The official document that verifies the accuracy of a weighing scale for vehicles and their loads is called a weighbridge calibration certificate (WCC). It certifies that the weighbridge meets acceptable industry standards for accuracy, and records the latest calibration test results to prove it.
What goes on a calibration certificate?
Aside from calibration test results, a valid WCC details the equipment used to test the weighbridge, the individual who performed the tests, where and when it happened, and which methodologies and procedures were followed. The WCC includes details such as the serial number and type of weighing device, its capacity, accuracy class, and the scale interval with which it was tested. A qualified technician authenticates the certificate with a signature. In a lab setting, it can be validated by an organisation accredited by the United Kingdom Certification Service (UKAS).
Why is a calibration certification needed?
A calibration certificate is not a legal requirement for weighbridges. However, when used for trade purposes, a weighbridge is required to have a unique, valid WCC ready for inspection. A ‘trade approved’ weighbridge, as it is known, indicates that the weighbridge can be operated for trade purposes in accordance with the Weights and Measures Act 1985. In the UK, trading standards officers monitor loading sites to check that trade approved equipment is within specification and correctly marked. Whether trade approved or not, most weighbridges need to be recalibrated on an annual basis to guarantee accuracy, and identify potential issues such as hysteresis.
Operator certification
Whoever operates a weighbridge that people pay to use needs to hold a certificate of competence and adhere to its conditions. The conditions of competence include weighing on demand and fairly; providing statements of weight, usually in the form of a weighbridge ticket; and retaining two years worth of weighing information as a record, including dates, times, names, addresses, vehicle identifications (usually the number plate), and load types. Failure to comply can incur a fine of up to £5,000 and 6 months imprisonment.
3 types of calibration certificate
Weighbridge calibration certificates fall into three categories. ‘In-service’ certificates are used to verify that an existing scale complies with industry standards. ‘As new’ certificates are issued when a newly purchased or manufactured weighing device is tested and found to be accurate within its specified accuracy class. ‘Calibration confirmed’ certificates usually apply to a previously calibrated scale whose accuracy levels have been returned to acceptable levels following repairs or maintenance work.
How do I get a weighbridge calibration certificate?
In the UK, local councils can provide a verification, testing and calibration service in exchange for a fee. Tests are carried out by an Inspector of Weights and Measures from the local trading standards office. When buying a weighbridge, or at the point of initial verification, a declaration of conformity can also be issued by either a trading standards officer (TSO), an approved verification officer (AVO), or the manufacturer.
