Document ID: chunk:federal_register_of_legislation:F2016L00418:body:0:p46
Version: federal_register_of_legislation:F2016L00418
Segment Type: other
Provision Reference: 
Character Range: 119194–122100

compressors.
The HEPA filter must comply with AS 4260:1997 High efficiency particulate air (HEPA) filters – Classification, construction and performance or its equivalent.
    * A coarse pre-filter should be installed on the air intake side of the negative air unit to prolong the useful life of the HEPA filter.
    * These pre-filters may need to be changed once per work shift or more frequently depending on dust loads.
    * Used pre-filters must be disposed of as asbestos waste.
    * A process of regular inspection of the integrity of the HEPA filter and seal fittings in conjunction with a static pressure alarm should indicate failures in the system.
The negative air units should operate continuously (24 hours a day) until all asbestos removal work and decontamination within the enclosure has been completed, a clearance certificate issued and the enclosure dismantled. If the units stop during removal work, the licensed asbestos removalist must ensure all removal work ceases immediately until the problem is rectified and the required number of units are in operation. To minimise the risk of airborne asbestos fibres escaping the enclosure, the delay should be as short as possible to avoid interruption. Consideration should be given to backup negative pressure exhaust units and the use of a generator.
Maintenance work on these units should only be performed after they have been thoroughly decontaminated, or the work may be carried out under controlled conditions, such as in an asbestos removal enclosure while wearing appropriate PPE.

Bulk stripping and cleaning within an enclosure
Sprayed asbestos insulations need to be wet thoroughly using a fine water spray. Aim to achieve maximum saturation with minimum run-off to minimise any subsequent clean-up and slip hazards.
Wetting, scraping and vacuuming methods need to be used wherever reasonably practicable. Where the asbestos or ACM is covered with cloth, metal cladding or wire reinforcing, it should be wet thoroughly during the removal process.
Once a competent person has determined the removal area is clean, the licensed asbestos removalist should, wherever reasonably practicable, spray clean surfaces within the removal area with tinted PVA or a similar acrylic emulsion using airless spraying equipment. This includes any layer of plastic forming the inner surface of the enclosure to ensure any loose asbestos fibres on the plastic are firmly adhered to prior to its dismantling.
After the PVA has dried and sufficient time has elapsed for it to dissipate, air (clearance) monitoring should take place, where required. The plastic enclosure must not be dismantled until a satisfactory visual inspection and monitoring has taken place.

Dismantling an asbestos removal enclosure
The licensed asbestos removalist should only dismantle a structure used to enclose an asbestos removal area once all of the following are