ToolsAsbestosAir Sampling

Control Limit Compliance Checker

Check a fibre concentration against UK asbestos control limits — clearance indicator, control limit, and short-term exposure limit under CAR 2012.

Last updated 25 February 2026

About this tool

Check a measured airborne fibre concentration against the three key UK asbestos thresholds: the clearance indicator level (0.01 f/ml), the control limit (0.1 f/ml, 4-hour TWA), and the short-term exposure limit (0.6 f/ml, 10-minute TWA). The tool provides a clear traffic-light indication of compliance status.

How to use

Enter the measured fibre concentration in fibres per millilitre (f/ml). The tool compares it against the three statutory thresholds and displays a colour-coded result — green for below clearance level, amber for between clearance and control limit, and red if any limit is exceeded.

Reference

Control of Asbestos Regulations 2012 (CAR 2012). The control limit for asbestos is 0.1 fibres per cubic centimetre of air averaged over a continuous 4-hour period. The short-term exposure limit is 0.6 fibres per cubic centimetre averaged over 10 minutes. HSG248 specifies the clearance indicator level of 0.01 f/ml for 4-stage clearance procedures.

Revision history

25 February 2026: Initial release.

Disclaimer

This tool is provided for educational and general information purposes only. It is not a substitute for professional engineering advice, design or verification.

Diggy and its contributors are not licensed engineering consultants and no results generated by this tool should be used directly for construction, design or safety-critical decisions.

All values and outputs are based on published empirical correlations and should be independently checked and confirmed by a qualified geotechnical engineer before use.

By using this tool, you accept full responsibility for how you interpret and apply the information provided.

Spotted an error? Let us know.

Measured fibre concentration (f/ml)