ZZ-V-25E
valves, type 1, classes 4 and 7, and type II, classes 3, 6, and 8
3.4.1.5.3 Factory-bent valves.
shall not be cracked.
3.4.1.6 Hardness of valve rubber rovers and bases. The snore A durameter hardness of unaged rubber
compound shall be not less than 55 not more than 70 for tube applications. The Shore A durameter hardness
of the rubber shall be not less than 60 nor more than 70 for snap=in valve applications.
shall not increase to more than 75 for valves aged in storage up to 2 years.
3.4.2 Spuds.
3.4.2.1 Hardness of rubber bases. The durameter hardness of rubber compound of type
shall be the same as for valves with rubber bases.
class 2, and class
3.4.2.2 Tensile strength . Type III, class 1, class 2, and class 4 spuds Shall conform to the pull
value of Table I.
3.4.2.3 Base closure. Spuds, type III, class 1, class 2, and class 4, shall trove sufficient spinning
or closing of the inner wall of the metal groove to effect a mechnaical lock of the rubber in the groove.
There stall be no cracks or flaws in the spuds wall.
3.5 Environmental requipements.
3.5.1 Valves. Unless otherwise specified (see 6.2), rubber used externally cm valves, type II, class
1, shall meet resis tance-to-ozone cracking requirements as specified herein (see 4.5.4.7), valve being
cantilevered 10° out of normal position.
3.5,1.1 Low temperature leakage. Unless otherwise specified valve cores, type V, shall meet the
following low temperature and pressure requirements without leaking in excess of one bubble per minute
with valve mouth in down position:
Classes 2 and 3 - -40°F at 200 ± 5 psig.
3.5.1.1 High temperature leakage. Unless otherwise specified, valve cores, type V, shall meet the
following high temperature and pressure requirements without leaking in excess of one bubble per minute
with valve mouth in down position:
Class 2 - 200°F at 200 ±5 psig.
class 3 - 165°F at 200 ±5 psig.
To assure that damage has not occurred to the cores during test, no removal torque of cores that have not
keen retightened shall be more than 1/2 pound-inches more than the permissible installation torque (see
4.5.2). All barrel gaskets shall be intact and undamaged.
3.6 Performance.
3.6.1 Valves. Valves, having type V , class 2 cores as part of their assembly, shall allow an air flew
input rate of at least 4.3 cubic feet per minute. Valves, having type V, class 3 cores as part of their
assembly , shall allow an air flow input rate of at least 8.0 cubic feet per minute.
3.6.2 Caps. Caps TR VC2 and TR VC3 shall pneumatically seal the mouth of the valve stems and
demonstrate no visble leakage of air file under 100 psig of air pressure for 30 seconds. In addition,
the TR VC8 shall be capable of withstanding finger tightening with no effects in the performance of its
intended service.
3.6.3 Cores.
3.6.3.1 Air flow input rate.
Valve core. type V, class 2, shall allow an air flow input rate of at
valve cores , type V , class 3, shall allow an air flow input rate of at
least 4.3 cubic feet per minute.
least 8.0 cubic feet per minute
3.6.3.2 Pressue retention. Unless otherwise specified, valve cores, type V, shall
pressure retention requirements for at last one minute without visible leakage:
Classes 2 and 3 - 25 psig and 200 psig .
cores, and spuds
outlined in the
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