ISO 815 Rubber, Vulcanized or Thermoplastic - Determination of Compression Set

The ISO 815 standard, developed by the International Standards Organization (ISO), essentially consists of the following two parts under the main title "Rubber, vulcanized or thermoplastic - determination of compression set":

• ISO 815-1 Part 1: At ambient or elevated temperatures
• ISO 815-2 Part 2: At low temperatures

The first part of this standard defines the following test methods for determining compression set properties:

• A test method of vulcanized and thermoplastic rubbers at ambient temperature
• Three test methods (test methods A, B and C) at elevated temperatures, depending on the way the test piece is finally released

These test methods measure the ability of rubbers with a hardness in the range of 10 IRHD to 95 IRHD to retain their elastic properties at certain temperatures after prolonged compression at constant tension (normally 25 percent) under one of the described sets of alternative conditions. A lower compression stress is used for rubber with a nominal hardness of 80 IRHD and above.

When rubber is held under compression, physical or chemical changes occur that prevent the rubber from returning to its original dimensions after the deforming force is released. Results vary depending on the compression time and temperature and recovery conditions. At high temperatures, chemical changes become more and more significant and acquire a permanent state.

In the second part of this standard, two test methods are defined for determining the compression set properties of vulcanized and thermoplastic rubbers at low temperatures. The first of these is derived from the methodology used in the first chapter. The second uses a tester that allows measuring and recording test piece thickness during recovery. Due to the load applied during recovery in this method, a correlation cannot be established between the results given by both methods.

In the test methods described in this section, when the rubber is kept under compression, physical or chemical changes occur that prevent the rubber from returning to its original dimensions after the deforming force is released.

Among the numerous test, measurement, analysis and evaluation studies it provides for businesses in various sectors, our organization also provides testing services for the determination of compression set in rubber, vulcanized or thermoplastics within the scope of ISO 815 standard, with its trained and expert staff and advanced technological equipment.