How to Choose a COSHH Store: Capacity, Ventilation and Compliance
Choosing the right COSHH store is one of the most important decisions a health and safety manager can make. Get it wrong and you risk regulatory enforcement action, insurance issues, and — most critically — a serious incident involving your workforce or the surrounding environment.
Under the Control of Substances Hazardous to Health Regulations 2002 (COSHH), employers must not only assess the risks of hazardous substances but implement adequate controls for their storage. A purpose-built COSHH store is one of the most effective control measures available, but only if it is correctly specified for your site and substances.
Key Legislation Governing Chemical Storage
- COSHH Regulations 2002 — requires safe storage of hazardous substances as part of risk control
- Dangerous Substances and Explosive Atmospheres Regulations 2002 (DSEAR) — applies to flammable liquids and gases; requires hazardous area classification and ATEX-rated equipment where appropriate
- Environmental Permitting Regulations 2016 — requires containment of substances that could pollute controlled waters
- Building Regulations (Approved Document B) — fire separation requirements applicable to storage structures
- HSE Guidance HSG71 — Chemical warehousing: the storage of packaged dangerous substances
Choosing the Right Capacity
The capacity of your COSHH store must reflect the maximum volume of hazardous substances on site at any one time. As a starting point:
- Audit all hazardous substances currently stored across your site
- Determine maximum stock levels (not just typical usage)
- Factor in delivery frequency — if deliveries arrive weekly, you may hold up to a week of stock at once
- Include contingency for seasonal demand or supply chain disruption
Remember that spill containment (bunding) is required within the store. Under the Environmental Permitting Regulations and PPG 2 (Pollution Prevention Guidance), the sump or bund must be capable of holding at least 110% of the largest single container, or 25% of the total stored volume — whichever is greater.
Compliance Checklist: What a COSHH Store Must Have
| Requirement | Standard / Regulation | Detail |
|---|---|---|
| Bunded sump | Environmental Permitting Regs | 110% of largest container or 25% total volume |
| Ventilation | COSHH / DSEAR | Natural or forced ventilation; ATEX fans for flammable liquids |
| Fire resistance | Building Regs / HSG71 | Minimum 30 min; 60 min recommended for flammable stores |
| Hazard signage | COSHH / Safety Signs Regs 1996 | GHS/CLP hazard pictograms, No Smoking, No Naked Flames |
| Electrical equipment | DSEAR / ATEX | ATEX-rated lighting and switches if flammable vapours present |
| Secure access | COSHH | Lockable; restricted to authorised personnel |
| Emergency information | COSHH / HSG71 | SDS for all stored substances displayed or readily accessible |
| Spill response equipment | COSHH / Environmental Regs | Appropriate absorbents and PPE within or adjacent to store |
Ventilation: The Critical Factor
Adequate ventilation is one of the most frequently underspecified aspects of COSHH stores. The ventilation requirements depend on the substances stored:
- Flammable liquids (e.g., solvents, fuels): Ventilation must prevent the accumulation of flammable vapours. ATEX-rated fans and fittings are required. Openings at both high and low level are needed to address vapours of varying densities.
- Toxic or irritant substances: Ventilation must prevent worker exposure above Workplace Exposure Limits (WELs) during routine access to the store.
- Oxidising agents: Must be stored separately from flammables; ventilation must prevent build-up of oxygen-enriched atmospheres.
A minimum of 8-10 air changes per hour is typically recommended for stores containing flammable substances. Always verify requirements against the SDS for each stored substance.
Siting Your COSHH Store
The location of a COSHH store affects both compliance and practical risk management. Key siting principles include:
- Locate away from site boundaries, public areas, and building openings
- Ensure emergency services can access the store easily
- Position downwind of occupied buildings where possible
- Maintain separation distances from drains and watercourses
Browse our full range of COSHH stores and chemical storage cabinets, including bunded options for flammable and toxic substances, to find the right solution for your workplace. We also stock the spill kits and absorbents needed to complete your chemical storage safety setup.
Need expert advice? Call 01744 520 110