The CP12 Gas Rate Calculator is a Premium App for Domestic and Light Commercial (Non-Dom) gas engineers and heating engineers.*Speed up your gas safety tests for gas appliances and pipework.*A one button countdown for domestic Let-By and Tightness testing.*A timer for commercial Tightness and Strength testing.*Calculates appliance gas rates on metric and imperial meters, domestic and light commercial (U6 up to U25).*Over-sized buttons make it easy to time meter tests and gas rates.*This app does NOT reset on phone orientation change.*Calibrated for Natural Gas, and LPG gasses - Propane and Butane.*Speed up your Gas Safety Cerificates (CP12's).This was developed by an active Domestic and Commercial heating engineer for other gas engineers.Suggestions for additional features welcomed.