The Trade Metrology Unit provides a range of calibration services centered around but not restricted to the trading parameters of mass, length and volume. These calibrations are directly traceable to the national standards.

Measured Values for mass are usually quoted on a weight - in - air basis, being the mass of a standard of density 8g/cm3, which would balance the weight in air of density 0.0012g/cm3.

The results can be given in any other basis at the request of the customer.

The Unit maintains secondary standards for length, which are calibrated periodically at CSIR and can therefore offer calibrations of line standards with direct traceability to the national standards.

The unit also offers calibration of metal content measures over the range of 1 to 20litres. The unit has the capability to calibrate volumetrically by discharge of a transfer liquid from a reference delivery vessel, ranging from small laboratory glassware to 10litres.

Verification Service

All weighing or measuring instruments used or intended for use in trade in Botswana must be verified before they can be used. The Weights and Measures Act makes it an offence for anybody who is found in possession of an instrument used for trade that has not been verified.

Trade Metrology Unit caries out verification of weighing and measuring instruments used in trade. This is done to ensure that the instruments conform to their metrological requirements (that it is suitable for use in the regulated area in such a way that it is expected to provide reliable measurements) and to the requirements of the Weights and Measures Act. The instruments covered are as follows.

Weighing Instruments (these are divided into two classes)

• Automatic and,
• Non - automatic.

An automatic instrument is an instrument that weighs without the intervention of an operator and follows a pre-determined programme of automatic processes characteristic of the instrument. e.g. automatic fillers in a packaging industry.

A non automatic instrument requires the intervention of an operator during the weighing process, for example to deposit on or remove from the receptor the load to be measured and also to obtain the results, either displayed or printed. For example an electronic counter scale or a weighbridge.

Measuring Instruments

• Liquor Measuring Instruments. e.g. tot measures, Bottle top pourers, beer/cider meters
• Fuel Pumps
• Petrol Tankers
• Bulk Flow meters

Measures of Length

• Tape Measures ( steel, fiberglass)
• Veneer Calipers
• Micrometers
• Rigid, semi rigid, folding and mounted rules

Prepackaged Commodities
The unit carries out tests by sampling on the packer's premises or at traders premises to check for the following;

• The labeling of the product (that it conforms with the requirement of the Weights and Measures Act)
• The accuracy and suitability of the equipment and whether it was properly maintained
• The adequacy of the quality control system, and that it was being followed.
• The adequacy of the records, and their accuracy by checking packages from the appropriate batch.
• The quantity in packages.
• Compliance with recommended pack sizes.