ASSE International is working with the worlds largest airplane manufacturers, as well as the U.S. Food and Drug Administration (FDA) to develop a standard that covers backflow and plumbing requirements for toilet assemblies and galley waste disposal units installed on aircraft. Requirements for backflow prevention on self-contained potable water systems on conveyances such as airplanes currently reside internally with government agencies. This standard will leverage existing plumbing knowledge to develop a similar set of requirements for passenger conveyances.
During the typical use of an aircraft vacuum toilet, the bowl itself is initially empty. When the toilet is flushed, a vacuum blower turns on, which pulls in water from the potable water system to rinse the bowl. At the same time, a flush valve is opened that draws the waste from the bowl into the airplane waste system. Employing a vacuum breaker is critical in preventing contamination of the potable water system.
Much like vacuum toilet assemblies, a galley waste disposal unit consists of a connection to potable water stored on the aircraft, a waste collection receptacle, a means to rinse waste collection receptacle, a means to protect the potable water supply, and a connection to the vacuum waste system. To meet the requirements of the new ASSE 1098, the potable water system protection will be required to vent to atmosphere.
This new ASSE standard will adopt relevant portions of ASSE 1001, Performance Requirements for Atmospheric Type Vacuum Breakers, IAPMO IGC 132, Vacuum Toilet Systems for Recreational Vehicles, and USPHS-302, Handbook on Sanitation of Airlines, and CSA B45.13:19/IAPMO Z1700-2019, Vacuum Waste-Collection Systems.
ASSE 1098 will provide performance criteria for vacuum toilets and galley waste disposal units designed to be integrally installed on passenger aircraft. The purpose of these devices is to provide protection of the potable water supply against pollutants and/or contaminants that enter the system due to backsiphonage through the outlet.
The performance tests in ASSE 1098 focus on several critical areas of importance. These include deterioration at extreme temperatures and pressures, backsiphonage and backflow preventions; tilt, turn, and turbulence performance, as well as hydrostatic and life cycle testing of the device. Likewise, the effects of water hammer as well as the shock cause by turbulence and/or landings will be tested.
The working group for ASSE 1098 has already met and collaborated multiple times, and the standard will continue to be refined. ASSE applauds the work done by the members of the aircraft industry, as well as the contributions of our partners at the FDA. It is hoped that ASSE 1098 will be published in the fall of 2020 and is expected to be adopted by most of the commercial airline industry and recommended by the FDA.
