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 Assessments
ASBESTOS SURVEYING
In July 2001, The HSE published the MDHS 100 Methods for the Determination of Hazardous Substances.
The MDHS 100 sets out how to survey and assess asbestos containing materials (ACM/s)
There are three types of survey referred to in the MDHS.
Type 1
Location and Assessment Survey ( a visual / presumptive survey ).
As the name implies, the purpose of this type of survey is to locate and assess materials
that could contain asbestos as far as reasonably practicable.
Materials that could contain asbestos are 'presumed'.
Materials that are highly likely to contain asbestos are 'strongly presumed'.
A type 1 survey defers the need to take samples of materials for laboratory analysis.
Example,
Artex can contain asbestos and would therefore be a 'presumed' material.
Corrugated cement roofing is almost always asbestos based and would therefore be 'strongly presumed'.
Whilst conducting the survey and assessment is made of each item to determine its overall risk potential.
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Type 2
Standard Sampling and Assessment Survey.
This type of survey builds on from the type 1 visual inspection and now incorporates sampling of
materials. Along with the sampling, an assessment is also made of the materials.
This type of survey may be conducted:
• where sites have a mixture of asbestos and non-asbestos materials
• for large uniform properties such as Housing Stock Surveys.
Access will be necessary to all areas that can be readily accessed, such
as, ceiling voids, risers, service ducts, lift shafts.
Additional tradespersons will be required at site to aid the surveyor, ie. lift engineers,
boiler and electrical engineers.
If an area is not accessed, it is presumed to contain asbestos.
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Type 3
Full Access Sampling and Identification Survey.
This survey builds on the Type 2 inspection and requires access to all areas. The survey is
intended for use prior to demolition or major refurbishment of buildings.
The survey must be designed to be intrusive. This can present problems, as a Type 3
survey is not easily performed in occupied buildings.
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Pre-Survey Work
This should wherever possible be a key element in all surveys and is necessary for all types
of survey.
It should include:
• an assessment of any available plans
• an inspection of the site to include an assessment of any hazards
• production of a suitable and relevant risk assessments.
The sampling of asbestos materials unless undertaken correctly is hazardous task.
Materials can have varying compositions and knowledge of this is essential.
MDHS 100 details the amount of samples that need to be collected from different materials.
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ASSESSMENTS
Assessments of materials under MDHS100 will be composed of 2 elements:
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Material Assessment Algorithm |
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Risk assessment of each sample that contains asbestos products |
Material Assessment Algorithm. This is proposed to have 4 components
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The type of products - insulation or floor tiles |
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The condition of the material - good, fair or poor |
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What surface treatment is present on the material - unsealed or painted |
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The asbestos type present in the material - Chrysotile Amosite Crocidolite |
These variables when combined will assist in determining the ability of a material to release asbestos fibre
Poor, untreated, loosely bound material, eg pipe insulation, will score higher than well bound sealed materials, eg floor tiles.
Many factors will play an important role in determining the accuracy of a survey:
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The surveyor must be a suitably qualified and experienced Building Surveyor with knowledge of buildings construction - type, design, age, form and function. |
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The surveyor must also have achieved as a minimum BIOH P402 certification. |
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The surveyor must be able to demonstrate independence, impartiality and integrity. |
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Have adequate insurances in place professional indemnity public and employers liability. |
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Ensure that the surveying company is an accredited Inspection body
to the government approved body for asbestos inspection Ukas and also to the
recognised standard BS EN ISO/IEC 17020.
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Managing & Uses
