CLEAPSS GL123 “Fume Cupboard Buying Guide”

Choosing the Right Fume Cupboard for Schools and Colleges

CLEAPSS Guide GL123 provides practical advice to schools, colleges and laboratory designers on selecting suitable fume cupboards for educational environments.

The guide compares the advantages and disadvantages of ducted fume cupboards and recirculatory filtration fume cupboards, helping decision-makers understand which type is most appropriate for their intended use. It also highlights important specification criteria that are often overlooked during procurement, including airflow performance, visibility, mobility, commissioning requirements, noise levels and ongoing maintenance costs.

Although written specifically for schools and colleges, the guide contains valuable lessons for anyone involved in specifying containment systems and LEV equipment.

The guide covers:

Ducted fume cupboards
Recirculatory filtration fume cupboards
Procurement considerations
Airflow requirements
Visibility and teaching requirements
Mobility considerations
Installation and commissioning
Testing requirements
Filter management
Whole-life costs

This resource is relevant to:

School Science Technicians & Teachers
School Estates Teams
Academy Trust Estates Managers
Laboratory Designers
Health & Safety Professionals

Source Document

View the CLEAPSS guidance here:

View CLEAPSS Guidance

Source: Health and Safety Executive (HSE)
Document Type: Buying Guide
Status: Current
Last reviewed by LEVCentral: June 2026

LEVCentral Expert Commentary

Many schools purchase fume cupboards only once or twice during the life of a laboratory.

As a result, procurement decisions are often based on initial purchase price rather than a full understanding of performance requirements, maintenance obligations and operational suitability.

CLEAPSS GL123 addresses this problem by providing a straightforward comparison of the main fume cupboard options available to schools. Rather than concentrating solely on technical specifications, the guide focuses on the practical questions schools should ask before making a purchasing decision.

One of the most useful aspects of the guide is that it challenges the assumption that all fume cupboards perform the same function.

In practice, significant differences exist between:

Ducted systems
Recirculatory filtration systems
Mobile units
Fixed installations
Demonstration cupboards
Preparation room cupboards

Each has advantages and limitations that need to be considered before purchase.

From a LEVCentral perspective, one of the most valuable messages contained within GL123 is:

A fume cupboard should be selected based on its intended use, not simply its purchase cost.

A cheaper system may ultimately become more expensive when maintenance, filter replacement, testing and operational limitations are taken into account.

The guide therefore encourages a whole-life approach to procurement rather than a purely capital-cost decision.

Key Learning Points

Not All Fume Cupboards Are the Same

Different cupboard designs offer different levels of flexibility, containment performance and maintenance requirements.

Ducted Systems Remain the Preferred Option for Many Applications

Ducted fume cupboards physically remove contaminants from the laboratory and generally provide the broadest chemical compatibility.

Filtration Systems Have Limitations

Recirculatory filtration cupboards rely upon filter performance and may not be suitable for all substances or processes.

Whole-Life Costs Matter

Filter replacement, maintenance, testing and servicing costs should be considered alongside initial purchase price.

Commissioning Is Part of the Buying Process

The guide highlights that commissioning should form part of the procurement process and should ideally involve teaching and technical staff.

Ducted Versus Filtration Fume Cupboards

Ducted Fume Cupboards

Ducted cupboards remove contaminated air from the laboratory and discharge it externally via a dedicated extract system.

Advantages include:

Broad chemical compatibility
Long service life
Minimal consumable costs
Proven containment performance

Disadvantages may include:

Higher installation costs
Requirement for ductwork
Building modifications
More complex installation arrangements

CLEAPSS notes that ducted systems generally remain the preferred option where practical.

Recirculatory Filtration Fume Cupboards

These systems filter contaminated air before returning it to the room.

Advantages include:

Lower installation costs
Greater mobility
Easier deployment in existing laboratories
No external ductwork required

Limitations include:

Dependence on filter performance
Ongoing filter replacement costs
Restrictions on certain substances
Additional testing requirements

The guide highlights the importance of understanding filter limitations before selecting this type of system.

Specification Considerations

Face Velocity

The guide recommends a minimum face velocity of approximately 0.3 m/s at a sash height of 400 mm, with an ideal operating range of approximately 0.4–0.45 m/s. It also notes that excessively high velocities can create operational problems and waste energy.

Variable Air Volume (VAV)

The guidance highlights the benefits of VAV systems, which automatically adjust airflow as the sash position changes, reducing energy consumption compared with traditional bypass arrangements.

Visibility

Educational laboratories often require demonstration activities. Visibility for students should therefore be considered during selection and positioning of cupboards.

Noise Levels

Excessive fan noise can interfere with teaching. The guide recommends selecting systems that allow classroom instruction to continue without disruption.

Mobility

Whilst mobile cupboards offer flexibility, CLEAPSS notes that in practice many schools rarely move them because of technician workload and logistical constraints.

Why This Guidance Matters to LEV Professionals

Although aimed at schools, GL123 provides valuable lessons for anyone involved in specifying containment systems.

The guide demonstrates that successful procurement should consider:

Intended use
User behaviour
Whole-life costs
Maintenance requirements
Testing obligations
Operational practicality

These principles apply equally to industrial LEV systems, laboratory containment devices and specialist extraction equipment.

For LEV consultants and commissioning engineers, the guide also reinforces the importance of involving end users during specification and commissioning stages.

Recommended Learning

Thought Leadership

Containment Versus Airflow
Defensible LEV Commissioning
Whole-Life Costing of Engineering Controls
Procuring the Right LEV System First Time

LEVCentral Observation

CLEAPSS GL123 demonstrates that buying a fume cupboard is not simply a purchasing decision; it is a risk-control decision.

The guide encourages schools to move beyond headline purchase costs and consider how a cupboard will actually be used, maintained and tested throughout its life.

For LEV professionals, the document provides a useful reminder that successful engineering controls are rarely defined by technical specifications alone.

Long-term effectiveness depends equally on suitability, maintainability and the needs of the people who use them every day.