AS ISO 16900.11:2015 pdf free.Respiratory protective devices- Methods of test and test equipment Part 11: Determination of field of vision.
5 General test requirements
Unless otherwise specified, the values stated in this part of Iso 16900 are expressed as nominal values. Except for temperature limits, values which are not stated as maxima or minima shall be subject to a tolerance of ±5 %. Unless otherwise specified, the ambient conditions for testing shall be between 16 °C and 32 °C and (50 ± 30) % relative humidity. Any temperature limits specified shall be subject to an accuracy of ±1 °C.
6 Principle
This test quantifies the field of vision of a respiratory protective device (RPD) by measuring the functional visual field score. The RPD is mounted on a headform containing small light sources instead of eyes. The light from the light sources is projected onto the apertometer, creating a light area outlined by a shadow that follows the periphery of the visual obstruction of the RPD system. The light area represents the visual field, or peripheral isopter. A quantitative value for the visual field score is obtained by comparing the peripheral isopter with a visual field score defined for different segments of the unrestricted field of vision.
7 Apparatus
The following apparatus are used for determining the visual field score.
a) Headforms: see Annex B.
b) Apertometer: see Figure 1.
c) Visual field score plotting chart: See Figure 2.
8 Device preparation
Prepare the RPD to the ready for use condition in accordance with the manufacturer’s instructions for use.
This involves attaching any accessories that may obscure vision, such as demand valve or filter(s), or filter
simulator (ISO 1690 0-5) for devices containing the thread connection in accordance with ISO 1742 0-3.
The headform size(s) appropriate to the size of RPD being tested shall be selected for the test.
8.1 Mounting the device
Mount the RPD on the selected headform in accordance with the manufacturer’s donning instructions. Position the RPD symmetrically on the headform. If the RPD has wearer-adjustable head harness straps, tighten the straps to the extent that would be expected when wearing the device as specified by the manufacturer.
NOTE If necessary, apply a friction reducing material talcum powder to the headform to allow the RPD to slide more easily over the headform surface during adjustment.
Position the head form correctly within the apertometer (see Figure 1).
The head form is positioned correctly when the centre of the light source of the illuminated eyes are aligned with the 90 degree meridians on the dome, symmetrically about the centre line of the dome and the horizontal axis of the headform is coincident with the axis of the apertometer.AS ISO 16900.11 pdf download.