2.2.21
Freeze Protection
Low points of all piping and tubing shall be equipped with drains for
freeze protection.
2.2.22
Fire Protection
Boilers shall meet the requirements of NFPA 8501.
2.3
BOILER AUXILIARY EQUIPMENT
2.3.1
Boiler Fittings and Appurtenances
Boiler fittings, and all other boiler appurtenances shall comply with ASME
BPVC SEC I. Boilers shall be provided with a continuous blowdown
connection from an internal pipe running the length of the steam drum at
the point of the highest concentration of dissolved solids. Blowoff
provisions shall be provided from the mud drum or lower part of a fire-tube
boiler. Pressure gauges for high-pressure steam units shall include a
siphon, gauge cock, and test connection. Trim and appurtenances shall
include a 150 mm 6 inch minimum pressure gauge and a safety valve. A
chemical feed connection with internal distribution pipe shall be provided.
2.3.1.1
Water Column
Water column with straight-through type drain valve shall be provided.
Water column shall be complete with gauge glass, high- and low-water alarm,
and three quick-closing gauge valves and try cocks fitted with the
necessary chains and handles for operation from the boiler room floor.
Water column shall also include a test valve, blowdown valve, and a
straight-through type drain valve. Water column shall not be combined with
the low water cutoff. [Water column lighting shall be provided for ease of
reading at all times.]
2.3.1.2
Low Water Cutoff
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NOTE: When the boiler is used as a "heat recovery
unit," an alternate path is usually provided to vent
or bypass the hot gases in the event the boiler is
unable to perform its function. In all other cases,
activation of the low-water cutoff will cause the
loss of all support to the combustion process
including loss of combustion air and fuel.
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A low-water cutoff, with alarm located on instrument panel, shall include
either a float-actuated switch as a means of making electrical contact or
an electrically-actuated probe type low water cutoff. The float chamber
shall be provided with a blowdown connection. The cutoff shall cause a
safety shutdown and sound an alarm when the boiler water level drops below
a safe minimum level [and hot gases from the combustion equipment shall be
routed to the bypass stack]. [Two low-water cutoffs shall be installed on
each boiler. Low-water cutoffs for the boilers shall be piped separately
with separate drum connections. Each low-water cutoff shall have a
separate housing. Two elements in one housing will not be permitted.] A
safety shutdown due to low-water cutoff shall require a manual reset before
operation can be resumed and shall prevent recycling of the combustion
equipment. The cutoff shall be in strict accordance to the latest version
SECTION 15846A
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