HSE RR1010 – Standardisation of the Measurement of Capture Efficiency of On-Gun Extraction for Welding

Measuring the Effectiveness of On-Gun Welding Fume Extraction

HSE Research Report RR1010 investigates methods for measuring the capture efficiency of on-gun (on-torch) welding fume extraction systems and proposes a standardised approach for assessing their performance.

On-gun extraction systems have become increasingly popular following growing awareness of welding fume health risks and the subsequent strengthening of HSE enforcement expectations. Unlike conventional LEV hoods, on-gun extraction systems capture welding fume directly at the arc through extraction ports integrated into the welding torch.

The report was commissioned to address an important industry challenge:

How can the effectiveness of on-gun extraction systems be measured consistently and compared objectively?

The research examines:

On-gun extraction technology
Capture efficiency measurement
Laboratory testing methodologies
Welding fume control effectiveness
Performance benchmarking
Exposure-control verification
Standardised testing procedures
Engineering control evaluation

This resource is relevant to:

LEV Designers
Welding Engineers
P601 TExT Engineers
Occupational Hygienists
Health & Safety Professionals
Duty Holders

Source Document

View the HSE guidance here:

View Original HSE Guidance

Source: Health and Safety Executive (HSE)
Document Type: Research Report (RR1010)
Status: Published Research
Last reviewed by LEVCentral: June 2026

LEVCentral Expert Commentary

Following HSE’s 2019 welding fume enforcement changes, many organisations sought practical alternatives to traditional extraction hoods for welding operations. On-gun extraction systems emerged as an attractive solution because they provide source capture directly at the point of fume generation whilst allowing welders greater flexibility of movement.

However, one challenge quickly became apparent.

Manufacturers often quoted capture efficiencies using different test methods, making direct comparison difficult. A system claiming 90% efficiency under one test methodology could not necessarily be compared with another system claiming a similar figure using a different methodology.

RR1010 addresses this issue by investigating how capture efficiency can be measured in a repeatable and standardised manner.

The report is particularly valuable because it moves beyond theoretical airflow calculations and focuses on actual contaminant capture performance. This aligns closely with modern occupational hygiene principles, which increasingly focus on exposure reduction rather than engineering specifications alone.

For LEV professionals, the report reinforces an important lesson:

Airflow measurements alone do not determine how effectively contaminants are controlled

Two extraction systems operating at similar airflow rates may achieve significantly different capture efficiencies depending upon:

Torch design
Extraction nozzle geometry
Arc position
Shielding gas flow
Welding parameters
Operator technique
Workpiece configuration

The research demonstrates that capture efficiency testing can provide a more meaningful assessment of performance than airflow measurements alone when evaluating on-gun extraction systems.

The report is also useful because it highlights the limitations of relying solely on manufacturer performance claims. Competent evaluation requires understanding how systems perform under representative operating conditions.

From a LEVCentral perspective, RR1010 supports the broader principle of defensible exposure control. Effective welding fume management requires more than simply installing extraction equipment. Organisations should be able to demonstrate that controls are capable of reducing exposure and protecting workers under real operating conditions.

Key Learning Points

Capture Efficiency Is More Important Than Airflow Alone

A high airflow rate does not necessarily guarantee effective contaminant capture. The proportion of fume actually captured is often the more meaningful performance indicator.

On-Gun Extraction Can Be Highly Effective

When properly designed and used correctly, on-gun extraction systems can achieve significant reductions in welding fume exposure.

Standardised Testing Improves Comparisons

The report sought to establish a repeatable methodology that would allow different systems to be compared more consistently.

Exposure Control Should Be Verified

Engineering controls should be evaluated on their ability to reduce worker exposure rather than solely on design specifications.

Further Resources

Recommended Learning

LEVCentral Observation

RR1010 is an excellent example of the industry’s gradual shift from measuring engineering performance to measuring exposure-control effectiveness.

While airflow, static pressure and duct velocities remain important engineering parameters, the ultimate purpose of any LEV system is to prevent contaminants reaching the worker’s breathing zone.

By focusing on capture efficiency, this research helps bridge the gap between traditional LEV testing and occupational hygiene outcomes, making it particularly relevant to modern welding fume control programmes.