For situations where removing asbestos containing materials is neither possible or practicable, encapsulation can sometimes be the answer. However, encapsulation should only be considered if the ACM is not in a bad state and is firmly in place against its adjacent surfaces.
Any potential future damage to the ACM should also be considered before encapsulation takes place. This can be anything from excessive movement and friction, to water damage.
Liquid encapsulation agents, like Bostik’s ET150, when applied in several layers can be suitable for the encapsulation of asbestos insulation, boards, and sprayed coatings. However, it’s important to note that depending on the condition of the ACM and its makeup, you may require to be a licensed contractor to deal with it.
The requirements to make an asbestos job non-licensed, as guided by the HSE, are as follows:
The material is in good condition; and
The Control Limit (0.1 f/cm3 4 hour Time Weighted Average) will not be exceededduring the work; and
The Short Term Exposure Value (0.6 f/cm3 measured over any 10 minute period) willnot be exceeded during the work.
ET150 application best practises
It may be necessary to apply a thinned light coat of encapsulation paint to the surface of the ACM, depending on its condition. This will help bond and consolidate the surface area, prior to the thinker recommended layers.
If you believe that additional reinforcement is required, non-asbestos fibres can be added in between each encapsulation layer while they are still wet.
If encapsulating surfaces where asbestos has been removed, or asbestos residue remains, you should encapsulate over and beyond where the ACM was. This helps to ensure that no gaps in the paint are created, and that the asbestos is completely encapsulated.
Encapsulated areas should be reevaluated annually, to check for damage and integrity.