Ohaus Defender 5000 Waterproof Scale

A calibration certificate proves the accuracy of your weighing equipment. It is very likely that if accuracy matters in your workplace, certification will be required by your industry regulators. They are straightforward to get hold of though. Just ask our team.

If you are trading or transacting anything by weight, you will probably need to demonstrate your weighing equipment is verified for trade use. This gives your customers confidence in your business and will make sure buying and selling run smoothly. We can help get you with relevant approvals for your equipment.

The answer will vary depending on how your equipment is used. As a minimum, we typically recommend once a year but our team can provide advice based on your individual circumstances.

The International Organization of Legal Metrology (OIML) has established standards for the classification of calibration test weights. Varying from E0 & E1, which are the most accurate to M2 which are commonly used for calibrating platform scales, floor scales and other industrial weighing instruments.

As a rough guide we have listed desired accuracy against class below.

+/- 0.1% – UNclassed Proof Load Test Weights
+/- 0.05% – M3 (Check/calibrate coarse scales)
+/- 0.005% – M1 (Check/calibrate standard scales)
+/- 0.0015% – F2 (Check/calibrate portable balances)
+/- 0.0005% – F1 (Check/calibrate precision balances)
+/- 0.00015% – E2 (Check/calibrate analytical balances)

The choice of weight class depends on the intended use and the level of accuracy required for a particular application. If you’re unsure, talk to our team who can advise you on the right class for your equipment.

If you’re sending a scale back to us for recalibration, it is ideal to use the original packaging. If this is not available choose a sturdy well-padded box to avoid shocks. Where possible, protect the load sensor by removing the weighing pan and any under-pan support and pack these separately in the box. You may be able to use the equipment’s locking pins or screws too.

Do ensure all the paperwork, including your contact details, is included to ensure we can return it once calibration is complete.