Load Cell Calibration
What does WorkSafeBC explicitly require regarding load cell calibration on cranes and hoists?
WorkSafeBC OHS Regulation 14.37 requires load weighing devices on cranes and hoists to be calibrated at manufacturer-specified intervals and whenever there is indication of incorrect functioning. Calibration dates must be recorded in inspection and maintenance records.
What are standard technical steps in a formal load cell calibration procedure?
Standard steps include environmental conditioning (e.g., 20±2°C, ≤70% RH), pre-loading to maximum capacity three times, zero check, applying known loads at multiple points (minimum 5), recording outputs, calculating calibration factors and uncertainty, and issuing a calibration certificate with all details.
How often should load cells be calibrated?
Annual calibration is recommended as a minimum for critical applications. WorkSafeBC defers to manufacturer-specified intervals, with additional recalibration required when malfunction is indicated. For high-accuracy work, calibrate just prior to and after a test.
Load cell calibration is the process of verifying and adjusting a load cell or integrated load-weighing system so that its output corresponds accurately and traceably to known applied loads over the cell's working range, within defined tolerances and uncertainty. It is critical for safe lifting, accurate rated capacity, and regulatory compliance under WorkSafeBC and related standards.
On a shop floor, load cell calibration applies to cranes, hoists, and lifting devices under WorkSafeBC 14.37, requiring calibration at manufacturer-specified intervals and when malfunction is indicated. It also applies to process weighing systems (bins, tanks, conveyors) and test machines. Calibration involves applying known reference loads, comparing output, adjusting parameters, and documenting results. Integration with safety systems like SafeDesk ensures compliance through scheduled and conditional calibration events, linking calibration certificates to asset records.
Ignoring manufacturer-specified calibration intervals and indications of malfunction, leading to inaccurate load measurement and overloading risks.
Calibrating only the load cell without the complete measurement chain (indicator, DAQ, peripherals), causing incorrect readings despite cell accuracy.
Poor control of environmental and setup conditions during calibration, such as temperature swings or inadequate pre-loading, resulting in non-repeatable and misleading results.