The American Society of Heating, Refrigerating and Air-conditioning Engineers (ASHRAE) has proposed a standard that will define air quality and comfort levels on commercial airplanes, but it is not related to any FAA study or any planned rulemaking.

The proposed “Standard 161P, Air Quality within Commercial Aircraft” would apply to commercial passenger aircraft carrying 20 or more passengers. It is intended to apply to all phases of flight operations and to ground operations whenever there are passengers or crewmembers on board.

A spokesman for the FAA said the agency is “monitoring” ASHRAE’s progress but is not funding its effort. “It is actually something they are doing on their own,” he said. “We are interested in the data, but we are not sponsoring it.”

ASHRAE also proposed a companion to the standard, “Guideline 28P, Air Quality within Commercial Aircraft,” that provides supplemental information on air quality in airline aircraft as well as on measurement and testing related to aircraft air quality.

A ‘Unique’ Environment

“The environment aboard commercial aircraft is different from that found in other spaces commonly occupied by people,” said Byron Jones, chair of the 161 committee. “While aircraft are operated with the comfort of passengers and crew in mind, their safety and health must always be paramount.”

Aircraft cabin environments are unique, ASHRAE said, because occupant activity levels range from nearly sedentary (passengers) to active (flight attendants). Because the passengers and crew make up a wide cross-section of the general population, the aircraft must be regarded as both a public place (passengers) and a workplace (crew).

The proposed standard requires a minimum total air supply of 15 cu ft per minute per person and recommends 20 cu ft per minute per person. Operators could meet the requirement with either a mixture of outside air and filtered recirculated air or with 100 percent outside air. The proposal mandates a minimum of 7.5 cu ft of outside air per minute per person.

[How does this compare with the current climate in a business jet cabin? A company spokesman told AIN that passengers and crew in current large-cabin Gulfstreams are provided with 800 cu ft of fresh air every minute, for a complete change every two minutes. With a maximum load of 19 pax and three crew, that equates to 36 cu ft per person per minute–nearly five times ASHRAE’s proposed minimum amount, and another reason a trip aboard a Gulfstream is easier on the body than an airline trip.–Ed.]

In addition to ventilation requirements, the proposed standard addresses supply air quality and control and monitoring of contaminants to further ensure that satisfactory air quality is maintained, Jones said. Requirements for comfort factors–such as rate of change of cabin pressure, air temperatures and surface temperatures, as well as minimum and maximum air velocities–are also included.

An appendix to standard 161P provides background information on a variety of potential air contaminants, methods of measurement, references to standards and guidelines of allowable levels, and data for levels measured on aircraft.

According to ASHRAE, there are currently no standards encompassing ventilation, thermal comfort and filtration for aircraft.