Standard Specification for Aerospace Parts Machined from Polychlorotrifluoroethylene (PCTFE)
|Publication Date:||1 July 2005|
|ICS Code (Space systems and operations):||49.140|
|ICS Code (Rubber and plastics):||49.025.40|
This specification is intended to be a means of calling out finished machined parts ready for aerospace use. Such parts may also find use in selected commercial applications where there are clear benefits derived from the use of parts with known or controlled crystallinity, high molecular weight, good molecular weight retention, dimensional stability in the finished part, and tightly controlled engineering tolerances.
This specification establishes requirements for parts machined from
virgin, unplasticized, 100 %
This specification does not cover parts machined PCTFE copolymers, PCTFE film or tape less than 0.25-mm [0.010-in.] thick, or modified PCTFE (containing pigments or plasticizers).
This specification does not allow parts containing recycled material.
This specification classifies parts into three classes based upon intended uses and exposures: oxygen-containing media, reactive media, and inert gases.
- PCTFE components covered by this specification are virgin, 100 % PCTFE resin, free of plasticizers and other additives. The components are combustion resistant in oxygen, dimensionally stable, and meet other specific physical characteristics appropriate for their end use. They are used in valves, regulators, and other devices in oxygen, air, helium, nitrogen, hydrogen, ammonia, and other aerospace media systems. The components typically are used as valve seats, o-rings, seals, and gaskets. They are removed and replaced during normal maintenance procedures. The components provide reliable sealing surfaces resulting in proper closure of valves and related devices and no leakage from the system into the environment. They will experience static mechanical loading, cyclic mechanical loading, temperatures ranging from cryogenic to 71°C [160°F], and pressures up to 46.2 MPa [6700 psi].
The values stated in SI units are to be regarded as standard. The values in brackets are for information only.
The following precautionary caveat pertains only to the test methods portion, Section 12, of this specification: This standard does not purport to address all of the safety concerns, if any, associated with its use. It is the responsibility of the user of this standard to establish appropriate safety and health practices and to determine the applicability of regulatory limitations prior to use.
NOTE 1 - There is no equivalent ISO standard.