Yield and ultimate thermal loads for hardware subject to thermal tests shall be calculated by either Alternate A or Alternate B, as defined below, whichever produces the maximum load. These thermal loads are not to be used for fatigue.
Yield thermal load (YTL) = Predicted thermal load (PTL) x 1.32
Ultimate thermal load (UTL) = (PTL) x 1.50
YTL = (Predicted temperature +/- 27 deg F) x 1.10
UTL = (Predicted temperature +/- 27 deg F) x 1.25
For hardware not subject to thermal testing, the following method is used to calculate yield and ultimate thermal loads.
YTL = PTL x 1.50
UTL = PTL x 2.00