compressors. Combined intakes must be sized for no restriction
while flowing maximum intake possible, and provided with an
isolation valve at the header for each compressor served.
M.
Combine discharge from each laboratory vacuum pump into one
discharge pipe, sized for no restriction while flowing maximum
discharge possible, and provide an isolation valve at the
header for each pump served. Exhaust discharge at the highest
point of the building, above and at least 7500 mm (25 feet)
horizontally (may be more depending upon prevailing wind
direction and velocity) from any door, window, louvered or
ventilating opening of the building.
13.2
A.
Design natural gas piping systems in accordance with NFPA 54.
Design other pressure piping systems not to exceed 35 kPa (5
psi) loss from source to point of use. Design vacuum piping
systems not to exceed 10 Pa (3 inches Hg) from source to point
of use.
B.
Provide main line supply line with a shut-off valve. Locate
valve as to be accessible by authorized personnel only and be
located downstream of the source valve and outside of the
source room, enclosure, or where the main valve enters the
building. Identify this valve. A main line valve is not
required when the source shut-off valve is accessible within
the building.
C.
Each branch and riser supplied from the main line shall have
an in-line shut-off valve adjacent to the main. Each branch
supplied from a riser shall have an in-line shut-off valve
adjacent to the riser. Conceal in-line shut-off valves (e.g.
above ceiling with ceiling tag, or in a locked equipment
room). Comply with applicable codes and standards for
concealed valves of flammable gases.
D.
Include a zone valve in a cabinet with other laboratory gas
zone valves for branches serving laboratory gas outlets.
Located separate natural gas zone valve cabinets adjacent to
other laboratory gas zone valve cabinets. Provide additional
service valves above ceiling to subdivide areas for
maintenance.
E.
Laboratory gas outlets and vacuum inlets shall be standard
F.
Locations of piped laboratory gas outlets and vacuum inlets
are indicated in VA Program Guide 7610, Equipment Guide List,
under "Outlets".
G.
Provide emergency natural gas solenoid valve for each
laboratory area. Locate emergency shut-off switch adjacent to
exit.
13.3
Alarms:
A.
To insure continuous responsible observation, two master
system alarms, in separate warning locations, are required for
each laboratory gas and vacuum system.
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