HSE EIS21 Immersion & Cold Cleaning of Engineering Components

Controlling Health, Fire and Explosion Risks During Solvent Cleaning Operations

LEVCentral Expert Commentary

Cleaning and degreasing engineering components is a routine activity across many industries. Whether parts are immersed in tanks, cleaned using solvent sprays or degreased during maintenance, these operations can expose workers to hazardous solvent vapours while also creating significant fire and explosion risks.

HSE Engineering Information Sheet EIS21 – Immersion and Cold Cleaning of Engineering Components provides practical guidance on the safe selection and use of cleaning solvents and outlines the measures required to minimise both health and fire risks. The guidance covers immersion cleaning, in-situ cleaning and the use of aqueous cleaning systems, whilst emphasising the importance of carrying out suitable COSHH risk assessments before selecting cleaning methods.

For LEV professionals, the guidance reinforces an important occupational hygiene principle:

Where hazardous solvent vapours are generated, exposure should be controlled at source wherever reasonably practicable.

Depending upon the solvent used and the process involved, HSE explains that effective Local Exhaust Ventilation (LEV) may be necessary to prevent workers inhaling harmful solvent vapours. The guidance also discusses the importance of suitable respiratory protection where engineering controls alone cannot adequately control exposure.

The document is equally valuable because it reminds Duty Holders that cleaning processes should themselves be challenged. Before considering alternative solvents or additional controls, organisations should first ask whether cleaning is actually necessary or whether process changes could eliminate or significantly reduce the need for solvent cleaning altogether. This reflects the Hierarchy of Control and the principle that elimination remains the most effective form of risk control.

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View Original HSE Guidance

Key Learning Points

The guidance explains:

Health hazards associated with solvent cleaning.
Fire and explosion risks during immersion and cold cleaning.
Why organisations should first consider eliminating the need for cleaning altogether.
Selecting safer cleaning solvents where practicable.
The importance of COSHH risk assessment.
Reading and applying information contained within Safety Data Sheets (SDS).
The health effects of chlorinated and hydrocarbon solvents.
Skin absorption, dermatitis and eye protection.
The role of Local Exhaust Ventilation (LEV) in controlling solvent vapours.
Safe storage and handling of flammable solvents.
Good practice for immersion cleaning tanks.
Precautions when cleaning components in situ.
The use of aqueous cleaning systems as an alternative to solvent cleaning.
Maintenance of cleaning equipment and ventilation systems.

Source Document Information

Organisation: Health and Safety Executive (HSE)

Document: EIS21 – Immersion and Cold Cleaning of Engineering Components

Document Type: Engineering Information Sheet

Primary Topics: Solvent Cleaning, Degreasing, LEV, COSHH, Fire Safety, Flammable Liquids

Audience: Maintenance Engineers, Manufacturing Engineers, LEV Designers, Occupational Hygienists, Health & Safety Professionals, Duty Holders and Process Engineers.

LEVCentral Perspective

Although this guidance focuses on solvent cleaning, many of its principles apply to hazardous substance control generally.

Cleaning operations are often regarded as secondary processes, yet they may expose workers to solvent vapours, skin contact and fire risks that exceed those encountered during normal production. Selecting the correct cleaning method therefore requires consideration of health, safety, environmental impact and engineering controls.

For LEV professionals, EIS21 reinforces the importance of understanding the properties of the contaminants being controlled. Different solvents have different toxicological characteristics, vapour pressures and flammability, meaning that ventilation requirements cannot simply be standardised across every cleaning process.

Perhaps the most valuable message within the guidance is the simplest: before improving the cleaning process, first ask whether cleaning is required at all. Eliminating unnecessary cleaning operations can remove both exposure and fire risks while often reducing operating costs.

Further Resources

Recommended Learning

Thought Leadership

Solvent cleaning provides an excellent example of why effective exposure control begins long before ventilation is considered. The choice of cleaning method, solvent selection, process design and working practices all influence the level of risk presented to workers.

Where solvent cleaning remains necessary, well-designed LEV can play an important role in controlling vapour exposure. However, EIS21 reminds us that engineering controls form only one part of a wider risk management strategy.

Successful control depends upon combining appropriate process design, safer chemical selection, effective ventilation, competent maintenance and robust management arrangements to protect both workers and the workplace from health and fire hazards.