Understanding LEV Regulations
Local Exhaust Ventilation (LEV) systems are critical engineering controls that protect workers from airborne contaminants such as dust, fumes, vapours, and mists. Both UK and European regulations mandate their proper design, installation, maintenance, and testing to ensure workplace safety and legal compliance.
Key Regulatory Areas: COSHH Regulations (UK), HSE Guidance (UK), DSEAR (UK), European Directives (EU-OSHA), ATEX Directives (EU), and Harmonised EN Standards.
This guide provides authoritative sources and practical information to help you navigate the complex landscape of LEV legislation and maintain compliance.
UK Legislation & Guidance
Control of Substances Hazardous to Health (COSHH) 2002
COSHH forms the legal foundation for controlling exposure to hazardous substances in UK workplaces. LEV is a primary control measure under COSHH.
- Regulation 7: Requires employers to prevent or, where not reasonably practicable, adequately control exposure to hazardous substances.
- Regulation 9: Mandates that any control measure (like LEV) is properly maintained, examined, and tested to ensure it remains effective.
- Employers must keep records of examinations and tests for at least 5 years and provide information, instruction, and training to employees.
Dangerous Substances & Explosive Atmospheres Regulations (DSEAR) 2002
DSEAR applies where flammable/explosive substances are present (e.g., wood dust, flour dust, solvents). It requires employers to:
- Carry out a risk assessment of fire and explosion risks.
- Implement measures to eliminate or control risks.
- Classify areas into hazardous zones (see ATEX section).
- Use appropriate (ATEX-certified) equipment in zoned areas.
HSG258: Controlling Airborne Contaminants at Work
HSG258 is the HSE's definitive "how-to" guide for LEV. It provides practical advice on the design, commissioning, and testing of systems to comply with COSHH.
- Provides clear checklists, diagrams, and benchmarks for good practice.
- Covers principles of hood design, ductwork, filters, fans, and discharge.
- Details the role of the "Competent Person" in LEV testing.
- Includes logbook templates and examples of test reports.
"LEV is an engineering control. It is not a 'fit and forget' solution. It must be properly designed, installed, commissioned, tested, and maintained."
Thorough Examination and Test (TExT)
This is the legal requirement under COSHH Regulation 9. It's a detailed check to ensure the LEV system is still providing adequate protection.
- Frequency: At least **every 14 months**. This can be more frequent for high-risk processes (e.g., every 6 months for certain carcinogens).
- Who can do it: A "Competent Person". This typically means someone with the BOHS P601 qualification or equivalent knowledge and experience.
- What it includes:
- A visual check for damage, blockages, or unauthorized changes.
- Technical measurements (e.g., capture velocities at hoods, transport velocities in ducts, static pressures).
- Assessment of filter and fan performance.
- Checking alarms and indicators are functional.
- Comparing performance against the original commissioning report.
- A "Pass" or "Fail" is given, with a report detailing any actions needed.
UK Standards (BS & BS EN)
These standards (many harmonised from EU standards) provide the technical "rules" for design and testing.
- BS EN 481:1993: Defines particle size fractions (inhalable, thoracic, respirable) for air sampling.
- BS EN 689:2018: Guidance on for assessing exposure to chemical agents and measurement strategy.
- BS EN 1093 Series: Safety of machinery - Methods for determining emissions of hazardous substances.
- BS EN 60079 Series: Standards for equipment used in explosive atmospheres (links to ATEX/DSEAR).
European Legislation & Standards
EU Directives
EU member states implement these directives into their own national laws (like COSHH in the UK).
- Framework Directive (89/391/EEC): The core directive for workplace health and safety, setting out general principles.
- Chemical Agents Directive (98/24/EC): Sets minimum requirements for protecting workers from chemical risks. The EU equivalent to COSHH.
- Carcinogens and Mutagens Directive (2004/37/EC): Sets stricter limits for cancer-causing substances like hardwood dust and silica.
ATEX Directives (Explosive Atmospheres)
This is the EU's primary framework for controlling explosive atmospheres, implemented in the UK as DSEAR.
- ATEX 153 (1999/92/EC): For employers (the "User" directive). Requires risk assessment, zoning of areas, and use of appropriate equipment.
- ATEX 114 (2014/34/EU): For manufacturers (the "Equipment" directive). Defines standards for equipment (e.g., fans, filters) intended for use in ATEX zones. Equipment must have the 'Ex' mark.
Harmonised EN Standards
These are standards used across the EU (and adopted by the BSI in the UK) to provide a "presumption of conformity" with the directives.
- EN 481: Workplace atmospheres - Particle size definitions.
- EN 689: Workplace exposure - Measurement strategy.
- EN 12198: Safety of machinery - Assessment of airborne hazardous substances.
- EN 1093 Series: Safety of machinery - Air-borne hazardous substances.
- EN 60079 / EN 80079 Series: The primary standards for designing and testing electrical and non-electrical equipment for explosive atmospheres (ATEX).
Compliance with these standards is the main way manufacturers and designers prove their systems are safe and effective.
EU-OSHA Guidance
The European Agency for Safety and Health at Work (EU-OSHA) provides a wealth of practical information, similar to the UK's HSE.
- Publishes factsheets, case studies, and reports on controlling hazardous substances.
- Runs the "OiRA" (Online interactive Risk Assessment) tool, a free tool for small businesses.
- Coordinates Europe-wide campaigns on topics like "Dangerous Substances" and "Stop Carcinogens".
Industry Bodies & Competency
Industry Bodies
These organizations lead the way in professional standards and competency.
- BOHS (British Occupational Hygiene Society): The UK's chartered society for worker health protection. They develop the "P-Series" qualifications for LEV competency.
- I-SLE (Institute of LEV Engineers): A professional institute for engineers and technicians working in LEV, promoting best practice and providing a register of competent engineers.
Competency & Training (BOHS)
HSG258 and COSHH require work to be done by "competent" people. This is often demonstrated with BOHS qualifications:
- P601: Thorough Examination & Test (TExT) of LEV Systems.
- P602: Basic Design Principles of LEV Systems.
- P603: Control of Hazardous Substances & COSHH.
- P604: Performance Evaluation & Management of LEV.
Key Concepts & Practical Resources
Industry Terminology & Key Concepts
Key Terms
- Capture Hood: The part of the LEV that 'captures' the contaminant at the source. Its design and position are critical.
- Capture Velocity: The speed of air required at the contaminant source to "pull" it into the hood.
- Face Velocity: The speed of air moving into the hood opening (the "face").
- Transport Velocity: The minimum air speed inside the ductwork needed to keep the contaminant (e.g., dust) airborne and prevent it from settling.
- Static Pressure: The measure of resistance in the system (from ducts, filters, bends). The fan must overcome this.
What is Capture Distance? This is the maximum distance a hood can be from the contaminant source and still effectively 'capture' it. It is the single most important factor in LEV design. If the hood is too far away, the system will not work, no matter how powerful the fan. Air velocity drops exponentially with distance from the hood.
Common Contaminants & Processes
- Wood Dust (Hardwood/Softwood): From sawing, sanding, routing. Hardwood dust is a known carcinogen. High explosion risk (ATEX).
- Silica Dust (RCS): From cutting/grinding concrete, stone, bricks. High-risk carcinogen.
- Welding Fume: Particulates from MIG, TIG, MMA welding. Risk depends on the metal and welding rod.
- Flour Dust: From bakeries and food production. A major cause of occupational asthma. High explosion risk (ATEX).
- Solvent Fumes (VOCs): From painting (bodyshops), printing, gluing. Can be flammable (ATEX) and hazardous to health.
- Oil Mist: From CNC machining, milling, lathing using metalworking fluids.
ATEX / DSEAR Zones (Explosive Atmospheres)
These zones classify the risk of an explosive atmosphere forming. The LEV equipment used *in* or *handling* air *from* these zones must be appropriately rated.
- For Dusts:
- Zone 20: Explosive cloud present continuously (e.g., inside a filter hopper).
- Zone 21: Explosive cloud likely in normal operation (e.g., near bagging points).
- Zone 22: Explosive cloud not likely, but possible for short periods (e.g., area around a well-maintained process).
- For Gases/Vapours:
- Zone 0: Explosive gas present continuously (e.g., inside a solvent tank).
- Zone 1: Explosive gas likely in normal operation (e.g., around filling nozzles).
- Zone 2: Explosive gas not likely, but possible (e.g., general area around a sealed process).
HSE Resources & Guides
Key HSE Documents
Practical, often sector-specific, guidance from the UK's Health & Safety Executive.
- INDG408: Clearing the Air: A simple guide for employers on buying and using LEV.
- WIS13: Wood Dust - Controlling the Risk.
- WL3: Welding Fume Control.
- CIS36: Construction Dust (Silica).
HSE LEV Tools
The HSE provides tools to help understand and manage LEV.
- LEV Calculator: A simple tool to estimate the air speed needed at a given distance from a simple hood.
- LEV Logbook Template: A template for the logbook required by HSG258.
- COSHH Essentials: A tool that provides "e-sheets" with specific control advice for different tasks.