There are three types of survey referred to in MDHS 100 these are:

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

Type 1 Asbestos Survey: Presumptive Surveys

Walk-through asbestos surveys are a rapid, visual assessment of the suspected asbestos installations present on a site. The survey technique relies on the ability of the surveyor to visually identify asbestos and does not normally include the taking of samples to confirm the presence of asbestos. Hence the surveyor has presumed the asbestos of asbestos using his / her knowledge of asbestos in buildings.

Type 2 Asbestos Survey: Standard Sampling Survey

Standard sampling asbestos surveys are the most common form of asbestos survey undertaken. They require the surveyor, again, to identify any installations on a site that she/he suspects may contain asbestos. These installations are then sampled (may require several samples depending on size and complexity of the suspect installation) and analysis carried out at an UKAS-accredited laboratory. This allows confirmation of whether the sampled materials definitely contain asbestos or are asbestos free.

The benefits of this survey technique are that a much more accurate result than the walk through-survey is achieved, by confirming where asbestos is present. It will also give additional information on asbestos types / concentrations on which to base an assessment of risk.

Type 3 Asbestos Survey: Full access Intrusive Survey

Full access intrusive asbestos surveys extend the ‘standard sampling asbestos survey’ to include investigations into reasonably accessible sealed voids and the fabric of the building.

This will include breaking through partition walls, ceilings etc. to confirm the presence or absence of asbestos and, normally, this is carried out prior to demolition or major refurbishment works where significant damage to the building will not be a problem. The survey requires full control measures to be put in place including air tight enclosures around the area for survey and carryout air monitoring.

The purpose of undertaking an asbestos survey is to create an ‘Asbestos Register’, that is easy to use by owners, managers, staff and anyone visiting the premises to undertake building or maintenance tasks.

These are the people most likely to be at risk of asbestos exposure, to the fibres in ducts and service areas. The ‘Asbestos Register’ requires regular updating to ensure that asbestos containing materials have not deteriorated causing danger.