05-06M
cannot be used as building attachments. The structural drawings must show
sufficient structural members for each hanger and support location.
8.8 Fuel Tanks: May be located underground or aboveground. Provide secondary
containment systems on tanks and piping. All steel buried tanks, piping, and
secondary containment shall be coated and cathodically protected. Provide leak
detectors located in the interstitial spaces of the tanks and in piping
systems between the carrier pipes and outer casings. Provide spill and
overfill prevention measures as required by pollution control authorities.
8.9 Natural Gas Systems: Header pressure in the boiler plant shall be as low
as practical which, for water tube boilers is 70 - 100 kPa (10 - 15 psi) and,
for fire tube boilers is 35 - 70 kPa (5 - 10 psi). Higher gas pressures may
be required for low-NOx burners or high turndown burners. Coordinate system
design with requirements of local gas supplier. Provide separate gas meter for
the boiler plant.
8.10 Liquid Petroleum (LP) Gas System: Provide system for operation of
igniters (pilots) when natural gas is not available or is interrupted and the
burners will be fired on oil. If natural gas is normally utilized, the LP gas
igniter system is for emergency use only. The LP gas igniter system shall
operate at 35 kPa (5 psi) or less. The VAMC will supply replaceable propane
cylinder tanks. The A/E must design the tank piping, valve system, and provide
concrete pad and chains for supporting the tanks. Locate the tanks outside.
8.11 Boiler Plant Building Hazardous Gas Detection System: Industrial-type
system with central alarm panel and multiple sensors is required. Provide
carbon monoxide sensors at breathing level near the front of each boiler and
in personnel spaces where there is exhaust ventilation. If natural gas is a
main fuel, provide combustible gas detectors at the ceiling of the boiler
room. If propane is utilized as a main fuel, provide combustible gas sensors
at the low points in the boiler plant.
8.12 Steam Pressure Reducing Stations: Use single-stage reducing stations to
obtain required pressure. Parallel pressure reducing valves in which two
pressure reducing valves share the load are preferred on the services to the
feedwater deaerator and the steam distribution systems. Safety valve capacity
selections for PRV stations must conform to recommendations in an Appendix to
the National Board Inspection Code, published by the National Board of Boiler
and Pressure Vessel Inspectors. Manual bypass globe valves should be sized to
limit the maximum flow through the bypass to the flow capacity of the largest
PRV in the PRV station. Safety valves must have sufficient capacity to handle
the wide open flow of the largest pressure reducing valve or the wide open
bypass, whichever is greater.
steam shall be located in the boiler plant where they can be monitored by
boiler plant operating personnel.
boiler room.
9. STACKS AND EMISSIONS:
9.1 Boiler stack location, height, and diameter shall be determined by an
engineering study which considers boiler/burner operational requirements, air
flow around the stacks and the boiler plant and adjacent buildings, and
emissions regulations. Avoid impingement of stack gases on fresh air intakes
of building ventilating or air conditioning systems. Comply with federal,
state and local emissions regulations.
9.2 Generally, individual stacks on each boiler are preferred. A common
breeching and single stack system for all boilers is acceptable if warranted
by project conditions.
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