Appendix D Test Equipment

1. Introduction
c. Decelerometers
a. Exhaust Gas Analysers
The MOT Testing Conditions of Appointment stipulate the minimum test bay equipment and other requirements. The MOT list of Acceptable Equipment lists the various makes and models of test equipment that have a measuring capability eg. headlamp aim testers, brake testers etc. The suitability of other test equipment is individually assessed at each testing station. Must be calibrated at intervals not exceeding 2 years. This can be done by a decelerometer manufacturer or a National Measurement Accreditation Service (NAMAS) A technician accredited by NAMAS. There are two exceptions
  i. non-catalyst OIML Class I equipment with an approved self-gassing facility requires a 6 monthly NAMAS calibration with an immediate calibration which may be performed by testing station staff.
  ii. equipment (non-catalyst or catalyst) with an approved automatic monthly self-gassing facility requires a 12 monthly NAMAS calibration with a monthly calibrations which may be performed by testing station staff.
2. Equipment Maintenance and calibration
d. Tyre Tread Depth Gauges
b. Roller and Plate Brake Testers and Headlamp Aim Testers
All MOT testing equipment must be properly maintained and kept in good order. Measuring equipment must also be calibrated and shown to be accurate at the appropriate time intervals (see paragraph 3) and in all cases calibration records must be kept, except for tyre tread depth gauges. A periodic accuracy check is required. This can be done by placing the base foot onto a flat surface (eg. window glass and checking that the zero datums align. Either
  i. the original manufactureror
  ii. a firm which has taken over responsibility for equipment support from the manufacturer,or
  iii. a calibration specialistor
  iv. an experienced person from the testing station. The Vehicle Inspectorate will witness a calibration prior to confirmation of this arrangement and may subsequently require periodic demonstration of continuing competence.
3. Frequency and Location of Calibration
e. Diesel smoke meters
5. Documentation
a. Exhaust Gas Analysers
i. Daily (checks by the user)

Carry out a leak check on the hose and probe. Most machines have an automatic facility for doing this. If not, a physical check of the hose and probe must be carried out to confirm that there are no leaks.

ii. Three, six or twelve monthly - depending on make/type

An exhaust gas analyser must be calibrated with a certified calibration gas and when the ambient temperature is above 5 deg C (see item 4a)

Note: Gas analysers cannot be properly calibrated if the mains AC voltage is less than 204v or more than 264v.
i. Weekly checks by the user

ii. Annual calibration by a technician accredited by NAMAS.
In cases where a testing station employs either the manufacture or a calibration specialist, there must be a written contract and the test station must obtain a certificate of each calibration
b. Roller Brake Testers and Headlamp Aim Testers
4. Calibration Personnel
Must be calibrated in situ every 6 months. It is acceptable for calibration certificates to be issued at any time during every sixth month. Equipment may be calibrated on site only by the following personnel: 
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