CLEAPSS Guide G9 – Fume Cupboards in Schools

The Definitive Guide to School Fume Cupboards

CLEAPSS Guide G9 is the principal UK guidance document covering the selection, installation, use, maintenance and testing of fume cupboards in schools and colleges.

Produced specifically for educational environments, the guidance replaced the former DfEE Building Bulletin 88 (BB88) and remains the benchmark document used by schools, science technicians, laboratory designers, LEV engineers and contractors involved with school fume cupboard systems.

Unlike general laboratory guidance, G9 recognises that school laboratories present unique challenges:

Demonstration-based practical work
Student use of laboratories
Multi-purpose teaching environments
Mobile fume cupboards
Limited technician resources
Budgetary constraints

The guide provides practical advice on:

Ducted fume cupboards
Recirculatory filtration fume cupboards
School laboratory design
Fume cupboard siting
Airflow requirements
Containment performance
Annual testing
Maintenance requirements
Filter replacement
Procurement and specification

This resource is relevant to:

School Science Technicians & Teachers
School Estates Managers
Academy Trust Estates Teams
LEV Designers, Commissioners and Tester
Occupational Hygienists
Health & Safety Professionals
Fume Cupboard Suppliers

NOTE:- This guide is available ONLY to CLEAPSS Members. The link below will take you to the Log-In page

To become a member of CLEAPSS – follow this link:-http://science.cleapss.org.uk/Resources/Membership/

Source Document

View the CLEAPSS guidance here:

View Original CLEAPSS Guidance

Source: CLEAPSS
Document Type: Technical Guidance
Status: Current (Rev 2025)
Last reviewed by LEVCentral: June 2026

LEVCentral Expert Commentary

For anyone involved with fume cupboards in schools, G9 is arguably the single most important guidance document available.

Whilst industrial and university laboratories often follow standards such as BS EN 14175, school laboratories have operational requirements that differ significantly from commercial laboratories. CLEAPSS developed G9 specifically to address those differences and provide practical guidance tailored to educational settings.

One of the strengths of the document is that it goes far beyond simply specifying airflow values.

The guidance explains:

How fume cupboards work
Why containment matters
The limitations of face velocity measurements
The importance of siting and room airflow
The strengths and weaknesses of filtration systems
Appropriate testing methodologies

This is particularly valuable because many users incorrectly assume that a satisfactory face velocity automatically guarantees containment.

G9 repeatedly reinforces a principle well understood by experienced LEV engineers:

A fume cupboard is a containment device, not simply an airflow device.

A cupboard can have apparently satisfactory airflow readings yet still perform poorly if:

Room air currents disrupt containment
The sash is incorrectly positioned
Internal seals have deteriorated
Filters are leaking
The cupboard has been poorly installed

The guidance therefore takes a more holistic approach to performance assessment than simple airflow testing alone.

From a LEVCentral perspective, G9 is one of the best examples available of how engineering controls should be assessed based on actual performance rather than solely on measured airflow.

Key Learning Points

School Laboratories Have Unique Requirements

School fume cupboards are used differently from industrial and research laboratory systems and therefore require dedicated guidance.

G9 Replaced Building Bulletin 88

CLEAPSS G9 superseded the former BB88 guidance and is now regarded as the primary reference document for school fume cupboards.

Containment Is More Important Than Airflow Alone

Face velocity measurements are useful but do not by themselves guarantee effective containment of hazardous substances.

Ducted and Filtration Systems Have Different Strengths

The guidance provides detailed advice on the selection and application of both ducted and recirculatory filtration fume cupboards.

Annual Testing Remains Essential

School fume cupboards should be inspected and tested regularly to ensure they continue to provide effective protection.

Topics Covered by G9

How Fume Cupboards Work

Explanation of airflow, containment principles, sash operation and contaminant control.

Ducted Fume Cupboards

Guidance covering systems that discharge contaminated air externally through a dedicated extract system.

Recirculatory Filtration Fume Cupboards

Detailed guidance on filtration technologies, filter limitations and filter management.

Siting and Installation

Advice on positioning cupboards to minimise the impact of doors, windows and pedestrian traffic on containment performance.

Procurement and Specification

Guidance to help schools purchase systems suitable for educational use rather than relying on generic laboratory specifications.

Testing and Maintenance

Practical guidance covering annual testing, routine checks, record keeping and maintenance arrangements.

Occupational Hygiene Considerations

Fume Cupboards Are LEV Systems

School fume cupboards are examples of Local Exhaust Ventilation and should be managed as safety-critical engineering controls.

Risk Assessment Determines Need

The requirement for a fume cupboard should be based upon the hazards associated with practical activities and chemical use.

Filtration Systems Require Ongoing Management

Recirculatory filtration cupboards depend upon effective filter performance and correct maintenance.

User Behaviour Influences Performance

Sash position, work practices and cupboard loading can all affect containment effectiveness.

Relationship to Other Key Guidance

G9 complements a number of important laboratory and LEV documents including:

Together these documents provide a comprehensive framework for the specification, management and testing of school laboratory containment systems

Recommended Learning

Thought Leadership

Containment Versus Airflow
Defensible LEV Commissioning
School Laboratory Risk Management
Engineering Controls in Educational Environments

LEVCentral Observation

CLEAPSS G9 is far more than a purchasing guide for schools. It provides one of the clearest explanations available of how fume cupboards actually achieve containment and why airflow measurements alone do not tell the whole story.

For LEV professionals, occupational hygienists and school science departments, the guidance serves as an excellent reminder that effective contaminant control depends on design, installation, maintenance, testing and user behaviour working together.

In many respects, the principles contained within G9 apply equally well to industrial LEV systems as they do to school laboratories.