Frequently Asked Questions
Please see below for answers to frequently asked questions.
Are readability and accuracy the same thing?
No, the readability of weighing equipment is the smallest quantity that it will display. Accuracy is the maximum difference between the applied test weight and the displayed weight. Some manufacturers quote the accuracy on the product datasheets. No measuring device is 100% accurate and typically the accuracy of standard weighing scales in a stable environment is approximately +/- (2 x division size) throughout the weighing range.
Do I need a calibration certificate?
A calibration certificate provides verification that the weighing equipment has been checked and has been found to be reading within the specification quoted. Weighing equipment is compared against calibrated test weights and the information on the certificate gives traceability back to national standards. A traceable certificate provides the documentary evidence of calibration as required by a quality system such as BRC or ISO accreditation etc.
Calibration certificate options and prices are on the product pages.
Please note that calibration certificates do not make the scale Trade Approved.
Do I need a "Verified For Trade Use" scale?
If you are buying or selling by weight, the scale or balance must be 'Trade Approved', also known as 'Verified for Trade Use', 'Stamped', 'Weights & Measures Approved' or 'Class III Approved'.
Only certain scales can be Trade Approved. Accuracy tests are carried out on the scale and stickers added to the scale to confirm the tests were successful.
Medical scales used in hospitals, doctors' surgeries and pharmacies etc. must be 'Class III Approved' when used for treatment or diagnosis.
Scales used for buying or selling gold and silver must be 'Class II Approved'.
How often should I have my scales calibrated?
Typically we suggest that all weighing equipment is calibrated at minumum frequency of once per annum and more often if the weighing results are important to your process.
If the results are critical or for high accuracy applications, we recoMmend that in addition to the regular calibration visits by an engineer, the equipment is also checked daily prior to use, using calibrated test weights.
A longer certification frequency of two or three years can be justified if the accuracy drift between calibrations is much smaller than the accuracy that is required and if the application is not critical.
What are the accuracy classes for test weights, M1 , F1 etc.?
Accuracy (100g & up) - Class of weight (Suggested use)
+/- 0.1% - Proof Load Test Weights (LOLA testing etc)
+/- 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)
How to pack a scale
If the original packaging is not available, choose a sturdy box that is significantly larger than the item so that when the packing material is added, the item is securely held in place and cannot touch the sides. Cushioning and shock absorbing packaging material such as bubble-wrap is the ideal packaging material.
To protect the load sensor, where possible, remove the weighing pan and any under pan support and pack these items separately in the box. If the equipment has a shipping/locking device or screw then secure it as per the manual.
Please ensure that your contact details are sent with the item. Please see the home page for our address.
Please note: We cannot accept any liability for damage caused when an item you send us is damaged in transit.