Appendix B – Asbestos risk control options Method of control Description Appropriate when: Not appropriate when: Advantages: Disadvantages: Removal Removal of asbestos must be performed under certain controlled conditions, depending on the type of ACM to be removed. Where demolition or refurbishment works are to occur, and this work is likely to impact on ACM, the ACM must be removed under controlled conditions prior to the commencement of any site works. Surface friable or asbestos poorly bonded to substrata. Asbestos is severely damaged or liable to further damage or deterioration. Located in A/C duct. Airborne asbestos monitoring results exceed recommended exposure standard. Other control techniques inappropriate. Located on complex or inaccessible areas. Removal extremely difficult & other techniques offer satisfactory alternative. Hazard removed and no further action required. Cost-effective long term option. Increases immediate risk of exposure especially to removal workers. Creates major disturbance in building. Highest cost, most complex & time consuming method. Removal may increase fire risk within building; substitute required. Possible contamination of structure and increase in airborne fibre levels in adjacent occupied areas if the removal program is not strictly controlled. Encapsulate or Seal Coating of the outer surface of the ACM by the application of some form of sealant compound that usually penetrates to the substrate and hardens the material making it impermeable to asbestos. Helps protect the ACM from mechanical damage, and is designed Removal difficult or not feasible. Firm bond to substrata. Damage unlikely. Short life structure. Readily visible for Asbestos deteriorating. Application of sealant may cause damage to material. Water damage likely. Large areas of Quick and economical for repairs to damaged areas. May be adequate technique to control release of Hazard remains. Cost for large areas may be near removal cost. Eventual removal may be more difficult and costly.
to reduce the risk of exposure by inhibiting the release of asbestos fibres into the airborne environment, and increase the length of serviceability of the material. regular assessment. damaged asbestos. asbestos dust. Enclosure Enclosure involves installing a barrier between the ACM and adjacent areas where it is effective in inhibiting further mechanical damage to the asbestos. The type of barrier installed may include plywood or sheet metal products, constructed as a boxing around the asbestos. Removal extremely difficult. Fibres can be completely contained within enclosure. Most of surface already inaccessible. Disturbance to or entry into enclosed area not likely. Enclosure itself liable to damage. Water damage likely. Asbestos material cannot be fully enclosed. May minimise disturbance to occupants. Provides an adequate method of control for some situations. Hazard remains. Maintenance of enclosure. Need to remove enclosure before removal of ACM. Precautions for entry into enclosure. Defer The identification of ACM in a building does not automatically necessitate its immediate removal. Asbestos in a stable condition and not prone to mechanical damage can generally remain in situ. The ACM will need to be regularly monitored, and inspected every 2 years as part of the review of the asbestos registers to ensure its integrity is maintained. No risk of exposure. Asbestos inaccessible and fully contained. Asbestos stable and not liable to damage. Possibility of deterioration or damage. Airborne asbestos monitoring results exceed recommended exposure standard. No initial cost. Cost of removal deferred. Hazard remains. Need for continuing assessment and management.