AIRCRAFT CABIN AIR QUALITY BRIEF // JULY 2020

AIR MANAGEMENT SYSTEMS

Essential systems for a safer, more comfortable flight INTRODUCTION Collins Aerospace is a leading supplier of environmental control systems (ECSs) for military and commercial transport, which include the ATA Chapter 21 systems for air conditioning, ventilation and cabin pressure control systems. Collins Aerospace is pleased to provide this brief summary regarding information on aircraft cabin air quality, with specific emphasis on contamination originating from inside the cabin. A list of noted reference material can be found at the end of this summary.

Three main characteristics of cabin air management systems help mitigate the spread of airborne pathogens within a typical ECS:

1) Fresh air inflow regulations

2) High efficiency particulate air (HEPA) filters for recirculated air

3) Airflow distribution design in an aircraft cabin

2 Air Management Systems | July 2020 A HIGHER FILTRATION STANDARD FOR AIRCRAFT CABIN AIR

FRESH-AIR INFLOW REGULATIONS HEPA FILTRATION OF RECIRCULATED AIR Aviation regulatory authorities such as the Federal Aviation In some aircraft ECS designs, approximately 50% of the airflow Administration and European Union Aviation Safety Agency within the cabin is recirculated and mixed with the outside fresh specify a minimum outside fresh airflow per occupant, based air flowed into the cabin. In some cases, the recirculated air on the maximum number of occupants (0.55 lb./min. of fresh passes through a HEPA filter prior to mixing fresh air with airflow per occupant)1. In a large commercial passenger aircraft, recirculated air. HEPA filters are commonly considered to be for example, a typical ECS that adheres to this specification an effective way to mitigate virus transmission3 and are used may replace the air occupying the cabin within about 3 minutes, in hospital protective environments4. For comparison, HEPA or about 20 changes per hour of the air occupying the cabin. filters can have a higher filtration efficiency (99.97%) than an This may vary slightly by aircraft, based on several factors “N95” respirator (95%)5. As is common for larger commercial such as the ratio of maximum passenger capacity to total cabin aircraft, Collins Aerospace products include HEPA recirculation volume, and distribution system layout. By comparison, the filters as part of the ECS on many platforms such as the general guidance on fresh air inflow for buildings is only 787. While HEPA filters are common, there may be some older four changes per hour2. and/or smaller aircraft platforms that do not have HEPA filtration. However, in many cases, there are OE and retrofit products available6.

Air Management Systems | July 2020 3 CABIN AIR QUALITY IS CRITICAL TO PASSENGER SATISFACTION

CABIN AIRFLOW DISTRIBUTION Aircraft cabin air distribution systems often are designed Collins Aerospace’s air management systems are to distribute the airflow from high (crown) to low (floor designed to meet customer requirements for efficiency, vents), and not from the front to back of the cabin. One of the reliability, weight, performance, safety and maintainability. reasons for this design is to manage emergency situations such We offer advanced air management systems that enable as smoke events to ensure smoke does not permeate throughout a safer, healthier and more comfortable environment 7 the aircraft cabin . This design has the added benefit of reducing during flight. the spread of unfiltered, contaminated air throughout the cabin, but it does not eliminate the risk completely8. Visit collinsaerospace.com to learn more

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REFERENCES AND ADDITIONAL PUBLIC INFORMATION SOURCES

1. Federal Aviation Administration Regulations, 14 C.F.R. § 25.831(a); European Union Aviation Safety Agency, Certification Specifications, CS-25.831(a) 2. ASHRAE 62.2-2016 3. Pall Aerospace website https://shop.pall.com/us/en/aerospace/military-vehicles/cabin-air-filtration/zidgzyl8yrb 4. American Society for Healthcare – Hospital HEPA usage in “protective environment“ rooms https://www.ashe.org/compliance/ec_02_05_01/01/airfiltration 5. FDA website – N95 Respirators and Surgical Masks (Face Masks) https://www.fda.gov/medical-devices/personal-protective-equipment-infection-control/n95-respirators- and-surgical-masks-face-masks#s3 6. Pall Aerospace website https://shop.pall.com/us/en/aerospace/commercial-fixed-wing/electronics-cooling-filtration/zidgxiyphh4?CategoryName= Commercial-Fixed-Wing&CatalogID=Aerospace-Defense-Marine&tracking=searchterm 7. Federal Aviation Administration Advisory Circular 25-9A, Jan. 6, 1994. 8. The Cabin Environment and the Health of Passengers and Crew, specifically the sections on Air Distribution and Circulation, and recirculation https://www.ncbi.nlm.nih.gov/books/NBK207472/

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