How do you calibrate a dumpy level?

AIM/PURPOSE: To describe the instruction for the calibration of Dumpy Level to ensure that equipment is maintained in fully serviceable condition, is safe to operate and meets environmental requirements. FOR THE CALIBRATION OF DUMPY LEVEL The method described below is to be used on-site check prior to use as to the accuracy of the Dumpy level between calibration checks. This Work instruction shall be conducted at the commencement and completion of a contract. 1. Drive two pegs, "A" & "B", into the ground six metres or more apart 2. Set Dumpy up at "C" 3. Shoot a level at "A" and "B" 4. Relocate Dumpy to "D" and shoot a level at "A" and "B" 5. Record the appropriate result in the workbook. (Levels shot at "D" should be within ± 10mm of "C") D A C B