Guides

Resources · Resources overview

Practical guides on local exhaust ventilation, extraction systems, workplace airflow testing and indoor air quality for UK employers, health and safety managers, occupational hygienists and facilities teams. The library is organised by topic so you can move quickly from a general question to the specific technical, compliance or industry-focused page that answers it.

How this guide library is organised

Workplace ventilation covers a wide range of engineering, compliance and operational questions — from whether a single weld bay needs on-torch extraction, through to whether a whole production area is meeting its COSHH duties under HSG258. To make the material easier to navigate, the guides are grouped into four clusters: LEV and extraction, airflow and indoor air quality, compliance and risk management, and industry-specific guidance.

Each guide is written for working professionals — site managers, hygienists, engineering leads and responsible persons — rather than for a general audience. The aim is to give you enough technical context to make a defensible decision, brief a contractor, or scope an assessment, without pretending that every situation can be resolved without a site visit.

LEV and extraction guidance

These guides cover the core engineering controls used to capture airborne contaminants at source. They explain how local exhaust ventilation is designed, examined and tested under COSHH Regulation 9 and HSE HSG258, and how different families of extraction system are specified for dust, welding fume and process fume.

Use this cluster when you need to understand whether an existing LEV system is fit for purpose, what a thorough examination and test should cover, or how to brief a project to upgrade dust, welding or fume capture in a production environment.

Local exhaust ventilation (LEV) — design principles and where LEV is required
LEV testing — what HSG258 thorough examination and testing actually measures
LEV examination — the 14-monthly statutory inspection cycle
Extraction systems — capture, transport, filtration and discharge
Dust extraction systems — woodworking, silica and bulk-handling environments
Welding extraction systems — on-torch, hood and ambient capture
Fume extraction systems — chemical, solder and process fume
Workplace contaminant extraction — at-source capture for dust, fume, mist and vapour

Airflow and indoor air quality guidance

Airflow testing is how you prove that supply, extract and transfer arrangements are doing what the design intended. Indoor air quality (IAQ) is how you understand whether the resulting conditions are acceptable for occupants and compliant with relevant guidance.

This cluster is most useful when investigating draughts, dead zones, short-circuiting, elevated CO₂, odour complaints, or general concerns about office and industrial air. It also covers the role of dilution ventilation and where it is — and is not — an acceptable substitute for LEV.

Workplace airflow testing — measuring supply, extract and transfer airflow
Airflow assessment — capture velocity, distribution and short-circuiting
Ventilation performance assessment — whole-system review against design and HSG258
Indoor air quality — CO₂, VOCs, particulates and thermal comfort
Indoor air pollutants — common sources and control routes
Workplace odours — investigation and control strategies
Dilution ventilation — where it works and where LEV is required instead

Compliance and risk management guidance

Compliance guides explain how workplace ventilation fits into the wider duty to control hazardous substance exposure under COSHH, and how ventilation features in risk assessment and engineering control selection. They are written with the responsible employer in mind — the duty holder who has to demonstrate, not just claim, that controls are adequate.

These pages do not replace formal advice from a competent occupational hygienist on a specific site, but they provide a structured way to think through scope, evidence and follow-up actions.

LEV compliance — COSHH Regulation 9 and HSG258 in practice
Ventilation risk assessment — source, pathway, receptor and control adequacy
Ventilation control measures — LEV and dilution within the hierarchy of control
Ventilation health risks — respiratory, sensitiser, carcinogen and IAQ effects
Ventilation assessment — independent review of workplace ventilation adequacy

Industry-specific guidance

Ventilation requirements differ significantly between sectors. A welding bay, a wet chemistry laboratory and a commercial office all have legitimate ventilation needs, but the contaminants, regulatory drivers and acceptable engineering solutions are not the same.

Use the industry guides as a starting point for sector context. They identify the contaminants that typically drive ventilation design, the engineering controls that are usually appropriate, and the failure modes that show up most often during assessment.

Manufacturing ventilation — LEV, extraction and IAQ across production
Laboratory ventilation — fume cupboards, biosafety cabinets and general extract
Commercial building ventilation — offices, retail and mixed-use environments
Industrial ventilation — design and performance for production environments
Industrial air extraction — process and general extract strategies

How to use the guides alongside an assessment

The guides are a working reference, not a substitute for a competent assessment. Most defensible decisions about ventilation — whether a system passes HSG258, whether dilution is adequate, whether an upgrade is justified — depend on measurements taken on site against the actual process. Read the relevant guide, scope your question, and then commission an assessment or thorough examination where the answer turns on data you do not yet have.