Brittle fracture: API 570 says ADD 17 deg C (30 Deg F) to the MDMT for Hydrotesting? 1

[SAM_imported2]

If we see 17 Degrees C is not equal to 30 Degrees F (it is equal to minus 1.11 Degrees C).
Is it a Mistake in the code OR my understanding?

 

[IFRs]

One DegC is about 1.8 DegF. 17 x 1.8 = 30.6 ( rounded to 30 for some reason ). The 17 DegC is not meant to be an actual temperature. You are to add 17 DegC to the MDMT to find a new temperature. XX DegC + 17 = yyy DegC. The standard is saying that the adder to MDMT is 17 DegC or 30 DegF. For example, if your MDMT was 0 DegC / 32 DegF then your Hydrotest temperature to evaluate brittle fracture would be 17 DegC or 62 DegF.

 

[SAM_imported2]

Hello,
One Deg C = 1.8 F ?? (which books am I studying!)
I thought one Deg C = 33.8 Deg C.

Regards

 

[IFRs]

You are still looking at thermometers. Don't do that! It is an increase in temperature. If you increase the temperature of something one degree C you have raised its temperature 1.8 degrees F. It does not matter what the absolute temperature of the item is. The original post says to add 17 DegC or 30 DegF to the MDMT to find the new test temperature. It has nothing to do with 17 DegC or 30 DegF on a thermometer but raising the base temperature to find a test temperature.