Archive for November 9, 2010

Question : what is the best way to calbrate a floor scale in a cGMP environment?
The scales are in a cGMP facility and we’re not sure that the current calibration procedure is good enough. Currently a 3rd party is calibrating annually and they are just using four different weights on a range from 0 – 2000 kg. If they fall within tolerance, the calibration is done. If not, a corner load test is done and adjustments made. Is this enough? A lot more is done with the analytical balances.
floor scale

Best answer:

Answer by anza_1
Regulation 211.68 requires that “If such equipment is so used, it shall be routinely calibrated, inspected, or checked according to a written program designed to assure proper performance. Written records of those calibration checks and inspections shall be maintained.”

So in your particular case, there is nothing unique about calibrating your floor scale to be used in the cGMP environment except that you need to have a documented schedule, procedure, and records. What an auditor may ask is, why do you perform this more rigorous calibration for your analytical balances than your floor scale?

Only you can answer this question, but things to consider are:
what is the range of masses that the floor scale is used to measure? Do you cover this range in your calibration procedure?
Do you include calibration points outside the allowed range to ensure you are accurate at your limits?
While the scale is rated to 2000kg, do you allow it to be used at that limit (since operating near the equipments limit may result in a reduction in accuracy)?
Does your weighing process require the load to be centered on the balance? If not, do you calibrate the scale accuracy for offset loads?