SAE ARP85

Description / Abstract: This SAE Aerospace Recommended Practice (ARP) contains guidelines and recommendations for subsonic airplane air conditioning systems and components, including requirements, design philosophy, testing and ambient conditions.

The airplane air conditioning system comprises that arrangement of equipment, controls and indicators that supply and distribute air to the occupied compartments for ventilation, pressurization, and temperature and moisture control. The principal features of the system are:

a. A supply of outside air with independent control valve(s).

b. A means for heating

c. A means for cooling (air or vapor cycle units and heat exchangers)

d. A means for removing excess moisture from the air supply

e. A ventilation subsystem

f. A temperature control subsystem

g. A pressure control subsystem

Other system components for treating cabin air such as filtration and humidification are included, as are the ancillary functions of equipment cooling and cargo compartment conditioning.

The interface with the major associated system, the pneumatic system (Chapter 36 of ATA 100) is at the inlet of the air conditioning shutoff valves. This boundary definition aligns with that in the ATA 100 Specification.

Purpose

The purpose of this ARP is to provide guidance for the design, installation, and analysis of subsonic airplane air conditioning systems.

Field of Application

This ARP applies to subsonic airplane air conditioning systems within the ATA 100 Specification, Chapter 21. ATA Chapter 21 covers the air conditioning system that maintains passenger and crew environment, and ATA 21 also encompasses cabin pressure control systems. This ARP does contain cabin pressurization control guidelines; however the focus is on air conditioning systems. Refer to ARP1270 for detailed recommendations on cabin pressure control systems.