Air Testing and Four Stage Clearance Procedures

Asbestos air testing is an activity where a known volume of air is drawn through a filter over a measured period of time. During this time, airborne particles are collected on the filter which is then prepared for examination under a microscope.

A representative percentage of the filter is examined using phase contrast microscopy to count all fibres seen. Only fibres which meet the set size criteria are counted over the specified number of areas. From this, we can calculate the overall fibre concentration, shown as fibres per cubic centimetre of air (f/cm3).

The following testing services are available:

  • Personal air testing
  • Background air testing
  • Leak air testing
  • Reassurance air testing
  • 4 Stage Clearance Procedures (leading to the certificate of re-occupation)

Four stage clearances are also known as Certificates for Reoccupation. The key thing you need to know when asbestos removal works have been undertaken in your premises is that the former work area has been assessed to ensure it is thoroughly clean and is fit for reoccupation, prior to the area returning to normal use.

This assessment must be undertaken by an independent company (i.e. not the licensed contractor themselves) which is UKAS accredited in accordance with ISO 17025.

The 4 stage clearance certification process is the most important part of any asbestos removal project and you should ensure that you engage the right company.

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    How We Can Help?

    Here at Scopus, we offer a full/comprehensive range of air testing and four stage clearance services to ensure clients have access to independent professionals regardless of their reason/requirement to test the air for Asbestos fibres.

    Our air testing services (as detailed above) are UKAS accredited to 17025 and are carried out in accordance with HSE guidance including HSG248 Asbestos: The analysts’ guide for sampling, analysis and clearance procedures and in-house procedures.

    All of our Project Managing Asbestos Analysts hold the internationally recognised BOHS proficiency module P403 “Asbestos fibre counting” and P404 “Air sampling or the RSPH Level 3 Award in Asbestos Air Monitoring and Clearance Procedures and all actively participate in Regular Inter-Laboratory Counting Exchange (RICE) proficiency schemes administered by the Health and Safety Laboratory (HSL).

    Air monitoring paperwork and certification can be issued on site for both the building manager and the contractor (if required) in advance of any formal office issued report.

    Our asbestos air testing services can be offered on an emergency basis and are available 24 hours a day 365 days a year.


    • UKAS accredited for all Air Testing & 4 Stage Clearance
    • Asbestos Remedial Specification & Tendering Package
    • Project Managing Analysts
    • Removal Contractor Site Audits
    • Electronic Certification with Photographic Evidence
    • Nationwide Coverage
    • 24/7 Emergency Call Out Service – 365 days a year
    • Fixed Pricing for Nationwide Projects

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