I was always taught the “bubble test” method had a climate limitation regarding cold ambient temperatures. As we have discussed, ASME B31.3 refers us to ASME Section V for the Bubble Test method for leak testing. It is there we can find the “surface temperature” limitations…
(emphasis is by me)
I-1072 SURFACE TEMPERATURE
As a standard technique, the temperature of the surface of the part to be examined shall NOT be below 40°F (5°C) nor above 125°F (50°C) throughout the examination. Local heating or cooling is permitted provided temperatures remain within the range of 40°F (5°C) to 125°F (50°C) during examination. Where it is impractical to comply with the foregoing temperature limitations, other temperatures may be used provided that the procedure is demonstrated.