MIL-STD-293
18 October 1956
in a nearly infinite variety of sizes and shapes
1. SCOPE AND PURPOSE
so that there is no common or typical shape for
1.1 Scope. This document covers only
this class of item. Also, these items have
visual defects for "sponge" rubber items. These
several principal end uses or service require-
include chemically blown or expanded rubber
ments which are dissimilar in the amount of
items having either open and interconnecting
perfection or quality required. These include
cells or closed and noninterconnecting cells.
the following:
Also included are cellular products made from
a. Flexing. A critical use where the item
chemically or mechanically foamed latices or
undergoes constant or intermittent bending,
liquid elastomers.
twisting or deflecting during service such as a
1.2 Purpose. The primary objective of
vibration isolation material.
this document is to present word descriptions
b. Sealing. A critical use where the item
and photographs of possible defects in cellular
serves as an airtight or watertight closure such
rubber items that may be presented for in-
as a gasket.
spection. In addition it provides a training
c. Protecting. An intermediate use where
aid for inspectors.
the item serves as a covering material and physi-
1.2.1 In general this document is not in-
cal stress is not existent or occurs infrequently,
tended to take the place of a particular inspec-
such as rug underlay.
tion procedure aid which may be provided for
d. Filling. A noncritical use where the
inspectors to verify conformance with a par-
item serves merely as an internal space filler
ticular specification.
The quality require-
and physical stress is not existent or occurs
ments specified in the basic specification are
infrequently, as an insulation material.
governing.
A cellular rubber item may, and frequently
does, have two or more of these service require-
2. REFERENCED DOCUMENTS
ments in combination.
2.1 Standards
4.2 It is recognized that the rejection of an
M ILITARY
inspection lot of cellular rubber items for flaws
MILSTD105 Sampling procedures
which are not commensurate with the dimen-
and Tables for Inspection by At-
sional tolerances or degree of quality required
tributes
by the user can result in an appreciable increase
MIL-STD-177 Rubber Products,
in the cost of production. In some instances
Terms for Visible Defects of
the enforcement of very high standards could
result in an appreciable decrease in the volume
(Copies of specifications, standards, drawings, and
publications required by contractors in connection
of production. Accordingly, some of the visual
with specific procurement functions should be obtained
defects in this guide are classified under three
from the procuring agency or as directed by the con-
categories (major, minor, or acceptable) de-
tracting officer.)
pending on the type of service requirement.
4.3 Since the classification of certain visual
3. DEFINITIONS
defects depends on the service requirements of
3.1 Categories, major and minor defects, are
the item, it is imperative that the end usc be
as defined in Standard MILSTD105.
known before inspection is started. In the
3.2 Word descriptions of visible defects
majority of cases, the end uses will be apparent
used in this standard are in accordance with
or can be readily determined from the procure-
Standard MIL-STD-177.
ment document. However, in case of doubt,
the cognizant technical bureau or agency (on
4. GENERAL
primes) or the endorsing inspection service (on
4.1 The classification of visual defects for
subs) should be requested to supply this
cellular rubber items is more complex than for
information.
a single-shape, single-application item such as
4.4 The following flaws may be allowed,
V-belts. Cellular rubber goods are produced
provided they are corrected as indicated and
2