# How you calculate the temperature scaling factor?

Used to obtain the corresponding pressure at ambient temperature. Example when testing Proof or burst pressure to a given value at 300°F, but you will test with corresponding pressure (higher) to ambient temperature.

Example. Proof Supply Pressure @ 300°F = 1161 psig Proof Supply Pressure @ AMBIENT = 1161 X Temperature Scaling Factor = 1161 X 1.15 = 1335 psig

     Burst Supply pressure @ 300°F = 1251 psig
Burst Supply pressure @ AMBIENT = 1251 X Temperature Scaling Factor
= 1251 X 1.24
= 1551 psig


Please note different values for TSF for Proof and Burst pressures. Are these values obtained from the material the part is made off? Is there is a calculation, what it is?

• This could be a straightforward application of the ideal gas law or somehting else entirely. Can you tell us more about the problem and possibly the relevant codes etc. you work with? The question was migrated to a site where not everyone is an aerospace person!
– mart
Aug 12, 2020 at 8:53
• Material properties depend on temperature. The proof strength and ultimate tensile strength of the material at room temperature will be higher than at 300F, but they probably don't scale in the same proportion. I don't think this has anything to do with gas laws. We don't know the material specification so there is no way to tell how the 15% and 24% factors were derived. Aug 12, 2020 at 12:28

This is the essence of the ASME Boiler Code ;allowable stresses for materials at various temperatures. It is NOT a calculation . It is based on a great many creep and stress rupture tests which have been analyzed and reviewed for over a hundred years.If you are building a pressure vessel in the civilized world ,it is required to conform to "code" , or a local national interpretation. The code addresses all aspects of the pressure vessels such as welding, inspection,quality control , piping , nuclear pressure vessels, hazardous materials, etc,etc,etc. Some aspects of quality are now handled through ISO 9000. The code roots go back well past 100 years.

• Wikipedia list the first issue of code in 1914 but that is misleading. Steam boiler explosions were unfortunately common and in the 1880's efforts began to write a document to define safe (steam) pressure vessels , particularly on locomotives. Apparently it took about 20 years to finish the first "code". The ASTM material specifications initially were developed for the ASME code. Aug 12, 2020 at 19:47