Why Phelps' compressed gasket material is superior

March 9th at 3:04am

Phelps Compressed Gasket Materials (our famous green sheet) have been extensively tested for pressure and high temperature performance. In particular, the green sheet has undergone two tests - the DIN 52913 and the Hot Compression Test both demonstrate the high temperature resistance of the gasket material.

Hot Compression Test Procedure

  1. A force of 7250 PSI is applied to a washer.
  2. Heat is applied every minute the washer is under pressure and is raised at the rate of 10°C per minute. This is done until 572°F (300°C) is reached.
  3. If the washer cracks before 572°F (300°C) is reached, the result is recorded at that temperature. When the washer does not crack, the amount of compression is recorded in percentage.
  4. The test result for the low temperature test, 68°F (20°C), is recorded in percentage as well.

Hot Compression test results for Phelps Style 7010 (1/16" Thickness Used For Testing)
7250 PSI @ 572°F (300°C): 16% Total
7250 PSI @ 68°F (20°C):     9%  Total 

The Competition

  1. Some manufacturers publish the test results for the high and low temperature Hot Compression Test that need to be added together to show the actual high temperature test results.  This is shown only in the fine print.
  2. Other competitors publish test results that are performed at half the stress load, 3675 PSI.  This of course is not an accurate Hot Compression Test.  Still others will state test results showing no temperature. 
  3. We have tested some of our competitors’ material to find they failed the Hot Compression Test at 572°F (300°C).
  4. Phelps has chosen to disclose full and accurate Hot Compression Test results.

DIN 52913

  1. Both temperature tests are performed for 16 consecutive hours under the stress load of 7250 PSI.
  2. Test one is performed at a temperature of 347°F (175°C).
  3. Test two is performed at a temperature of 572°F (300°C).

The test results are expressed in retained stress in PSI.

DIN 52913 test results for Phelps Style 7010
Stress Relaxation @ 7250 PSI (50 MPA)
16 Hrs @ 347°F (175°C) > 5510 PSI (38 MPA)
16 Hrs @ 572°F (300°C) > 4350 PSI (30 MPA)

The Competition

  1. Some manufacturers will show a value under DIN 52913 with no temperature stated.
  2. The questions is: “what test temperature was used”?


  1. Phelps compressed gasket materials can withstand elevated temperatures and high stress loads.
  2. The higher temperature/pressure resistance a material has, the better the overall performance will be in your application.

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