CEN/TC 79

Date: 2025-11

prEN 144‑4:2025

Secretariat: DIN

Respiratory protective devices — Gas cylinder valves — Part 4: Excess flow devices

Atemschutzgeräte - Gasflaschenventile - Teil 4: Abströmsicherung

Appareils de protection respiratoire — Robinets de bouteilles à gaz — Partie 4 : Limiteurs de débit

CCMC will prepare and attach the official title page.

Contents Page

European foreword 4

Introduction 5

1 Scope 6

2 Normative references 6

3 Terms and definitions 6

4 Requirements 7

4.1 General 7

4.2 Excess flow device – non activated state 7

4.3 Excess flow device – activated state 7

4.3.1 General 7

4.3.2 Maximum flow 7

4.3.3 Activation pressure 8

4.4 Strength 8

4.5 Lifespan 8

4.6 Materials 8

5 Testing 8

5.1 General 8

5.2 Maximum flow at 300 bar and activation pressure 8

5.3 Strength 8

5.3.1 Impact test 8

5.3.2 Drop test 9

5.4 Lifespan test 9

5.4.1 Filling process – Excess flow device in non-activated state 9

5.4.2 Activation cycle-– Activation test of the Excess Flow Device 9

5.5 Visual inspections 9

5.6 Test schedule 9

6 Marking 10

7 Information supplied by the manufacturer 10

Annex A (informative) History/derivation of tests for Excess Flow Devices 11

A.1 General 11

A.2 Functional testing 11

Annex B (normative) Flow and activation pressure 12

B.1 Test equipment 12

B.2 Test samples 12

Annex C (normative) Drop test 14

C.1 Test equipment 14

C.2 Test samples 14

Annex D (normative) Life test 16

D.1 Test equipment 16

D.2 Test samples 16

D.3 Test procedure 16

European foreword

This document (prEN 144‑4:2026) has been prepared by Technical Committee CEN/TC 79 “Respiratory protective devices”, the secretariat of which is held by DIN.

This document is currently submitted to the CEN Enquiry.

Introduction

Respiratory protective device, among other things, of compressed gas cylinder(s) equipped with a valve, can be equipped with excess flow devices as an additional component to increase safety in the event of demolition or unintentional opening (see Annex A).

This document specifies the technical requirements and the necessary tests of Excess Flow Device (EFD) for use with respiratory protective devices (RPD), up to 300 bar operating pressure.

Devices that only close the flow in the event of a valve break-off do not fall within the scope of this document.

NOTE Throughout the breathing apparatus market exists a variety of cylinder valves that can have different ways of connecting to an EFD. The interchangeability of the EFD is only possible in the case of verified combinations of cylinder valve and EFD. The use of unverified combinations is not considered safe.

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.

prEN 137, Respiratory protective devices — Self-contained open-circuit compressed air breathing apparatus with full face mask — Requirements, testing, marking

EN 1146, Respiratory protective devices — Self-contained open-circuit compressed air breathing apparatus incorporating a hood for escape — Requirements, testing, marking

EN 144‑1:2018, Respiratory protective devices — Gas cylinder valves — Part 1: Inlet connections

EN 12021, Respiratory equipment — Compressed gases for breathing apparatus

EN ISO 10286, Gas cylinders — Vocabulary (ISO 10286)

EN ISO 11114‑1, Gas cylinders — Compatibility of cylinder and valve materials with gas contents — Part 1: Metallic materials (ISO 11114-1)

EN ISO 11114‑2, Gas cylinders — Compatibility of cylinder and valve materials with gas contents — Part 2: Non-metallic materials (ISO 11114-2)

EN ISO 11117:2019, Gas cylinders — Valve protection caps and guards — Design, construction and tests (ISO 11117:2019)

EN ISO 13341, Gas cylinders — Fitting of valves to gas cylinders (ISO 13341)

For the purposes of this document, the following terms given in EN ISO 10286 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

operating pressure

pressure that occurs after a complete filling of a breathable air cylinder at a uniform reference temperature of 15 °C in bar

Note 1 to entry: Referred to as “nominal filling pressure” in prEN 137:2025 or also referred to as “filling pressure”.

3.2

Excess Flow Device (EFD)

device that limits the flow escaping from a compressed air cylinder, not connected to an RPD, when the valve is suddenly opened or sheared off by accident

Note 1 to entry: Its function is to reduce the risk of the cylinder flying around or spinning thus becoming a risk for the persons and the environment.

An EFD shall be connected to the inlet thread of the valve. Both when filling and when extracting breathing air from the compressed gas cylinder, the total volume flow shall pass through the excess flow device.

In the event of shearing of the valve, the EFV shall remain integral within the cylinder shell.

The EFD shall not restrict the function of the respiratory protective device under operational conditions. This shall be checked as part of the tests of respiratory protective devices, e.g. prEN 137 or EN 1146.

a) In the event of unintentional opening of a cylinder valve, during handling, where securing by a sealing plug is not possible, e.g.:

— connecting to and detaching from the filling line;

— when connecting/mounting to an RPD;

— when checking the operating pressure with a separate pressure gauge;

b) in case of damage with crack or break off the cylinder valve, e.g.:

— a firefighter falls from a height;

— fall of the breathing air cylinder due to improper handling.

The excess flow device, even after activation, shall permit complete depressurisation of the breathing air cylinder.

The maximum flow rate with activated excess flow device at 300 bar operating pressure shall be 2 100 l/min (Figure B.1).

With this value, determined based on practical tests, the energy of the outgoing air no longer leads to uncontrolled movements of the cylinder.

Testing shall be made according to 5.2.

The excess flow device shall activate at a pressure between 15 bar and 100 bar (Figure B.1).

NOTE Depending on the valve design, particularly the nominal diameter, the arrangement of the outlet connections and sealing systems, as well as the design of the excess flow device used, there are existing safe systems on the market that allow a greater dispersion of pressures during activation. The values were determined in laboratory tests.

Testing shall be made according to 5.2.

Breathing air cylinders are subject to rough operation during use. As a consequence, it shall be ensured that the function of the EFD is kept unaltered.

Even after a fall of the breathing air cylinder or a direct impact on the cylinder valve, which can lead to a valve break, the EFD shall still function according to 5.2.

Testing shall be made according to 5.3.1 and 5.3.2.

A service life test is intended to simulate the resistance to ageing of the EFV in practical use.

For this purpose, the filling, emptying and unplanned activation of the EFV are considered.

The excess flow device shall withstand at least 400 filling cycles and 200 activation cycles at 300 bar, thus simulating actual use.

Testing shall be made according to 5.4.

The materials used shall comply with ISO 11114‑1 and ISO 11114‑2.

The manufacturer shall supply a declaration that this was addressed by a risk assessment, e.g. a FMEA.

The reliable function in standard operation in conjunction with a respiratory protective device shall be tested in accordance e.g. with prEN 137 or EN 1146.

When the cylinder valve is fully open (operating state), the pressure on the cylinder side is increased until the excess flow device is activated. The pressure is then further increased to the highest cylinder pressure (300 bar).

The flow and activation pressure test are described in Annex B.

Based on EN 144‑1:2018, 5.2, a cylinder valve with excess flow device and by means of an adapter shall be subjected to the 120-joule impact test. The hydraulic pressure test and the leak test are omitted. For further tests, the cylinder valve is replaced by a new, identical one, in which the excess flow device exposed to the shock is then mounted.

After this test, the test according to 5.2 shall be repeated.

A breathing air cylinder with cylinder valve and excess flow device is exposed to a free fall from a height of 2 m flat onto the cylinder shell surface.

After this test, the test according to 5.2 shall be repeated.

The drop test shall be performed as described in Annex C.

This test is to be carried out as an impulse test (puncture). The cylinder valve with excess flow device is screwed into an adapter. The direction of flow is from the output connection (pressure reducer connection) towards the input connection (cylinder connection).

400 filling cycles at 300 bar.

After this test, the test according to 5.2 shall be repeated.

The test shall be performed as described in Annex D, a schematic view of a test arrangement is shown in Figure D.1.

This test is to be carried out as an impulse test (puncture). The cylinder valve with EFV is screwed into an adapter. The flow direction is from the input connection (cylinder connection) towards the output connection (pressure reducer connection).

200 removal cycles at 300 bar.

After this test, the test according to 5.2 shall be repeated.

The test shall be performed as described in Annex D, a schematic view of a test arrangement is shown in Figure D.2.

After each test a visual inspection shall be carried out. No parts shall be damaged and/or loose, and no material cracks shall be visible.

The tests shall be carried out in accordance with the protocol set out in Table 1.

The eight samples shall be identified with letters from A to H and shall be tested according to column 5 of Table 1 below.

Table 1 — Test plan Excess Flow Device

All tests are carried out at a test temperature of typically 15 °C to 30 °C.

Excess flow devices that meet the requirements of this document shall bear a permanent marking with the following information:

a) identification of the manufacturer (manufacturer's mark);

b) article or type number for unique identification;

c) date of manufacture (year/month);

d) number of this document.

The manufacturer shall provide the following information about the cylinder valve with EFD:

a) interface breathing air cylinder;

b) interface cylinder valve (permissible combination);

c) types of breathing air cylinders (e.g. suitability for composite designs);

d) what to do in the event of incidents and damage (e.g. fall damage);

e) life expectancy;

f) compliance with this document.

1. 
   (informative)
   
   History/derivation of tests for Excess Flow Devices
   1. General

As a result of incidents involving flying breathing air cylinders, excess flow devices have been developed which prevent the breathing air cylinder from moving dangerously in the event of a rupture of the cylinder valve or unintentional opening.

During development, tests were carried out at the time to determine that the breathing air cylinder no longer poses any further danger when the excess flow device is activated with a flow rate of max. 2 100 l/min. For several years now large numbers of excess flow devices exist on the market, proving that such incidents do not occur again when using an excess flow device. Further investigations of excess flow devices on the market confirm that the hazard potential has been significantly reduced.

When measuring the recoil force of a suddenly opened 300 bar breathing air cylinder:

— without excess flow device forces of approx. 20 kg are obtained;

— with excess flow device forces of approx. 2 kg.

These forces provide a good assessment of the potential hazard with and without excess flow device.

• 1. Functional testing

In principle, the function can be checked by opening the cylinder valve with a breathing air cylinder filled with 300 bar without the sealing plug screwed on. However, this should only be done under appropriate safety precautions, and the test personnel should be appropriately trained. Due to the service life test carried out, a regular functional test is not necessary.

1. 
   (normative)
   
   Flow and activation pressure
   1. Test equipment

— A typical schematic view of a test arrangement for checking activation pressure and flow is shown in Figure B.2.

— The minimum cross-section of the test equipment shall be at least 50 % larger than the maximum cross-section of the cylinder valve to be tested without an excess flow device.

— Breathing air in accordance with EN 12021 shall be used for the test.

— The test equipment shall not restrict the flow.

• 1. Test samples

— The cylinder valve shall be fully open during the test.

— The excess flow device shall be attached to the cylinder valve in accordance with the manufacturer’s information (see Clause 7).

Figure B.1 — Visual representation accepted/ unaccepted test result

The activation pressure and the flow rate shall be documented up to test at 300 bar.

Key

Figure B.2 — Schematic view of a test arrangement for checking activation pressure and flow

1. 
   (normative)
   
   Drop test
   1. Test equipment

— A typical schematic view of a drop test is shown in Figure C.1.

— A steel breathing air cylinder with a capacity of 6 L and a diameter of 140 mm with a weight of 6,5 kg to 9 kg shall be used.

— The breathing air cylinder shall be unfilled (empty) in this case.

— A concrete block shall be used as the impact surface. This concrete block shall be protected by a steel plate of least 10 mm thickness. The impact surface shall be according to EN ISO 11117:2019, 7.7.3.

• 1. Test samples

— The excess flow device shall be attached to the cylinder valve in accordance with Clause 7.

— The cylinder valve shall be screwed into the breathing air cylinder in accordance with EN ISO 13341.

— The cylinder valve shall be completely closed during the test.

— If the cylinder valve has been damaged by direct contact with the ground during the drop test, this shall be replaced by a new, identical one for further tests, in which the previously tested excess flow device is then mounted.

Key

Figure C.1 — Schematic view of a drop test

1. 
   (normative)
   
   Life test
   1. Test equipment

— The minimum cross-section (nominal diameter) of the test equipment shall be at least 50 % larger than the maximum cross-section of the cylinder valve to be tested without an excess flow device.

— Breathing air in accordance with EN 12021 shall be used for the test.

— The design-related switching time of the solenoid valve used for full opening shall be less than 1 second.

• 1. Test samples

— The cylinder valve shall be fully open during the test.

— The excess flow device shall be mounted on the cylinder valve in accordance with Clause 7.

• 1. Test procedure

— The pressure surge duration (solenoid valve open) shall be at least 1 second.

— The pressure from the accumulator or the pressure source at the solenoid valve shall be 300 bar.

— The rest time between pressure surges shall be variable so that the supply pressure can be rebuilt or the permissible temperature of −30 °C is not undercut.

Key

Figure D.1 — Schematic view of a test arrangement for life span testing (filling direction)

Key

Figure D.2 — Schematic view of a test arrangement for life span testing (extracting direction)