Fed. Std. No. 143a
AUGUST 9, 1960
(W-S-506, Issue on Effect)
SUPERSEDING
Int. Fed. Std. No. 143
October 13, 1959
FEDERAL STANDARD
SPARK PLUG, HEAT RATING OF,
METHOD OF CLASSIFYING
Authority..-This standard is issued pursuant to the Federal Property and
Administrative Services Act of 1949, as amended, and its application to the pur-
chase of commodities referred to herein is mandatory on all Federal agencies.
S1. Purpose and scope.-The purpose of this
Federal Standard is the establishment of
uniform heat rating descriptions for use in
classifying spark plugs of the unshielded type.
The content of this standard is for use in
describing unshielded spark plugs, pro- cured,
catalogued, stocked, or used by the
Government.
S2. Application.- Purchases from commer-
cial sources under Federal Specification W-
S-506 of the issue in effect on date of invi-
tation for bids, shall be limited to items which
have characteristics, and packaging and pack-
ing requirements conforming to the standard
items specified herein. Existing Government
stocks of items with other characteristics,
and packaging and packing shall continue to
be utilized until exhausted. In those cases
where this Federal Standard eliminates sup-
ply items and the items as eliminated are
under contract, if the contract cannot be ne-
gotiated or amended to conform to the stand-
ard items, the Federal Standard becomes
mandatory at the contract expiration date.
570397/60/4
S3. Heat rating descriptions:
Heat Rating IMEP*
Hot Below -100
Normal-Hot 100 - 135
Normal 135 - 175
Normal-Cold 175 - 210
Cold Above -210
*The IMEP (Indicated Mean Effective Pressure) is
expressed in p.s.i. (pounds per square inch) using
the test procedure and engine operating conditions
as specified in the SAE (Society Automotive En-
gineers) Recommended Practices of the SAE Manual.
S4. Changes.- When a Federal agency
considers that a Federal Standard does not
provide for its essential needs, written re-
quest for adding to or otherwise changing
the standard, supported by adequate justi-
fication, shall be sent to the Administration.
This justification shall explain wherein the
standard does not provide for essential needs.
The request shall be sent in duplicate, to
the General Services Administration, Federal
Supply Service, Standardization Division,
Washington 25, D.C. The Administration will
determine the appropriate action to be taken
and will notify the agency.
FSC 2920
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