Compatibility is based on full immersion tests of three different lengths: 2hr, 4hr, and 24 hr. 

The worst of any of these tests is the prevailing recommendation of compatibility. 

A test coupon sourced from McMaster Carr is cut into a 1” x 1” square and weighed and measured. The prevailing method we use for compatibility is weight. The measurements can be used if there is a noticeable physical change. IF there is noticeable cracking or physical breakdown that warrants a non-compatibility, but the weight passed, the compatibility will be based off of the physical. 

A new coupon is used for each immersion. The coupons are immersed in a sealed container for the prescribed time and then taken out. They are dried for 2 minutes, allowing for surface evaporation, and then weighed. 

R < 2wt% change 

M = 2-8 wt% change 

N > 8 wt% change