12.7
Connection to Existing Medical Gas Systems:
A.
Install shut off valve at the connection of new line to
existing line. The valve assembly should be fabricated and
brazed onto the connecting line.
B.
Coordinate time for shut down of the existing with the VAMC.
C.
All oxygen zone valves and gas riser valves should be shut off
if the section to be connected to cannot be totally isolated
from the remainder of the system.
D.
Prior to any work being done, the new pipeline should be
checked for particulate or other forms of contamination.
E.
Insure that the correct type of pipe tubing and fittings are
being used.
F.
A spot check of the existing pipelines in the facility should
also be made to determine the level of cleanliness present.
G.
Reduce the pressure to "0", and make the tie-in as quickly as
possible. A nitrogen purge is not required since this would
require another opening in the pipeline.
H.
After the tie in is made and allowed to cool, the source gas,
i.e., oxygen, is slowly bled back into the pipeline. The work
area is tested for leaks with soapy water and the leaks, if
any, are repaired.
I.
After all leaks, if any, are repaired and the line is fully
recharged, blow down and testing are performed. The zone
closest to the main is opened to the system, the closest
outlet to the work is accessed, and the main blown through the
outlet. After the outlet blows clear into a white cloth, an
oxygen analyzer is used to determine that only oxygen is
present. An additional check is made at a zone most distant
from the site of the work.
J.
The use of shape memory alloy couplings is recommended when
making connections to existing. This type of coupling reduces
the down time. The couplings are applied without the use of
heat. It reduces the risk of fire in confined space and
eliminated carbon build-up on the interior of the pipe.
13.
RESEARCH AND CLINICAL LABORATORY GAS AND VACUUM SYSTEMS
Design laboratory compressed air, laboratory vacuum, natural gas and
miscellaneous laboratory cylinder gas systems in accordance with current
editions of NFPA 54 and 99, VA Master Specification 15488 and the
following:
13.1
Central Supply Systems:
A.
Provide minimum 690 kPa (100 psi) laboratory air at the
compressor discharge. Run 690 kPa (100 psi) air to a storage
room (or other non-working or unfinished space) in the
laboratory area being served. Valve and cap the 690 kPa (100
psi) air line for future connection. Tee off the 100 psi line
and locate a pressure regulating valve to reduce the air
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