Aircraft Cabin Air – Quality or Contamination?

AIRCRAFT DESIGN AND SYSTEMS GROUP (AERO) Hochschule für Angewandte Wissenschaften Hamburg Hamburg University of Applied Sciences Aircraft Cabin Air – Quality or Contamination? Personalversammlung "Kabine", Deutsche Lufthansa AG Frankfurt, 20. November 2017 Dieter Scholz Hamburg University of Applied Sciences https://doi.org/10.5281/zenodo.17960887 Personalversammlung "Kabine" Deutsche Lufthansa AG Dieter Scholz: A/C Cabin Air – Quality or Contamination? 20.11.2017, Slide 1 Aircraft Design and Systems Group (AERO) Hochschule für Angewandte Wissenschaften Hamburg Hamburg University of Applied Sciences Abstract Aircraft Cabin Air  Quality or Contamination? All aviation fluids (e.g. oil, fuel, hydraulic fluid) are spilled and subsequently ingested from the ground at airports. Jet engines leak oil internally in small quantities in normal operation by design and potentially in large amounts in failure cases. The oil gets into the engine compressor and via bleed air into the passenger cabin. The same is true for the auxiliary power unit (APU). Hydraulic fluids leak from the landing gear bay via the bottom of the fuselage into the APU inlet. As such, hydraulic fluids can also reach the potable water tank. Technical solutions are necessary: filtration in the recirculation path; better: complete air filtration; much better: a bleed-free air conditioning architecture. What can be done today? Crew members can get informed with a personal chemical detector. Cabin crew can get protected with a breathing mask, used in case of a fume or smoke event. In such cases, pilots can descend to 10000 ft to use direct venting of the cabin and cockpit to make a difference for passengers. Personalversammlung "Kabine" Deutsche Lufthansa AG Dieter Scholz: A/C Cabin Air – Quality or Contamination? 20.11.2017, Slide 2 Aircraft Design and Systems Group (AERO) Hochschule für Angewandte Wissenschaften Hamburg Hamburg University of Applied Sciences Contents Aircraft Cabin Air  Quality or Contamination? • Introduction •All Aviation Fluids: Ingestion from the Ground! •Engine Oil => Cabin Air? Yes oAir Conditioning Technology oJet Engine oAuxiliary Power Unit (APU) •Engine Oil => Water? Yes •Hydraulic Fluid => Cabin Air / Water? No •Technical Solutions (in the Future?) oFiltration in the Recirculation Path oComplete Air Filtration oBleed-free Architecture •Hints (for Today!) • Summary • Contact Personalversammlung "Kabine" Deutsche Lufthansa AG Dieter Scholz: A/C Cabin Air – Quality or Contamination? 20.11.2017, Slide 3 Aircraft Design and Systems Group (AERO) Hochschule für Angewandte Wissenschaften Hamburg Hamburg University of Applied Sciences Introduction Personalversammlung "Kabine" Deutsche Lufthansa AG Dieter Scholz: A/C Cabin Air – Quality or Contamination? 20.11.2017, Slide 4 Aircraft Design and Systems Group (AERO) Hochschule für Angewandte Wissenschaften Hamburg Hamburg University of Applied Sciences Introduction Definition: Aircraft Cabin Air A mixture of outside as well as recirculated and filtered air. In unpressurized aircraft cabins the air is at ambient pressure. In pressurized cabins the air is at a pressure equivalent to below 8000 ft (referring to the ICAO Standard Atmosphere). In most aircraft, the air temperature is controlled. Aircraft flying at high altitude usually show low relative humidity. Adapted from: http://aircrewhealth.com/Topics/hazards/cabinair.htm Personalversammlung "Kabine" Deutsche Lufthansa AG Dieter Scholz: A/C Cabin Air – Quality or Contamination? 20.11.2017, Slide 5 Aircraft Design and Systems Group (AERO) Hochschule für Angewandte Wissenschaften Hamburg Hamburg University of Applied Sciences Definition: Contamination The process of making a material unclean or unsuited for its intended purpose, usually by the addition or attachment of undesirable foreign substances. Adapted from: http://en.wiktionary.org/wiki/contamination The presence of a minor and unwanted constituent (contaminant). Related to health: A harmful intrusion of toxins or pathogens e.g. in food, water, or air. Adapted from: http://en.wikipedia.org/wiki/Contamination Definition: Quality Degree to which a set of inherent characteristics fulfills requirements. ISO 9000 Introduction Personalversammlung "Kabine" Deutsche Lufthansa AG Dieter Scholz: A/C Cabin Air – Quality or Contamination? 20.11.2017, Slide 6 Aircraft Design and Systems Group (AERO) Hochschule für Angewandte Wissenschaften Hamburg Hamburg University of Applied Sciences Health Effects: Occupational Health & Flight Safety Health effects may be experienced soon after exposure or, possibly, years later: •Long-term heath effects: • to passengers • to crew => occupational health (OH) => CS 25.831 usually related to Time-Weighted Average (TWA) Permissible Exposure Limits (PEL) •Immediate health effects: • to passengers • to cabin crew • to cockpit crew => flight safety implications can lead to: injury or death of • passenger • crew => CS 25.1309 (Eurofins 2017, EASA CS-25) Introduction Personalversammlung "Kabine" Deutsche Lufthansa AG Dieter Scholz: A/C Cabin Air – Quality or Contamination? 20.11.2017, Slide 7 Aircraft Design and Systems Group (AERO) Hochschule für Angewandte Wissenschaften Hamburg Hamburg University of Applied Sciences Introduction Potential Concerns Related to Air Quality • Cabin Pressure Can effect people with cardio-respiratory diseases from lack of oxygen • Relative Humidity Temporary drying of skin, eyes, and mucous membranes • Carbon Monoxide High concentrations during air-quality incidents. Frequency is believed to be low. CS 25.831: Concentration must be lower than 50 ppm. • Carbon Dioxide Concentrations are generally below FAA regulatory limits. Associated with increased perceptions of poor air quality. CS 25.831: Concentration must be lower than 0.5%. • Ozone Elevated concentrations on aircraft without ozone converters. Airway irritation and reduced lung function. CS 25.832: Concentration < 0.25 ppm resp. 0.1 ppm. • Pesticides From aircraft “disinsection" with pesticides. • Engine Oil Fumes from hot engine oil may enter the cabin via the bleed air system. • Hydraulic Fluids Frequency of incidents is expected to be relatively low. Mild to severe health effects. • Deicing Fluid Hazardous substance. Skin sensitizing and irritant. • Airborne Allergens Exposure frequency is not known. Irritated eye and nose; sinusitis; acute increases of asthma; possible anaphylaxis. • Nuisance Odors Can be present on any flight. Adapted from: http://aircrewhealth.com/Topics/hazards/cabinair.htm Personalversammlung "Kabine" Deutsche Lufthansa AG Dieter Scholz: A/C Cabin Air – Quality or Contamination? 20.11.2017, Slide 8 Aircraft Design and Systems Group (AERO) Hochschule für Angewandte Wissenschaften Hamburg Hamburg University of Applied Sciences Introduction Potential Concerns Related to Water Quality • Original Water Quality Depending on urban water management • Purity of Tank and Water Lines Depending on aircraft potable water system maintenance • Pesticides Aircraft "Disinsection" with pesticides • Engine Oil Fumes from hot engine oil may enter water via the bleed air system. • Hydraulic Fluids Hydraulic fluids are unlikely to enter the water via the bleed air system. Personalversammlung "Kabine" Deutsche Lufthansa AG Dieter Scholz: A/C Cabin Air – Quality or Contamination? 20.11.2017, Slide 15 Aircraft Design and Systems Group (AERO) Hochschule für Angewandte Wissenschaften Hamburg Hamburg University of Applied Sciences Air Conditioning Technology Air Conditioning with Recirculation Adapted from (NRC 2002) Personalversammlung "Kabine" Deutsche Lufthansa AG Dieter Scholz: A/C Cabin Air – Quality or Contamination? 20.11.2017, Slide 16 Aircraft Design and Systems Group (AERO) Hochschule für Angewandte Wissenschaften Hamburg Hamburg University of Applied Sciences cabin cabin Air Conditioning Technology Adapted from (FCOM A340) 1) compress the air 1) compress the air "Bleed Air" Generation and Treatment compress and cool the air 2a) cool the air 2b) cool the air "Bleed Air" is "precious air" taken off the engine compressor – air which was initially intended to be used for the engine cycle Personalversammlung "Kabine" Deutsche Lufthansa AG Dieter Scholz: A/C Cabin Air – Quality or Contamination? 20.11.2017, Slide 17 Aircraft Design and Systems Group (AERO) Hochschule für Angewandte Wissenschaften Hamburg Hamburg University of Applied Sciences Adapted from (FCOM A320) hot cold warm Air Conditioning Technology Temperature Control (ii) A320 bleed air 50 % outflow valve 50 % recirculation recirculation fan Temperature Control 2b) Air Cooling Temperature Control (i) Personalversammlung "Kabine" Deutsche Lufthansa AG Dieter Scholz: A/C Cabin Air – Quality or Contamination? 20.11.2017, Slide 18 Aircraft Design and Systems Group (AERO) Hochschule für Angewandte Wissenschaften Hamburg Hamburg University of Applied Sciences Cabin Air Distribution (GENFAM A320) Air Conditioning Technology A320 Personalversammlung "Kabine" Deutsche Lufthansa AG Dieter Scholz: A/C Cabin Air – Quality or Contamination? 20.11.2017, Slide 19 Aircraft Design and Systems Group (AERO) Hochschule für Angewandte Wissenschaften Hamburg Hamburg University of Applied Sciences Engine Overview K. Aainsqatsi https://upload.wikimedia.org/wikipedia/commons/7/77/Turbofan_operation_lbp.svg Jet Engine Personalversammlung "Kabine" Deutsche Lufthansa AG Dieter Scholz: A/C Cabin Air – Quality or Contamination? 20.11.2017, Slide 20 Aircraft Design and Systems Group (AERO) Hochschule für Angewandte Wissenschaften Hamburg Hamburg University of Applied Sciences Engine Overview Jet Engine Engine Alliance GP7000 Download from: https://goo.gl/images/gYIW31 bearing (example) Personalversammlung "Kabine" Deutsche Lufthansa AG Dieter Scholz: A/C Cabin Air – Quality or Contamination? 20.11.2017, Slide 21 Aircraft Design and Systems Group (AERO) Hochschule für Angewandte Wissenschaften Hamburg Hamburg University of Applied Sciences Jet Engine Bearing Jet Engine (Exxon 2016b) Personalversammlung "Kabine" Deutsche Lufthansa AG Dieter Scholz: A/C Cabin Air – Quality or Contamination? 20.11.2017, Slide 22 Aircraft Design and Systems Group (AERO) Hochschule für Angewandte Wissenschaften Hamburg Hamburg University of Applied Sciences TCP Judging Jet Engine Oil Based on Warnings Given by Manufacturer Jet Engine (Cannon 2016) Personalversammlung "Kabine" Deutsche Lufthansa AG Dieter Scholz: A/C Cabin Air – Quality or Contamination? 20.11.2017, Slide 23 Aircraft Design and Systems Group (AERO) Hochschule für Angewandte Wissenschaften Hamburg Hamburg University of Applied Sciences "a ... list of 127 compounds [VOC] was ... identified ... ". The hazard profile is given in Appendix 6: Health Effects? => EASA Study 2017: AVOIL AVOIL – Characterisation of the toxicity of aviation turbine engine oils after pyrolysis (EASA 2017a) How much Oil Gets into the Cabin? Personalversammlung "Kabine" Deutsche Lufthansa AG Dieter Scholz: A/C Cabin Air – Quality or Contamination? 20.11.2017, Slide 24 Aircraft Design and Systems Group (AERO) Hochschule für Angewandte Wissenschaften Hamburg Hamburg University of Applied Sciences Engine Air and Oil System Jet Engine based on: Exxon 2016b (oil) (air & oil) (oil & air) & oil & oil (oil & air) Normal operation of engine seals: 1. The "drain" discharges oil. 2. The "dry cavity" contains oil. 3. Air and oil leak from bearings into the bleed air. => Engines leak small amounts of oil by design! 1. 2. 3. Personalversammlung "Kabine" Deutsche Lufthansa AG Dieter Scholz: A/C Cabin Air – Quality or Contamination? 20.11.2017, Slide 31 Aircraft Design and Systems Group (AERO) Hochschule für Angewandte Wissenschaften Hamburg Hamburg University of Applied Sciences Hydraulic Fluid => Cabin Air / Water? No Personalversammlung "Kabine" Deutsche Lufthansa AG Dieter Scholz: A/C Cabin Air – Quality or Contamination? 20.11.2017, Slide 32 Aircraft Design and Systems Group (AERO) Hochschule für Angewandte Wissenschaften Hamburg Hamburg University of Applied Sciences Aircraft Systems Investigated - Hydraulic Reservoir Pressurization • Hydraulic reservoirs are connected via bleed lines with the potable water tanks. • Pressurized air is in free contact with the hydraulic fluid surface. •In flight, hydraulic fluid would need to flow upstream and opposite sense through two check valves to get into the bleed line. •On the ground, contaminated air with remaining pressure in the reservoir (3.5 bar) could flow downstream – but only if check valves allow for wrong flow direction. GenFam, A320 Personalversammlung "Kabine" Deutsche Lufthansa AG Dieter Scholz: A/C Cabin Air – Quality or Contamination? 20.11.2017, Slide 33 Aircraft Design and Systems Group (AERO) Hochschule für Angewandte Wissenschaften Hamburg Hamburg University of Applied Sciences Technical Solutions (in the Future?) Personalversammlung "Kabine" Deutsche Lufthansa AG Dieter Scholz: A/C Cabin Air – Quality or Contamination? 20.11.2017, Slide 34 Aircraft Design and Systems Group (AERO) Hochschule für Angewandte Wissenschaften Hamburg Hamburg University of Applied Sciences Technical Solutions • Ozone concentration increases with altitude. •Low flying aircraft do not need an ozone converter. •Catalytic ozone converters have found to be effective also in removing VOCs resulting from contaminated bleed air. Ozone Converter BASF 2014 https://www.basf.com/en/company/news-and-media/news-releases/2014/06/p-14-265.html Personalversammlung "Kabine" Deutsche Lufthansa AG Dieter Scholz: A/C Cabin Air – Quality or Contamination? 20.11.2017, Slide 35 Aircraft Design and Systems Group (AERO) Hochschule für Angewandte Wissenschaften Hamburg Hamburg University of Applied Sciences filter in Technical Solutions Pall offers Odour/VOC Removal Filters • "The carbon adsorbent is effective at adsorbing volatile organic compounds (VOC). Test results have shown a removal efficiency of 65% ... 73% when challenged with TCPs in the gaseous phase." (Pall 2011) Application of Carbon Filters • HEPA-Carbon filters have been added to 33 A321 aircraft at Lufthansa Group so far. (Lufthansa 2017) • These filters are located in the recirclulation path of the cabin air. Schematic of carbon filter (Pall 2011) Filter in the Recirculation Path Adapted from (NRC 2002) (Lufthansa 2017) Personalversammlung "Kabine" Deutsche Lufthansa AG Dieter Scholz: A/C Cabin Air – Quality or Contamination? 20.11.2017, Slide 36 Aircraft Design and Systems Group (AERO) Hochschule für Angewandte Wissenschaften Hamburg Hamburg University of Applied Sciences Example calculation: • With a filtration rate, xfil = 0.7 (Pall 2011) and a recirculation rate, xre = 0.5 (A320) the filter in the recirculation path reduces the incoming concentration to 58.9% or around  60% . Efficiency of Filter in the Recirculation Path   refil re incont cabcont xx x x x   11 1 , , re incont cabcont fil x x x x   1 :1for , , filtration rate, xfil Technical Solutions Personalversammlung "Kabine" Deutsche Lufthansa AG Dieter Scholz: A/C Cabin Air – Quality or Contamination? 20.11.2017, Slide 37 Aircraft Design and Systems Group (AERO) Hochschule für Angewandte Wissenschaften Hamburg Hamburg University of Applied Sciences 50 % outflow valve 50 % recirculation recirculation fan cross bleed valve (normally closed) Engine 1 APU Engine 2 Technical Solutions Full Filtration Option: 1 VOC Filter Combined HEPA & VOC Filter (HEPA-Carbon Filter) Filtration aft of source (engine / APU). Filtration in recirculation. 18.06.03.0 )1( , ,   recircfil incont cabcont fx x x => reduces incoming pollutant concentrations to  18% Personalversammlung "Kabine" Deutsche Lufthansa AG Dieter Scholz: A/C Cabin Air – Quality or Contamination? 20.11.2017, Slide 38 Aircraft Design and Systems Group (AERO) Hochschule für Angewandte Wissenschaften Hamburg Hamburg University of Applied Sciences 50 % outflow valve 50 % recirculation recirculation fan cross bleed valve (normally closed) Engine 1 APU Engine 2 Technical Solutions Full Filtration Option: 2 VOC Filter Combined HEPA & VOC Filter (HEPA-Carbon Filter) Filtration before or directly aft of Pack Flow Control Valve. Filtration in recirculation. 18.06.03.0 )1( , ,   recircfil incont cabcont fx x x => reduces incoming pollutant concentrations to  18% Personalversammlung "Kabine" Deutsche Lufthansa AG Dieter Scholz: A/C Cabin Air – Quality or Contamination? 20.11.2017, Slide 39 Aircraft Design and Systems Group (AERO) Hochschule für Angewandte Wissenschaften Hamburg Hamburg University of Applied Sciences 50 % outflow valve 50 % recirculation recirculation fan cross bleed valve (normally closed) Engine 1 APU Engine 2 Technical Solutions Full Filtration Option: 3 VOC Filter Combined HEPA & VOC Filter (HEPA-Carbon Filter) Filtration of cold air and of hot trim air. Filtration in recirculation.   refil re recirc xx x f  11 1 18.06.03.0 )1( , ,   recircfil incont cabcont fx x x => reduces incoming pollutant concentrations to  18% Personalversammlung "Kabine" Deutsche Lufthansa AG Dieter Scholz: A/C Cabin Air – Quality or Contamination? 20.11.2017, Slide 40 Aircraft Design and Systems Group (AERO) Hochschule für Angewandte Wissenschaften Hamburg Hamburg University of Applied Sciences 50 % outflow valve 50 % recirculation recirculation fan cross bleed valve (normally closed) Engine 1 APU Engine 2 Technical Solutions Full Filtration Option: 4 VOC Filter Combined HEPA & VOC Filter (HEPA-Carbon Filter) Filtration of air directly before it is intering the respective cabin zone. Filtration in recirculation. 18.06.03.0 )1( , ,   recircfil incont cabcont fx x x => reduces incoming pollutant concentrations to  18% Personalversammlung "Kabine" Deutsche Lufthansa AG Dieter Scholz: A/C Cabin Air – Quality or Contamination? 20.11.2017, Slide 47 Aircraft Design and Systems Group (AERO) Hochschule für Angewandte Wissenschaften Hamburg Hamburg University of Applied Sciences Summary • All aviation fluids can get into aircraft cabin air: sucked up from the ground and ingested into the engine. • There are many reasons for odors and contamination, but: • Concentrate on the big issue: Engine seals leak a small amount of oil by design! • Demand a technical change of the system! • Think about what you can do today to make a change. Hints are given! Aircraft Cabin Air  Quality or Contamination? Personalversammlung "Kabine" Deutsche Lufthansa AG Dieter Scholz: A/C Cabin Air – Quality or Contamination? 20.11.2017, Slide 48 Aircraft Design and Systems Group (AERO) Hochschule für Angewandte Wissenschaften Hamburg Hamburg University of Applied Sciences Contact [email protected] http://www.ProfScholz.de Aircraft Cabin Air  Quality or Contamination? A List of References is contained in my presentation from 19.09.2017: https://doi.org/10.5281/zenodo.4495495.