EN ISO 21904-4:2020

Health and safety in welding and allied processes - Equipment for capture and separation of welding fume - Part 4: Determination of the minimum air volume flow rate of capture devices (ISO 21904-4:2020)

This document specifies two methods for establishing the minimum air volume flow rate. One method is dedicated for use with captor hoods, nozzles and slot nozzles with a ratio of slot length to hose diameter of 8:1 or less. The other method is dedicated for use with on-gun extraction devices.
These methods are not applicable to down draught tables.

Arbeits- und Gesundheitsschutz beim Schweißen und bei verwandten Verfahren - Einrichtungen zum Erfassen und Abscheiden von Schweißrauch - Teil 4: Bestimmen des Mindestluftvolumenstromes von Absaugeinrichtungen (ISO 21904-4:2020)

Dieses Dokument legt zwei Verfahren zur Festlegung des Mindestluftvolumenstroms fest. Ein Verfahren ist für die Verwendung mit Abzugshauben, Düsen und Schlitzdüsen mit einem Verhältnis der Schlitzlänge zum Schlauchdurchmesser von 8 : 1 oder weniger geeignet. Das andere Verfahren ist für die Verwendung mit brennerintegrierten Absaugeinrichtungen geeignet.
Diese Verfahren sind nicht für abgesaugte Schweißtische geeignet.

Hygiène et sécurité en soudage et techniques connexes - Équipements de captage et de filtration des fumées - Partie 4: Détermination du débit volumique minimal d'air des dispositifs de captage (ISO 21904-4:2020)

Le présent document spécifie deux méthodes qui permettent de déterminer le débit volumique d'air minimal. Une méthode est applicable pour l'utilisation avec des dispositifs de captage, des buses et des fentes aspirantes ayant un rapport longueur de fente sur diamètre du tuyau inférieur ou égal à 8:1. L'autre méthode est applicable pour l'utilisation avec des torches aspirantes de soudage.
Ces méthodes ne s'applique aux tables aspirantes.

Zdravje in varnost pri varjenju in sorodnih postopkih - Oprema za zajem in ločevanje varilnega dima - 4. del: Določanje najmanjšega volumenskega pretoka zraka skozi odsesovalne naprave (ISO 21904-4:2020)

General Information

• Status: Published
• Publication Date: 10-Mar-2020
• Withdrawal Date: 29-Sep-2020
• ICS: 13.100 - Occupational safety. Industrial hygiene
• ICS: 25.160.01 - Welding, brazing and soldering in general
• ICS: 25.160.30 - Welding equipment
• Technical Committee: CEN/TC 121 - Welding
• Drafting Committee: CEN/TC 121/WG 9 - Health and safety in welding and allied processes
• Current Stage: 6060 - Definitive text made available (DAV) - Publishing
• Start Date: 11-Mar-2020
• Completion Date: 11-Mar-2020
• Directive: 2006/42/EC - Directive 2006/42/EC of the European Parliament and of the Council of 17 May 2006 on machinery, and amending Directive 95/16/EC (recast)
• Mandate: M/396 - Mandate to CEN and Cenelec for standardisation in the field of machinery
• Ref Project: SIST EN ISO 21904-4:2020 - Health and safety in welding and allied processes - Equipment for capture and separation of welding fume - Part 4: Determination of the minimum air volume flow rate of capture devices (ISO 21904-4:2020)

Relations

• Replaces: EN ISO 15012-2:2008 - Health and safety in welding and allied processes - Requirements, testing and marking of equipment for air filtration - Part 2: Determination of the minimum air volume flow rate of captor hoods and nozzles (ISO 15012-2:2008)
• Effective Date: 04-Mar-2020

Overview

EN ISO 21904-4:2020 defines test methods to determine the minimum air volume flow rate required for effective capture of welding fume by local extraction devices. It covers two dedicated approaches: one for captor hoods, nozzles and slot nozzles (slot length to hose diameter ratio ≤ 8:1) and one for on-gun (on-torch) extraction devices. The procedures ensure capture devices provide the suction field and air velocity specified in ISO 21904‑1. Methods in this standard are not applicable to down‑draught tables. Computational Fluid Dynamics (CFD) may be used as an alternative to physical measurement where indicated.

Key topics and requirements

• Scope: Establishes minimum volumetric flow required to achieve specified capture air velocities and suction-field dimensions (at least 1.5 D long and 1 D wide at a distance of 1.5 D; D = internal duct diameter).
• Two methods:
  • Method A: Captor hoods, nozzles and slot nozzles (slot:length to hose dia ratio ≤ 8:1).
  • Method B: On-gun extraction devices (test and reporting specifics adapted to torch-mounted capture).
• Test setup: Free-standing device, away from obstructions; ambient draughts < 0.1 m/s (5‑minute average).
• Measurement plane: Parallel to entry plane and located at 1.5 D from the entry.
• Instrumentation:
  • Non-directional anemometer for 0.2–0.5 m/s with ±0.06 m/s uncertainty.
  • Distance measuring device ±1 mm.
  • Duct flow measurement (venturi or orifice plate) with ±5% uncertainty.
  • Adjustable flow generator (fan with frequency converter or valve).
• Procedure details: Set volumetric flow, measure velocities along x and y axes in the measurement plane, identify positions meeting required velocity, calculate suction-field dimensions. Each velocity measurement must be averaged over at least 5 minutes with logging intervals no greater than 5 seconds.
• Reporting: Document test conditions, measured flow rates, positions, uncertainties and compliance with ISO 21904‑1 velocity requirements.

Applications and users

This standard is essential for:

• Manufacturers of welding fume capture hoods, nozzles and on‑gun extraction systems (product design and performance verification)
• Testing and certification laboratories validating minimum air volume flow rates
• Occupational hygienists and safety engineers specifying local exhaust ventilation (LEV) for welding workstations
• Procurement teams and compliance officers requiring documented evidence of capture performance for regulatory and workplace health reasons
• Designers using CFD to validate capture performance as an alternative to physical testing

Keywords: EN ISO 21904-4:2020, welding fume capture, minimum air volume flow rate, local exhaust ventilation, on‑gun extraction, captor hoods, welding fume control.

Related standards

• ISO 21904‑1:2020 - General requirements for equipment for capture and separation of welding fume
• ISO 12100:2010 - Safety of machinery - Risk assessment and risk reduction
• Supersedes: ISO 15012‑2:2008 (previous edition)

Standards Content (Sample)

SLOVENSKI STANDARD
01-maj-2020
Nadomešča:
SIST EN ISO 15012-2:2008
Zdravje in varnost pri varjenju in sorodnih postopkih - Oprema za zajem in
ločevanje varilnega dima - 4. del: Določanje najmanjšega volumenskega pretoka
zraka skozi odsesovalne naprave (ISO 21904-4:2020)
Health and safety in welding and allied processes - Equipment for capture and
separation of welding fume - Part 4: Determination of the minimum air volume flow rate
of capture devices (ISO 21904-4:2020)
Arbeits- und Gesundheitsschutz beim Schweißen und bei verwandten Verfahren -
Einrichtungen zum Erfassen und Abscheiden von Schweißrauch - Teil 4: Bestimmen des
Mindestluftvolumenstromes von Absaugeinrichtungen (ISO 21904-4:2020)
Hygiène et sécurité en soudage et techniques connexes - Équipements de captage et de
filtration des fumées - Partie 4: Détermination du débit volumique minimal d'air des
dispositifs de captage (ISO 21904-4:2020)
Ta slovenski standard je istoveten z: EN ISO 21904-4:2020
ICS:
13.040.40 Emisije nepremičnih virov Stationary source emissions
13.100 Varnost pri delu. Industrijska Occupational safety.
higiena Industrial hygiene
25.160.30 Varilna oprema Welding equipment
2003-01.Slovenski inštitut za standardizacijo. Razmnoževanje celote ali delov tega standarda ni dovoljeno.

EN ISO 21904-4
EUROPEAN STANDARD
NORME EUROPÉENNE
March 2020
EUROPÄISCHE NORM
ICS 13.100; 25.160.30 Supersedes EN ISO 15012-2:2008
English Version
Health and safety in welding and allied processes -
Equipment for capture and separation of welding fume -
Part 4: Determination of the minimum air volume flow
rate of capture devices (ISO 21904-4:2020)
Hygiène et sécurité en soudage et techniques connexes Arbeits- und Gesundheitsschutz beim Schweißen und
- Équipements de captage et de filtration des fumées - bei verwandten Verfahren - Einrichtungen zum
Partie 4: Détermination du débit volumique minimal Erfassen und Abscheiden von Schweißrauch - Teil 4:
d'air des dispositifs de captage (ISO 21904-4:2020) Bestimmen des Mindestluftvolumenstromes von
Absaugeinrichtungen (ISO 21904-4:2020)
This European Standard was approved by CEN on 20 January 2020.

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. Up-to-date lists and bibliographical references
concerning such national standards may be obtained on application to the CEN-CENELEC Management Centre or to any CEN
member.
This European Standard exists 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.

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COMITÉ EUROPÉEN DE NORMALISATION

EUROPÄISCHES KOMITEE FÜR NORMUNG

CEN-CENELEC Management Centre: Rue de la Science 23, B-1040 Brussels
© 2020 CEN All rights of exploitation in any form and by any means reserved Ref. No. EN ISO 21904-4:2020 E
worldwide for CEN national Members.

Contents Page
European foreword . 3

European foreword
This document (EN ISO 21904-4:2020) has been prepared by Technical Committee ISO/TC 44 "Welding
and allied processes" in collaboration with Technical Committee CEN/TC 121 “Welding and allied
processes” the secretariat of which is held by DIN.
This European Standard shall be given the status of a national standard, either by publication of an
identical text or by endorsement, at the latest by September 2020, and conflicting national standards
shall be withdrawn at the latest by September 2020.
Attention is drawn to the possibility that some of the elements of this document may be the subject of
patent rights. CEN shall not be held responsible for identifying any or all such patent rights.
This document supersedes EN ISO 15012-2:2008.
According to the CEN-CENELEC Internal Regulations, the national standards organizations of the
following countries are bound to implement this European Standard: 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, Turkey and the
United Kingdom.
Endorsement notice
The text of ISO 21904-4:2020 has been approved by CEN as EN ISO 21904-4:2020 without any
modification.
INTERNATIONAL ISO
STANDARD 21904-4
First edition
2020-02
Health and safety in welding and allied
processes — Equipment for capture
and separation of welding fume —
Part 4:
Determination of the minimum air
volume flow rate of capture devices
Hygiène et sécurité en soudage et techniques connexes —
Équipements de captage et de filtration des fumées —
Partie 4: Détermination du débit volumique minimal d'air des
dispositifs de captage
Reference number
ISO 21904-4:2020(E)
©
ISO 2020
ISO 21904-4:2020(E)
© ISO 2020
All rights reserved. Unless otherwise specified, or required in the context of its implementation, no part of this publication may
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Published in Switzerland
ii © ISO 2020 – All rights reserved

ISO 21904-4:2020(E)
Contents Page
Foreword .iv
Introduction .v
1 Scope . 1
2 Normative references . 1
3 Terms and definitions . 1
4 Captor hoods, nozzles and slot nozzles . 1
4.1 Principle . 1
4.2 Apparatus . 2
4.3 Test method . 2
4.3.1 Test setup . 2
4.3.2 Determination of the position of the entry and the measurement plane . 2
4.3.3 Procedure . 3
4.4 Test report . 4
5 On-torch extraction devices . 5
5.1 Principle . 5
5.2 Apparatus . 6
5.3 Test method . 6
5.3.1 Test setup . 6
5.3.2 Procedure . 6
5.4 Test report . 7
Annex A (informative) Additional information for on-torch extraction. 8
Bibliography .10
ISO 21904-4:2020(E)
Foreword
ISO (the International Organization for Standardization) is a worldwide federation of national standards
bodies (ISO member bodies). The work of preparing International Standards is normally carried out
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ISO collaborates closely with the International Electrotechnical Commission (IEC) on all matters of
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The procedures used to develop this document and those intended for its further maintenance are
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Attention is drawn to the possibility that some of the elements of this document may be the subject of
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iso/ foreword .html.
This document was prepared by Technical Committee ISO/TC 44, Welding and allied processes,
Subcommittee SC 9, Health and safety.
Any feedback or questions on this document should be directed to the user’s national standards body. A
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A list of all parts in the ISO 21904 series can be found on the ISO website.
This first edition cancels and replaces ISO 15012-2.
iv © ISO 2020 – All rights reserved

ISO 21904-4:2020(E)
Introduction
Welding and allied processes generate fume and gases, which, if inhaled, can be harmful to human
health. Control is often required to maintain exposure at acceptable levels and this can be achieved by
capturing the fume and gases using local exhaust ventilation.
For a particular capture device, the air velocity
...