Asbestos Surveys

There are three types of survey referred to in MDHS 100;

• Type 1: Location and assessment Survey (presumptive survey)
  
  
• Type 2: Standard sampling, identification and assessment survey (sampling survey)
  
  
• Type 3: Full access sampling and identification survey (pre-demolition / major refurbishment surveys)
  
  

Type 1 MDHS100 Asbestos Surveys (Presumptive Surveys)

Type 1 surveys are to locate, as far as reasonably practicable, the presence and extent of any suspect asbestos containing materials in the building, and assess their condition.

A well-trained surveyor, familiar with asbestos products, can usually say whether a material can be 'presumed' to contain asbestos. This can only be tested by laboratory analysis of representative samples.

Therefore, a Type 1 survey may list many materials presumed to contain asbestos that would otherwise be eliminated from the asbestos register by laboratory analysis of samples.

However, it is more difficult to confirm that a material does not contain asbestos, and without analytical evidence, some non-asbestos materials may be presumed to contain asbestos.

The main points of a Type 1 Survey;

• All areas are accessed and inspected as far as reasonably practicable (e.g. above false ceilings and inside risers, service ducts, lift shafts, etc).
• Areas not accessible will be presumed to contain asbestos.
• Materials which can reasonably be expected to contain asbestos, will be presumed to contain asbestos.
• Where materials appears highly likely to contain asbestos, there will be a strong presumption that they do.
• They essentially defer the need to sample and analyse materials for asbestos until a later time, prior to any disturbance by demolition, alteration or maintenance.

The duty holder bears the potentially significant additional costs of management for some non-asbestos containing materials. Our experience suggests that the added cost of this usually outweighs the additional cost of a Type 2 survey with representative sampling of materials for laboratory analysis.

Type 2 MDHS100 Asbestos Surveys (Sampling Survey)

The purpose and procedures in this survey are the same as for Type 1, except that representative samples of suspected asbestos-containing material are collected and analysed. These are used to confirm or refute the surveyor's judgement on the presence of asbestos.

If the material sampled is found to contain asbestos, other similar homogeneous materials used in the same way in the building can be strongly presumed to contain asbestos.

Less homogeneous materials will require a greater number of samples for sufficient assessment of whether asbestos is present or not. Samples may be taken at the same time as the survey, or as in the case of some larger surveys, as a separate exercise after the Type 1 survey is complete.

We always recommend Type 2 surveys as the additional cost of representative sampling means the duty holder has a definitive report on all accessible asbestos containing materials. Non-asbestos materials will have been identified and eliminated by laboratory analysis, and therefore can be removed from the management plan, reducing future management costs.

Type 3 MDHS100 Asbestos Surveys (Full access and sampling)

This type of survey is used to locate and describe, as far as reasonably practicable, all asbestos containing materials in the building prior to demolition or major alteration.

The inspection will involve destructive inspection, as necessary, to gain access to all areas, including those that may be difficult to reach.

This typically involves breaking open ceilings, floors, partitions and internal boxing. It may also mean removing part of a roof covering that would potentially affect its integrity. A full sampling programme is undertaken to identify possible asbestos containing materials, and to make estimates of the volume and surface area of those asbestos containing materials.

The survey is to be used as a basis for tendering the removal of asbestos containing materials from a building prior to the demolition or major refurbishment. It does not assess the condition of the asbestos other than to note areas of damage, or where additional asbestos debris may be expected to be present.