oSIST prEN 17436:2021
(Main)Cabin air quality on civil aircraft - Chemical compounds
Cabin air quality on civil aircraft - Chemical compounds
This document defines requirements and recommendations dealing with the quality of the air on civil aircraft concerning chemical compounds potentially originating from, but not limited, to, the ventilation air supplied to the cabin and flight deck.
A special emphasis is on the engine and APU bleed air contaminants potentially brought into the cabin through the air conditioning, pressurization and ventilation systems.
The document is applicable to civil aircraft in operation from the period that is defined as when the first person enters the aircraft until the last person leaves the aircraft.
The document defines requirements and recommendations in relation to the presence of, and means to prevent exposure to, chemical compounds, including those that could cause adverse effects, taking into account the Precautionary Principle.
Kabinenluftqualität in Verkehrsflugzeugen - Chemische Parameter
Dieses Dokument legt Anforderungen und Empfehlungen für die Luftqualität in Verkehrsflugzeugen in Bezug auf chemische Parameter fest, die möglicherweise aus der Belüftungsluft stammen, die der Kabine und dem Cockpit zugeführt wird, aber nicht darauf beschränkt sind.
Im Vordergrund stehen Schadstoffe, die aus der Zapfluft des Triebwerks und des Hilfsaggregats (en: Auxiliary Power Unit, APU) stammen, die möglicherweise durch die Klima , Druck und Luftversorgungssysteme in die Kabine gelangen.
Das Dokument ist anwendbar für den Zeitraum in dem ein Verkehrsflugzeug in Betrieb ist: Ab dem Zeitpunkt, in dem die erste Person in das Luftfahrzeug einsteigt, bis die letzte Person das Luftfahrzeug verlässt.
Das Dokument definiert Anforderungen und Empfehlungen in Bezug auf das Vorhandensein von chemischen Parametern und die Mittel zur Verhinderung der Exposition gegenüber chemischen Verbindungen, einschließlich solcher, die unter Berücksichtigung des Vorsorgeprinzips nachteilige Auswirkungen haben können.
Qualité de l'air en cabine d'avions civils - Composés chimiques
Le présent document définit les exigences et recommandations applicables à la qualité de l'air dans les avions civils, en ce qui concerne les composés chimiques potentiellement émis, sans toutefois s'y limiter, par l'air de ventilation qui alimente la cabine et le poste de pilotage.
Il met tout particulièrement l'accent sur les contaminants présents dans l'air de prélèvement du réacteur et du groupe auxiliaire de puissance et qui sont potentiellement véhiculés jusque dans la cabine à travers les systèmes de climatisation, de pressurisation et de ventilation.
Le présent document s'applique aux avions civils en service entre la période définie comme étant l'intervalle entre le moment où la première personne pénètre dans l'avion et le moment où la dernière personne quitte l'avion.
Le présent document définit les exigences et recommandations en lien avec la présence de composés chimiques, y compris ceux pouvant avoir des effets indésirables, ainsi qu'avec les moyens de prévenir l'exposition à de tels composés chimiques, en appliquant le principe de précaution.
Kakovost zraka v kabini civilnih letal - Kemijske spojine
General Information
Relations
Standards Content (Sample)
SLOVENSKI STANDARD
oSIST prEN 17436:2021
01-april-2021
Kakovost zraka v kabini civilnih letal - Kemijske spojine
Cabin air quality on civil aircraft - Chemical compounds
Kabinenluftqualität in Verkehrsflugzeugen - Chemische Parameter
Qualité de l'air en cabine d'avions civils - Composés chimiques
Ta slovenski standard je istoveten z: prEN 17436
ICS:
13.040.01 Kakovost zraka na splošno Air quality in general
49.095 Oprema za potnike in Passenger and cabin
oprema kabin equipment
oSIST prEN 17436:2021 en,fr,de
2003-01.Slovenski inštitut za standardizacijo. Razmnoževanje celote ali delov tega standarda ni dovoljeno.
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oSIST prEN 17436:2021
DRAFT
EUROPEAN STANDARD
prEN 17436
NORME EUROPÉENNE
EUROPÄISCHE NORM
March 2021
ICS 49.095
English Version
Cabin air quality on civil aircraft - Chemical compounds
Qualité de l'air en cabine d'avions civils - Composés Kabinenluftqualität in Verkehrsflugzeugen - Chemische
chimiques Parameter
This draft European Standard is submitted to CEN members for second enquiry. It has been drawn up by the Technical
Committee CEN/TC 436.
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 17436:2021 E
worldwide for CEN national Members.
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prEN 17436:2021 (E)
Contents Page
European foreword . 4
Introduction . 5
1 Scope . 6
2 Normative references . 6
3 Terms and definitions . 7
4 Cabin air quality — chemical compounds . 11
4.1 Chemical compounds in cabin air . 11
4.2 Sources of chemical compounds. 11
4.3 Sources of engine oil leakage in the bleed air system . 11
4.4 Fume event . 11
4.5 Marker compounds . 12
4.6 Environmental control systems (ECS) . 12
5 Precautionary Principle and hierarchy of controls . 13
5.1 General. 13
5.2 Precautionary Principle . 13
5.3 Hierarchy of controls . 14
5.4 Elimination measures . 14
5.5 Mitigation measures . 15
6 Filtration . 16
6.1 General. 16
6.2 Recirculation cabin air filtration. 16
6.3 Catalytic conversion filtration . 16
7 Air monitoring . 17
7.1 General. 17
7.2 Air monitoring planning/development . 17
7.3 Air monitoring methodology . 20
8 Preventative and corrective actions . 22
8.1 General. 22
8.2 Preventative measures pre-flight . 22
8.3 Corrective measures in-flight . 22
8.4 Corrective measures post-flight . 23
8.5 Aircraft Maintenance Manual (AMM) . 23
9 Monitoring of air crew and passengers . 24
9.1 Monitoring air crew . 24
9.2 Monitoring passengers . 24
10 Data compilation, analysis and reporting . 25
10.1 General. 25
10.2 Data compilation . 25
10.3 Analysis and reporting . 27
11 Airline worker education and training . 28
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11.1 General . 28
11.2 Requirements . 28
Annex A (informative) Environmental Control Systems (ECS) . 30
A.1 General . 30
A.2 Bleed air environmental control systems (ECS) . 30
A.3 Bleed-free environmental control system . 32
Annex B (normative) Chemical marker compounds . 33
Annex C (informative) Precautionary Principle . 37
C.1 Precautionary Principle . 37
C.2 Precautionary Principle considerations: background information . 38
Annex D (informative) Approaches for online monitoring . 40
D.1 General . 40
Annex E (informative) Reference method for real-time and time-integrated measurement
of chemical marker compounds and (ultra) fine particles . 41
Annex F (informative) Examples of best practice intended to prevent or minimize
contamination . 53
Annex G (informative) Chemical marker compounds introduced into the cabin . 55
Annex H (informative) Sources of engine oil leakage into the bleed air system and
ventilation supply air . 58
H.1 Description of oil lubrication system . 58
H.2 Description of seal technology . 59
H.3 Oil path into bleed air system and ventilation supply air . 59
H.4 Maintenance response to oil fumes sourced to bleed air system (renumber H.4) . 60
Annex I (informative) Overview of aircraft cabin air and bleed air monitoring studies . 61
I.1 Introduction . 61
I.2 References cited in Table I.1 . 71
Bibliography . 74
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European foreword
This document (prEN 17436:2021) has been prepared by Technical Committee CEN/TC 436 “Cabin air
quality”, the secretariat of which is held by AFNOR.
This document is currently submitted to the second Enquiry.
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Introduction
Air quality on civil aircraft requires particular attention, given the characteristics of the cabin
environment.
An environmental control system (ECS) is used to regulate the aircraft cabin pressure, temperature and
ventilation supply air to provide a safe and comfortable environment for the passengers and air crew.
The aircraft cabin by design and operation is enclosed and is a densely occupied environment (with
only a small amount of per person dilution volume), creating the potential for elevated levels of bio-
effluents in the cabin, such as carbon dioxide (see Annex A). ECS architecture on civil passenger aircraft
can be broadly separated in two categories: bleed air ECS systems and bleed free ECS systems (see
Annex A). Most aircraft manufactured today, and nearly all aircraft in service, have bleed air ECS.
This document focuses on the chemical compounds potentially present in cabin air. It sets out
requirements, recommendations, and supporting annexes to enable airline operators, manufacturers
and suppliers to identify - and either prevent or mitigate - exposure to contaminants in the cabin air,
with particular emphasis on bleed air contaminants sourced to or generated from engine oil and
hydraulic fluid. This includes some limited measures intended to protect workers assigned to
troubleshoot and service the aircraft ventilation supply air systems.
NOTE Aircraft accident investigation agencies, aviation regulators from the EU and US, and the International
Civil Aviation Organization (ICAO) have recognized that bleed air contamination can compromise flight safety.
The requirements and recommendations in this document take into account that the fluids used in
aviation (including jet engine oils) and their pyrolysis products are complex mixtures. Some of these
mixtures contain organophosphates, ultra-fine particles, and other chemical compounds.
The requirements set out in the document take into account current and developing legal frameworks
in order to enable the industry to meet their legal obligation to provide a safe environment for air crew
and passengers. This document also acknowledges, at the European Commission level, the value of
using the Precautionary Principle in relation to risk management, and the use of risk assessment in this
industry to protect workers and the environment.
Within this document, emphasis is placed upon exposure prevention, sensor technology, worker
training, reporting systems, and collation of data and information from air crew and passengers. Safety
Management Systems (SMS) can be a useful tool to enable operators to apply these measures to
monitor and respond to system degradation.
This document does not define acceptability/suitability for health, comfort, safety, or airworthiness of
the cabin air.
Annex I contains a summary of maximum levels of the marker compounds listed in Annex B that have
been published.
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1 Scope
This document defines requirements and recommendations dealing with the quality of the air on civil
aircraft concerning chemical compounds potentially originating from, but not limited, to, the ventilation
air supplied to the cabin and flight deck.
A special emphasis is on the engine and APU bleed air contaminants potentially brought into the cabin
through the air conditioning, pressurization and ventilation systems.
This document is applicable to civil aircraft in operation from the period that is defined as when the
first person enters the aircraft until the last person leaves the aircraft.
This document defines requirements and recommendations in relation to the presence of, and means to
prevent exposure to, chemical compounds, including those that could cause adverse effects, taking into
account the Precautionary Principle.
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 1822-1, High efficiency air filters (EPA, HEPA and ULPA) - Part 1: Classification, performance testing,
marking
EN ISO 16000-1, Indoor air - Part 1: General aspects of sampling strategy (ISO 16000-1)
ISO 29463-1, High efficiency filters and filter media for removing particles from air — Part 1:
1)
Classification, performance, testing and marking
IEST-RP-CC001, HEPA and ULPA filters
1)
Published by: ISO International Organization for Standardization http://www.iso.ch/
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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 http://www.iso.org/obp
• IEC Electropedia: available at http://www.electropedia.org/
3.1
adverse effect
change in morphology, physiology, growth, development or lifespan of an organism which results in
impairment of its functional capacity or impairment of its capacity to compensate for additional stress
or increased susceptibility to the harmful effects of other environmental influences
[SOURCE: ISO 13073-3:2016, 2.1]
3.2
aerosol
system of solid particles and/or liquid droplets suspended in gas
3.3
air crew
people working on an aircraft in the period that is defined as when the first person boards the aircraft
until the last person leaves the aircraft, including pilots and cabin crew
3.4
airline operator
entity authorized by an Air carrier Operator Certificate (AOC) from its national Civil Aviation Authority
to operate civil transport aircraft flights for commercial carriage of passengers, cargo or mail
Note 1 to entry: The airline operator holds responsibility for compliance with civil aviation authority regulations
on its flights, including when the relevant tasks are performed by sub-contractors.
[SOURCE: ISO 16412:2005, 3.3, modified — The terms originally defined were “operator”, “airline” and
“carrier”.][2]
3.5
auxiliary power unit
APU
gas turbine-powered unit delivering rotating shaft power, compressor air, or both, which is not
intended for direct propulsion of an aircraft
[SOURCE: EASA CS Definitions] [3]
3.6
best available technology
BAT
most effective and advanced stage in the development of activities and their methods of operation
which indicate the practical suitability of particular technologies for providing, in principle, the basis to
mitigate, or eliminate exposure to contaminants in cabin air
[SOURCE: Council Directive 2008/1/EC, modified] [4]
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3.7
bleed air
air bled off the compressor stages of the aircraft engines or APU, prior to the combustion chamber;
source of ventilation air
3.8
cabin air
air within the section of an aircraft in which passengers and/or air crew travel (including the cabin and
flight deck)
3.9
cabin material
cabin interior which includes seats, flooring, walls, cabinets and overhead bins
3.10
chemical compound
chemical element or compound on its own or admixed as it occurs in the natural state or as produced,
used, or released, including release as waste, by any work activity, whether or not produced
intentionally and whether or not placed on the market
[SOURCE: Council Directive 98/24/EC Art. 2(a)][5]
3.11
contaminant
substance emitted into the air adversely affecting air quality
[SOURCE: ISO 4225:2020] [6]
3.12
early warning system
system or a procedure to detect the presence of contaminants that may require intervention
3.13
electrical-environmental control system
E-ECS
bleed-free ECS
3.14
environment control system
ECS
system of an aircraft which provides ventilation supply air, temperature control, and cabin
pressurization for the crew and passengers
3.15
fresh air (see also: outside air)
air taken from outside the vehicle
Note 1 to entry: In this document, the vehicle is the aircraft.
3.16
fumes
odorous, gaseous emission of compound(s) and/or aerosols which may be sourced to the cabin/flight
deck ventilation supply air vents and is not visible
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3.17
hazardous
substance or mixture fulfilling the criteria relating to physical hazards, health hazards, or
environmental hazards
[SOURCE: Regulation (EC) No 1272/2008 “CLP”, Article 3] [7]
Note 1 to entry: (i) any chemical agent which meets the criteria for classification as hazardous within any physical
and/or health hazard classes laid down in Regulation (EC) No 1272/2008 of the European Parliament and of the
Council, whether or not that chemical agent is classified under that Regulation; and(ii) any chemical agent which,
whilst not meeting the criteria for classification as hazardous in accordance with point (i) may, because of its
physico-chemical, chemical or toxicological properties and the way it is used or is present in the workplace,
present a risk to the safety and health of workers, including any chemical agent that is assigned an occupational
exposure limit value under Article 3.
[SOURCE: Directive (EC) No 98/24, Article 2]
Note 2 to entry This definition of hazardous is different to the definition applied in the airworthiness context.
3.18
marker compound
chemical compound representing/indicating specific/potential sources of airborne contaminants in the
cabin air
3.19
outside air (see also: fresh air)
air taken from outside the vehicle
[SOURCE: ISO 19659-1:2017, 3.4.1] [8]
Note 1 to entry: In this document, the vehicle is the aircraft.
3.20
real-time sampling
use of online monitoring using instrumental analysers with sensors; the output describes the change in
concentration of the analyte(s) as a function of time during the sampling period
3.21
risk analysis
systematic use of available information to identify hazards and to estimate the risk
[SOURCE: ISO/IEC Guide 51:2014, 3.10] [9]
3.22
safety management system
SMS
administrative framework that is designed to manage safety risks in workplaces and is applied to
enable the operator to systematically monitor and respond to fume events
3.23
sensor
electronic device that senses a physical condition or chemical compound and delivers an electronic
signal proportional to the observed characteristic
[SOURCE: ISO/IEC TR 29181-9:2017,3.14] [10]
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3.24
soot
particulate matter with a particle size of 0 nanometres (nm) to 10 nm produced and deposited during
or after combustion
[SOURCE: EN ISO 472:2013, 2.1278 modified] [11]
3.25
steady state
condition during single engine power setting characterized by stable temperature and bleed pressure
[SOURCE: SAE (2018)] [12]
3.26
supply air
air introduced into an enclosure by mechanical means including engines, APU, onboard electric
compressors, or ground supply units
3.27
time-integrated sampling
either passive or active sampling methodology, followed by analysis of the collected sample in
dedicated equipment or a laboratory; the output describes the average concentration of the analyte(s)
during the sampling period
3.28
transient operating condition
condition other than steady state engine power setting characterized by unstable temperature and/or
changing pressure; examples include engine start, take-off top-of-descent and changes in engine regime
including changing the power setting from idle to take off power and back
3.29
ultra-fine particles
ultra-fine particles (UFP) or ultrafine dust are the most commonly used definitions of airborne particles
with a diameter between 1 and 100 nanometres (nm)
[SOURCE: ISO 2007] [13]
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4 Cabin air quality — chemical compounds
4.1 Chemical compounds in cabin air
The presence and concentration of many chemical compounds have been measured in the cabin air and
are reported in numerous studies, providing a large database of chemical compounds. Most of these
data were collected in the cabin or flight deck during normal operating conditions and not during a
reported “fume event” (see 4.4). Some of these data were collected directly from a bleed air source.
Monitoring the cabin air for the presence of appropriate chemical marker compounds is a method to
indicate the source(s) of contamination, rather than to assess any health effects of exposure.
4.2 Sources of chemical compounds
Chemical compounds can be sourced to the outside environment and can also originate from the
aircraft itself. These may include, but are not limited to the following:
— engine oil;
— hydraulic fluid;
— engine exhaust;
— fuel (unburned and vapours);
— de-icing fluid;
— chemical products used to wash engines or turbines;
— occupants;
— cabin materials and cleaning products;
— air conditioning equipment;
— faulty/failed electrical items.
An overview of a subset of the chemical compounds associated with some of these sources that may be
introduced to the cabin air is provided in Annex G.
4.3 Sources of engine oil leakage in the bleed air system
The presence of oil fumes in the cabin air can, in some instances, be linked to the oil lubrication system.
A description of the oil lubrication system, the seal technology and possible contamination of the cabin
air with engine oil are discussed in Annex H.
4.4 Fume event
A fume event is characterized by the presence of fumes in the cabin, emanating from the ventilation
supply air vents which can indicate the presence of a specific contamination of the ventilation supply air
(e.g. engine oil, hydraulic fluid, de-icing fluid) that has originated from or entered the engine or APU.
Alternatively, the presence of fumes and/or aerosols in cabin may emanate from a source within the
cabin (e.g. galley ovens, electrical faults).
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4.5 Marker compounds
A subset of marker compounds that can be present in cabin air is listed in Annex B, Table B.1. These
marker compounds are associated with major contaminant sources from bleed air and outside air.
They are deemed to be useful markers for these specific sources of air contamination in the aircraft
environment.
Table B.2 lists “reliability ratings” (A through C) for each marker compound, intended to assist the
reader in determining which combination of compounds to monitor for each source of contamination
listed in 4.2.
Annex I lists published studies that, together, include measurement data for 14 of the 16 marker
compounds in Annex B. The maximum value of each measured compound was commonly reported so is
provided in Table I.1 for comparison purposes.
4.6 Environmental control systems (ECS)
The purpose of the ECS is to provide ventilation supply air and regulate the aircraft cabin pressure and
temperature in order to provide a safe and comfortable environment for the passengers and crew.
Most commercial passenger aircraft are equipped with an ECS that processes bleed air from engine
compressors, whilst some ECS process air from electrical compressors. Airborne chemical compounds
can be introduced into the cabin air through the aircraft ventilation supply air system. Further details
on these two types of ECSs are provided in Annex A.
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5 Precautionary Principle and hierarchy of controls
5.1 General
Airborne chemical agents can be sourced to the ventilation supply air (e.g. engine oil, hydraulic fluid,
de-icing fluid, and exhaust fumes) and the aircraft cabin surfaces, equipment, and occupants (see
Clause 4). Exposure to these chemical agents can be prevented/minimized through the application of
t
...
SLOVENSKI STANDARD
oSIST prEN 17436:2019
01-oktober-2019
Kakovost zraka v kabini civilnih letal - Kemijske spojine
Cabin air quality on civil aircraft - Chemical compounds
Kabinenluftqualität in Verkehrsflugzeugen - Chemische Parameter
Ta slovenski standard je istoveten z: prEN 17436
ICS:
13.040.01 Kakovost zraka na splošno Air quality in general
49.095 Oprema za potnike in Passenger and cabin
oprema kabin equipment
oSIST prEN 17436:2019 en,fr,de
2003-01.Slovenski inštitut za standardizacijo. Razmnoževanje celote ali delov tega standarda ni dovoljeno.
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oSIST prEN 17436:2019
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oSIST prEN 17436:2019
DRAFT
EUROPEAN STANDARD
prEN 17436
NORME EUROPÉENNE
EUROPÄISCHE NORM
September 2019
ICS 49.095
English Version
Cabin air quality on civil aircraft - Chemical compounds
Kabinenluftqualität in Verkehrsflugzeugen - Chemische
Parameter
This draft European Standard is submitted to CEN members for enquiry. It has been drawn up by the Technical Committee
CEN/TC 436.
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
© 2019 CEN All rights of exploitation in any form and by any means reserved Ref. No. prEN 17436:2019 E
worldwide for CEN national Members.
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prEN 17436:2019 (E)
Contents Page
European foreword . 4
Introduction . 5
1 Scope . 7
2 Normative references . 7
3 Terms and definitions . 7
4 Cabin air quality – chemical compounds . 10
4.1 Presence of chemical compounds in cabin air . 10
4.2 Sources of airborne contaminants . 11
4.3 Sources of engine oil leakage in the bleed air system. 11
4.4 Fume event . 11
4.5 Marker compounds . 11
4.6 Environmental Control System (ECS) . 12
5 Requirements for cabin air quality . 12
5.1 General . 12
5.2 Requirements for the Precautionary Principle and hierarchy of controls . 13
5.2.1 Precautionary Principle. 13
5.2.2 Hierarchy of controls . 13
5.2.3 Filtration . 14
5.3 Requirements . 15
5.3.1 General . 15
5.3.2 Requirements for air monitoring . 16
5.4 Air monitoring strategy . 16
5.4.1 General . 16
5.4.2 Planning . 16
5.4.3 Sampling approaches . 17
5.5 Air monitoring methodology . 18
5.5.1 General . 18
5.5.2 Real-time or online monitoring . 18
5.5.3 Off-line monitoring . 20
5.5.4 Monitoring cabin air crew (pilots and flight attendants) . 21
5.5.5 Passenger monitoring . 22
6 Requirements for analysis and reporting . 22
6.1 Analysis reporting . 22
6.1.1 General . 22
6.1.2 Use of reporting information derived from monitoring data . 22
6.2 Reporting and recording cabin air quality events . 23
6.2.1 General . 23
6.2.2 Cabin air quality reporting systems . 23
7 Corrective and preventative action . 24
7.1 General . 24
7.1.1 Actions to identify and remedy contaminant sources post-flight . 24
7.1.2 Requirements . 24
7.2 Aircraft Maintenance manual (AMM) . 26
8 Airline worker education and training . 26
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8.1 General . 26
8.2 Requirements . 26
8.2.1 General . 26
8.2.2 Pilot specific training and education . 27
8.2.3 Cabin crew-specific training and education. 27
8.2.4 Maintenance worker-specific training and education . 27
8.2.5 Training of maintenance staff . 27
8.2.6 Crew checklists and crew manuals . 27
Annex A (informative) Environmental Control Systems (ECS) . 29
A.1 General . 29
A.2 Bleed air environmental control system (ECS) . 29
A.2.1 General . 29
A.2.2 Bleed free environmental control system . 30
Annex B (normative) Chemical Marker Compounds . 32
Annex C (informative) Precautionary principle . 48
C.1 Precautionary Principle . 48
C.2 Background . 50
Annex D (informative) Reference method for online and offline measurement of chemical
marker compounds and (ultra) fine particles . 51
Annex E (informative) Examples of Best Practice for flight crew and maintenance operations
intended to prevent or minimize contamination. 53
Annex F (informative) Chemical compounds introduced into the cabin . 55
Annex G (informative) Sources of engine oil leakage in the bleed air system . 57
G.1 General . 57
G.2 Normal . 57
G.3 Abnormal . 57
Annex H (informative) Overview of aircraft cabin and bleed air monitoring data. 58
Bibliography . 94
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European foreword
This document (prEN 17436:2019) has been prepared by Technical Committee CEN/TC 436 “Cabin Air
Quality on civil aircraft – Chemical Agents”, the secretariat of which is held by AFNOR.
This document is currently submitted to the CEN Enquiry.
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Introduction
Air quality on civil aircraft differs in many important ways from air quality in other indoor environments.
The cabin environment is, by definition, enclosed and confined. The aircraft cabin is a densely occupied
environment with only a small amount of per person dilution volume, creating the potential for elevated
levels of bio-effluents in the cabin, such as carbon dioxide.
The partial pressure of air and the amount of oxygen is reduced inflight. Aircraft are designed to ensure
that the effective cabin altitude does not exceed 2 438 m which corresponds to a partial pressure of
0.74 atm (75.2 kPa) (CS25.841).
An environmental control system (ECS) is used to regulate the aircraft cabin pressure and temperature
to provide a safe and comfortable environment for the passengers and crew. The ECS provides fresh air,
thermal control and cabin pressurization for the crew, attendants and passengers so as to ensure a
suitable composition of the air. ECS architecture on civil passenger aircraft can be broadly separated in
two categories: bleed air ECS systems and bleed free ECS systems. In a conventional ECS, the air source
can be pneumatic (bled from the engine) or electric. Most commercial passenger aircrafts manufactured
today and nearly all such aircraft in service have ECS's using engine bleed air.
This document sets out requirements and recommendations and supporting annexes to enable operators
to eliminate and mitigate exposure to contaminants in the cabin air, including a special emphasis on the
bleed air contaminants sourced to engine oil and hydraulic fluid.
Fluids used in aviation and jet engine oils and their pyrolysis products are complex mixtures. Chronic
low-level exposure to complex mixtures, including organophosphates and the interdependence of
chronic low dose exposure to subsequent higher dose fume events appears to make air crew more
susceptible to harm. In addition to the effects, ultrafine particles generated in association with pyrolyzed
oil entering the bleed air, while known to have associated long-term health effects may also increase the
transference of toxicants to the brain. Most chemicals that produce systemic toxicity do not cause a
similar degree of toxicity in all organs but usually produce their major toxicity in one or two organs. These
are referred to as target organs of toxicity for that chemical. Examples would be the hepato-toxicity of
alcohol and the neurotoxicity of organophosphorus compounds. A major reason why the brain is
susceptible to target organ toxicity in mammals is that nerve cells last for the lifetime of the organism and
cannot, like most other tissues, repair by cell proliferation. In assessing the risks and potential harm, on
average a pilot over a 20,000-h flying career will, conservatively breathe 9,000,000 l of engine bleed air.
This document sets out requirements and recommendations to enable the industry to meet their legal
obligations and provide a safer working environment for the air crew, and safer travel for passengers.
Emphasis is placed upon increasing knowledge and understanding of air quality issues on civil aircraft
through a wider use of testing, sensor technology and collation of data and information from aircrew and
passengers.
NOTE Numerous aircraft accident investigation agencies, Regulators from the EU and US and the International
Civil Aviation Organization (ICAO) have recognized that bleed air contamination may pose a threat to flight safety.
The requirements set out in the document takes into account current and developing regulation and the
acknowledgement at the European Commission level, of the value of using the Precautionary Principle in
relation to risk management and the use of risk assessment in this industry to protect workers and the
environment.
Safety Management Systems (SMS) are a vital tool in the consideration, analysis and problem solving
within the operation of an aircraft. The use of an SMS is particularly vital on the issue of cabin air quality
and is referred to in this document. This document does acknowledge that whilst an SMS is the main
methodology used by airline operators, not all operators use such a system and deploy other
methodologies consistent with the objectives of an SMS.
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A number of studies have been carried out in relation to the quality of aircraft cabin air. The spreadsheet
in Annex H contains a comprehensive list of studies in the public domain of chemicals detected in various
air monitoring studies. The studies are of cabin air or engine or APU bleed air studies. The maximal levels
of the compounds recorded in each specific study are presented. It is needful to refer to the original
studies to determine the respective methodology employed.
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1 Scope
This document defines requirements and recommendations dealing with the quality of the air on civil
aircraft concerning chemical compounds potentially originating from, but not limited, to, the ventilation
air supplied to the cabin and flight deck.
A special emphasis is on the engine and APU bleed air contaminants potentially brought into the cabin
through the air conditioning, pressurization and ventilation systems.
The document is applicable to civil aircraft in operation from the period that is defined as when the first
person enters the aircraft until the last person leaves the aircraft.
The document defines requirements and recommendations in relation to the presence of, and means to
prevent exposure to, chemical compounds, including those that could cause adverse effects, taking into
account the Precautionary Principle.
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 1822-1, High efficiency air filters (EPA, HEPA and ULPA) — Part 1: Classification, performance testing,
marking
EN ISO 16000-1, Indoor air — Part 1: General aspects of sampling strategy (ISO 16000-1)
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 http://www.iso.org/obp
— IEC Electropedia: available at http://www.electropedia.org/
3.1
adverse effects
change in morphology, physiology, growth, development or lifespan of an organism which results in
impairment of its functional capacity or impairment of its capacity to compensate for additional stress or
increased susceptibility to the harmful effects of other environmental influences
[SOURCE: ISO 13073-3:2016, 2.1, modified — The term "adverse effect" was at the singular in the original
definition.]
3.2
aerosol
system of solid or liquid particles suspended in gas
[SOURCE: ISO 15900:2009, 2.1]
3.3
air crew
people working on an aircraft in the period that is defined as when the first-person boards the aircraft
until the last person leaves the aircraft (pilots and cabin attendants)
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3.4
air supply
air introduced into an enclosure by mechanical or natural means
[SOURCE: ISO 16814:2008, 3.41, modified — The term originally defined was "supply air".]
3.5
airline operator
entity authorized by an Air carrier Operator Certificate (AOC) from its national Civil Aviation Authority
to operate civil transport aircraft flights for commercial carriage of passengers, cargo or mail
Note 1 to entry: The operator holds responsibility for compliance with Civil Aviation Authorities Regulations on
its flights, including when the relevant tasks are performed by sub-contractors.
[SOURCE: ISO 16412:2005, 3.3, modified — The terms originally defined were "operator", "airline" and
"carrier".]
3.6
auxiliary Power Unit
APU
gas turbine-powered unit delivering rotating shaft power, compressor air, or both, which is not intended
for direct propulsion of an aircraft
[SOURCE: EASA CS Definitions]
3.7
bleed air
air taken from the compressor stages of the aircraft engines or APU, prior to the burning chamber, and
from which the hot and compressed air is bled of to the aircraft cabin
3.8
cabin air
air within the section of an aircraft in which passengers and/or crew travel
3.9
cabin material
cabin interior which includes seats, flooring, and casings
3.10
chemical compound
any chemical element or compound on its own or admixed as it occurs in the natural state or as produced,
used, or released, including release as waste, by any work activity, whether or not produced intentionally
and whether or not placed on the market
[SOURCE: Council Directive 98/24/EC Art. 2(a)]
3.11
contaminants
any material or combination of materials (solid, liquid or gaseous) that can adversely affect the system
[SOURCE: ISO/TR 15640:2011, 3.1, modified — The term "contaminant" was at the singular in the
original definition.]
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3.12
duct residual contamination
contamination of the ducts by duct material degradation or chemical compounds, which can be deposited
in the ducts and reintroduced/re-entrained in the ventilation air
3.13
early warning system
system or a procedure to detect the presence of engine-generated contaminants that may require
intervention
3.14
environment control system (ECS)
system of an aircraft which provides air supply, temperature control and cabin pressurization for the
crew and passengers
3.15
fresh air
outside air
[SOURCE: EASA CS 25.831]
3.16
fumes
odorous, gaseous compounds which are typically sourced to the cabin/flight deck air supply vents
3.17
hazardous
substance or mixture fulfilling the criteria relating to physical hazards, health hazards or environmental
hazards
[SOURCE: Regulation (EC) No 1272/2008 “CLP”, Article 3]
3.18
marker compound
chemical compound representing/indicating contamination of the cabin air
3.19
monitoring
collection and assessment of status data for a process or a system
[SOURCE: CEN ISO/TS 17444-2:2017, 3.17]
3.20
outside air
air taken from outside the vehicle
[SOURCE: ISO 19659-1:2017, 3.4.1, modified — The terms originally defined were "fresh air" along with
"outside air".]
Note 1 to entry: In this document, the vehicle is the aircraft.
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3.21
particulate matter
solid and liquid matter of a sufficiently small size to be suspended in gas
[SOURCE: ISO 19867-1:2018, 3.46]
3.22
precautionary Principle
PP
approach to risk management whereby if there is the possibility that a given policy or action might cause
harm to the public or the environment and if there is still no scientific consensus on the issue, the policy
or action in question should not be pursued
[SOURCE: European Union law]
3.23
risk analysis
systematic use of available information to identify hazards and to estimate the risk
[SOURCE: ISO/IEC Guide 51:1999, 3.10]
3.24
sensor
electronic device that senses a physical condition or chemical compound and delivers an electronic signal
proportional to the observed characteristic
[SOURCE: ISO/IEC TR 29181-9:2017, 3.14]
3.25
sooting
particulate matter produced and deposited during or after combustion
[SOURCE: EN ISO 472:2013, 2.1278, modified — The term originally defined was "soot".]
3.26
transient power settings
short-term engine power setting characterized by unstable temperature and/or pressure
EXAMPLE Examples include engine start, take-off, and top-of-descent, changes in engine regime including
changing the power setting from idle to take off power and back.
3.27
ultra-fine particles
ultra-fine particles (UFP) or ultrafine dust are the most commonly used definitions of airborne particles
with a diameter between 1 and 100 nanometres (nm)
[SOURCE: ISO 2007]
4 Cabin air quality – chemical compounds
4.1 Presence of chemical compounds in cabin air
The presence of chemical compounds in cabin air is measured in many studies, providing a large base set
of chemical compounds. A comprehensive list of chemical compounds detected in cabin air and/or air
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supply is included in Annex B, Table B.2 “List of supplementary chemical compounds found in cabin and
supply air”.
The quality of the cabin air in aircraft can be reflected by chemical marker compounds. Identification of
these chemical marker compounds takes into account the different sources of contamination,
measurability and reported presence in cabin air.
4.2 Sources of airborne contaminants
Chemical agents sources consist of but are not limited to:
— Engine oil;
— Hydraulic fluid;
— Engine Exhaust;
— Fuel(unburned);
— De-icing Fluid;
— Occupants;
— Cabin material;
— Bleed system and air conditioning equipment material;
— Duct residual contamination.
An overview of chemical compounds that are introduced via different sources into the cabin via outside
air is given in Annex F, Table F.1. Chemical compounds that originate from inside the cabin and can
contaminate the cabin air are listed in Annex F, Table F.2.
4.3 Sources of engine oil leakage in the bleed air system
Pressurized compressor air is used to seal the engine bearing chambers and is responsive to variations
in engine operating conditions. All dynamic seals are designed to leak, with the leakage amount
depending on many factors including seal design, balance, lubricating regime, operating conditions,
compartment condition, wear life and distortion. It is accepted that oils seals commonly utilized will leak
a very small amount of oil vapour in normal service. Labyrinth seals operate with a clearance, while
mechanical face seals operate with a lubricated face, with both types of seals designed to limit sealed
product migration and therefore limiting emissions, rather than preventing them. Oil passing over the
seals in the area of the compressor has a path to enter the cabin air supply, if the leakage or emissions
occur prior to the compressor bleed air off-take port. Further information can be found in Annex G.
4.4 Fume event
The presence of fumes and/or aerosols, sourced to the air supply vents, when aircraft occupants are
present can indicate the presence of some type of contaminant in the supply air (e.g. oil, hydraulic fluid,
de-icing fluid, etc.) that has been heated in either the engine(s) or the APU, or electrical fire.
4.5 Marker compounds
Based on these data, a subset of marker compounds that can be present in cabin air is identified and
listed. The marker compounds cover all contaminant sources as mentioned above. Based on expert
judgement and support from experts and stakeholders, marker compounds are selected. An overview of
the selected marker compounds is shown in Annex B, Table B.1 “Chemical Marker Compounds”. The
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