PACKAGE : I Bid Document VOLUME : II - Public Health Engineering

14.1 Pressure gauges
Material:
Chapter - 14
Miscellaneous
The brief specifications for pressure gauges is as follows:
The pressure gauges shall be of Bourdon type having a range
between 0 to 20kg/sq.cm. The diaphragm material should be of 316 SS. Accuracy
of the pressure gauge shall be 1% with a dial diameter of 150mm. The case shall be
of IP 65, die cast AI. The pressure gauge shall be directly mounted with connection
of ½ “ N.P.T.M.
Erection:
The pressure gauges shall be, mounted as near to the process as possible. Impulse
tubing/piping length shall be minimum possible. The pressure gauges shall be
mounted in a vibration free location. They shall be readily accessible from grade,
platform, fixed walkway or fixed ladder and shall be visible from where related
equipment is operated.
The pressure gauges shall have one isolating valve and one drain/vent valves for
depressuring. The drain/vent valve shall be plugged. The valves used shall be
having ½ “ NPTF connections and the material shall be ASTM A 216 GR. WCB or
ASTM A 105 unless otherwise specified. The trim shall be AISI 410 unless
otherwise specified. All connection shall be made using thread seals preferably
PTFE tape. Right tools shall be used and any limits regarding torque for tightening
shall be strictly adhered to. Impulse piping shall be done using ½“ o.d seamless
annealed ss tubing to ASTM A 269 GR.TP -136 L with minimum wall thickness of
1.65mm. Compression fittings shall be used. The impulse piping must be supported
by an angle of channel and strapped at every meter length. The angle/channel itself
must be supported by welding it to some structure. The pressure gauge shall be
covered with box.
GTS : General Technical specification. Page 101