© ISO 2014 Respiratory protective devices — Methods of test and test equipment — Part 1 Determination of inward leakage Appareils de protection respiratoire — Méthodes d’essai et équipement d’essai —[.]
General
Before conducting tests with human test panels, it is essential to consider relevant national regulations regarding the medical history, known allergies, and the examination or supervision of the test subjects.
7.1.2 Test subjects shall be trained by a competent person in wearing the type of RPD being tested.
Unless specified by the RPD manufacturer's user instructions, male panel members must be clean shaven in the face seal area if they have facial hair.
Individuals with scars or facial blemishes near the face seal that could potentially lead to leakage should not be chosen for the test panel.
Individuals designated as test subjects must adhere to the manufacturer's donning instructions, which may involve performing a wearer seal check If a proper seal cannot be achieved according to these instructions, the individual is not eligible for the inward leakage test.
7.1.2.4 Where a manufacturer specifies a size range for wearers of the device, only subjects who fall within the specified range shall be used for the test.
7.1.2.5 If more than one size of respiratory interface is manufactured, the test subjects shall select the most appropriate size in accordance with the information supplied by the manufacturer.
When using particle counting detection method, the test subject should refrain from smoking for at least
30 min before wearing the RPD.
Selection of test subjects
The human test panel will be defined according to ISO/TS 16976-2:2010, section 8.3, which pertains to the principal component analysis (PCA) panel, with additional details available in Annex D The selection of test subjects must adhere to the specifications set by the RPD manufacturer in compliance with ISO 17420 requirements.
Three test agents are specified for the inward leakage tests: a) test agent 1 = sulfur hexafluoride gas (SF 6 ); b) test agent 2 = sodium chloride aerosol (NaCl); c) test agent 3 = corn oil aerosol.
All three test agents are equally acceptable for determination of inward leakage or total inward leakage, subject to the selection requirements of Figure 2.
If porosity is indicated by the results from the materials porosity test (Annex C), then it shall be tested using sulfur hexafluoride gas.
The test enclosure must be spacious enough to allow each subject to complete the exercise regimen without any restrictions Additionally, a consistent and uniform flow of the relevant test atmosphere should be maintained within the enclosure.
The enclosure design and air flow management system must ensure that the test atmosphere concentration remains homogeneous and stable (within ±10%) for the duration of all exercises conducted by the RPD and wearer.
The air velocity near the test subject's head, positioned centrally on the treadmill and without crosswind conditions, must be adequate to sustain the required concentration, while not exceeding 0.2 m/s.
The enclosure must be designed to ensure that the test subject is always visible from the outside Additionally, a communication system should be established to facilitate interaction between the test subjects and the test supervisors.
For RPD to be tested under crosswind conditions, provision shall be made to generate a crosswind of
2 m/s across the enclosure, from the front, rear or side (left or right), in the vicinity of the test subject’s head.
NOTE Such provision might need to be adjustable in height to generate the crosswind at the appropriate position for all test subjects.
The design of the enclosure shall be such that the device worn by the subject can be supplied with clean air (free of the test agent), where necessary.
The test chamber must have a sufficient volume to ensure that the test atmosphere is not diluted by clean air from the device being tested When using SF6 gas as the test atmosphere, it is advisable for the chamber to allow for the recirculation of the air/SF6 mixture to reduce the release of SF6 into the surrounding environment.
9.2 Treadmill, capable of working up to the speed as required by the exercise regime defined in
9.3 Test agent generator - General, capable of generating the test agent in the required concentration, and, in case of an aerosol, of the required particle size distribution.
9.4 Detection system - General, either one detector or different detectors for measuring the test enclosure and the respiratory interface sample concentrations.
The detection system including sampling probes and connections shall have a response time of less than
20 s for a response of 10 % to 90 % of the full-scale deflection of the range used Further details of the detections system required for each specified test agent are given in 11.2, 11.3, and 11.4.
General
Before conducting the inward leakage test, it is essential to inspect the RPD according to the manufacturer's guidelines to confirm that it is functioning properly and safe for the test subject.
Prepare the RPD for testing based on its design and the test agent, determining whether to assess the inward leakage of a respiratory interface or the total inward leakage of the complete device, with additional details provided in sections 10.4, 10.5, and 10.6.
Sample tubes and probe
To sample and analyze air within the respiratory interface, utilize the adapter typically supplied by the manufacturer If an adapter is unavailable, create a hole in the respiratory interface and insert a probe to draw the sample using an appropriate sample pump.
To reduce sampling bias in the respiratory interface, it is recommended to use a multiple-hole sampling probe While single-hole probes with chamfered entries are also deemed acceptable, various fixation methods for these probes are illustrated in the accompanying figures.
1 eight holes, diameter 1,5 mm, equally spaced
3 direction of drying air (for sodium chloride only)
Figure 3 — Example of ball probe
1 eight holes, diameter 1,5 mm, equally spaced
3 direction of drying air (for sodium chloride only)
Figure 4 — Example of disc probe
Figure 5 — Example of sampling probe (surface fixed)
Figure 6 — Example of a ball probe used on device with rigid visor
Figure 7 — Example of a disc probe used on filtering device
Figure 8 — Typical arrangement for sampling from device with soft plastic hoods
Figure 9 — Example of sampling probe (surface fixed) in filtering device
The probe shall be fitted securely to the respiratory interface, terminating as near as possible to the wearer’s face (