GB/T 2891-1995 English PDF (GBT2891-1995)

Delivery: 3 seconds. Download true-PDF + Invoice.
Get QUOTATION in 1-minute: Click GB/T 2891-1995
Historical versions: GB/T 2891-1995
Preview True-PDF (Reload/Scroll if blank)

GB/T 2891-1995: Performance test methods for facepiece of filfer type respirator
GB/T 2891-1995
GB
NATIONAL STANDARD OF THE
PEOPLE’S REPUBLIC OF CHINA
UDC 614.2.001.4
C 73
Replacing GB 2891.1 ~ 2891.6-82
Performance test methods for facepiece of filter type
respirator
ISSUED ON: JUNE 28, 1995
IMPLEMENTED ON: JANUARY 01, 1996
Issued by: State Bureau of Technical Supervision
Replaced (Obsolete)
Table of Contents
1 Subject content and scope of application ... 3
2 Normative references ... 3
3 Technical content ... 3
Additional information: ... 21
Performance test methods for facepiece of filter type
respirator
1 Subject content and scope of application
This Standard specifies the air leakage coefficient for the wearing, actual dead space,
field of view, assembly air tightness, exhalation valve air tightness, exhalation valve
resistance to air, lens transmittance (transmittance ratio) and facepiece inhalation
resistance and other performance test methods for filter type respirators.
This Standard applies to the test and evaluation of the performance of filter type
respirators (hereinafter referred to as facepieces); it also applies, as a reference, to other
related products.
2 Normative references
GB/T 528, Rubber, vulcanized or thermoplastic - Determination of tensile stress-
strain properties
GB 2410, Transparent plastics - Transmissivity and haze test
GB 2428, Head-face dimensions of adults
3 Technical content
3.1 Test method for air leakage coefficient for the wearing of facepiece (oil mist method)
3.1.1 Principle
After a person wears a respirator, the ratio OF the concentration c of harmful substances
leaked into the facepiece through the facepiece sealing frame, exhalation valve and
facepiece component assembly parts AND the external concentration c0 is called the air
leakage coefficient of the facepiece, which is expressed in percentage (%).
3.1.2 Test device
See Figure 1 for the test device system.
c. Speak and take a deep breath for about 1 minute.
3.1.3.4 The oil mist concentration in the oil mist chamber shall be within the range of 1
000 ~ 2 500 mg/m3.
3.1.3.5 The filtration efficiency of the canister for oil mist shall be higher than 99.995%.
During the test, measures shall be taken to make the canister absorb the air outside the
oil mist chamber.
3.1.3.6 The air tightness of the exhalation valve and the air tightness of the assembly of
the tested facepiece shall meet the standard requirements.
3.1.3.7 Mount a sampling tube on the tested facepiece; ensure air tightness of the
interface; make the tube end close to the mouth and nose area.
3.1.4 Test procedures
3.1.4.1 Preparation
3.1.4.1.1 Prepare the tested facepiece; mount the sampling tube; take measures to make
the canister absorb the air outside the oil mist chamber; prepare alcohol cotton balls for
disinfection;
3.1.4.1.2 Select the subjects; register the selected head and face size and special features;
inform the subjects of the test requirements;
3.1.4.1.3 Check all instruments and equipment to make them in normal working
condition.
3.1.4.2 Test
3.1.4.2.1 Pass the oil mist into the oil mist chamber, and make its concentration meet
the requirements and be basically stable. Start the air pump to take a sample of the
airflow; measure it through the oil mist turbidity meter; adjust the instrument indication
to 100%, which is c0;
3.1.4.2.2 Let the subject wear a respirator; conduct a preliminary air tightness inspection
according to the use method; adjust it properly; connect the sampling tube to the
turbidity meter;
3.1.4.2.3 Start the air pump; measure the concentration of air flow when the subject
breathes in the smoke-free air outside the oil mist chamber; take 5 samples, and get the
background concentration ce on average;
3.1.4.2.4 Let the subject enter the oil mist chamber and act according to the regulations
in 3.1.3.3; measure the concentration of air flow in each case, 5 data for each; obtain
the air leakage concentration c on average;
d. Make the instrument in a state available for working according to the instructions
of the selected CO2 analysis instrument;
e. Start the ventilation equipment to keep the indoor CO2 concentration indoors not
greater than 1%.
3.2.4.2 Test
a. Unscrew the CO2 steel cylinder; inflate about 3 ~ 5 L into the air storage bag 1
and drain it. Rinse 2 times in this way; fill 1 bag with about 3/4 volume, and slow
down the inflation speed;
b. Put the facepiece under test on the standard head-face; pay attention to wearing it
correctly, properly loose and tight, and the sealing frame is airtight;
c. Start the mechanical lung to breathe for about 0.5 min; then, remove the air storage
bag 5 to exhaust air; repeat it twice; at this time, the concentration of the air bag
and the mechanical lung sampling system reaches a stable balance;
d. Stop the operation of the mechanical lung 1 minute after the formal breath
sampling; take off the facepiece under test;
e. Detect the gas sample concentration of the CO2 analysis instrument supplied from
the gas storage bag 5; analyze the gas sample 3 times each time; calculate the
average value.
3.2.4.3 Retest
a. For each facepiece, follow the steps in 3.2.4.2 and repeat 3 ~ 4 times;
b. During the test, sample and analyze the CO2 concentration from the surrounding
environment of the facepiece to obtain c. If c is not greater than 0.5%, when
calculating P according to Formula (4), c can be ignored.
3.2.5 Test result
Calculate the average value and standard deviation from the obtained 4 ~ 5 P values for
each facepiece.
3.2.6 Test report
According to 3.1.6.
3.3 Test method for the field of view of the facepiece
3.3.1 Principle
Mount a low-voltage light bulb at the eyeball position of a standard head-face, so that
the solid angle of the light is equal to the solid angle of the average Chinese adult’s field
of view. After wearing the facepiece, the light cone shrinks due to the limitation by the
eye window of the facepiece; and the percentage it preserves is equivalent to the
preservation rate of field of view after the standard head-face wears the facepiece. Use
a medical perimeter to measure the field of view after wearing the facepiece. Measure
the total area of field of view of the two eyes together and the area of the binocular field
of view of the common part of the two eyes. Find their corresponding percentages when
not wearing a facepiece, and use the correction coefficient to correct the total field of
view preservation rate and the binocular field of view preservation rate. The lower field
of view (degree) of wearing the facepiece is then determined by the position of the
lower cross point of the binocular field of view.
3.3.2 Test devices
3.3.2.1 Perimeter: consists of three parts:
a. Semi-circular arc bow: radius 300 ~ 340 mm; can rotate around the horizontal
radius passing through the midpoint of 0°; there is a scale every 5° from 0° on
both sides, extending to 90°; the arc bow is equipped with a slidable white visual
target;
b. Recording device: the recording needle is linked with the visual target through the
shaft wheel and other components; record the orientation and angle of the visual
target on the visual field drawing;
c. Stand: used for supporting the semi-circular arc bow and fixing the recording
device.
3.3.2.2 Standard head-face: shall comply with GB 2428; with black paint on the surface,
6.3 V small light pools installed in the pupils of the two eyes; t...