Our CT-109 (Now MPQP) Certification Service includes:

Calibration tests for cement and aggregate proportioning devices must be conducted with a platform scale located at the calibration site. This platform scale must have a maximum capacity not exceeding 2.5 tons with maximum graduations of 1.0 pound. Perform witness scale error testing with test weights conforming to this MPQP to produce a witness scale that is within two graduations of the test-weight load. The scale and equipment needed for the calibration of proportioning systems must be available for use at the production site during production