I cannot provide or link to copyrighted PDFs. If you clarify the exact standard number (e.g., BS EN 772-1:2011+A1:2015), I can help with a summary, scope, or how to access it legally.
The compressive strength is calculated by dividing the maximum load at failure by the gross cross-sectional area of the unit. bs en 7721 pdf
Understanding BS EN 772-1:2011+A1:2015 - Compressive Strength of Masonry Units I cannot provide or link to copyrighted PDFs
Masonry units cannot simply be pulled off the pallet and crushed. The standard specifies how the units must be prepared. This usually involves drying the units in an oven until they reach a constant mass, ensuring that moisture does not skew the results. BS EN 772-1:2011+A1:2015)
Compressive Strength=Maximum Load at FailureCross-sectional AreaCompressive Strength equals the fraction with numerator Maximum Load at Failure and denominator Cross-sectional Area end-fraction