Removing asbestos in workplaces - Compliance ... - WorkSafe Victoria

Paraoccupational air monitoring andclearance inspections397. The person who performs paraoccupational air monitoring needs to determineall air monitoring requirements. Among other things, they need to decide:• the location, rate and frequency of sampling• whether it is necessary to monitor air quality in areas next to, above andbelow the asbestos removal area and in routes used for removing asbestoswaste, taking account of the potential exposure of current and futureoccupants of these areas• whether additional routine air sampling is warranted (eg in nearby highoccupancyareas)• clearance air monitoring requirements (see page 67).398. Paraoccupational air monitors generally need to be placed in the middle of thesampling area, away from areas where there may be poor air-mixing (eg closeto walls, corners or large objects) or fast air movements (eg in front ofairconditioning inlets or exhausts).399. If an enclosure is used, paraoccupational air monitoring needs to occur:• prior to any work (background monitoring)• throughout the duration of the removal work (commencing before theasbestos removal work commences and finishing after asbestos removalwork finishes for the day or shift)• at least at the boundary of the asbestos removal work area• as part of preliminary clearance monitoring following a satisfactory visualinspection• during dismantling of the enclosure• as part of the final clearance inspection.400. If an enclosure and a decontamination unit are used, paraoccupationalair monitoring needs to occur at the following locations:• clean side of the decontamination unit• change area• lunch room (where applicable)• surroundings of the asbestos work area, including near the negativeair unit (where possible).401. Air monitoring of the exhaust from the extraction unit is a specialised task.The membrane filter method (MFM) is unsuitable because the results obtaineddo not always truly reflect actual fibre concentrations in the exhaust air. Airmonitoring devices also should not be positioned at the exit point of a negativeair unit because this can lead to unwarranted confidence in the filter’s integrity.If the exhaust is to be monitored directly, isokinetic sampling techniques needto be used.402. The person who commissioned the removal work must arrange for the analysisof samples to be done by an approved asbestos analyst. An approved asbestosanalyst is a person approved by NATA to perform asbestos fibre counting (orto identify asbestos in samples) and to issue reports under the authority ofa NATA-accredited laboratory. Such persons may be found at nata.asn.au.If an analysis is requested for the purpose of meeting a regulatory requirement,ensure the report has a NATA stamp.403. Air monitoring needs to be done in accordance with the ASCC GuidanceNote Membrane filter method for estimating airborne asbestos fibres(available at ascc.gov.au).66 Compliance code / Removing asbestos in workplaces WorkSafe Victoria