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TTL PLC, National Control Centre. DN6 7HH

UKAS Accredited Asbestos Air Monitoring & 4-Stage Clearances

The Testing Lab PLC provides UKAS ISO/IEC 17025:2017 accredited asbestos air monitoring and 4-stage clearance testing throughout England, Scotland and Wales.

UKAS Accredited Asbestos Air Monitoring & 4-Stage Clearances

The Testing Lab PLC provides UKAS ISO/IEC 17025:2017 accredited asbestos air monitoring and 4-stage clearance testing throughout England, Scotland and Wales.

Asbestos Air Monitoring & 4 Stage Clearances Across the UK

Our highly trained and experienced staff hold all the qualifications and accreditations needed to ensure our services are provided in full accordance with current legislation and industry best practice.

The Testing Lab PLC provides UKAS ISO/IEC 17025:2017 accredited asbestos air monitoring and 4-stage clearance testing across domestic, commercial and industrial sites throughout England, Scotland and Wales.

Our independent analysts support licensed and non-licensed asbestos removal work, helping dutyholders comply with the Control of Asbestos Regulations 2012 and the HSE Analysts’ Guide (HSG248).

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Why asbestos air monitoring is essential

When work is carried out on or near asbestos-containing materials (ACMs), you must ensure that exposure to airborne fibres is prevented or kept as low as reasonably practicable, and that control measures are effective.

Asbestos air monitoring helps you to:

  • Confirm that control measures (e.g. enclosures, negative pressure units, wet stripping techniques) are working effectively

  • Demonstrate that employee exposure is adequately controlled and remains below the control limit of 0.1 fibres/cm³ (4-hour TWA)

  • Provide reassurance to building occupants and stakeholders that areas are safe

  • Provide the evidence needed for certificates of reoccupation following asbestos removal, using the 4-stage clearance procedure

Air monitoring and four-stage clearance are an integral part of a compliant asbestos management and removal strategy, not an optional extra.

Types of asbestos air monitoring we provide

In line with HSG248 and industry guidance, we offer a full range of asbestos air tests, including:

Background air monitoring
Carried out before asbestos work starts, to establish ambient fibre levels in a work area.

Leak air monitoring
Used during licensed removal work to check for leaks from enclosures or equipment into adjacent areas.

Reassurance air monitoring
Performed after non-licensed work or minor disturbances, or following incidents, to reassure occupants and verify that fibre levels are acceptably low.

Personal exposure monitoring
Sampling close to the breathing zone of workers to measure individual exposure, confirm adequacy of RPE, and demonstrate compliance with the control limit.

Clearance air testing (Stage 3 of 4-stage clearance)
High-volume sampling within an enclosure or work area after licensed removal, to demonstrate that airborne fibre concentrations are below the clearance indicator (typically 0.01 fibres/cm³) before an area can be reoccupied.

All monitoring is carried out by independent, UKAS accredited analysts, using methods aligned with HSG248 – Asbestos: The Analysts’ Guide

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What is the 4-stage asbestos clearance process?

The 4-stage clearance procedure is a formal process carried out after licensed asbestos removal to ensure an area is thoroughly clean and safe for reoccupation.

The stages are:

  • Stage 1 – Preliminary check of site condition and job completeness
    The analyst confirms that removal is complete, the enclosure is intact, and there are no obvious signs of debris before entry.

    Stage 2 – Thorough visual inspection
    A detailed visual inspection of all surfaces, fixtures, fittings and equipment inside the work area/enclosure, ensuring there is no visible dust or debris. Updated guidance emphasises thoroughness, photographic evidence and adequate time being allowed for this stage.

  • Stage 3 – Clearance air testing
    Airborne fibre monitoring is carried out under carefully controlled disturbance conditions. To pass, the results must demonstrate that fibre concentrations are below the clearance indicator (0.01 fibres/cm³).

    Stage 4 – Final assessment on completion of the work
    Once the enclosure has been dismantled, the analyst carries out a final check of the surrounding area to confirm it is clean and free from contamination before issuing a Certificate of Reoccupation.

The 4-stage clearance must be carried out by a competent, independent analyst and is a key element of demonstrating compliance with the Control of Asbestos Regulations 2012.

Our asbestos air monitoring and 4-stage clearance service

We provide a complete, integrated service for air monitoring and clearance:

  • 1. Planning & coordination

    • Liaison with dutyholders, licensed contractors and principal contractors

    • Review of the plan of work, enclosure design and programme

    • Agreement of monitoring strategy (background, leak, reassurance, personal and clearance tests)

    2. On-site air monitoring

    • Set up and operate calibrated air sampling pumps

    • Carry out sampling at agreed flow rates and durations

    • Ensure representative sampling positions and disturbance regimes where required

    3. Sample analysis

    • Filters are prepared and analysed in our UKAS ISO/IEC 17025 accredited laboratory using recognised methods aligned with HSG248

    • Quality control includes blanks, replicate counts and participation in external proficiency testing schemes

  • 4. Four-stage clearance and Certificates of Reoccupation

    • Full 4-stage clearance procedure following licensed removal

    • Time- and date-stamped photographic evidence and detailed notes where required by the latest guidance

    • Issue of formal Certificate of Reoccupation once all stages are passed

    5. Reporting & advice

    • Clear, concise air monitoring reports with fibre counts, durations and calculated concentrations

    • Interpretation of results, including assessment against control limit and clearance indicator

    • Practical advice on any further actions required (additional cleaning, repeat testing, changes to control measures, etc.)

Why choose The Testing Lab PLC?

UKAS accredited testing (ISO/IEC 17025)
Independent assurance of technical competence, reliable results and robust quality systems.

Independent from asbestos removal contractors
Analysts are independent of the contractor undertaking the work, as recommended by industry guidance.

Experienced asbestos analysts
Specialist staff with extensive experience across commercial, industrial, residential, education, healthcare and public sector projects.

Comprehensive service offering
Integrated with asbestos surveys, bulk analysis, re-inspections and removal support, providing continuity from initial identification through to final clearance.

Nationwide coverage
Teams based across England, Scotland & Wales for responsive support on planned works and emergency situations.

Areas we cover

From our National Control Centre in Doncaster, we provide asbestos air monitoring and 4-stage clearance services throughout:

We can support single projects, frameworks and multi-site programmes for national clients.

Frequently asked questions about asbestos air monitoring & 4-stage clearances

  • Is air monitoring always required during asbestos work?
    The Control of Asbestos Regulations 2012 require employers to monitor exposure where it is necessary to safeguard health or demonstrate that control measures are effective. In practice, air monitoring is routinely used during licensed removal and often during higher-risk non-licensed work, as well as for reassurance and investigations after incidents.

  • What is the difference between reassurance, leak and clearance air tests?
    Reassurance: Provides confidence that areas are safe after minor work, incidents or outside enclosures.
    Leak: Checks for potential fibre leaks from enclosures or RPE failures into adjacent areas.
    Clearance (Stage 3): Part of the formal 4-stage clearance after licensed removal, confirming that fibre levels are below the clearance indicator (0.01 fibres/cm³).

  • Who can carry out 4-stage clearance testing?
    Four-stage clearance must be carried out by a competent, independent analyst working for a UKAS accredited organisation, using methods set out in HSG248 – Asbestos: The Analysts’ Guide.

  • What happens if the area fails 4-stage clearance?
    If visible debris is found or air test results exceed the clearance indicator, the area fails clearance. The contractor must carry out further cleaning or remedial work, after which the analyst repeats the relevant stages until standards are met and a Certificate of Reoccupation can be issued.

  • How long must air monitoring and clearance records be kept?
    Asbestos-related records (including air monitoring, clearance test results and certificates) should be retained for at least 40 years under the Control of Asbestos Regulations and associated guidance.

Our Accredited Testing Services

Asbestos Testing & Analysis
UKAS accredited for bulk materials, soils, and air.
Legionella & Water Compliance
LCA registered risk assessments, testing, and remedial works.
Geotechnical Laboratory Testing
UKAS accredited soil and material testing.
WAC & Radon Testing
Externally accredited testing for waste and radon safety.
Mundic Block Testing
Specialist testing for concrete degradation.
RAAC Testing
Identify and manage RAAC risks in buildings.
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Douglas
Lothian Hotels Ltd

Dear The Testing Lab PLC,

Many thanks for your prompt and professional asbestos survey report service, I would not hesitate to recommend your company in this regard.

 

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Anonymous
Poole Housing Partnership

This must be an absolute record for getting a report back, considering the surveyor arrived around 3pm – very well done!
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Anonymous
ECORE Construction

Thank you for the very quick response for the quote and scheduling the survey. There’s never any fuss, and always straight forward. Thanks again.

 

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Stuart Meadowcroft
MRICS

Thank you for offering such a prompt turnaround for ACM testing and for your courteous service in doing so – I had a nervous client to placate and knowing the report would be back with them in such a short time was very reassuring to them, and for no more than a basic service from the competition!

 

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Anonymous
ARW Specialist Building Contractors Limited

Bradley, thank you for your efforts at short notice today, please pass on our gratitude to your surveyor Tim who did your company proud!

 

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Pawel Juraszczyk
British Pepper & Spice
H&S Manager

Thank you very much for the air sampling results – and please accept our grateful thanks for resolving this issue so quickly and for the promptness of the report.

Your analyst, Lee, was very helpful and his suggestions and advice appreciated.

We would have no hesitation in recommending The Testing Lab and will be in touch soon with regards arrangements for a full asbestos survey for the rest of the site.

 

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Gary Collinson MCIOB
Hull City Council
Programme Manager

TTL have been working directly as my analyst for the last 12 months on a very complex asbestos removal scheme, they have achieved all of their KPI’s without fail and on a number of occasions surpassed their SLA in acting for us on planning issues associated with the demolition in regard to contamination which cannot be removed as part of the normal sequence of operation.

 

There reports are always issued within timescales and they have policed the reports by the Licensed asbestos contractor faultlessly sometimes in very difficult circumstances.

 

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