This standard covers oronasal type masks which use a continuous flow oxygen supply. Each such mask comprises a facepiece with valves as required, a mask suspension device, a reservoir, or rebreather bag (when used), a length of tubing for connection to the oxygen supply source, and a means for allowing the crew to determine if oxygen is being delivered to the mask. The assembly shall be capable of being stowed suitably to meet the requirements of its intended use.

Purpose:

This standard establishes the minimum requirements for the design, construction and performance of continuous flow oxygen masks for passenger cabin occupants in civil commercial aircraft.

Presentation:

When presented, the mask assembly's application shall be obvious. The mask shall be capable of quick and easy donning regardless of any special orientation requirements.

Coding of Performance Classification:

An eight-digit performance classification number shall be assigned to each class of masks. This number shall correspond to the number assigned to the minimum performance curve established in 6.1.7.2.2 and shall represent the required minimum oxygen flow rates (NTPD) to the mask shown on curve "C" of Figure 1 at cabin pressure altitudes of 15 000, 25 000, 30 000 ft and the maximum approved altitude, respectively. Flow rates shall be to one decimal.

Typical Example - AS 8025-08233248-YY*-XX*

0.8 - required minimum oxygen flow, L/min, NTPD, at 15 000 ft

2.3 - required minimum oxygen flow, L/min, NTPD, at 25 000 ft

3.2 - required minimum oxygen flow, L/min, NTPD, at 30 000 ft

4.8 - required minimum oxygen flow, L/min, NTPD, at maximum approved altitude

*YY - Maximum approved altitude in thousands of feet

*XX - Additional coding which the mask manufacturer may desire to add

Interchangeability of Mask Assemblies:

Same Coding: Masks with the same coding shall be interchangeable.

Different Performance Classification Numbers (remainder of coding the same): Only those masks whose performance classification number shows that at all certified cabin altitudes, the required oxygen flow rates are equal to or less than the flow rates supplied to the mask from the airplane system shall be used on that airplane.