SIST EN 4856:2023
(Main)Aerospace series - Rotorcraft - Emergency Breathing Systems (EBS) - Requirements, testing and marking
Aerospace series - 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 capable of being successfully and reliably deployed in air and underwater, for use by adults only.
This document is applicable to compressed air and hybrid rebreather designs of EBS. It does not apply to EBS that cannot be successfully and reliably deployed underwater.
Luft-und Raumfahrt - Drehflügler - Notfallbeatmungssystem (EBS) - Anforderungen, Prüfung und Kennzeichnung
Série aérospatiale - 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. Il s’applique aux EBS pouvant être correctement déployés à l’air libre et sous l'eau, destinés à être utilisés uniquement par des adultes.
Le présent document s'applique aux modèles d'EBS à air comprimé ainsi qu’à masque à recirculation hybride. Il ne s’applique pas aux EBS ne pouvant pas être correctement déployés sous l'eau.
Aeronavtika - Rotoplani - Sistem prezračevanja v sili (EBS) - Zahteve, preskušanje in označevanje
Ta 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 za sisteme EBS, ki jih je mogoče uspešno in zanesljivo uvede v zraku in pod vodo ter so namenjeni samo odraslim osebam.
Ta dokument se uporablja za modele EBS dihalnih aparatov na stisnjen zrak in hibridne dihalne aparate z zaprtim krogom. Ne velja za sisteme EBS, ki jih ni mogoče uspešno in zanesljivo uvesti pod vodo.
General Information
Relations
Standards Content (Sample)
SLOVENSKI STANDARD
SIST EN 4856:2023
01-april-2023
Aeronavtika - Rotoplani - Sistem prezračevanja v sili (EBS) - Zahteve, preskušanje
in označevanje
Aerospace series - Rotorcraft - Emergency Breathing Systems (EBS) - Requirements,
testing and marking
Luft-und Raumfahrt - Drehflügler - Notfallbeatmungssystem (EBS) - Anforderungen,
Prüfung und Kennzeichnung
Série aérospatiale - Giravion - Système de ventilation d'urgence (EBS) - Exigences,
essais et marquage
Ta slovenski standard je istoveten z: EN 4856:2023
ICS:
49.095 Oprema za potnike in Passenger and cabin
oprema kabin equipment
SIST EN 4856:2023 en,fr,de
2003-01.Slovenski inštitut za standardizacijo. Razmnoževanje celote ali delov tega standarda ni dovoljeno.
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SIST EN 4856:2023
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SIST EN 4856:2023
EN 4856
EUROPEAN STANDARD
NORME EUROPÉENNE
February 2023
EUROPÄISCHE NORM
ICS 49.095 Supersedes EN 4856:2018
English Version
Aerospace series - Rotorcraft Emergency Breathing
Systems (EBS) - Requirements, testing and marking
Série aérospatiale - Systèmes de ventilation d'urgence Luft-und Raumfahrt - Drehflügler
(EBS) de giravion - Exigences, essais et marquage Notfallbeatmungssystem (EBS) - Anforderungen,
Prüfung und Kennzeichnung
This European Standard was approved by CEN on 18 December 2022.
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, 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.
EUROPEAN COMMITTEE FOR STANDARDIZATION
COMITÉ EUROPÉEN DE NORMALISATION
EUROPÄISCHES KOMITEE FÜR NORMUNG
CEN-CENELEC Management Centre: Rue de la Science 23, B-1040 Brussels
© 2023 CEN All rights of exploitation in any form and by any means reserved Ref. No. EN 4856:2023 E
worldwide for CEN national Members.
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SIST EN 4856:2023
EN 4856:2023 (E)
Contents Page
European foreword . 4
Introduction . 5
1 Scope . 6
2 Normative references . 6
3 Terms and definitions . 7
4 Design types . 11
4.1 Compressed air EBS . 11
4.2 Hybrid rebreather EBS . 11
5 Performance requirements . 11
5.1 General. 11
5.2 Design . 12
5.3 Materials . 13
5.4 Breathing performance . 13
5.4.1 General. 13
5.4.2 Work of breathing . 14
5.4.3 Respiratory pressures. 14
5.4.4 Hydrostatic imbalance . 14
5.4.5 Extreme cold water temperatures . 14
5.5 Safety devices . 14
5.6 Deployment . 15
5.7 Ease of use and manoeuvrability in water . 15
5.8 Buoyancy . 15
5.9 Cold water performance . 16
5.10 Compatibility . 16
5.10.1 General. 16
5.10.2 Performance of equipment combination(s) . 16
6 Testing . 19
6.1 Visual inspection . 19
6.2 Nominal values and tolerances . 19
6.3 Magnetic properties testing . 19
6.4 Temperature cycling. 19
6.5 Breathing performance . 20
6.6 Breathable volume of counterlung . 22
2
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6.7 Buoyancy. 23
6.8 Ergonomic performance . 23
6.8.1 General . 23
6.8.2 Test subjects . 24
6.8.3 Deployment. 26
6.8.4 Ease of use, manoeuvrability and helicopter escape . 26
6.9 Cold water performance . 28
6.10 Compatibility and performance of equipment combination(s) . 28
6.10.1 General . 28
6.10.2 Test subjects . 28
6.10.3 Clothing . 28
6.10.4 Compatibility and equipment combination performance testing . 29
6.10.5 Donning and fit . 29
6.10.6 Ride-up . 29
6.10.7 Helicopter underwater escape . 30
6.10.8 Jump into water . 30
6.10.9 Freeboard . 31
6.10.10 Turning . 31
6.10.11 Self-righting . 31
6.10.12 In-water stability . 32
6.10.13 Freedom of movement and use of accessories . 32
6.10.14 Life raft boarding . 33
6.10.15 Rescue and recovery . 33
6.10.16 Escape buoyancy . 33
6.11 Crew equipment compatibility . 34
6.12 Reporting . 36
7 Marking . 36
8 Information supplied by the manufacturer . 37
Annex A (normative) Rating of breathing effort . 38
A.1 Instruction . 38
Annex B (informative) Evolution sheet. 39
Bibliography . 40
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SIST EN 4856:2023
EN 4856:2023 (E)
European foreword
This document (EN 4856:2023) 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 document has
received the approval of the National Associations and the Official Services of the member countries of
ASD-STAN, prior to its presentation to CEN.
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 August 2023, and conflicting national standards shall
be withdrawn at the latest by August 2023.
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 4856:2018.
Any feedback and questions on this document should be directed to the users’ national standards body.
A complete listing of these bodies can be found on the CEN website.
According to the CEN-CENELEC Internal Regulations, the national standards organisations 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, Türkiye and the
United Kingdom.
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SIST EN 4856:2023
EN 4856:2023 (E)
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 EBS 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 document the term helicopter is used generically hereinafter.
5
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EN 4856:2023 (E)
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 capable of being successfully and reliably deployed in air and
underwater, for use by adults only.
This document is applicable to compressed air and hybrid rebreather designs of EBS. It does not apply
to EBS that cannot be successfully and reliably deployed underwater.
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 250, Respiratory equipment — Open-circuit self-contained compressed air diving apparatus —
Requirements, testing and marking
1
EN 4862, Aerospace series — Rotorcraft constant wear lifejackets — Requirements, testing and marking
1 2
EN 4863:— , Aerospace series — Rotorcraft immersion suits — Requirements, testing and marking
3
EN 4886, Aerospace series — Rotorcraft life rafts — 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)
EN ISO 14116:2015, Protective clothing — Protection against flame — Limited flame spread materials,
material assemblies and clothing (ISO 14116:2015)
EN ISO 15025:2016, Protective clothing — Protection against flame — Method of test for limited flame
spread (ISO 15025:2016)
EASA CS-25 Amendment 26:2020, Certification Specifications and Acceptable Means of Compliance for
Large Aeroplanes CS-25, Book 1 — Appendix F
1
Under preparation. Current stage is: FprEN 4862:2022.
2
Under preparation. Current stage is: ASD-STAN prEN 4863:2022.
3
In preparation at the date of publication of this document.
6
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EN 4856:2023 (E)
3 Terms and definitions
For the purposes of this document, the following terms and definitions apply.
ISO and IEC maintain terminological 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
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
lifejacket
garment or device which, when correctly worn and used in water will provide the user with buoyancy
positioned to provide protection from drowning and increase the likelihood of survival and rescue
3.3
helicopter constant wear lifejacket
lifejacket worn on the body throughout a helicopter flight, provided to protect the user in the event of a
ditching or water impact
3.4
immersion suit
garment designed to protect the user’s body from the cooling effects of unintended immersion in water
Note 1 to entry: Cooling effects include cold shock and hypothermia.
Note 2 to entry: An immersion suit may be integrated or worn with a separate constant wear lifejacket.
3.5
integrated immersion suit
immersion suit that incorporates the functionality of a lifejacket
3.6
buoyancy element
inflatable chamber incorporated into an integrated immersion suit that, when inflated, provides the suit
with the functionality of a lifejacket
3.7
helicopter immersion suit
immersion suit worn on the body throughout a helicopter flight, provided to protect the user in the
event of a ditching or water impact
3.8
immersion suit system
helicopter immersion suit (with or without thermal insulation) and its components and accessories
including a constant wear lifejacket or buoyancy element and its components and accessories with or
without an emergency breathing system
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3.9
fully inflated
inflation of a lifejacket or buoyancy element achieved by using the manual inflation system (stored gas)
with no subsequent deflation
3.10
manual inflation system
means of inflation achieved by a person operating a mechanism that actively releases stored gas into
the buoyancy chamber(s) of a lifejacket or buoyancy element
3.11
oral inflation system
means of inflation achieved by a person blowing expired air into the buoyancy chamber(s) of a
lifejacket or buoyancy element
3.12
rotorcraft
heavier-than-air aircraft that depends principally for its support in flight on the lift generated by one or
more rotors
3.13
helicopter
rotorcraft that, for its horizontal motion, depends principally on its engine-driven rotors
3.14
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
3.15
water impact
helicopter contact with water that is unintentional or exceeds the ditching capability of the helicopter
for water entry
3.16
crew member
person assigned by an operator to perform duties on board an aircraft
3.17
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
3.18
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.
3.19
demand regulator
device which consists of a pressure reducer connected to a demand valve
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EN 4856:2023 (E)
3.20
medium pressure hose
hose with an interface connection at each end, between the pressure reducer and a demand valve
3.21
breathing hose
flexible hose connecting a counterlung to the mouthpiece of a hybrid rebreather EBS, at approximately
ambient pressure
3.22
pressure indicator
device to indicate to the user the pressure of gas in a cylinder
3.23
purging device
part of the demand regulator that can be operated manually to deliver breathable gas, intended to force
water out of the mouthpiece
3.24
dead space
volume of the cavity formed between the mouth and the inhalation and exhalation parts
3.25
activation device
mechanism which switches breathing from the atmosphere to the counterlung of a hybrid rebreather
EBS
3.26
counterlung
variable volume container for the user to exhale to and inhale from
3.27
breathable gas
gas that will support life under the intended conditions of use
3.28
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 J/l.
3.29
respiratory pressure
differential pressure at the mouth relative to the no flow pressures measured at the end of inhalation
and exhalation
3.30
hydrostatic imbalance
difference at end exhalation no flow between the pressure at the mouth and that at the lung centroid
reference point
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3.31
tidal volume
volume of breathing gas displaced by the breathing simulator during one half cycle (inhalation or
exhalation)
Note 1 to entry: Measured in l.
3.32
respiratory minute volume
product of the tidal volume and breathing frequency
Note 1 to entry: Measured in l/min.
3.33
useable volume of air
volume of breathable air available to the user while the demand regulator is operating within the
specified breathing performance
3.34
rated working pressure
maximum working pressure of the respective components
3.35
pressure volume diagram
diagram generated during one breathing cycle by plotting the respiratory pressure against the
displaced (tidal) volume
3.36
elastance
change in pressure that results from a given volume change of the human lung
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.
3.37
reference pressure
equilibrium pressure which exists in the mouthpiece when there is no respiratory flow at the end of
exhalation
3.38
escape buoyancy
buoyancy of an equipment combination, with the lifejacket or buoyancy element uninflated, that must
be overcome when escaping from an immersed helicopter
Note 1 to entry: It includes the inherent buoyancy of the components of the immersion suit system and entrapped
air but excludes the inflated buoyancy elements.
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4 Design types
4.1 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.
4.2 Hybrid 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. 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.
5 Performance requirements
5.1 General
5.1.1 EBS covered by this document shall be capable of being rapidly deployed and used both in air
and underwater. They shall be suitable for use when capsize and/or sinking occurs immediately after
the helicopter makes contact with the water.
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5.1.2 Where applicable, EBS shall be tested in combination with associated equipment, including an
immersion suit, accessories and/or lifejacket that is intended to be worn with it, 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).
NOTE Helicopter immersion suits are hereinafter referred to as immersion suits. Helicopter constant wear
lifejackets are hereinafter referred to as lifejackets.
5.1.3 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 hybrid 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 system 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 hybrid rebreather system, the counterlung shall
have sufficient breathable capacity to accommodate an expired volume of at least 6 l (STPD). Additional
capacity shall be provided equivalent to the volume of breathable gas discharged into the counterlung
from the gas cylinder. The gas cylinder shall provide a minimum useable volume of air of at least 3 l
STPD, meeting the requirements of EN 12021. The counterlung shall be designed to prevent collapse,
taking panic breathing into account. Testing shall be carried out in accordance with 6.1, 6.5.2 and 6.6.
5.2.6 The EBS design shall minimize 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, 6.8.4.5 and 6.8.4.6.
5.2.7 Subje
...
SLOVENSKI STANDARD
oSIST prEN 4856:2022
01-februar-2022
Aeronavtika - Rotoplani - Sistem prezračevanja v sili (EBS) - Zahteve, preskušanje
in označevanje
Aerospace series - Rotorcraft - Emergency Breathing Systems (EBS) - Requirements,
testing and marking
Luft-und Raumfahrt - Drehflügler - Notfallbeatmungssystem (EBS) - Anforderungen,
Prüfung und Kennzeichnung
Série aérospatiale - Giravion - Système de ventilation d'urgence (EBS) - Exigences,
essais et marquage
Ta slovenski standard je istoveten z: prEN 4856
ICS:
49.095 Oprema za potnike in Passenger and cabin
oprema kabin equipment
oSIST prEN 4856:2022 en,fr,de
2003-01.Slovenski inštitut za standardizacijo. Razmnoževanje celote ali delov tega standarda ni dovoljeno.
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oSIST prEN 4856:2022
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oSIST prEN 4856:2022
DRAFT
EUROPEAN STANDARD
prEN 4856
NORME EUROPÉENNE
EUROPÄISCHE NORM
December 2021
ICS 49.095 Will supersede EN 4856:2018
English Version
Aerospace series - Rotorcraft - Emergency Breathing
Systems (EBS) - Requirements, testing and marking
Série aérospatiale - Giravion - Système de ventilation Luft-und Raumfahrt - Drehflügler -
d'urgence (EBS) - Exigences, essais et marquage Notfallbeatmungssystem (EBS) - Anforderungen,
Prüfung und Kennzeichnung
This draft European Standard is submitted to CEN members for enquiry. It has been drawn up by the Technical Committee ASD-
STAN.
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, Turkey 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
© 2021 CEN All rights of exploitation in any form and by any means reserved Ref. No. prEN 4856:2021 E
worldwide for CEN national Members.
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oSIST prEN 4856:2022
prEN 4856:2021 (E)
Contents Page
European foreword . 4
Introduction . 5
1 Scope . 6
2 Normative references . 6
3 Terms and definitions . 6
4 Design types . 10
4.1 Compressed air EBS . 10
4.2 Hybrid rebreather EBS . 11
5 Performance requirements . 11
5.1 General. 11
5.2 Design . 12
5.3 Materials . 13
5.4 Breathing performance . 13
5.4.1 General. 13
5.4.2 Work of breathing . 14
5.4.3 Respiratory pressures. 14
5.4.4 Hydrostatic imbalance . 14
5.4.5 Extreme cold water temperatures . 14
5.5 Safety devices . 14
5.6 Deployment . 15
5.7 Ease of use and manoeuvrability in water . 15
5.8 Buoyancy . 15
5.9 Cold water performance . 15
5.10 Compatibility . 15
5.10.1 General. 15
5.10.2 Performance of equipment combination(s) . 16
6 Testing . 18
6.1 Visual inspection . 18
6.2 Nominal values and tolerances . 19
6.3 Magnetic properties testing . 19
6.4 Temperature cycling. 19
6.5 Breathing performance . 19
6.6 Breathable volume of counterlung . 22
6.7 Buoyancy . 22
6.8 Ergonomic performance . 22
6.8.1 General. 22
6.8.2 Test subjects . 23
6.8.3 Deployment . 25
6.8.4 Ease of use, manoeuvrability and helicopter escape . 25
6.9 Cold water performance . 27
6.10 Compatibility and performance of equipment combination(s) . 27
6.10.1 General. 27
6.10.2 Test subjects . 27
6.10.3 Clothing. 28
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6.10.4 Compatibility and equipment combination performance testing . 28
6.10.5 Donning and fit . 28
6.10.6 Ride-up . 28
6.10.7 Helicopter underwater escape . 29
6.10.8 Jump into water . 29
6.10.9 Freeboard . 30
6.10.10 Turning . 30
6.10.11 Self-righting . 31
6.10.12 In-water stability . 31
6.10.13 Freedom of movement and use of accessories . 32
6.10.14 Life raft boarding . 32
6.10.15 Rescue and recovery . 32
6.10.16 Escape buoyancy . 32
6.11 Crew equipment compatibility . 34
6.12 Reporting . 35
7 Marking . 35
8 Information supplied by the manufacturer . 36
Annex A (normative) Rating of breathing effort . 37
A.1 Instruction . 37
Annex B (informative) Evolution sheet. 38
Bibliography . 39
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European foreword
This document (prEN 4856:2021) 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 document has
received the approval of the National Associations and the Official Services of the member countries of
ASD-STAN, prior to its presentation to CEN.
This document is currently submitted to the CEN Enquiry.
This document will supersede EN 4856:2018.
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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 EBS 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.
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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 capable of being successfully and reliably deployed in air and
underwater, for use by adults only.
This document is applicable to compressed air and hybrid rebreather designs of EBS. It does not apply
to EBS that cannot be successfully and reliably deployed underwater.
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 250, Respiratory equipment — Open-circuit self-contained compressed air diving apparatus -
Requirements, testing and marking
1
EN 4862, Rotorcraft — Constant Wear Lifejackets — Requirements, testing and marking
2
EN 4863:— , Aerospace series — Rotorcraft immersion suits — Requirements, testing and marking
prEN 4886, Aerospace series — Rotorcraft — Liferafts for operations in hostile sea areas — 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 CS-25 Amendment 26:2020, Certification Specifications and Acceptable Means of Compliance for
Large Aeroplanes CS-25, Book 1 — Appendix F
3 Terms and definitions
For the purposes of this document, the following terms and definitions apply.
ISO and IEC maintain terminological 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/
1
Under preparation; current stage is: prEN 4862:2021.
2
Under preparation; current stage is: prEN 4863:2021.
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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
lifejacket
garment or device which, when correctly worn and used in water will provide the user with buoyancy
positioned to provide protection from drowning and increase the likelihood of survival and rescue
3.3
helicopter constant wear lifejacket
lifejacket worn on the body throughout a helicopter flight, provided to protect the user in the event of a
ditching or water impact
3.4
immersion suit
garment designed to protect the user’s body from the cooling effects of unintended immersion in water
Note 1 to entry: Cooling effects include cold shock and hypothermia.
Note 2 to entry: An immersion suit may be integrated or worn with a separate constant wear lifejacket.
3.5
integrated immersion suit
immersion suit that incorporates the functionality of a lifejacket
3.6
buoyancy element
inflatable chamber incorporated into an integrated immersion suit that, when inflated, provides the suit
with the functionality of a lifejacket
3.7
helicopter immersion suit
immersion suit worn on the body throughout a helicopter flight, provided to protect the user in the
event of a ditching or water impact
3.8
immersion suit system
helicopter immersion suit (with or without thermal insulation) and its components and accessories
including either a constant wear lifejacket or buoyancy element and/or emergency breathing system, as
applicable
3.9
fully inflated
inflation of a lifejacket or buoyancy element achieved by using the manual inflation system (stored gas)
with no subsequent deflation
3.10
manual inflation system
means of inflation achieved by a person operating a mechanism that actively releases stored gas into
the buoyancy chamber(s) of a lifejacket or buoyancy element
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3.11
oral inflation system
means of inflation achieved by a person blowing expired air into the buoyancy chamber(s) of a
lifejacket or buoyancy element
3.12
rotorcraft
heavier-than-air aircraft that depends principally for its support in flight on the lift generated by one or
more rotors
3.13
helicopter
rotorcraft that, for its horizontal motion, depends principally on its engine-driven rotors
3.14
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
3.15
water impact
helicopter contact with water that is unintentional or exceeds the ditching capability of the helicopter
for water entry
3.16
crew member
person assigned by an operator to perform duties on board an aircraft
3.17
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
3.18
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.
3.19
demand regulator
device which consists of a pressure reducer connected to a demand valve
3.20
medium pressure hose
hose with an interface connection at each end, between the pressure reducer and a demand valve
3.21
breathing hose
flexible hose connecting a counterlung to the mouthpiece of a hybrid rebreather EBS, at approximately
ambient pressure
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3.22
pressure indicator
device to indicate to the user the pressure of gas in a cylinder
3.23
purging device
part of the demand regulator that can be operated manually to deliver breathable gas, intended to force
water out of the mouthpiece
3.24
dead space
volume of the cavity formed between the mouth and the inhalation and exhalation parts
3.25
activation device
mechanism which switches breathing from the atmosphere to the counterlung of a hybrid rebreather
EBS
3.26
counterlung
variable volume container for the user to exhale to and inhale from
3.27
breathable gas
gas that will support life under the intended conditions of use
3.28
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 J/l.
3.29
respiratory pressure
differential pressure at the mouth relative to the no flow pressures measured at the end of inhalation
and exhalation
3.30
hydrostatic imbalance
difference at end exhalation no flow between the pressure at the mouth and that at the lung centroid
reference point
3.31
tidal volume
volume of breathing gas displaced by the breathing simulator during one half cycle (inhalation or
exhalation)
Note 1 to entry: Measured in l.
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3.32
respiratory minute volume
product of the tidal volume and breathing frequency
Note 1 to entry: Measured in l/min.
3.33
useable volume of air
volume of breathable air available to the user while the demand regulator is operating within the
specified breathing performance
3.34
rated working pressure
maximum working pressure of the respective components
3.35
pressure volume diagram
diagram generated during one breathing cycle by plotting the respiratory pressure against the
displaced (tidal) volume
3.36
elastance
change in pressure that results from a given volume change of the human lung
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.
3.37
reference pressure
equilibrium pressure which exists in the mouthpiece when there is no respiratory flow at the end of
exhalation
3.38
escape buoyancy
buoyancy of an equipment combination, with the lifejacket or buoyancy element uninflated, that must
be overcome when escaping from an immersed helicopter
Note 1 to entry: It includes the inherent buoyancy of the components of the immersion suit system and entrapped
air but excludes the inflated buoyancy elements.
4 Design types
4.1 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;
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• gas cylinder;
• demand regulator;
• pressure indicator;
• purging device;
• nose occlusion system.
4.2 Hybrid 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. 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.
5 Performance requirements
5.1 General
5.1.1 EBS covered by this European standard shall be capable of being rapidly deployed and used
both in air and underwater. They shall be suitable for use when capsize and/or sinking occurs
immediately after the helicopter makes contact with the water.
5.1.2 Where applicable, EBS shall be tested in combination with associated equipment, including an
immersion suit, accessories and/or lifejacket that is intended to be worn with it, 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).
NOTE Helicopter immersion suits are hereinafter referred to as immersion suits. Helicopter constant wear
lifejackets are hereinafter referred to as lifejackets.
5.1.3 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.
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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 hybrid 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 system 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 hybrid rebreather system, the counterlung shall
have sufficient breathable capacity to accommodate an expired volume of at least 6 l (STPD). 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 The EBS design shall minimize 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, 6.8.4.5 and 6.8.4.6.
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
and for underwater use. Testing shall be carried out in accordance with 6.1.
NOTE Some composite cylinders are not approved for underwater use.
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.
...
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