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IS0
I NTERN AT1 O N A L O RG A N IZ AT1 O N FOR STAN DA RDlZ AT1 ON
IS0 RECOMMENDATION
R 844
P LAST1 CS
COMPRESSION TEST OF RIGID CELLULAR PLASTICS
1st EDITION
October 1968
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The copyright of IS0 Recommendations and IS0 Standards
belongs to IS0 Member Bodies. Reproduction of these
documents, in any country, may be authorized therefore only
by the national standards organization of that country, being
a member of ISO.
For each individual country the only valid standard is the national standard of that country.
Printed in Switzerland
Also issued in French and Russian. Copies to be obtained through the national standards organizations.
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BRIEF HISTORY
The IS0 Recommendation R 844, Plastics - Compression test of rigid cellular plastics, was
drawn up by Technical Committee ISO/TC 61, Plastics, the Secretariat of which is held by the
United States of America Standards Institute (USASI).
‘-A
Work on this question by the Technical Committee began in 1961 and led, in 1963, to the
adoption of a Draft IS0 Recommendation.
In August 1964, this Draft IS0 Recommendation (No. 752) was circulated to all the IS0
Member Bodies for enquiry. It was approved, subject to a few modifications of an editorial nature, by
the following Member Bodies :
Argentina India South Africa, Rep. of
Australia Israel Spain
Austria Italy Sweden
Belgium Japan Switzerland
Canada Korea, Rep. of Turkey
Czechoslovakia Morocco U.A.R.
Finland United Kingdom
Netherlands
France U.S.A.
New Zealand
U.S.S.R.
Germany Poland
Hungary
Romania
No Member Body opposed the approval of the Draft.
The Draft IS0 Recommendation was then submitted by correspondence to the IS0 Council,
which decided, in October 1968, to accept it as an IS0 RECOMMENDATION.
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ISO/R 844-1%8 (1
IS0 Recommendation R 844 Octo ber 1968
PLASTICS
COMPRESSION TEST OF RIGID CELLULAR PLASTICS
1. SCOPE
This IS0 Recommendation describes a method of test for determining either :
(U) the compressive strength, or
(b) the compressive stress at 10 deformation
of rigid cellular plastics materials.
2. PRiNCIPLE
A test piece from the material is subjected over its entire cross-sectional area to increasing compres-
sion at a fxed rate of deformation until 10 deformation is reached, and the maximum stress
sustained by the test piece is calculated. If this maximum occurs before 10 deformation is reached,
the result is reported as compressive strength. If it occurs at 10 deformation, it is reported as
compressive stress.
3. DEFINITIONS
3.1 Compressive strength. Stress at maximum load to break down a cellular material, calculated on
the original cross-sectional area.
3.2 Compressive stress at IO yo deformation. Quotient of the compression force at 10 'lo defor-
mation and the original cross-sectional area.
Deformation. Extent to which the test piece is compressed, expressed as a percentage of its
3.3
original height.
4. APPARATUS
4.1 Compression testing machine. Any suitable compression testing machine capable of operat
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