity is
larger than 5.0 HP, two convertors and pumps of 50% capacity each
shall be provided. No standby equipment is required.
C. SYSTEM CONFIGURATION: As far as possible, provide a common heating
system for all heating terminal units and for the unit mounted
preheat coils for which there is no danger of coil freeze up. With a
common heating system for perimeter heating and interior reheat
applications, care must be taken to ensure that the hot water
temperature, reset schedule, and the flow rates can satisfy perimeter
and interior duties with by selected parameters. Two independent
heating systems, one for interior reheat and another for perimeter
heating, shall be considered only if such an arrangement is proved
cost effective.
D. SYSTEM CONTROLS:
1. Temperatures: The maximum hot water temperature, to meet the peak
shall be on an inverse reset schedule with the outdoor temperature
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