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Welfare Provision Calculator
Calculate welfare facilities required under CDM 2015
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How We Calculate This
Enter the number of workers on site and the project duration. The calculator applies the ratios used in the HSE Construction Welfare Standards: 1 chemical closet per 7 workers (weekly emptying, BS 6465-1), wash basins at 1 per 10 up to 50 then +1 per 20 (heavy soiling foreseeable in construction), a rest area at 1.0 m² per person (AD-B Appendix C floor-space factor, 4 m² minimum), and an estimated drinking-water volume of about 1.2 L per person per day (NHS guideline). First-aid provision follows INDG214 Table 2 for higher-hazard work: fewer than 5 workers → an appointed person; 5 to 50 → a trained first-aider; over 50 → one first-aider per 50. Separate toilets for female workers and drying facilities for projects over 2 weeks are added automatically.
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Last updated: March 2026
Verified against UK standards · estimates only, confirm with your supplier.