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General Asbestos Work Information
Introduction
Asbestos Removal Operative
Asbestos removal or repair can be a complex task. As such there are many methods and details which differ from project to project. Below there are some examples and brief details of the type of controls and methods which can be used. Every asbestos project is unique and as such these methods or examples may not be suitable for your particular project. Please contact us for free advice and information if you require further guidance. All work with asbestos should be carried out by a suitably competent contractor, insured for such works and in full accordance with all regulations, approved codes of practice and guidance notes.
Area Segregation & Preparation
The importance or area segregation and preparation prior to work with asbestos cannot be under estimated. Area segregation is a control which is utilised to reduce the risk of exposure to airborne asbestos fibre to those outside of the work area. The segregation utilised will depend upon the works being undertaken and the assessment of risk carried out prior to the works.
For example the repair of an asbestos board followed by careful encapsulation poses far less risk than say; full removal of an asbestos insulating board.
As a minimum every asbestos work area should be cordoned off with an appropriate physical barrier such as warning tape and have sufficient signage posted to warn others of the risks within the segregated area. Where the risk is higher, such as during asbestos removal then it is normal practice for a full enclosure to be constructed which forms a complete sealed physical barrier around the work area.
Licensed asbestos removal contractors
The proposed work area should be inspected and checked to prepare for the asbestos works. The main purpose of this inspection is to identify the need for a pre clean, prepare the site for work (e.g. by sheeting or removing items, i.e. a soft strip), and to deal with matters which may cause difficulties in obtaining clearance certification / certificate of reoccupation.
The construction of an enclosure is complicated by nature and for the purposes of this brief introduction we have not included the large amounts of detail that are required to be carried out by asbestos contractors. However full information on this subject can be found within “Asbestos: The licensed contractors’ guide HSG247″.
The Basic Construction of an Enclosure
The most widely used form of enclosure is a self supporting temporary unit built to accommodate the work area. These consist of a frame to which sheeting material is securely fixed. Polythene is the usual material used, providing a flexible impervious and easily erected barrier. The frame is usually constructed from timber. All joints in the polythene are then adequately sealed with adhesive tape. Airlocks and bag locks are then attached to the enclosure. These form the ingress and egress points for waste and personnel.
Whatever the type of enclosure, it is important to remember that no construction method will give an absolute air tight seal and that some form of leakage will be present. For this reason, mechanical extract ventilation needs to be applied to maintain the air pressure inside the enclosure slightly below that of the external. This ensures that the airflow through any leaks in the enclosure will be inwards rather \than outwards, so that asbestos dust is contained within the enclosure.
Remediation / Repair
Asbestos waste disposal
Where asbestos products have been damaged, but are still fairly intact and are not likely to be disturbed in the future, repair works are often a good solution. Repair, encapsulation and protection of asbestos products is generally far more cost effective and less hazardous than asbestos removal.
Although this action will differ for each asbestos containing material the basic principles are the same. Repair of the asbestos is undertaken to lengthen the lifespan of the material and to allow for adequate encapsulation. For example where an asbestos board has been damaged and has a hole through it; the repair strategy would be to either bond a new non asbestos board over the top, utilising a non damaging fixing such as a ‘no nails’ glue, or to use a type of ‘scrim’ tape which can then allow for filling of the hole with a basic filling material.
Once the asbestos has been repaired encapsulation is required. Encapsulation of asbestos containing materials is undertaken for two main reasons. 1) The sealing of the surface prevents the release of airborne fibre. This is particularly important for more friable materials such as boards or sprayed coatings. 2) The recommended encapsulant utilised is a latex type paint which affords the asbestos some impact protection. This may prevent uncontrolled fibre release in the event of accidental minor impact to the material.
Protection of the repaired and encapsulated asbestos containing material is usually undertaken in circumstances where the likelihood of accidental damage is quite high. Although it may be prudent to remove asbestos from such areas; if adequate protection can be applied to reduce the risk of damage as low as is practicable this is often a more cost effective and suitable alternative. This protection can be undertaken in a number of ways and could be a timber or metal panel covering the asbestos, a purpose built timber boxing or even a metal barrier to prevent accidental damage from vehicles.
Shadow vacuuming techniques
Removal
In all cases no matter what type of asbestos containing material is being removed the method should disturb the fibres as little as possible. As such controlled stripping techniques are utilised. The technique utilised will depend upon many factors such as: type of asbestos product, thickness of the product, any coatings on the product, type of fixings (e.g. nailed or screwed) and condition, accessibility etc.
However there are basic guidelines which are observed for removal of all asbestos containing materials:
- Power tools should be avoided
- Abrasives should be avoided
- Dry stripping should be avoided
- Hot working should be avoided
- Controlled wet stripping techniques must be utilised (Water on its own will not adequately wet asbestos fibres)
- Careful Handling must be carried out
- Avoidance of unnecessary breakage
- Good waste control should be adhered to (clearing waste as the removal progresses)
- Shadow vacuuming techniques should be utilised where possible (with an ‘H’ type vacuum)
- Cleaning methods should not create dust
This information page is designed as a brief introduction. There are whole section of information not listed such as decontamination procedures, waste disposal etc. This id due to the large volume of information which could be written on the subject. However if you require any further information or advice with regards to asbestos removal or remediation; please contact us for free impartial advice.
