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Consistence tolerance - slump test

Consistence, measured using the slump test (BS EN 12350-2), is either specified as a class or target. Although a supplier will endeavour to provide the required value or range, deviations in production and sampling apply. The following tables give the maximum allowable deviation based on a spot sample taken from the initial discharge of a ready-mixed concrete truck. 


Slump range

Max. allowable deviation on
range limit (mm)

S1 10 - 40     0 - 60

50 - 90

    30 - 110
S3 100 - 150     80 - 170
S4 160 - 210     140 - 230

Due to lack of sensitivity of slump test values less than 10mm or greater than 210mm, it recomended to only use the test for slump 10mm and 210mm 


Target slump (mm)

Max. allowable deviation on
target value (mm)



  50 - 90    




Based on BS 8500-1:2015 +A1: 2016

Slump test apparatus
Acknowledgement: The Concrete Society

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