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YY/T 0866-2011 PDF in English

YY/T 0866-2011 (YY/T0866-2011, YYT 0866-2011, YYT0866-2011)
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YY/T 0866-2011: PDF in English (YYT 0866-2011)

YY/T 0866-2011
ICS 11.140
C 48
Total Inward Leakage Determination Method of
Protective Face Mask for Medical Use
Issued by: China Food and Drug Administration
Table of Contents
Foreword ... 3 
1 Scope ... 4 
2 Normative References ... 4 
3 Terms and Definitions ... 4 
4 Test Methods ... 5 
5 Evaluation of Test Results ... 10 
Bibliography ... 12 
Total Inward Leakage Determination Method of
Protective Face Mask for Medical Use
1 Scope
This Standard stipulates the determination method for total inward leakage of
protective face mask for medical use.
This Standard is applicable to the evaluation of total inward leakage of half-facepiece
protective face mask for medical use (hereinafter referred to as face mask). The
evaluation of the leakage performance of other protective face masks may take this
Standard as a reference.
2 Normative References
The following documents are indispensable to the application of this document. In
terms of references with a specified date, only versions with a specified date are
applicable to this document. In terms of references without a specified date, the latest
version (including all the modifications) is applicable to this document.
GB/T 2428-1998 Head-face Dimensions of Adults
GB/T 10000-1988 Human Dimensions of Chinese Adults
3 Terms and Definitions
The following terms and definitions are applicable to this document.
3.1 Half Facepiece
Half facepiece refers to close-fitting face mask that can cover mouth and nose, or,
mouth, nose and jaw.
[GB 2626-2006, Definition 3.8]
3.2 Total Inward Leakage; TIL
Total inward leakage refers to under the test conditions specified by the laboratory, the
ratio of the concentration of simulant leaking into the mask from all mask components,
including the filter element, to the concentration of the simulant in the inhaled air when
the subject inhales, expressed in percentage.
Total inward leakage is constituted of three factors: leakage due to loose-fitting of face
when opening, without any restrictions;
b) The minimum pressure change that a pressure sensor can determine is
approximately 5 Pa (0.05 mbar). In addition, it can be connected to a probe
inserted into a hole on the mask. The threshold of this sensor is adjustable;
the sensor can acquire differential signals that exceed the threshold from any
direction. When the subject’s head movement generates accelerated speed,
the connected sensor shall be able to work stably;
c) An interface system that can activate the valve in response to a signal from
the pressure sensor;
d) A timing device that is used to record the ratio of the sampling time to the total
time of the entire breathing cycle.
During the test, aerosol concentration in the closed test chamber is monitored through
an independent sampling system, so as to avoid contamination of the mask sampling
line. If possible, an independent flame photometer is recommended.
If there is no second photometer, on the premise of using an independent sampling
system to sample aerosol in the closed test chamber, it is also feasible to use the same
photometer. However, it will take time to restore the photometer to a clean background.
4.1.6 Sampling probe
Sampling probe shall be securely fixed in the mask in a sealed manner; be as close
as possible to the centerline of the mask. During the determination, measures shall be
taken (provide dry air) to prevent the test probe from being affected by condensation
of the sampling probe. The probe shall be adjusted to the center of the breathing area.
During the operation, ensure that the sampling probe does not affect normal wearing
or the shape of the mask.
4.1.7 Sampling pump
If there is no pump matching the photometer, an adjustable-flow pump may be used to
collect air sample in the mask. Adjust the pump to collect sample, at a constant flow
rate of 1 L/min, from the sampling probe. In accordance with the performance of the
photometer, if necessary, dilute the sample with clean air.
4.1.8 Pressure detection probe
Near the sampling probe, install another probe; connect it to the pressure sensor.
4.1.9 Test reagent
In the closed test chamber, the average mass concentration of NaCl shall be (8 ± 4)
mg/m3. The deviation of the entire effective working space shall not exceed 10%. The
4.4 Test Process
4.4.1 Method and principle
During the test, subjects wearing a mask shall walk on a treadmill in a closed test
A certain concentration of NaCl aerosol flows into the closed test chamber. In the
inspiration phase of the breathing cycle, sample and analyze the air in the mask;
determine the NaCl concentration. By making a hole on the mask and inserting a probe,
export the collected samples. Insert another probe to test pressure change inside the
mask and actuate a switching valve, so that merely the inhaled air can be sampled.
4.4.2 Test Preparation
Ask the subjects to read the mask manufacturer’s wearing instructions. If the mask has
more than one specification, ask the subjects to choose a most suitable size. If
necessary, test organizer shall demonstrate to the subjects how to properly wear the
mask in accordance with the wearing instructions. In addition, make it clear to the
subjects that the mask may be adjusted during the test. If the subjects adjust the mask,
the system must be reset, then, redo relevant parts of the test.
After each subject wears the mask, the organizer shall ask “Is the mask suitable?” If
the answer is “Yes”, then, continue the test. If the answer is “No”, ask the subject to
leave the test; report the actual situation and switch to another subject. Test procedures
In accordance with the following procedures, conduct the test:
a) In the initial stage of the test, ensure that the test airflow is turned off;
b) The subjects enter the closed test chamber; connect to a face sampling probe.
The subjects walk on the treadmill at the speed of 5 km/h for 2 minutes.
Determine the concentration of aerosol inside the mask; consider it as the
background level and record it as the zero point. When the reading becomes
stable, read the background value;
c) Enable the test airflow;
d) The subjects continue to walk for 2 min, or, walk till the test airflow becomes
e) Meanwhile, the subjects who are still walking shall take the following five
Source: Above contents are excerpted from the PDF -- translated/reviewed by: www.chinesestandard.net / Wayne Zheng et al.