prEN 14175-9

• Abstract:

  This document specifies characteristics concerning the design and performance requirements together with type testing and on-site testing procedures especially for ducted filtration fume cupboards (DFFCs) not described in the other parts of EN 14175. Filters in DFFCs can be specific filters or a combination of filters dependent on the characteristics of the contaminants to be removed. ; This part of EN 14175 is related to and refers to other parts of EN 14175 regarding definitions, technologies, testing methodologies, design factors and functional aspects and is read in conjunction with these.; This standard covers the specific layout version of ducted fume cupboards with integral filtration. These devices called ducted filtration fume cupboards can be designed to partially reuse filtered air for internal dilution. Therefore, the term “hybrid” fume cupboards is sometimes used.; Fume cupboards with associated filters are considered as standard fume cupboards according EN 14175 1 to EN 14175 3. ; NOTE Their filter requirements, description and testing are listed in Annex A for information.; The requirements for fume cupboards and filters for radioactive work are described in detail in EN 14175 8.; Recirculatory filtration fume cabinets which return the filtered exhaust air back into the surrounding room are not part of this document but described in prEN 17242.; DFFCs are not foreseen for work with pathogens. Appropriate microbiological cabinets are described in the EN 12469 series.

• Status: Not Published
• Publication Date: 07-Jul-2027
• ICS: 71.040.10 - Chemical laboratories. Laboratory equipment
• Technical Committee: CEN/TC 332 - Laboratory equipment
• Drafting Committee: CEN/TC 332/WG 4 - Fume cupboards
• Current Stage: 4060 - Closure of enquiry - Enquiry
• Start Date: 06-Aug-2026
• Due Date: 16-Jun-2026
• Completion Date: 06-Aug-2026
• Ref Project: oSIST prEN 14175-9:2026 - Fume cupboards - Part 9: Fume cupboards, ducted with filtered internal recirculation

prEN 14175-9 is a CEN draft European Standard for fume cupboards with ducted filtration and filtered internal recirculation. It specifies design and performance requirements, together with type testing and on-site testing procedures, for Ducted Filtration Fume Cupboards (DFFC). It is aimed at people who select, design, test, install, maintain, or assess these fume cupboards in laboratory use.

What does prEN 14175-9 specify?

prEN 14175-9 specifies the characteristics of DFFC, including how they are designed, how they perform, and how they are tested in the laboratory and on site. It is written to be read together with other parts of EN 14175, especially for definitions, test methods, and general fume cupboard requirements.

The scope is focused on ducted filtration fume cupboards with integral filtration, where some filtered air may be reused inside the cupboard for internal dilution. Fume cupboards with associated filters are treated under the general EN 14175 approach, and Annex A gives informative notes on filter systems. The document also separates DFFC from recirculatory filtration fume cabinets that return filtered exhaust to the room, and from cabinets for radioactive work or pathogens.

Annex	What it covers
Annex A	Informative overview of filter systems used with fume cupboards and typical filtration principles

What are the key requirements of prEN 14175-9?

prEN 14175-9 combines general fume cupboard requirements with DFFC-specific controls for airflow, filtration, testing, documentation, and marking. In practice, this means the cupboard must be specified as a complete system, not just as a hood with a filter.

Design and risk-based selection

Clause 4.1 ties DFFC selection to a risk assessment and the manufacturer’s recommendation. The assessment is expected to consider the chemicals handled, quantities, needed containment, lab air capacity, filter type, filter change method, sampling or filter testing, and the containment performance class.

For users, this means the filter set-up must match the actual task. A DFFC is not a generic solution - the filter media and airflow concept have to suit the contaminants and the operating site.

Clause 4.1 also requires the filter type and intended use to be clearly visible to the operator. That matters because the front of the cupboard must tell the user what protection level and what filter configuration is in place.

Monitoring and alarms

Clause 4.2 requires continuous monitoring and alarms for relevant filter conditions, such as active carbon saturation or retention, and pressure drop where particle filters are used. Clause 4.3 adds monitoring of airflow conditions, especially when an air curtain is fitted.

In practice, this means operators need warning signals before performance drops below the intended level. It also means the cupboard should be maintained and checked regularly, not only after a fault is noticed.

Test methods for type testing and on-site checking

Clause 4.4 says the EN 14175-2, EN 14175-3, and EN 14175-4 test methods apply, but DFFC need additional detail. For type testing, three procedures are specified: the standard SF6 test, an adapted SF6 procedure without internal SF6 enrichment, and an additional containment test using isopropanol (IPA) tracer gas.

For readers, this is important because a DFFC may need both conventional test evidence and a test that better reflects its filter and recirculation behaviour. On-site testing can also use the IPA containment test so that commissioning and later checks can be compared with the original type test results.

Airflow, pressure, and sash-related checks

Clause 4.4 includes face velocity, sash position alarm, pressure drop, extract air volume flow rate, and workspace air volume flow checks. Where the design allows low inflow velocity or air reuse, the measuring tools must be suitable and calibrated for low air speeds.

This matters because a DFFC may not behave like a conventional cupboard with the same face velocity pattern. The airflow controls have to show that the work opening, sash position, and extracted volume remain within the intended operating range.

Additional containment performance test

Clause 4.4.7 introduces an additional containment performance test that combines static containment and dynamic robustness in one pass. It uses IPA tracer gas, a moving dummy positioned at the sash, a defined sampling arrangement, and a timed test sequence with baseline, build-up, movement, purge, and data analysis periods.

For users, this is the most DFFC-specific performance check. It shows how the cupboard behaves when an operator-like object moves at the front opening, which is where real containment failures are likely to occur.

Clause 4.4.7.9 defines four containment performance levels from 0 to 3 based on this test. That helps the laboratory relate the measured performance to the chemicals and tasks allowed under its own risk assessment.

Filter-specific testing and reporting

Clause 4.4.8 covers HEPA filter integrity, active carbon retention, combinations of HEPA and active carbon, and specially treated filter media. Clause 4.4.9 and 4.4.10 cover pressure drop and differential pressure reporting.

In practice, this means the filter system is not treated as a black box. The cupboard must show whether the filters still perform as intended, and the test report must identify the filter(s) and compare results with the manufacturer’s limits.

Documentation and marking

Clause 5 requires a product manual with guidance on suitable filters, replacement procedure, service life, storage of replacement media, maintenance, pollutant checking, and logbook records. Clause 6 requires front markings for work opening height, containment performance level, and filter type.

For purchasers and operators, these clauses are practical controls. They tell the site what to document, how to maintain the cupboard, and what information must be visible at the point of use.

What terms does prEN 14175-9 define?

• Air curtain - an additional air flow barrier, often vertical, at the front opening that helps separate the inside of the cupboard from the outside workspace.
• Filtration system - one or more filter components or devices, including fittings and seals, used to remove airborne contaminants.
• Integral filtration system - a filtration system built into the cupboard as a coherent, self-contained unit.
• Associated filtration system - a separate filtration system installed in the ductwork between the cupboard and the discharge point.
• Ducted Filtration Fume Cupboard (DFFC) - a ducted fume cupboard with integrated filters that allows internal recirculation of air as part of the make-up air.
• Prefilter - an initial filter stage used to protect or improve later filter components.
• Safe change - provisions that allow safe replacement and disposal of filters and prefilters to reduce operator exposure.
• Containment performance test - a test procedure that combines predetermined steps to assess containment, robustness, and air exchange efficiency.

Who uses prEN 14175-9?

prEN 14175-9 is used by manufacturers of laboratory fume cupboards, test laboratories, commissioning teams, maintenance providers, laboratory designers, and safety staff. It is also relevant to buyers, quality managers, and operators who need to specify or verify a DFFC for chemical laboratories.

The document is especially useful where hazardous particulates, gases, vapours, aerosols, or combinations of these are handled. It helps users decide which filter arrangement, monitoring, test method, documentation set, and marking are appropriate for the work.

Which standards are used with prEN 14175-9?

• EN 14175-1 - provides the vocabulary used across the EN 14175 series.
• EN 14175-2:2003 - gives the general safety and performance requirements that prEN 14175-9 builds on.
• EN 14175-3:2019 - supplies the type test methods, including the SF6 and IPA-based containment procedures used here.
• EN 14175-4 - provides the on-site test methods used for installation and field checks.
• EN 14175-6 - covers variable air volume fume cupboards and is part of the related EN 14175 family.
• EN 14175-7 - covers fume cupboards for high heat and acidic load.
• EN 14175-8 - covers fume cupboards for work with radioactive materials.
• EN 14387 - is used for the colour-band style filter marking referred to in the marking clause.
• EN ISO 14644-3 - is used for HEPA filter integrity testing.
• prEN 17242 - is referenced for recirculatory filtration fume cabinets and related adsorption filter methods.

What does the prEN 14175-9 document contain?

The document contains a scope, normative references, terms and definitions, detailed requirements, product manual and documentation requirements, and marking and labelling rules. It also includes an informative annex on filter systems used with fume cupboards.

Its technical core is the testing section, which lays out the standard and adapted SF6 procedures, the IPA-based containment performance test, airflow and pressure checks, filter integrity and retention tests, alarm checks, and reporting of filter results. The figures illustrate the DFFC concept, the air curtain arrangement, the adapted SF6 test set-up, the moving dummy containment test set-up, and the filter marking approach. Annex A summarizes filter principles and typical applications for particulates, gases, acids, bases, and special chemicals.

SLOVENSKI STANDARD
01-julij-2026
Digestoriji - 9. del: Digestoriji, opremljeni s filtriranim notranjim kroženjem zraka
Fume cupboards - Part 9: Fume cupboards, ducted with filtered internal recirculation
Abzüge - Teil 9: Abzüge, kanalisiert mit interner gefilterter Umwälzung
Sorbonnes - Partie 9 : Sorbonnes à recirculation partielle de l'air
Ta slovenski standard je istoveten z: prEN 14175-9
ICS:
71.040.10 Kemijski laboratoriji. Chemical laboratories.
Laboratorijska oprema Laboratory equipment
2003-01.Slovenski inštitut za standardizacijo. Razmnoževanje celote ali delov tega standarda ni dovoljeno.

DRAFT
EUROPEAN STANDARD
NORME EUROPÉENNE
EUROPÄISCHE NORM
May 2026
ICS
English Version
Fume cupboards - Part 9: Fume cupboards, ducted with
filtered internal recirculation
EN 14175-9: Sorbonnes - Partie 9: Sorbonnes à filtres EN 14175-9: Laborabzüge - Teil 9: Angeschlossene
raccordées Filterlaborabzüge
This draft European Standard is submitted to CEN members for enquiry. It has been drawn up by the Technical Committee
CEN/TC 332.
If this draft becomes a European Standard, CEN members are bound to comply with the CEN/CENELEC Internal Regulations
which stipulate the conditions for giving this European Standard the status of a national standard without any alteration.

This draft European Standard was established by CEN in three official versions (English, French, German). A version in any other
language made by translation under the responsibility of a CEN member into its own language and notified to the CEN-CENELEC
Management Centre has the same status as the official versions.

CEN members are the national standards bodies of Austria, Belgium, Bulgaria, Croatia, Cyprus, Czech Republic, Denmark, Estonia,
Finland, France, Germany, Greece, Hungary, Iceland, Ireland, Italy, Latvia, Lithuania, Luxembourg, Malta, Netherlands, Norway,
Poland, Portugal, Republic of North Macedonia, Romania, Serbia, Slovakia, Slovenia, Spain, Sweden, Switzerland, Türkiye and
United Kingdom.
Recipients of this draft are invited to submit, with their comments, notification of any relevant patent rights of which they are
aware and to provide supporting documentation.

Warning : This document is not a European Standard. It is distributed for review and comments. It is subject to change without
notice and shall not be referred to as a European Standard.

EUROPEAN COMMITTEE FOR STANDARDIZATION
COMITÉ EUROPÉEN DE NORMALISATION

EUROPÄISCHES KOMITEE FÜR NORMUNG

CEN-CENELEC Management Centre: Rue de la Science 23, B-1040 Brussels
© 2026 CEN All rights of exploitation in any form and by any means reserved Ref. No. prEN 14175-9:2026 E
worldwide for CEN national Members.

Contents Page
European foreword . 3
Introduction . 4
1 Scope . 5
2 Normative references . 5
3 Terms and definitions . 6
4 Requirements for ducted filtration fume cupboards . 7
4.1 General. 7
4.2 Filter monitoring and alarms . 10
4.3 Additional air flow monitoring . 10
4.4 Test methods . 10
4.4.1 General. 10
4.4.2 Face velocity test . 11
4.4.3 Sash Position alarm test . 11
4.4.4 Pressure drop test . 11
4.4.5 Extract air volume flow rate test . 11
4.4.6 Workspace air volume flow . 11
4.4.7 Additional Containment performance test . 12
4.4.8 Filter tests . 15
4.4.9 Filter pressure drop test . 16
4.4.10 Filter differential pressure test . 16
4.4.11 Tests of monitoring and alarms . 16
4.4.12 Reporting of filter tests . 17
5 Product manual and documentation . 17
6 Marking and labelling . 17
Annex A (informative) Filter systems in use with fume cupboards. 19
Bibliography . 20

European foreword
This document (prEN 14175-9:2026) has been prepared by Technical Committee CEN/TC 332
“Laboratory equipment”, the secretariat of which is held by DIN.
This document is currently submitted to the CEN Enquiry.
Introduction
Ducted Filtration Fume Cupboards (DFFC) are especially adapted devices intended to protect their users
and/or the external environment by means of:
— The ability to contain potentially hazardous materials.
— The ability to remove potentially hazardous materials from air exhausted from within the fume
cupboard housing by means of filtration before the air is discharged to the external environment.
The protection of operators is the main purpose of fume cupboards. As health risks are rising from more
and more potent hazardous products, additional barriers may be necessary. Regarding the installation
sites of cupboards there are growing efforts to improve environmental protection by additional filtration
of contaminated air directly at the source. As dilution is not a solution to pollution, the intention is to
minimise the discharge of contaminants into the atmosphere as well as to protect the exhaust air system,
to make the maintenance safer of this, and to prevent burden to the public environment. Use of filtration
also reduces the potential for re-entrainment of contaminated exhaust air through the air intakes. With
the possibility of partial filtered air reuse such ducted fume cupboards may reduce the volume of exhaust
air discharged. So, they may serve as an alternative solution, where building make up air ventilation is at
capacity limit, contributing to climate protection and energy saving.
The types of potentially hazardous materials to be removed include particulates, gases, vapours, aerosols,
and combinations of these. This objective is driven by aspects of performance based on health risks,
nuisance effects, environmental impacts, or a combination of these. The guidance for filter use is based
upon an operator risk assessment considering particulate or chemical hazards and work processes.
1 Scope
This document specifies characteristics concerning the design and performance requirements together
with type testing and on-site testing procedures especially for ducted filtration fume cupboards not
described in the other parts of EN 14175. Filter in DFFCs can be specific filters or a combination of filters
dependent on the characteristics of the contaminants to be removed.
This document is related to and will refer to other parts of EN 14175 regarding definitions, technologies,
testing methodologies, design factors and functional aspects.
This document covers the specific layout version of ducted fume cupboards with integral filtration. These
devices called Ducted Filtration Fume Cupboards (DFFC) may be designed to partially reuse filtered air
for internal dilution.
Fume cupboards fitted with filters which only act on the extracted air stream are not covered by this part.
Their filter requirements, description and testing could be taken from this standard, in particular in
Annex A.
Recirculatory Filtration Fume Cabinets which return the filtered exhaust air back into the surrounding
room are not part of this standard but described in the EN 17242.
The requirements for fume cupboards and filters for radioactive work are described in detail in
EN 14175-8.
DFFCs are not foreseen for work with pathogens. Appropriate microbiological cabinets are described in
EN 12469.
2 Normative references
The following documents are referred to in the text in such a way that some or all of their content
constitutes requirements of this document. For dated references, only the edition cited applies. For
undated references, the latest edition of the referenced document (including any amendments) applies.
EN 14175-1, Fume cupboards – Part 1: Vocabulary
EN 14175-2:2003, Fume cupboards - Part 2: Safety and performance requirements
EN 14175-3:2019, Fume cupboards - Part 3: Type test methods
EN 14175-4, Fume cupboards – Part 4 : On-site test methods
EN 14175-6, Fume cupboards – Part 6 : Variable air volume fume cupboards
EN 14175-7, Fume cupboards – Part 7: Fume cupboards for high heat and acidic load
EN 14175-8, Fume cupboard – Part 8: Fume cupboards for work with radioactive materials
3 Terms and definitions
For the purposes of this document, the terms and definitions given in EN 14175 (all parts), and the
following apply.
ISO and IEC maintain terminology databases for use in standardization at the following addresses:
— ISO Online browsing platform: available at https://www.iso.org/obp/
— IEC Electropedia: available at https://www.electropedia.org/
3.1
air curtain
additional (for instance vertical) air flow barrier in the front opening of a fume cupboard to support
containment efficiency in separating the inside from the outside of the workspace
3.2
filter
container or a frame containing a collecting filter medium to separate and trap impurities or solid
particles from a liquid or gases passed through it
3.3
filtration system
assembly of one or more filter components or devices that are used to remove/trap airborne
contaminants, including filter, fittings, seals and other connecting parts
Note 1 to entry: A non-exclusive list of types may include one or several particulate filters, chemical absorptive and
physical adsorptive filters (such as e.g., activated carbon), electrostatic precipitators, cyclones, washers, and
scrubbers; see Annex A.
3.4
integral filtration system
filtration system that is fully integrated into the construction of a fume cupboard insofar as it can be
regarded as a coherent, self-contained unit
Note 1 to entry: Fume cupboards with integral filtration systems may also be connected to associated filtration
systems.
3.5
associated filtration system
filtration system that is separate from, but associated with, a fume cupboard and is in the ductwork
between the fume cupboard(s) and the point of discharge from the laboratory
3.6
Ducted Filtration Fume Cupboard
DFFC
ducted fume cupboard equipped with integrated filters to enable internal recirculation of the air as part
of the make up air
3.7
prefilter
initial filtering stage used to remove particulates and/or gases/vapours to protect or improve other
components (e.g. of a filtration system) having higher removal efficiencies
3.8
extract air flow control arrangement
an installation, a control system or sub-system to provide consistent extract air flow conditions
3.9
‘Safe change’ of filters
provisions that allow safe replacement and disposal of filters and prefilters to reduce potential exposure
(e.g., inhalation, skin contact contamination) of the maintenance operator to potentially harmful material
or conditions
3.10
plenum
enclosure part of fume cupboards and cabinets, connected on the one hand to a filter system and on the
other hand to an air supply or an extract air system to isolate zones of air volumes of different pressure
levels
3.11
draught
uncontrolled air flow pattern, directed or turbulent, interfering with intended flow pattern
Note 1 to entry: As a result, draughts may influence the containment performance of fume cupboards.
Note 2 to entry: Low and high temperature draughts (e.g. from air conditioning or ceiling outlets) are often
particularly influential.
3.12
containment
resistance to egress or ingress of contents
Note 1 to entry: A device with containment is a containment enclosure.
3.13
containment performance test
specific test procedure to test the containment performance with a sequence of predetermined process
steps to evaluate containment, robustness, and air exchange efficiency in one pass
4 Requirements for ducted filtration fume cupboards
4.1 General
Fume cupboards (FC) with associated filtration systems are devices complying with EN 14175-2. They
are particularly characterised by the fact that they discharge all air exhausted from within them to the
duct after being filtered to reduce the levels of potential contaminants.
Ducted filtration fume cupboards (DFFC) have a layout with integral filters combined with partial internal
reuse of filtered air. For a schematic example, see figure 1. An overview of different filter systems is found
in the Annex A.
A variety of functional objectives may be addressed using a DFFC including:
— reduction in concentration of materials discharged that potentially present health risks;
— reduction in the level of contamination to exhaust ductwork installations;
— reduction in environmental impact of the fumes discharged;
— reduction in concentration of materials discharged that may represent a nuisance (odour, dust,
particulates as examples);
— protection from spillage effects;
— to overcome capacity limitations of air extract systems;
— energy savings.
The specific layout is characterised by the fact that all air volume flow to the exhaust is filtered before
discharge to the natural environment and thereby protecting it. A partial fraction of the filtered air
volume, e.g. 50 %, may be returned to the workspace within the fume cupboard to support retention of
contaminants. This principle may require or be supported by integral fans to overcome the pressure drop
of the filters and/or serve additional purposes.

Key
1 filtered exhaust air
2 filtered air
3 filtered air, returned to workspace as air curtain
4 potentially contaminated air
5 sash
6 supply air
7 workspace air volume flow
8 filter(s)
9 plenum for filtered air
10 fan
flow path of filtered air
flow path of supply air
potentially contaminated air
Figure 1 — Example for a DFFC concept
Solid arrows show the extraction of potentially contaminated air from the workspace through filters
underneath the work surface. The grey dashed arrows demonstrate the flow paths of the filtered air: One
fraction of the filtered air is released to duct and the other fraction returns to the workspace within the
fume cupboard envelope. Filter(s) may be positioned elsewhere within the overall envelope of the DFFC.
The specific requirements for DFFCs result from above concept example and shall be based on a risk
assessment and manufacturers recommendation. This could include:
— categories and quantities of chemicals being handled;
— special demands for retention of contaminants and containment;
— air flow capacities of the lab ventilation;
— filtration system and type;
— filter change procedure (Safe change of filters);
— sampling or filter testing;
— containment performance class of the fume cupboard.
NOTE CEN/TS 17441 “Ventilation systems in laboratories” can be a helpful reference.
The type of filters installed, and their intended use must always be clearly visible to the operator in front
of the fume cupboard.
DFFCs may have low face velocities and use an air curtain by design to improve the operator’s protection
at the work opening (see figure 2).

Key
1 potentially contaminated air
2 sash
3 supply air
4 air curtain
5 work surface
6 workspace air volume flow
flow path of filtered air
flow path of supply air
potentially contaminated air
Figure 2 — Example for a DFFC sash opening equipped with air curtain
The light grey dashed arrows demonstrate the flow path of the vertical air curtain to the work surface.
Dark grey solid arrows show the extraction of potentially contaminated air underneath the work surface.
4.2 Filter monitoring and alarms
Certain types of filters will have air flow resistances that increase with use, most typically due to
particulate loading of the filter media. Such increase in resistance is likely to affect (reduce) volume flow
rates of DFFCs. Active carbon filters are loaded with chemicals reducing their capture capacity and
efficiency as is the stripping agent in washers/scrubbers. Therefore, DFFCs should include continuous
monitoring and alarm(s) for:
— filter retention or saturation of active carbon filter(s), e.g. with solvent sensor or PID;
— filter pressure drop for particle filters, where appropriate;
— filters are an integral part of DFFCs and should be subject to regular maintenance and testing as part
of local safety regulations and manufacturer’s recommendations.
NOTE Other filter systems (see Annex A) can require additional items to be monitored (e.g. stripping liquid of
washers, e.g. with photometer or pH-meter).
4.3 Additional air flow monitoring
If the DFFC is equipped with an air curtain in the front opening, the efficiency of it is depending on the
airflow balance between inflow and downflow. An air curtain is fragile by design and may react
sensitively to draughts. The correct function of it assures the containment and therefore, it shall be
measured with a robustness test or containment test, e.g. see 4.3.6. Both the values of the total filtered
air volume and extract air volume flows must be monitored and determined alternatively.
The monitoring of the inflow, total filtered and extract air volume flow rates shall be in accordance with
EN 14175-2:2003, 8.2.
4.4 Test methods
4.4.1 General
The test methods of EN 14175-2, EN 14175-3 and EN 14175-4 apply.
Due to the specific characteristics of DFFCs some of the standard test methods need to be more detailed
hereafter. If the respective containment tests cannot be performed accordingly due to the fume cupboard
design and/or filter materials used an adapted testing described under 4.4.7 or additional containment
performance test described under 4.4.8 hereafter shall be carried out.
For the type testing of DFFC three test procedures shall be conducted in a type test laboratory according
to EN 14175-3:2019, Clause 4:
• the s
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