BS EN 13274-4:2020 pdf free.Respiratory protective devices一Methods of test Flame test.
BS EN 13274-4 Unless otherwise specified, the values stated in this document 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土30) % relative humidity. Any temperature limits specified shall be subject to an accuracy of士1。C. For each of the required measurements performed in accordance with this document, a corresponding estimate of the uncertainty of measurement shall have been evaluated [1]. This estimate of uncertainty  shall be applied and stated when reporting test results, in order to enable the user of the test report to assess the reliability of the result.The test rig consists mainly of head form, a propane cylinder with flow control device, flow meter, pressure gauge, flashback arrester and six propane burners which are adjustable in height. Figure 1 shows a schematic diagram of the apparatus. Figure 2 shows the top view of the arrangements of the six burners and the positioning of the head form relative to the burners. The head form may be any suitable head form to which the respiratory interface can be securely mounted and which is resistant to the flames.Mount the respiratory interface such that the central vertical plane of the visor is parallel to the axis of the burners, see Figure 2. Ensure that the free end of the head harness straps do not hang down from the respiratory interface. This can be achieved by positioning the free ends between the head harness and the head form. The neck strap if present shall be secured at the back of the head form. The inlet of the inhalation connector shall be plugged. Before lighting the burners, position the test sample above the array of six burners and individually adjust the height of each burner such that the distance between the burner tip and test sample is 250 mm. Figure 2 shows the adjustment of the burner tips for one example. With the test sample removed from above the burners, fully open the propane control valve on each of the six burners. Initially, close the air control valve on each of the six burners. Ignite the burners and adjust the propane cylinder output regulator to a pressure, such that a flow meter in the main propane supply line indicates a total flow to all six burners of (21土0,5) litres/min, propane. BS EN 13274-4 pdf download.