EN 149-2001 pdf download.Respiratory protective devices – Filtering half masks to protect against particles – Requirements, testing, marking.
Measures shall be taken to prevent the influence of condensation in the sampling probe on the measurement (by supplying dry air). Figure 5 shows a design that has been found suitable. The probe is adjusted so that It just touches the wearer’s lips.
Care shall be taken to ensure that the probe does not disturb the normal fit or shape of the mask.
8.5.2.2.6 Sample pump
If no pump is incorporated into the photometer an adjustable flow pump is used to withdraw an air sample from the particle filtering half mask under test, This pump is so adjusted as to withdraw a constant flow of 1 1/mm from the sample probe. Dependent on the type of photometer it may be necessary to dilute the sample with clean air.
8.5.2.2.7 Sampling of enclosure concentration
The enclosure aerosol concentration is monitored during the tests using a separate sampling system, to avoid contamination of the particle filtering half mask sampling lines. It is preferable to use a separate flame photometer for this purpose.
If a second photometer is not available, sampling of the enclosure concentration using a separate sampling system and the same photometer may be made. However, time will then be required to allow the photometer to return to a clean background.
8.5.2.2.8 Pressure detection probe
A second probe is fitted near to the sample probe and is connected to the pressure sensor.
8.5.2.3 Expression of results
The leakage P shall be calculated from measurements made over the last 100 s of each of the exercise periods to avoid carry over of results from one exercise to the other.
The test shall be repeated to enable an assessment to be made of all materials on the exterior of the
device. Any one component shall be passed through the flame once only.
8.7 Carbon dioxide content of the Inhalation air
A total of 3 particle filtering half masks shall be tested: all 3 as received.
The apparatus consists essentially of a breathing machine with solenoid valves controlled by the breathing machine, a connector, a CO2 flowmeter and a CO2 analyser.
The apparatus subjects the particle filtering half mask to a respiration cycle by the breathing machine.
For this test the particle filtering half mask shall be fitted securely in a leak-tight manner but without deformation to a Sheffield dummy head (see Figure 6).
Air shall be supplied to it from a breathing machine adjusted to 25 cydesimin and 2.0 I/stroke arid the exhaled air shall have a carbon dioxide content of 5 % by volume.
A typical test arrangement is shown in Figure 7.
If the design of the test equipment causes a CO2 build-up a CO2 absorber shall be used in the inhalation branch between solenoid valve and breathing machine.
The CO2 is fed into the breathing machine via a control valve, a ftowmeter, a compensating bag and two non-return valves.
Immediately before the solenoid valve a small quantity of exhaled air is preferably continuously withdrawn through a sampling line and then fed into the exhaled air via a CO2 analyser.
To measure the CO2 content of the inhaled air, 5 % of the stroke volume of the inhalation phase of the breathing machine is drawn off at the marked place by an auxiliary lung and fed to a CO2 analyser. The total dead space of the gas path (excluding the breathing machine) of the test installation should not exceed 2000 ml.
Measure the carbon dioxide content of the Inhaled air and record continuously. Test conditions are ambient atmospheric conditions.
The ambient carbon dioxide level is measured 1 m in front of and level with the tips of the nose of the dummy head. The ambient level is measured once a stabilized level for carbon dioxide in the inhalation air has been attained. Alternatively, the ambient level of carbon dioxide may be measured at the sampling tube with the carbon dioxide supply turned off. Results are deemed acceptable only if the measured value of the ambient level of carbon dioxide is less than 0,1 %.EN 149-2001 pdf download.