resistance. Material shall be resistant to the effects of aviation
hydrocarbon fuels. Provide full face insulating gaskets between flanges.
Provide full surface 0.76 mm 0.03 inch thick wall thickness, spiral-wound
mylar insulating sleeves between the bolts and the holes in flanges; bolts
may have reduced shanks of a diameter not less than the diameter at the
root of threads. Provide 3.20 mm 0.125 inch thick high-strength phenolic
insulating washers next to flanges and flat circular stainless steel
washers over insulating washers and under bolt heads and nuts. Provide
bolts 13 mm 0.5 inch longer than standard length to compensate for the
thicker insulating gaskets and the washers under bolt heads and nuts.
2.12.6
Electrically Isolating Unions
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NOTE: Indicate locations of each electrically
isolating connection.
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Provide with same electrical insulating materials as specified for
electrically isolating flanges.
2.13
VALVES
Steel body except stainless steel shall be Type 304L or Type 316, and
aluminum alloys shall be 3003, 6061-T6, or 356-T6, except as modified in
paragraph entitled "Special Requirements," in this section, suitable for
working pressure of ANSI Class 150 1896 kPa (gage) at 38 degrees C 275 psig
at 100 degrees F, with weatherproof housing designed to exclude driving
rain and snow for worm-gear operators. Flanged end connections, except as
modified herein. Nonaluminum sizes smaller than 50 mm 2 inches and
aluminum sizes smaller than 25 mm one inch may have union end connections,
or threaded end connections with a union on all but one side of the valve.
Viton or Teflon with metal backup seals. [Provide shut-off valves in tank
fill piping and tank suction piping with factory-installed limit switches
that are actuated by the valve operators. When valves are closed, limit
switches shall prevent operation of the refueling pumps and shall energize
red indicating lights in the control panels.]
2.13.1
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NOTE: Do not use the sentence in brackets unless
there are two sources of supply for each valve size
in project.
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API Spec 6D, ANSI Class 150. [Conform to fire test requirements of API
Spec 6FA.] Provide valves of the flexible wedge disc, conduit disc, or
double disc type. Rising stem type with closed yoke, or nonrising stem
type equipped with a device to give positive visual indication of the
valve's position; bevel or spur gear operated, except valves 300 mm 12
inches and smaller may be handwheel operated.
2.13.2
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NOTE: When pipe pigging is not required, use
"reduced bore." When pipe pigging is required, use
"full bore." When both are required, use "reduced
SECTION 15194N
Page 18
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