EN 4856:2018

Rotorcraft - Emergency Breathing Systems (EBS) - Requirements, testing and marking

This document specifies requirements for Emergency Breathing Systems (EBS) for use by helicopter crew and passengers in the event of a ditching or water impact, to ensure minimum levels of performance. It applies to EBS for use by adults only.
Two categories of EBS are addressed by this standard; Category A EBS capable of being successfully deployed in air and underwater and Category B EBS capable of being successfully deployed in air but not underwater.
This document is applicable to compressed air, rebreather and hybrid rebreather designs of EBS.

Drehflügler - Notfallbeatmungssystem (EBS) - Anforderungen, Prüfung und Kennzeichnung

Dieses Dokument legt Anforderungen an Notfallbeatmungssysteme (EBS) fest, die von der Hubschrauberbesatzung und Passagieren im Falle einer Notwasserung oder dem Aufprall auf Wasser verwendet werden, um Mindestniveaus für die Leistung sicherzustellen. Es gilt für EBS nur die Verwendung durch Erwachsene.
Diese Norm befasst sich mit zwei Kategorien von EBS; EBS der Kategorie A, die erfolgreich in der Luft und unter Wasser eingesetzt werden können, und EBS der Kategorie B, die erfolgreich in der Luft, aber nicht unter Wasser eingesetzt werden können.
Dieses Dokument ist anwendbar für Druckluft , Kreislaufatemgerät  und hybride Kreislaufatemgerät-Auslegungen von EBS.

Giravion - Système de ventilation d'urgence (EBS) - Exigences, essais et marquage

Le présent document spécifie les exigences relatives aux systèmes de ventilation d'urgence (EBS) destinés à être utilisés par l'équipage et par les passagers des hélicoptères en cas d'amerrissage forcé ou d'impact avec un plan d'eau, afin de garantir des niveaux minimaux de performance. Elle s'applique uniquement aux EBS destinés à être utilisés par des adultes.
La présente norme couvre deux catégories d'EBS : l'EBS de catégorie A pouvant être correctement déployé à l’air libre et sous l'eau, et l'EBS de catégorie B pouvant être correctement déployé à l'air libre mais pas sous l'eau.
Le présent document s'applique aux modèles d'EBS à masque à recirculation et à masque à recirculation hybride, tous deux à air comprimé.

Rotoplani - Sistem prezračevanja v sili (EBS) - Zahteve, preskušanje in označevanje

Ta tehnični dokument določa zahteve za sisteme prezračevanja v sili (EBS), ki jih uporabljajo helikopterske posadke in potniki v primeru pristanka v sili ali vdora vode, da se zagotovi minimalna raven zahtevanih lastnosti. Velja samo za sisteme prezračevanja v sili (EBS), ki jih uporabljajo odrasli.
Ta standard obravnava dve kategoriji sistemov za prezračevanje v sili; EBS kategorije A, ki se lahko uspešno uvede pod vodo, in EBS kategorije B, ki se lahko uspešno uvede v zraku, ne pa pod vodo.
Ta tehnični dokument se uporablja za modele EBS dihalnih aparatov na stisnjen zrak, z zaprtim krogom in hibridne dihalne aparate z zaprtim krogom.

General Information

• Status: Withdrawn
• Publication Date: 11-Dec-2018
• Withdrawal Date: 13-Apr-2025
• ICS: 49.095 - Passenger and cabin equipment
• Technical Committee: ASD-STAN - Aerospace
• Drafting Committee: ASD-STAN/D 12/WG 2 - Ditching Equipment
• Current Stage: 9960 - Withdrawal effective - Withdrawal
• Start Date: 08-Feb-2023
• Completion Date: 14-Apr-2025
• Ref Project: SIST EN 4856:2019 - Rotorcraft - Emergency Breathing Systems (EBS) - Requirements, testing and marking

Relations

• Replaced By: EN 4856:2023 - Aerospace series - Rotorcraft Emergency Breathing Systems (EBS) - Requirements, testing and marking
• Effective Date: 03-Feb-2021

Standards Content (Sample)

SLOVENSKI STANDARD
01-marec-2019
5RWRSODQL6LVWHPSUH]UDþHYDQMDYVLOL(%6=DKWHYHSUHVNXãDQMHLQ
R]QDþHYDQMH
Rotorcraft - Emergency Breathing Systems (EBS) - Requirements, testing and marking
Rotorkraft - Notfallbeatmungssystem (EBS) - Anforderungen, Prüfung und
Kennzeichnung
Giravion - Système de ventilation d'urgence (EBS) - Exigences, essais et marquage
Ta slovenski standard je istoveten z: EN 4856:2018
ICS:
49.095 Oprema za potnike in Passenger and cabin
oprema kabin equipment
2003-01.Slovenski inštitut za standardizacijo. Razmnoževanje celote ali delov tega standarda ni dovoljeno.

EN 4856
EUROPEAN STANDARD
NORME EUROPÉENNE
December 2018
EUROPÄISCHE NORM
ICS 49.095
English Version
Rotorcraft - Emergency Breathing Systems (EBS) -
Requirements, testing and marking
Giravion - Système de ventilation d'urgence (EBS) - Rotorkraft - Notfallbeatmungssystem (EBS) -
Exigences, essais et marquage Anforderungen, Prüfung und Kennzeichnung
This European Standard was approved by CEN on 8 July 2018.

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.

CEN members are the national standards bodies of Austria, Belgium, Bulgaria, Croatia, Cyprus, Czech Republic, Denmark, Estonia,
Finland, Former Yugoslav Republic of Macedonia, France, Germany, Greece, Hungary, Iceland, Ireland, Italy, Latvia, Lithuania,
Luxembourg, Malta, Netherlands, Norway, Poland, Portugal, Romania, Serbia, Slovakia, Slovenia, Spain, Sweden, Switzerland,
Turkey and United Kingdom.
EUROPEAN COMMITTEE FOR STANDARDIZATION
COMITÉ EUROPÉEN DE NORMALISATION

EUROPÄISCHES KOMITEE FÜR NORMUNG

CEN-CENELEC Management Centre: Rue de la Science 23, B-1040 Brussels
© 2018 CEN All rights of exploitation in any form and by any means reserved Ref. No. EN 4856:2018 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 Classification . 8
5 Performance requirements . 10
6 Testing . 15
7 Marking . 27
8 Information supplied by the manufacturer . 28
(normative) Rating of breathing effort . 29

European foreword
This document (EN 4856:2018) has been prepared by the Aerospace and Defence Industries
Association of Europe - Standardization (ASD-STAN).
After enquiries and votes carried out in accordance with the rules of this Association, this Standard has
received the approval of the National Associations and the Official Services of the member countries of
ASD, prior to its presentation to CEN.
This document shall be given the status of a national standard, either by publication of an identical text
or by endorsement, at the latest by June 2019, and conflicting national standards shall be withdrawn at
the latest by June 2019.
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.
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, Former Yugoslav Republic of Macedonia,
France, Germany, Greece, Hungary, Iceland, Ireland, Italy, Latvia, Lithuania, Luxembourg, Malta,
Netherlands, Norway, Poland, Portugal, Romania, Serbia, Slovakia, Slovenia, Spain, Sweden, Switzerland,
Turkey and the United Kingdom.
Introduction
This document prescribes the minimum standards of design and performance for rotorcraft emergency
breathing systems (EBS), used to reduce the risks of drowning in the event of submersion. An
emergency breathing system is a form of personal protective equipment that provides the user with a
means to breathe underwater, thereby improving the probability of successfully escaping from a
submerged rotorcraft cabin. If used correctly, EBS should mitigate the risk of drowning.
This document aims to ensure that the equipment user is able to carry out the necessary emergency
procedures whilst being provided with an appropriate level of protection under foreseeable conditions
of use. It also aims to ensure that the equipment presents a minimal hazard in relation to escape from
the rotorcraft, and that the equipment has no detrimental effect on the health and safety of the user or
on the performance of other equipment.
This document is applicable to all rotorcraft. Rotorcraft include helicopters, tilt rotor/wing and
gyroplanes. For the purpose of this standard the term helicopter is used generically hereinafter.
1 Scope
This document specifies requirements for Emergency Breathing Systems (EBS) for use by helicopter
crew and passengers in the event of a ditching or water impact, to ensure minimum levels of
performance. It applies to EBS for use by adults only.
Two categories of EBS are addressed by this standard; Category A EBS capable of being successfully
deployed in air and underwater and Category B EBS capable of being successfully deployed in air but
not underwater.
This document is applicable to compressed air, rebreather and hybrid rebreather designs of EBS.
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.
International standards
EN 250, Respiratory equipment — Open-circuit self-contained compressed air diving apparatus —
Requirements, testing and marking
EN 12021, Respiratory equipment — Compressed gases for breathing apparatus
EN 14143:2013, Respiratory equipment — Self-contained re-breathing diving apparatus
EN ISO 9227, Corrosion tests in artificial atmospheres — Salt spray tests (ISO 9227)
EN ISO 12894, Ergonomics of the thermal environment — Medical supervision of individuals exposed to
extreme hot or cold environments (ISO 12894)
EASA publications
EASA, Certification Specifications and Acceptable Means of Compliance for Large Aeroplanes CS-25,
Book 1 — Appendix F
EASA, ETSO-2C502, Helicopter crew and passenger integrated immersion suits
EASA, ETSO-2C503, Helicopter crew and passenger immersion suits for operations to or from helidecks
located in a hostile sea area
EASA, ETSO-2C504, Helicopter constant-wear lifejackets for operations to or from helidecks located in a
hostile sea area
NOTE In the near future it is anticipated that ETSO-2C502, ETSO-2C503 and ETSO-2C504 will be revised and
that the revised documents will make reference to two new standards: prEN/EN 4862 Rotorcraft — Constant
Wear Lifejackets — Requirements, testing and marking and prEN/EN 4863 Rotorcraft — Immersion Suits —
Requirements, testing and marking. It is intended that when these new documents are published they should be
used in place of the ETSO documents currently referenced.
Other publications
World Medical Association Declaration of Helsinki — Ethical principles for medical research involving
human subjects (as amended): URL https://www.wma.net/policies-post/wma-declaration-of-helsinki-
ethical-principles-for-medical-research-involving-human-subjects/
3 Terms and definitions
For the purposes of this document, the following terms and definitions apply.
3.1
Emergency Breathing System
EBS
system that allows a person to breathe underwater, overcoming the need to breath-hold for the
complete duration of an underwater escape from a helicopter, that can be deployed under emergency
conditions
3.2
rotorcraft
heavier-than-air aircraft that depends principally for its support in flight on the lift generated by one or
more rotors
3.3
helicopter
rotorcraft that, for its horizontal motion, depends principally on its engine-driven rotors
3.4
ditching
controlled emergency landing on water, deliberately executed in accordance with Rotorcraft Flight
Manual procedures, with the intent of abandoning the rotorcraft as soon as practical
3.5
water impact
helicopter contact with water that is unintentional or exceeds the ditching capability of the helicopter
for water entry
3.6
mouthpiece
device that goes into the mouth of the user, usually held by the teeth, sealing against the lips and
through which a breathable gas is inhaled and exhaled
3.7
nose occlusion system
means of preventing water from entering the nose
Note 1 to entry: A nose clip is one example of a nose occlusion system.
3.8
demand regulator
device which consists of a pressure reducer connected to a demand valve
3.9
medium pressure hose
hose with an interface connection at each end, between the pressure reducer and a demand valve
3.10
breathing hose
flexible hose connecting a counterlung to the mouthpiece of a rebreather EBS, at approximately ambient
pressure
3.11
pressure indicator
device to indicate to the user the pressure of gas in a cylinder
3.12
purging device
part of the demand regulator that can be operated manually to deliver breathable gas, intended to force
water out of the mouthpiece
3.13
dead space
volume of the cavity formed between the mouth and the inhalation and exhalation parts
3.14
activation device
mechanism which switches breathing from the atmosphere to the counterlung of a rebreather EBS
3.15
counterlung
variable volume container for the user to exhale to and inhale from
3.16
breathable gas
gas that will support life under the intended conditions of use
3.17
work of breathing
work expended during one breathing cycle which is proportional to the area bounded by the pressure
volume diagram divided by the tidal volume
Note 1 to entry: Measured in Joules per litre.
3.18
respiratory pressure
differential pressure at the mouth relative to the no flow pressures measured at the end of inhalation
and exhalation
3.19
hydrostatic imbalance
difference at end exhalation no flow between the pressure at the mouth and that at the lung centroid
reference point
3.20
tidal volume
volume of breathing gas displaced by the breathing simulator during one half cycle (inhalation or
exhalation)
Note 1 to entry: Measured in litres.
3.21
respiratory minute volume
product of the tidal volume and breathing frequency
Note 1 to entry: Measured in litres per minute.
3.22
useable volume of air
volume of breathable air available to the user while the demand regulator is operating within the
specified breathing performance
3.23
rated working pressure
maximum working pressure of the respective components
3.24
pressure volume diagram
diagram generated during one breathing cycle by plotting the respiratory pressure against the
displaced (tidal) volume
3.25
elastance
change in pressure that results from a given volume change of the human lung
−1
Note 1 to entry: Measured in kPa.L
Note 2 to entry: This is a typical term for the elastic behaviour of a breathing system.
3.26
reference pressure
equilibrium pressure which exists in the mouthpiece when there is no respiratory flow at the end of
exhalation
3.27
escape buoyancy
buoyancy of the combination of an EBS, uninflated lifejacket and immersion suit (as appropriate) to be
overcome when escaping from an immersed helicopter
Note 1 to entry: Escape buoyancy includes the inherent buoyancy of the components of the suit system and
entrapped air but excludes the inflated buoyancy of an inflatable buoyancy element when fitted to the suit.
3.28
crew member
person assigned by an operator to perform duties on board an aircraft
4 Classification
4.1 Design types
4.1.1 Compressed air EBS
A compressed air EBS is a system where air or some other breathable gas is supplied to the user on
demand from a high pressure gas cylinder, the period of breathing being limited by the volume of
useable gas.
The apparatus shall comprise at least the following components:
 mouthpiece;
 medium pressure hose;
 gas cylinder;
 demand regulator;
 pressure indicator;
 purging device;
 nose occlusion system.
4.1.2 Rebreather EBS
A rebreather EBS is a system with a counterlung which allows the user to move air out of and back into
their lungs, the period of rebreathing being limited by a build-up of carbon dioxide and a reduction in
oxygen concentration.
The system shall comprise at least the following components:
 mouthpiece;
 breathing hose;
 counterlung;
 activation device;
 nose occlusion system.
4.1.3 Hybrid rebreather EBS
A hybrid rebreather EBS is a rebreather system that incorporates a compressed gas cylinder, allowing a
small volume of air or other breathable gas to be introduced into the counterlung, the period of
rebreathing being limited by a build-up of carbon dioxide and a reduction in oxygen concentration.
The system shall comprise at least the following components:
 mouthpiece;
 breathing hose;
 counterlung;
 gas cylinder with gas release system;
 activation device;
 nose occlusion system.
4.2 Performance levels
4.2.1 Category A EBS
Category A systems have the capability to be rapidly deployed and used both in air and underwater.
These designs of EBS are suitable for use when capsize and/or sinking occurs immediately after the
helicopter makes contact with the water.
4.2.2 Category B EBS
Category B systems have the capability to be deployed in air and used both in air and underwater.
These designs of EBS are suitable for use where there is sufficient time to deploy the equipment prior to
any subsequent submersion. Category 'B'B systems have limited capability in water impact accidents as
capsize and/or sinking is likely to occur immediately after the helicopter makes contact with the water.
5 Performance requirements
5.1 General
5.1.1 Where applicable, EBS shall be tested in combination with associated equipment, including a
constant wear aviation lifejacket and/or constant wear immersion suit that it is intended to be worn
with, in accordance with 6.8. It shall be deployed in the same manner as it would be in normal service,
and from the intended stowed position (6.1 and 6.8.3).
5.1.2 If a compressed breathable gas other than air is used, additional assessment and testing might be
required. This shall be determined following visual inspection in accordance with 6.1.
5.2 Design
5.2.1 The EBS shall be practicable in use and light in weight without prejudice to the design strength
and performance. Testing shall be carried out in accordance with 6.1 and 6.8.
5.2.2 The EBS shall be simple to deploy and capable of being operated with either hand. The number
of deployment actions shall be minimized; for example, no more than one action should be required to
activate a rebreather system on submersion, i.e. opening the valve of the counterlung. Testing shall be
carried out in accordance with 6.1, 6.8.3 and 6.8.4.
5.2.3 The equipment shall not have any sharp edges or protruding parts which might injure the user,
or damage the lifejacket, immersion suit or other emergency equipment. Testing shall be carried out in
accordance with 6.1 and 6.8.
5.2.4 Compressed air EBS shall provide the user with a minimum useable volume of air of 50 L
Standard Temperature and Pressure Dry (STPD), meeting the requirements of EN 12021. Testing shall
be carried out in accordance with 6.1 and 6.5.
5.2.5 Where a counterlung is incorporated into a rebreather system, the counterlung shall have
sufficient breathable capacity to accommodate an expired volume of at least 6 L (STPD). In the case of a
hybrid rebreather EBS, additional capacity shall be provided equivalent to the volume of breathable gas
discharged into the counterlung from the gas cylinder. The counterlung shall be designed to prevent
collapse, taking panic breathing into account. Testing shall be carried out in accordance with 6.1 and
6.6.
5.2.6 In EBS designed for underwater deployment (Category A), the design shall minimise the amount
of water that can enter the mouthpiece (dead space). It shall be possible to expel this water from the
mouthpiece. Testing shall be carried out in accordance with to 6.1, 6.8.3.2, 6.8.4.4, 6.8.4.6 and 6.8.4.7.
5.2.7 Subjects shall be provided with a means to prevent water entering the nose that is easy to deploy
and effective when used underwater. Nose occlusion systems (including nose clips) shall be designed to
fit a wide range of user sizes. Nose clips shall be easy to open with either hand and shall be permanently
attached to the EBS, on or adjacent to the mouthpiece. Testing shall be carried out in accordance with
6.1 and 6.8.
5.2.8 Where an EBS includes a harness to fit the EBS to the body, this shall allow correct positioning
on the body when used according to the manufacturer's instructions. Testing shall be carried out in
accordance with 6.1 and 6.8.
5.2.9 Gas cylinders and connections with demand regulators shall comply with the appropriate
European specifications and shall be approved and tested with respect to the rated working pressure.
Testing shall be carried out in accordance with 6.1.
5.2.10 Leakage from compressed air EBS shall not exceed 10% of the initial cylinder pressure, in any
single case, when tested in accordance with 6.5.6.
5.3 Materials
5.3.1 The materials used shall have adequate mechanical strength to resist damage. Testing shall be
carried out in accordance with 6.1, 6.5, 6.8.3, 6.8.4 and 6.9.
5.3.2 The materials used shall have sufficient resistance to changes caused by the effects of
temperature. There shall be no signs of degradation to the materials and the EBS shall remain
functional following temperature cycling, when tested in accordance with 6.4.
5.3.3 Any fabric integral to the EBS and not part of a lifejacket or suit system, used to cover, retain or
secure the EBS on the user shall be of low flammability.
The cover fabric shall as a minimum meet the vertical test of CS-25 Appendix F Part 1 (a)(1)(ii) (or as
amended). Fabrics used to retain or secure the EBS on the user shall as a minimum meet the horizontal
test of CS-25 Appendix F Part 1 (a)(1)(iv) (or as amended).
5.3.4 All metallic components shall be made of corrosion-resistant materials or be protected from
corrosion. Metallic components shall not be significantly affected by corrosion when tested in
accordance with the neutral salt spray (NSS) test of EN ISO 9227 for a period of 160 h.
The EBS shall not affect a magnetic compass by more than 1° when placed 300 mm from the compass.
Testing shall be carried out in accordance with 6.3.
5.3.5 Any high or medium pressure parts and connections shall meet the requirements of EN 250.
5.3.6 All parts that have to be cleaned and/or disinfected shall be easy to clean, be insensitive to the
cleaning agents and disinfectants recommended by the manufacturer and remain functional after
having been cleaned or disinfected. Recommended cleaning or disinfectant products shall not be known
to have any adverse effect on the user. Testing shall be carried out in accordance with 6.1.
5.4 Compatibility
5.4.1 EBS intended for use by crew members shall be designed such that, when stowed, the crew
member shall be able to carry out all normal and emergency procedures, without undue impediment or
discomfort. Testing shall be carried out in accordance with 6.10.
5.4.2 The EBS shall not impair the performance of a seat harness or hinder harness release. The EBS
shall not impede or prevent escape from a submerged helicopter. Testing shall be carried out in
accordance with 6.8.3, 6.8.4 and 6.10.
5.4.3 The EBS shall not impede or prevent the boarding of a helicopter liferaft. At least two thirds of
the test subjects shall be able to board the liferaft without assistance, and the remaining test subjects
shall be able to board the liferaft with the assistance of no more than one other test subject, with the
EBS worn as used. Testing shall be carried out in accordance with 6.8.4.8.
5.4.4 The EBS shall not impair the performance of, and shall be compatible with, any lifejacket or
immersion suit that is intended to be worn with it. The performance of the EBS, immersion suit and/or
lifejacket combination shall be tested in accordance with 6.1, 6.8.1.2, 6.8.3, 6.8.4, 6.8.5 and 6.10 of this
standard, and the compatibility requirements of ETSO-2C502, ETSO-2C503 or ETSO-2C504, as
appropriate.
5.4.5 Potential snagging hazards shall be reduced to a minimum. Any part of the EBS that might pose a
snagging hazard during flight, emergency evacuation, escape or rescue shall be suitably covered,
protected or restrained. Testing shall be carried out in accordance with 6.1, 6.8.4.5, 6.8.4.6, 6.8.4.8,
6.8.4.9 and 6.10.
5.5 Breathing performance
5.5.1 General
The work of breathing, respiratory pressures, hydrostatic imbalance and extreme cold water
requirements specified in 5.5.2 to 5.5.5 shall be met under the following conditions:
 simulated breathing using a sinusoidal waveform, with respiratory minute volumes as shown in
Table 1;
 in water at a temperature of (4 ) °C, and extreme cold water (5.5.5) if specified by the
−2
manufacturer;
 simulated orientations of vertical (pitch +90°), inverted (pitch −90°) and face-down (pitch 0°) with
zero roll.
NOTE Pitch and roll definitions are as described in EN 14143.
When tested in accordance with 6.5, dynamic performance shall be determined from a pressure volume
diagram (see Figure 1 and Figure 2) generated by plotting pressure against displaced volume.
5.5.2 Work of breathing
−1 −1
Work of breathing shall not exceed 3,0 JL at ventilation rates up to and including 62,5 L.min ATP.
−1
The EBS shall remain functional at ventilation rates up to 75 L.min ATP. Testing shall be carried out
in accordance with 6.5.1, 6.5.2, 6.5.3 and 6.5.4.
5.5.3 Respiratory pressures
Peak-to-peak respiratory pressure shall be determined as shown in Figure 1 (compressed air EBS) or
Figure 2 (rebreather and hybrid rebreather EBS), expressed as b, and shall not exceed 5,0 kPa
(50 mbar).
For compressed air EBS peak expired respiratory pressure, expressed as c in Figure 1, shall not exceed
2,5 kPa (25 mbar) and peak inspired respiratory pressure, expressed as d in Figure 1, shall not exceed
2,5 kPa (25 mbar).
For rebreather EBS (including hybrid rebreather EBS) the elastance of the system, determined as
−1 −1
shown in Figure 2 and expressed by c/a, shall not exceed 1 kPa.L (10 mbar.L ).
For compressed air EBS the demand regulator shall not free-flow during testing.
Testing shall be carried out in accordance with 6.5.1, 6.5.2, 6.5.3 and 6.5.4.
5.5.4 Hydrostatic imbalance
For rebreather EBS (including hybrid rebreather EBS), hydrostatic imbalance shall be between
+2,5 kPa (+25 mbar) and −2,5 kPa (−25 mbar) relative to lung centroid pressure. Testing shall be
carried out in accordance with 6.5.5.
5.5.5 Extreme cold water temperatures
If the EBS is intended for use in water temperatures less than 4 °C the manufacturer shall state the
minimum operational temperature. The breathing performance of the EBS shall also be tested and meet
the requirements of 5.5.2 to 5.5.4 at the surface (immersed to a depth sufficient to preclude surface
effects) at that temperature. Testing shall be carried out in accordance with 6.5.
5.6 Safety devices
5.6.1 For a compressed air EBS, a pressure indicator shall be provided to confirm that there is
adequate gas in the cylinder. An indicator shall be provided to show that the system is ready for use.
Testing shall be carried out in accordance with 6.1.
5.6.2 For hybrid rebreather EBS, the gas cylinder shall have a status indicator to show that the gas
release system is in a ready to use condition. Testing shall be carried out in accordance with 6.1.
5.6.3 For rebreather and hybrid rebreather EBS, it shall be possible to check that the EBS is ready for
use and has not been tampered with. Testing shall be carried out in accordance with 6.1.
5.6.4 Where a security tag or anti-tamper stitching is used, this shall be a weak link that is easy to
break during emergency deployment. Testing shall be carried out in accordance with 6.1 and 6.8.3.1.
5.6.5 The risk of inadvertent operation or activation by the user shall be minimized, including the
inadvertent release of gas from a cylinder. Testing shall be carried out in accordance with 6.1, 6.8 and
6.10.
5.7 Deployment
5.7.1 It shall be possible to fully deploy Category A EBS in less than 12 s, using one hand only (this
time shall include deployment of the nose occlusion system). This shall be achievable with both the
right hand and the left hand. It shall be possible to deploy the mouthpiece within 10 s (this time may
exclude deployment of the nose occlusion system). Testing shall be conducted in dry conditions, in
accordance with 6.8.3.1.
5.7.2 It shall be possible to fully deploy Category B EBS in less than 20 s, using one hand only. This
shall be achievable with both the right hand and the left hand. Testing shall be conducted in dry
conditions, in accordance with 6.8.3.1.
5.7.3 For EBS designed for underwater deployment (Category A EBS) it shall be demonstrated that full
deployment can be achieved, with each hand, following submersion. Test subjects shall be able to clear
water from the mouthpiece if necessary, achieve a good seal at the mouth and breathe from the EBS.
Testing shall be carried out in accordance with 6.8.3.2.
It shall be possible to deploy Category A EBS when inverted underwater following a 180° sideways roll.
Testing shall be carried out in accordance with 6.8.4.4.
5.8 Ease of use and manoeuvrability in water
5.8.1 Test subjects shall be able to achieve a good seal at the mouth, whilst manoeuvring underwater
in different orientations including the face-down (prone) position. This shall be tested in accordance
with 6.8.4.1.
5.8.2 Each test subject shall demonstrate their ability to use the EBS for at least 60 s whilst pulling
themselves along an underwater rail in the face-down position. This shall be tested in accordance with
6.8.4.2.
5.8.3 Each test subject shall demonstrate their ability to use the EBS for at least 60 s whilst inverted.
This shall be tested in accordance with 6.8.4.3 (Category A and B) and 6.8.4.4 (Category A only).
5.8.4 Each test subject shall demonstrate their ability to use the EBS whilst successfully completing
underwater escape from a submerged and capsized helicopter simulator. No part of the EBS shall snag
or unduly hinder egress. The system shall not cause injury to the user nor impair the performance of
other equipment. This shall be tested in accordance with 6.8.4.5 (Category A and B), 6.8.4.6 (Category A
only) and 6.8.4.9.
5.8.5 Each test subject shall demonstrate their ability to escape from a submerged and capsized
helicopter simulator when the EBS is not deployed. No part of the EBS shall snag or unduly hinder
egress. The system shall not cause injury to the user nor impair the performance of other equipment.
This shall be tested in accordance with 6.8.4.5 and 6.8.4.9.
5.9 Buoyancy
5.9.1 The buoyancy of a hybrid rebreather EBS shall be no more than 40 N following release of gas
from the cylinder. This shall be tested in accordance with 6.7. This test is not be required for open
circuit compressed air systems or for simple rebreather systems where no additional gas is added to
the counterlung.
5.9.2 The escape buoyancy due to the combination of a helicopter immersion suit, lifejacket (as
appropriate), clothing and EBS shall meet the buoyancy requirement specified within ETSO 2C502 or
ETSO 2C503, as appropriate, when tested in accordance with 6.8.5.
5.10 Cold water performance
Each test subject shall demonstrate their ability to use the EBS in cold (12 °C) water for at least 60 s.
Testing shall be carried out in accordance with 6.9.
6 Testing
6.1 Visual inspection
Visual inspection shall be conducted at normal visual acuity by personnel with appropriate competence
to assess the equipment.
The visual inspection shall include the assessment of the device marking, information supplied by the
manufacturer, servicing and maintenance information, any safety data sheets relating to materials (if
applicable), and any relevant declarations applicable to its construction and design.
6.2 Nominal values and tolerances
Unless otherwise specified, the values shall be subjected to a limit deviation of ±5 %. Unless otherwise
specified, the room (ambient) temperature for testing shall be (24 ± 8) °C and at a relative humidity of
at least 50 %. The temperature limits with no specified tolerance shall be subject to a limit deviation of
±3 °C.
6.3 Magnetic properties testing
Place a direct-reading magnetic compass in an undisturbed magnetic area (i.e. an area in which
magnetic items and DC electrical cables are not continually moved or switched). Check the compass to
ensure that it has negligible pivot friction. This can be done by deflecting the compass card 10° by
means of a magnet and then removing the deflecting force, when the card should return to within 0,5°
of its original position.
Present the EBS to the compass on an approximately east to west line, to a position where the nearest
point of the EBS is (300 ± 10) mm horizontally from the centre of the compass. Lightly tap the compass
to eliminate the effect of friction. Record the angle, in degrees, of any deflection of the compass from its
position before the EBS was brought near the compass.
6.4 Temperature cycling
6.4.1 Temperature cycling shall be carried out before the tests described in 6.5, 6.6 and 6.7 and shall
be used as a pre-treatment for the EBS used in these tests unless otherwise stated.
6.4.2 The EBS shall be alternately exposed to temperatures of +65 °C and −30 °C. These alternating
temperatures need not follow immediately after each other and the following procedure is acceptable:
a) an 8 h exposure at (65 ± 2) °C to be completed in one day;
b) the EBS removed from the heat chamber the same day and left exposed to ordinary room
conditions until the next day;
c) an 8 h exposure at (−30 ± 2) °C to be completed in one day;
d) the EBS removed from the cold chamber the same day and left exposed to ordinary room
conditions until the next day;
e) for rebreather and hybrid rebreather EBS, the above procedure (a) to (d) to be repeated a further
9 times.
For compressed air systems the EBS shall be tested with the cylinder valve in the closed position and
pressurized to 50 % of the rated working pressure.
6.4.3 Following temperature cycling, the EBS shall be visually inspected for signs of degradation to the
materials. For compressed air EBS, the pressure in the gas cylinder shall be within 10 % of the pressure
at the start of the temperature cycling test. There shall be no signs of degradation, and it shall be
demonstrated that the EBS is functional by testing in accordance with 6.5.
6.5 Breathing performance
6.5.1 A breathing simulator shall be used to measure the breathing performance of the EBS, using a
sinusoidal gas flow with a maximum variation of ±3 % in both the frequency and amplitude of the wave
form. It shall be possible to test the EBS in different orientations on the breathing simulator.
6.5.2 For compressed air EBS, it shall be shown by calculation from the internal volume of the cylinder
and the pressure range of the testing that the system can provide 50 L of useable gas.
Testing shall be carried out with the apparatus supplied with high pressure air at the rated working
pressure of the regulator, as specified by the manufacturer. Testing shall also be conducted at a supply
pressure of either 5 000 kPa (50 bar) or a lower pressure specified by the manufacturer. If a
manufacturer specifies a lower pressure, it shall be the minimum supply pressure of the pressure range
from which the system is able to provide a minimum useable volume of gas of 50 L (i.e. rated working
pressure to minimum supply pressure). An external, regulated breathing gas supply shall be used.
6.5.3 Breathing performance shall be measured in air and in water at a temperature of (44 )°C.
−2
Testing shall be conducted at the surface (dry) and at a simulated depth (at the mouthpiece) of 4.0 m. A
range of tidal volumes from 1,5 L to 3,0 L and breathing rates of 10 to 25 breaths per minute shall be
used according to Table 1. The test duration shall be such as to obtain steady-state performance. The
tests at each work rate shall be conducted for a minimum of 60 s. Between each work rate there shall be
sufficient time to preclude the temperature effect of the previous test.
When tested in water, the equipment shall be immersed to a depth sufficient to preclude surface effects.
6.5.4 Measure the respiratory pressure at the mouth and determine performance from the pressure-
volume diagram generated by plotting the respiratory pressure against the displaced volume.
Analyse the pressure volume diagram in accordance with Figure 1 (compressed air EBS) or Figure 2
(rebreather and hybrid rebreather EBS) as appropriate.
6.5.5 Hydrostatic imbalance shall be measured by mounting the EBS on a rotating manikin, as
described in EN 14143:2013, Figure 1, fitted and secured as it would be when ready for use., in
accordance with the donning and use instructions supplied by the manufacturer. Completely immerse
in water at a depth sufficiently deep to preclude surface effects, but not deeper than 2 m. During this
test, the manikin shall be rotated about the lung centroid.
−1
Perform the test at a respiratory minute volume of 62,5 L.min and record the mouth pressure at the
end of exhalation (see Figure 2).
Table 1 — Breathing simulator settings
a
Tidal volume at ATP Breathing frequency Respiratory minute volume at ATP
−1 −1
L min L.min
1,5 10 15,0
1,5 15 22,5
2,0 20 40,0
2,5 25 62,5
3,0 25 75,0
a
Ambient Temperature and Pressure.

Key
1 work of breathing (marked area)
2 end of exhalation (“no flow”)
3 end of inhalation (“no flow”)
a
tidal volume
b
peak-to-peak respiratory pressure
c
expired respiratory pressure
d
inspired respiratory pressure
Figure 1 — Pressure volume loop (compressed air EBS)
Key
1 work of breathing (marked area)
2 reference point of hydrostatic imbalance; end of exhalation (“no flow”)
3 reference point of hydrostatic imbalance; end of inhalation (“no flow”)
a
tidal volume
b
peak-to-peak respiratory pressure
c
pressure difference between reference point 2 and 3
Figure 2 — Pressure volume loop (rebreather and hybrid rebreather EBS)
6.5.6 Three compressed air EBS shall be tested for resistance to leakage:
— one compressed air EBS that has been used in the temperature cycling test (6.4);
— one compressed air EBS that has been used for ergonomic performance testing (6.8);
— one compressed air EBS that has not been used in earlier tests.
Testing shall be carried out with the three EBS after they have been filled with air at the rated working
pressure of the regulator, as specified by the manufacturer. Cylinder pressure of each EBS shall be
measured after the systems have stabilized at an air temperature of (20 ± 2) °C.
The three EBS shall be tested as ready-for-use apparatus, with the cylinder valve in the open position,
for 48 h at (20 ± 2) °C. Following the 48 h test period the cylinder pressure of each EBS shall again be
measured at (20 ± 2) °C. Any reduction in pressure over the 48 h period shall be less than 10 %.
6.6 Breathable volume of counterlung
Secure the EBS on a manikin, fitted as it would be when ready for use. Immerse the EBS and manikin at
a pitch of +90° so that no part of the EBS is at a depth greater than 1 m. Fill the apparatus with air until
an internal pressure of +2,5 kPa (+25 mbar) referenced to the mouthpiece is achieved. A 3 L calibration
syringe can be used for this purpose.
Record the breathable volume (STPD).
6.7 Buoyancy
The buoyancy of a hybrid rebreather EBS shall be determined by measuring the maximum underwater
weight of the EBS after release of gas from the cylinder. The EBS shall be activated prior to evaluation,
with the additional breathable gas discharged into the counterlung. The EBS shall be placed in a net bag
and immersed in a tank of water at (20 ± 1) °C, using weights if necessary to fully submerge the
equipment just below the surface. Care should be taken to remove any trapped air from the surfaces of
the unit. The immersed weight shall be measured. The EBS shall then be removed, and the immersed
weight of the test equipment measured. The buoyancy of the EBS shall be calculated from the difference
in the two values of immersed weight.
6.8 Ergonomic performance
6.8.1 General
6.8.1.1 Ergonomic performance testing shall be assessed following satisfactory completion of testing
to 6.1, 6.4, 6.5, 6.6 and 6.7.
6.8.1.2 Testing shall demonstrate acceptable compatibility between the EBS and any lifejacket
and/or immersion suit with which it is intended to be used. Accordingly, tests shall be carried out in
combination with each constant wear aviation lifejacket and/or helicopter immersion suit that is
intended to be worn with the EBS. Hood and gloves shall not be used during testing unless this is
necessary for sealing the suit. Accessories such as goggles shall not be worn unless they are an integral
part of a lifejacket/suit system.
6.8.1.3 Any test stopped for reasons which were not directly related to EBS performance or any other
aspect of its design shall be excluded and the test may be repeated no more than three times for each
test subject. The ergonomic performance assessments using human subjects test the practicability and
ease of use of the equipment, ensuring that the design of the device is fit for purpose. Where ergonomic
performance tests show the apparatus has imperfections related to the wearer’s acceptance, the device
shall be deemed to have failed. The following examples are possible reasons for concluding that an
apparatus is unacceptable and not fit for use:
 if more than one test subject is unable to use the EBS due to poor fit, e.g. of mouthpiece or nose
occlusion system;
 if more than one test subject is unable to perform required tasks due to the EBS;
 if rating of the exertion of breathing (Annex A) exceeds 17 (very hard) in more than one test
subject.
Due to the high variability between human test subjects, and the difficulty in assessing some subjective
measures, it is permitted that an EBS does not completely meet the requirements of a single test and in
no more than one test subject. In these circumstances, two other test subjects within the same weight
category and with the same gender should be subjected to the same test. If this additional test is clearly
passed with both test subjects then the EBS will have passed the test overall.
6.8.1.4 Underwater tests shall be carried out in a pool at a water temperature of 20 °C to 25 °C, at
water depths between 0,1 m and 3,0 m. The pool shall be equipped with an underwater handrail at a
depth of between 0,2 m and 0,5 m.
6.8.1.5 The inversion test (6.8.4.3 and 6.8.4.4) shall be undertaken using a shallow water escape
trainer; a frame fitted with a seat and harness, with the seat floating at water level, allowing the test
subject to be inverted with the upper body below water by rolling sideways.
6.8.1.6 The underwater escape tests (6.8.4.5 and 6.8.4.6) shall be undertaken using a helicopter
simulator. High backed seats shall be used fitted with a four-point or five-point harness.
Escape tests shall be conducted using emergency exits which consist of a rectangular aperture with the
following dimensions:
 height of (549 ± 3) mm;
 width of (356 ± 3) mm;
 corner radius of (114 ± 3) mm;
 diagonal measurement between the corner radii of (559 ± 3) mm.
The top of the opening shall be at least 0,15 m below the water surface.
6.8.2 Test subjects
6.8.2.1 Manned tests (with the exception of cold water tests, 6.9) shall be carried out by test subjects
with no previous experience of using the EBS under evaluation. They shall not be experienced users of
underwater breathing apparatus.
It is permitted to pre-qualify test subjects for their ability to swim and board a helicopter liferaft,
without assistance, when wearing swimwear only.
6.8.2.2 At least 8 test subjects shall be used, with at least one test subject in each of the height and
weight categories described in Table 2.
Table 2 — Test subject size range
Subj
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