What is an Asbestos Enclosure?
An Asbestos Enclosure is a sealed habitat usually constructed of a timber or metal framework, covered in thick polythene, which is made airtight by the use of negative pressure air movers. Airlocks are installed on the entry /exit to provide suitable airflow and ensures an airtight environment when removing asbestos.
When do you need an Asbestos Enclosure?
An asbestos enclosure is required when the control limit of 0.1f/cm3 is likely to be exceeded or if the asbestos removal is in a sensitive area where a dust-free atmosphere must be maintained.
How can you be sure that it is airtight?
Before any asbestos removal can take place, a smoke test will highlight any area of the enclosure that is not airtight. A smoke machine fills the entire enclosure whilst a supervisor closely watches for any escaping smoke outside. If smoke is seen, the source will be sealed and the test will be repeated until the enclosure is demonstrably airtight.
How do you remove Asbestos within an enclosure?
Asbestos should only be removed when absolutely necessary for example when a building is to be demolished or refurbished to an extent which would disturb the asbestos materials The method of removal varies dependent on the type of ACM (asbestos containing material) however controlled wetting and dust suppression are standard control measures . This is the typical removal process with or without an enclosure.
During the removal process the asbestos materials are sealed into heavy duty red asbestos bags, these are then wiped clean and placed into the airlock where they are then placed into a clear labelled asbestos bag. This double bagging and cleaning process ensures no fibres are allowed to escape into the external atmosphere during the removal works.
How do you stop the release of fibres from Operatives clothing?
While removing asbestos the operatives will wear red disposable overalls. When they exit the enclosure via the airlock they wipe their masks and boots clean and vacuum the overalls before removing and placing into a waste bag, putting on clean overalls and then transiting to the decontamination shower unit.
The shower unit has two doors, one into the “dirty end” the other into the “clean end”. When coming from the asbestos enclosure, the operatives will enter the dirty end, remove their overalls and place these into a red waste bag for disposal. Once undressed, the operatives enter the shower section of the unit where they decontaminate thoroughly before passing into the clean end where they dress in their normal clothes and exit the unit.
For further information regarding the effectiveness and necessity of an asbestos enclosure alongside in-depth asbestos information the HSE website is a great source of data.