Sealant is put into metal rings, the mass measured and the volume calculated. They are then left to cure for 28 days at 23±2°C and 50±5% RH, following which they are subjected to 70±2°C dry heat for 7 days and brought back down to 23±2°C for another day. Once all the conditioning is done they are weighed again and the new volume calculated, these results are compared to the first set of measurements and the amount ofmass and volume lost is calculated.