As you know we have DOP and Servicing centres in our Christchurch, Wellington and Auckland branches. We have noted recently that people have been using non approved (manufacturers requirements) pre filters or even the use of media filter as a replacement for the pre filter. Please note this will void your warranty should this be found to be the case.
To ensure you warranties get honoured please follow the manufacturers operating manuals. Only use authorised agents who have been trained in servicing of your equipment. In one case we had a unit come to us with a new DOP certificate from another company yet it had not been decontaminated??? prior to testing.
Airflow testing is important as it proves whether your main H14 hepa filter is capable of extracting fibres down to the required standard of 99.995% efficiency. This is done at the exhaust end of the device using anemometer readings and calculations. From there it will determine whether the device operates within the manufacturers statement of use. It also proves to you what the air exchange capability of the device is when working out what your air exchanges are for the size of your room. If this is not done you may not have sufficient negative pressure in the enclosure and thus if there is a break in the enclosure which drops the pressure asbestos fibres may be released into the environment. Failure to take reasonably practicable steps may lead to punitive sanctions from WorkSafe.
Please note that part of ISO18001 will mention this requirement as part of your health and safety documentation.