BS 2N 1:1990 pdf free.Specification for Oro-nasal oxygen maskassemblies for use indemand systems.
BS 2N 1 exerted along the axis of symmetryof the breathing gas supply hose required to makeand break non-locking couplings shall be between 62 N and 107 N.
In both operation and handling use the maskshall be capable of withstanding a tensile force oneach of the suspension device attachment fittings ofnot less than 100 N in the direction of maximumpull for not less than 15 s.
The breathing gas supply hose attachment tothe aircraft equipment and the breathing gas supplyhose attachment to the mask, shall be capable ofwithstanding an axial load of not less than 100 N fornot less than 15 s without movement.
The breathing gas supply hose shall berestrained internally to limit the longitudinalextension to 20 % of the original free length.5.2.5 The breathing gas supply hose shall complywith BS 2F 65, and shall be kink resistant.
The expiratory valve compensating pressuresupply tube shall be kink and crush resistant.5.3 Pneumatic performance
NOTE The values of gas flow and gas pressure quoted are thoseobtained at 15 C and at 1 standard (ICAO) atmosphere,
i.e. nominally 101.3 kPa.The breathing gas supply hose assembly shallbe capable of withstanding an internal pressureof 3 times the maximum working pressure withoutfailure, and 1.5 times the maximum working pressure without leakage or permanent distortion.5.3.2 The breathing gas supply hose shall be capableof withstanding without collapsing a suction pressure of 6 kPa.
The total inward leakage into the mask whencorrectly fitted shall not exceed 5 % of the inspiratevolume when there is no safety pressure.The maximum inward and outward leakagevalues specified in 5.3.4,5.3.5 and 5.3.7 shall not beexceeded during movement of the head.
Where an inspiratory valve is installed inbreathing masks any leakage to the mask tube shallbe less than 1.02 L/min when the valve is subjectedto mask cavity pressure up to 0.5 kPa and shall notbe more than 4.8 L/min when subjected to a pressure of 9.1 kPa.The inspiratory valve shall continue to comply withthis standard after being subjected to mask cavitypressures of up to 20 kPa.
For systems not using mask mountedregulators, the total back pressure through theinspiratory components shall not exceed 0.4 kPa ata flow of 102 L/min, when measured between thebreathing gas supply hose inlet (excluding
connector) and the mask cavity.BS 2N 1 pdf download.