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What is the Pressure – Temperature rating of Class 150 Cast Stainless Steel Fittings?

MAXIMUM WORKING PRESSURE GUIDE ALLOWABLE (PSI / kPa) @ TEMPERATURE (°F / °C)  FOR CAST STAINLESS STEEL THREADED FITTINGS, CLASSES 150

 MANUFACTURERS STANDARDIZATION SOCIETY (MSS) STANDARD PRACTICE MSS-SP-114

&

INTERNATIONAL STANDARD – ISO 4144 

You will notice that the stated maximum working pressure at the maximum temperature are similar for the heavy pattern MSS-SP-114 and Lighter Pattern ISO-4144 Class 150 cast stainless steel pipe fittings. The fitting class is rated at the maximum temperature, and the pressure rating increases as the temperature goes down.  

FOR REFERENCE ONLY !

This information is a reference guide only. Specifying the correct pipe schedule and pressure class of fitting depends on many factors. It is the ultimate responsibility of the end user's piping engineer to specify the correct pipe schedule and pressure class of fitting which will meet the maximum operating pressures / temperatures of the system for safe operation in the intended application.

IMPORTANT NOTES:

1) Ratings are independent of the contained fluid and are maximum Non-Shock pressures at the tabulated temperatures. Intermediate ratings maybe obtained by linear interpolation between temperatures shown.

2) The temperature shown for the corresponding pressure rating shall be the material temperature of the pressure retaining structure. It may be assumed that the material temperatures is the same as the fluid temperature. Use of a pressure rating at a material temperature other than that of the contained fluid is the responsibility of the user and subject to the requirements of any applicable code.

3) Piping loads, stresses and moments are not taken into account.