Check out this FEDERAL SPECIFICATION L-P-390C for POLYETHYLENE type material. The date on this is from August 10, 1971. You won't find this FEDERAL spec easily anywhere else. This Spec is in PDF format, ready for immediate download after purchase. There are 35 Pages of this spec. Please hit me up for any questions you may have.
August 10, 1971
Fed. Spec. L-P-390B
July 2, 1965 and
August 29, 1963
PLASTIC, MOLDING AND EXTRUSION MATERIAL, POLYETHYLENE AND COPOLYMERS
(LOW, MEDIUM, AND HIGH DENSITY)
This specification was approved by the Commissioner, Federal Supply Service,
General Services Administration, for the use of all Federal agencies.
1. SCOPE AND CLASSIFICATION
1.1 Scope. This specification covers low, medium, and high density
polyethylene and copolymers molding and extrusion material for general
purpose use, for use as dielectric material, and for weather-resistant
applications (see 6. 1). For the purpose of this specification, the term
polyethylene is used when referring to any of the types, classes, grades, and
1.1.1 Coverage. This specification does not cover all the types,
classes, grades, and categories of polyethylene, but only those that are most
generally used by the Federal Government.
1.2.1 Types, classes, grades, and categories (see table III).
Polyethylene shall be of the types, classes, grades, and categories shown in tables I and II, as specified (see 6.2).