AS NZS 16900.14:2021 – Respiratory protective devices – Methods oftest and test equipment Method 14: Measurement of sound pressure level (ISO 1690o-14:2020, MOD).
6.4 Test report for method A
The test report shall include information regarding those parameters specified in Clause 4. together with the background sound pressure level and the maximum measured Lp.*,eqr value, The uncertainty of measurement shall be reported.
7 Method B — Measurement of warning sound pressure level
7.1 Principle
The RPD is operated on the RP[) headform 3 (medium size) as specified in ISO 16900-5, equipped with the special ear Inserts shown In FEgure 1. The RPD headform is attached to the RPD torso as specified in ISO 16900-5 and connected to a breathing machine or metabolic simulator. Microphones are placed in the special ear inserts, details of which are shown in Figure2 to 4. to measure the A-weighted continuous equivalent sound pressure level generated by the warning device, at the right or left ear whichever is closest to the warning device.
The RPD headform 3 shall be used regardless of the size of the respiratory interface and shall be attached to the RPD torso to avoid reflected noise.
7.2 Equipment
a) The RPD headform with soft surface finish lixed to the RPD torso shall be used. The torso shall be covered with a cotton T shirt. An omnidirectional microphone. 12 mm in diameter shall be fitted in each ear at the position as shown in Figures. The surface of the microphone shall be positioned at the surface of the flat ear ±1 mm.
b) A sound spectrum analyser capable of measuring one third octave bands shall be specified in accordance to IEC 61260-1.
c) A sound level calibrator meeting IF.C 60942 Class 2 and suitable adaptor (see Figurv6) for the microphone system and sound level meter.
d) A breathing machine or metabolic simulator as appropriate.
7.3 Procedure
a) The microphone(s) shall he mounted in the RPL) headlorm at the position shown in Figure 1.
b) The sound level meter and microphone system shall be calibrated using the specified sound level calibrator [see U c)]. The sound level calibrator including the adaptor shall be tightly fitted onto the microphone. See Figure 6. The sound level calibrator applies a sinusoidal tone to the microphone which is used by the sound level meter for calibration. The sound level calibrator and adaptor shall he removed after calibration.
c) The RPD shall be fitted on the RPD headlorm and RPD torso, making all the necessary adjustments to ensure a good fit in accordance with information supplied by the manufacturer.
d) The breathing machine or metabolic simulator shall be operated at the appropriate workrate for the dass of the RPD.
e) The RPD shall be operated as specified by the manufacturer at the workrate for its class and the warning device shall be activated and operated during this time. Assisted filtering RPD shall be operated as specified by the manufacturer at the manufacturer’s maximum flow conditions related to the workrate.
NOTE Modification of the RPD c.i n be necessary to permit the activation of the warning device.
f) The sound pressure level at the frequency range specified by the performance standards shall be measured during the operation of the warning device at the ear nearest to the warning device. Measurements shall be made over a period as required by the performance standards. While the RPD is functioning, the background sound pressure level in the test room, at the frequency range specified by the performance standard, without the warning device operating, shall be a maximum of 80 dRA.
NOTE Modification of the RPD can be necessary to permit the activation of the warning device.
7.4 Test report for method B
The test report shall include information regarding those parameters specified in Clause 4. together with the background sound pressure level and the minimum measured sound pressure levels measured at the ear nearest to the warning device at the specified frequency range generated by the warning device at the specified conditions. Report which ear was nearest to the warning device. The uncertainty of measurement shall be reported.