Asbestos Removal Process
The asbestos removal process is as follows:
Asbestos fibre release is controlled during the removal process by the construction of sealed enclosures.
The enclosures are constructed usually by a timber framework. 1000g polyethene is applied to the frame with joints and seams sealed with special spray tac adhesive and tape.
The entry point is in three stages and allows the asbestos operative to decontaminate before leaving to go into a mobile decontamination facility.
Waste materials also go a three-stage lock where double bagging of waste occurs before it leaves an enclosure.
Negative pressure is placed on the enclosures. This enables the air to be changed a minimum of eight times in an hour.
Negative pressure measures are used to reduce fibres within the enclosure. Additionally, it acts as a special control measure should the sheeting split during removal works accidentally. Fibres are drawn inwards instead of escaping outside.
Smoke tests confirm the integrity of the enclosure before removal works commence.
Operatives decontamination process
Disposable clothing is worn during live works in an enclosure. Colour coding is used to differentiate where it should be worn:
- Red – worn in “LIVE” enclosures
- Blue – transiting to and from the enclosure. Transporting double-bagged materials from the enclosure to a waste bin fitted with a lockable lid.
- White – general usage
Mobile units are used for the decontamination of asbestos operatives.
Self-contained decontamination units have built-in showers, water filtration systems for wastewater and negative pressure units.
Sealed lockable waste skip are safely store double bagged waste materials before transporting to landfill sites where all the waste is buried under license.
Wetting techniques are used using injection through needles or spraying. Encapsulation is another method using a sealant which is applied using a brush or roller. When the sealant dries, it forms a protective rubber coating.
During removal, asbestos is sprayed with dust suppressant liquids before removal. The liquid reduces and ensures airborne fibre release is below the protection limits of the operative’s breathing respirator during the asbestos removal process.
All resultant waste materials are single bagged in red asbestos waste bags before being wiped down and double bagged in the bag lock. The waste bags are clear.
After the encapsulation or removal of the asbestos material, the surfaces within the enclosure are cleaned environmentally to remove any debris or residue deposits. The area within an enclosure is vacuumed and cleaned. The supervisor then inspects the enclosure visually before passing it over to a UKAS accredited lab who will issue the certificate of reoccupation process.
The Certificate of Reoccupation
There are four stages involved which are
- 1: All paperwork and documentation is checked
- 2: Unless encapsulated the enclosure a visual check of the enclosure is carried out to ensure no asbestos is present and the level of cleanliness required has been achieved
- 3: Air test quality testing is carried out to check the air quality within the enclosure is below the clearance level
- 4: Plant and equipment are removed, and the enclosure sheeting is dismantled.
For more information on Environmental and Asbestos removal services
Tel: 01322 273517 or visit www.innercityenvironmental.co.uk
A guide to the asbestos removal process