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GB 2890-2009 (GB2890-2009)

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GB 2890-2009English185 Add to Cart 0--10 minutes. Auto-delivery. Respiratory protection -- Non-powered air-purifying respirators GB 2890-2009 Valid GB 2890-2009


GB 2890-2009: PDF in English
GB 2890-2009
NATIONAL STANDARD OF THE
PEOPLE’S REPUBLIC OF CHINA
ICS 13.340.30
C 73
Replacing GB 2890-1995, GB/T 2891-1995, GB/T 2892-1995
Respiratory Protection -
Non-Powered Air-purifying Respirators
ISSUED ON: APRIL 13, 2009
IMPLEMENTED ON: DECEMBER 1, 2009
Issued by: General Administration of Quality Supervision, Inspection and
Quarantine;
Standardization Administration (SAC) of the People’s Republic of
China.
Table of Contents
Foreword ... 3
1 Scope ... 5
2 Normative References ... 5
3 Terms ... 6
4 Classification and Designation ... 7
5 Technical Requirements ... 9
6 Test Method for mask ... 16
7 Filter test method ... 31
8 Inspection Rules ... 60
9 Identification ... 62
Appendix A (Informative) Comparison table of filter types and those in the
former standard ... 64
Appendix B (Informative) Main dimension of test head-form ... 65
Appendix C (Informative) Summary of test requirements ... 66
Bibliography ... 68
Respiratory Protection -
Non-Powered Air-purifying Respirators
1 Scope
This standard specifies the classification and designation, technical requirements,
mask test methods, filter test method, inspection rules and marking of non-powered
air-purifying respirators.
This standard is applicable to the respirators based on the non-powered air-purifying
principle.
This standard is not applicable to the respiratory protection equipment used in the
hypoxic environment, underwater operation, escaping and fire-fighting hotspot.
2 Normative References
The following standards contain provisions which, through reference in this text,
constitute provisions of this standard. For dated reference, subsequent amendments
to (excluding correction to), or revisions of, any of these publications do not apply.
However, the parties to agreements based on this standard are encouraged to
investigate the possibility of applying the most recent editions of the standards. For
undated references, the latest edition of the normative document referred to applies.
GB/T 2428-1998 Head-face dimensions of adults
GB 2626-2006 Respiratory protective equipment - Non-powered air-purifying
particle respirator
GB/T 5703-1999 Basic human body measurements for technological design
GB/T 10586-2006 Specifications for damp heat chambers
GB/T 10589-2008 Specifications for low temperature test chambers
GB/T 11158-2008 Specifications for high temperature test chambers
GB/T 12903-2008 Personal protective equipment terminology
GB 14866-2006 The specifications for personal eye-protectors
3.6
Inhalation valve
It refers to the one-way valve that only permits the inhalation air entering the mask but
prevents the exhalation air being exhausted from the mask through it.
3.7
Exhalation valve
It refers to the one-way valve that only permits the exhalation air being exhausted
from the mask but prevents the inhalation air entering the mask through it.
3.8
Inward leakage of mask
It refers to the ratio of simulant concentration leaked into the mask to the simulant
concentration in the inhalation air where the examinee inhales under specified
conditions.
3.9
Dead space
The volume of air re-inhaled from the previous exhalation
Note: it shall be expressed by the volume fraction of carbon dioxide in the inhalation
air.
3.10
Breathing hose
It refers to the air-tightness hose used for connecting mask and filter.
4 Classification and Designation
4.1 Non-powered air-purifying respirator
Non-powered air-purifying respirators may be divided into chest style respirator and
chin style respirator according to the connecting modes of mask and filter.
4.2 Mask
Masks may be divided into full mask and half mask according to the structure.
5.1.1.6 Anti-corrosion treatment shall be carried out for the metal material surfaces
of mask.
5.1.2 High-low temperature adaptability
Masks pre-treated according to Section 6.3 shall be free from obvious deformation;
threaded connection parts shall be able to well connect with the filter.
5.1.3 Fire resistance
Test shall be carried out according to the requirements of Section 6.4; after-flame time
shall not be greater than 5s.
5.1.4 Exhalation valve of mask
5.1.4.1 Exhalation valves shall be provided with exhalation valve covers which can
protect them from being damaged; exhalation valves shall have favorable action
performance.
5.1.4.2 Test shall be carried out according to the requirements of Section 6.5; test
results shall meet:
a) Where the exhalation valves are reduced pressure to -1180 Pa, the negative
pressure value of full mask exhalation valve shall not decrease more than 500
Pa within 45s;
b) Where the exhalation valves are reduced pressure to -1180 Pa, the time
required by half mask exhalation valve to recover to the normal pressure shall
not be less than 20s.
5.1.5 Inward leakage of mask
Test shall be carried out according to the requirements of Section 6.6; test results
shall meet:
a) Inward leakage of full mask shall not be greater than 0.05%;
b) Inward leakage of half mask shall not be greater than 2%.
5.1.6 Dead space of mask
Test shall be carried out according to the requirements of Section 6.7; test results
shall not be greater than 1%.
5.1.7 View
Test shall be carried out according to the requirements of Section 6.8; test results
shall be in accordance with those specified in Table 1.
6 Test Method for mask
6.1 Test sample
Test samples shall meet the description of product marks and have effective
functions; the total quantity of test samples shall be determined according to the
specific requirements of test, which is detailed in Appendix C.
6.2 Appearance inspection
Before the laboratory performance test, visual appearance inspection shall be
carried out for the samples, and the samples shall meet the requirements of Article
5.1.1.
6.3 Pretreatment
6.3.1 Equipment
a) Technical performance of high temperature test chamber shall meet the
requirements of GB/T 11158-2008;
b) Technical performance of low temperature test chamber shall meet the
requirements of GB/T 10589-2008;
c) Technical performance of damp heat test chamber shall meet the
requirements of GB/T 10586-2006.
6.3.2 Method
Take the samples out of the original package and carry out the following conditional
treatment in turn:
a) Place them in the (70±3)℃ high temperature test chamber with 20% relative
humidity for (72±3)h;
b) Place them in the (70±3)℃ damp heat test chamber with (95~100)% relative
humidity for (72±3)h;
c) Place them in the (-30±3)℃ low temperature test chamber for (24±1)h.
Before each procedure, the subsequent test shall be carried out at least 4h after the
samples recover to the room temperature.
Note: pretreatment shall be carried out under the condition that the samples do not
suffer thermal shock.
6.5.2.1 Constant volume cavity: volume (150±10)mL.
6.5.2.2 Gas flowmeter: measuring range is (0~800)mL/min, precision is grade-1.
6.5.2.3 Micromanometer: measuring range is (0~2000)Pa, precision is 1 Pa.
6.5.2.4 Stopwatch: precision is 0.1s.
6.5.3 Test conditions
6.5.3.1 Normal temperature and pressure, the relative humidity shall be less than
75%.
6.5.3.2 Exhalation valve and constant volume shall be airtight, and vertical to the
horizontal plane; valve plates shall not deform due to load carrying; exhalation valve
shall be clean and dry.
6.5.4 Test procedure
6.5.4.1 Seal the ventilation holes of constant volume cavity and exhalation valve,
extract air to -180Pa, close the air extraction control valve, and then observe.
Pressure change shall not be observed within 2min.
6.5.4.2 Install the exhalation valve on the constant volume cavity, extract air from
constant volume cavity at the flow rate not greater than 500 mL/min until the
pressure in the cavity is -1250 Pa, and close the control valve.
6.5.4.3 Start timing when the system is -1180 Pa.
6.5.5 Test results
6.5.5.1 Negative pressure variation value at 45s shall be recorded for the full mask.
6.5.5.2 Time required by half mask to recover to 0 Pa shall be recorded.
6.5.5.3 Test results shall meet the requirements of clause 5.1.4; if one of the four
samples is unqualified, the test shall be deemed as unqualified.
6.6 Inward leakage test of mask-oil-mist method
6.6.1 Sample quantity
Four samples; two of them are untreated samples, the other two are pre-treated
samples.
Masks shall be correctly assembled with the filters or breathing hoses provided by
manufacturers.
6.6.2 Test device
6.6.3.1 For each mask, 10 persons with corresponding head and facial dimensions
shall be selected for the wearing test according to the adaptive range, and the
examinees must shave off the beard. Mask wearing shall make the examinees feel
suitable; head bands shall not be regulated too tight or too loose. Face length and
surface width data of examinees shall be measured and recorded according to the
requirements of GB/T 5703-1999.
6.6.3.2 Oil-mist concentration of test-cabin shall be within the range of
(150~200)mg/m3.
6.6.3.3 Filter efficiency of filter to oil-mist shall be greater than 99.995%. If the
manufacturer do not have the filter of such oil-mist filter efficiency, it may be replaced
by the filter whose filter efficiency is greater than 99.995% in the test process, but the
replacing filter shall be able to be well assembled with the mask.
6.6.3.4 Sampling tubes of test-cabin shall be placed in the head activity areas of
the examinees. Sampling tubes shall be installed on the tested samples, the
interfaces shall maintain airtight and the tube ends shall be close to the mouth and
nose.
6.6.4 Test procedure
6.6.4.1 Fill the oil-mist into the test-cabin, regulate the concentration to the required
concentration of test, and make the concentration stable, start air extracting pump,
measure the gas flow concentration by photometer, namely, C0.
6.6.4.2 Examinees correctly wear the masks, carry out preliminary airtight
inspection according to the use methods, adjust appropriate, and connect the
sampling tube to the photometer.
6.6.4.3 Start air extracting pump, measure the gas flow concentration in the mask
where the examinees respire in the smog free air outside of the test-cabin, take five
values, and calculate mean of the five values as the background concentration Ce.
6.6.4.4 Sent the examinees into the test-cabin and make them complete the
following actions upon the commands, measure the gas flow concentration in the
cover under each action, take five values of each action, and calculate mean of the
five values as the leakage concentration C of the action.
a) At least 1min at calm state;
b) At least 1min when moving heads;
c) Speaking about 1min.
6.6.5 Test results
6.7.2.5 Total dead space of test device gas circuit (excluding respirator) shall not
be greater than 2000mL.
6.7.2.6 Electric fan: electric fan shall blow on the side of the tested sample, and
make the gas flow at 0.5m/s in front of the mask.
6.7.3 Test procedure
6.7.3.1 Masks shall be correctly worn to the tested head-forms, which shall be
airtight and free from deformation. If necessary, the mask perimeter and tested
head-form shall be sealed with PVC strip or other appropriate sealant.
6.7.3.2 Respirator shall be adjusted to respiratory frequency 25 times/min and
respiration tidal volume 2L/times.
6.7.3.3 CO2 shall be sent into the respirator by a flowmeter, compensation bag and
one-way valve. CO2 absorber shall be used on the inspiration circuit between
electromagnetic valve and respirator in order to prevent CO2 aggregation.
6.7.3.4 CO2 content in the inhalation gas shall be continuously measured and
recorded until the CO2 concentration is stable.
6.7.3.5 CO2 concentration in the environment 1m away from the tested head-form
nose shall be detected. Where the CO2 concentration in the inhalation gas achieves
stable, measure the CO2 concentration in the environment immediately. CO2
concentration in the environment may also be measured from the sampling tube
after the CO2 gas source is closed. Only when CO2 concentration in the environment
is less than 0.1%, the test results may be regarded as valid.
6.7.4 Test results
6.7.4.1 CO2 concentration in the test environment is deducted from the measured
value of CO2 content in the inhalation gas. Tested samples shall be tested three
times. The mean value shall be regarded as the CO2 content in the inhalation gas.
6.7.4.2 Test results shall meet the requirements of Article 5.1.6; if one of the two
samples is unqualified, the test shall be deemed as unqualified.
6.8 Visual field
6.8.1 Sample size
One untreated sample; masks shall be correctly assembled with filters or breathing
hoses provided by manufacturers.
6.8.2 Test device
6.10.2.2 Manometer: measuring range is (0~2000)Pa; precision is 1Pa.
6.10.2.3 Manometry three-way pipe: internal diameter of pipe Φ (16±0.5) mm;
length 100mm; opening of pressure transmission hole in air flow shall be no greater
than Φ6mm.
6.10.2.4 Air compressor: ventilation volume shall be not less than 250L/min.
6.10.3 Test procedure
6.10.3.1 Regulate ventilation volume to (30±0.6)L/min and measure systemic
resistance P1.
6.10.3.2 Install exhalant valve the test system, regulate ventilation volume
(30±0.6)L/min and record measured resistance P2.
6.10.4 Test result
Exhalant valve resistance shall be calculated according to Formula (7):
P=P2 - P1 ………..………………………………………….. (7)
P -- Inhalant valve resistance of the mask, in Pa;
P1 -- Inhalant valve resistance of the system, in Pa;
P2 -- Inhalant valve resistances of the mask and system, in Pa.
Test result shall meet those specified in 5.1.8; if one of three samples is unqualified,
the test shall be unqualified.
6.11 Lens light transmittance test
6.11.1 Sample size
Two samples; one of them is untreated sample, the other one is pre-processed
sample.
6.11.2 Test procedure
The test shall be carried out according to those specified in GB 14866-2006.
6.11.3 Test result
Test result shall meet those specified in 5.1.9.1; if one of two masks is unqualified,
the test shall be considered unqualified.
6.12 Bonding strength test for masks and filters
Test result shall meet those specified in 5.1.12.2.
7 Filter test method
7.1 General provisions
In all the items of tests, if the test samples entirely meet the requirements, this item
of test shall be considered qualified.
7.2 Test Samples
Test samples shall meet the description of product marks and have effective
functions; the total quantity of test samples shall be determined according to the
specific requirements of test, which is detailed in Appendix C.
7.3 Appearance inspection
Before performance test in laboratory, visual inspection shall be carried out on the
samples, and the samples shall meet the requirements of Article 5.2.1.
7.4 Pre-processing
7.4.1 Sample size and requirements
4 untreated samples; samples shall be their minimum packaging condition.
7.4.2 Temperature pre-processing
7.4.2.1 Equipment
a) Technical performance of high temperature test chamber shall meet the
requirements in GB/T 11158-2008;
b) Technical performance of low temperature test chamber shall meet the
requirements in GB/T 10589-2008.
7.4.2.2 Method
Take the samples out of the original package and carry out the following conditional
treatment in sequence:
a) Place it in dry high temperature test chamber of (70±3) ℃ for (24±1) h and
relative humidity less than 20%;
b) Place it in low temperature test chamber of (-30±3) for (24±1) h.
Next test shall be carried out after the sample temperature is returned to ambient
7.5.2.2 Gas flow-meter: measuring range is (0~100)L/min, precision is grade-1.
7.5.3 Test condition
7.5.3.1 Temperature: (16~32)℃.
7.5.3.2 Relative humidity: (30~60)%.
7.5.3.3 Test flow: (30±0.6)L/min, (95±4)L/min; if two and more fillers are assembled
at the same time on one filtering type respirator, the gas flow through each filter shall
be divided equally on the basis of total flow.
7.5.4 Test procedure
7.5.4.1 Regulate the airflow to specialized range.
7.5.4.2 Determine the resistance P1 of test device itself.
7.5.4.3 Install the filter to the supporter and make the total resistance P2 (to 1 Pa)
of its air tightness, determination sample and test device.
7.5.5 Test result
Filter ventilation resistance shall be calculated according to Formula (8):
P=P2 - P1 ………………………………………… (8)
Where,
P -- Filter ventilation resistance, in Pa;
P2 -- Total resistance of the filter and test device, in Pa;
P1 -- Test device resistance, in Pa.
Test result shall meet those specified in 5.2.3.
7.6 Filter dust emission test
7.6.1 Sample size
4 samples, two of them are untreated samples and the other two are those through
temperature and mechanical strength pre-processing.
7.6.2 Test device
Schematic diagram of test device is detailed in Figure 10.
7.7.3 Test condition
7.7.3.1 Air pressure: (0~20)kPa; precision is grade-1.
7.7.3.2 Test time: 1min.
7.7.3.3 Water temperature is not greater than 30℃.
7.7.4 Test procedure
Open the lamp in water tank, fill water into the water tank, and water surface shall
immerse the filter; the filter top shall be 2cm from the water surface. Clamp the
tested filter into special fixture, clamp the filter closely; open air switch and adjust
pressure to make the air pressure entering the filter to be (15±2) kPa; immerse the
clamp with the filter into the water tank for 1min; rotate and incline the filter and
observe whether there is bubble running away.
7.7.5 Test result
Test result shall meet those specified in 5.2.5.
Note: this item is only applicable to filters of tank type.
7.8 Filter strength test
7.8.1 Sample size
4 samples, two of them are untreated samples and the other two are those through
temperature and mechanical strength pre-processing in sequence.
7.8.2 Test procedure
7.8.2.1 Place the sample vertically free falling from height of (1 000±5)mm on the
Korean pine wood board with thickness of (50±2)mm.
7.8.2.2 Carry out air-tightness test on the sample according to those specified in
7.7.4.
7.8.3 Test result
Test result shall meet those specified in 5.2.6.
Note: this item is only applicable to filters of tank type.
7.9 Filter smoke filtering performance test
7.9.1 Sample size
(30±0.5)L/min; determine the heat-rejection luminous intensity of its tail-gas oil-mist.
7.9.5 Test result
Smoke filtering performance of filters shall be calculated according to Formula (9):
100100
2 
IK 
 ………………………………………….. (9)
Where,
K′ -- Smoke filtering efficiency, %;
ρ2 -- Oil-mist concentration of tail gas, in mg/m3;
ρ1 -- Initial concentration of oil-mist, in mg/m3;
I2 -- Heat-rejection luminous intensity when oil-mist concentration is ρ2;
I1 -- Heat-rejection luminous intensity when oil-mist concentration is ρ1;
When scattering coefficient of instrument itself is Ke, smoke filtering efficiency of
samples shall be calculated according to Formula (10):
K=K′ - Ke ……………………………………….. (10)
Where,
K -- Filter smoke filtering efficiency, %;
K′ -- Smoke filtering efficiency, %;
Ke -- Instrument smoke filtering efficiency, %.
Test result shall meet those specified in 5.2.7.
7.10 General method of protective time test
7.10.1 Sample size
4 samples, 2 of them are untreated and the other 2 are those through mechanical
strength pre-processing.
7.10.2 Instruments and equipment
7.10.2.1 Dynamic gas adsorption device
7.10.2.1.1 Method A dynamic gas adsorption device sees Figure 13.
7.10.5.2 Open the compressed air valve; regulate the total air flow; regulate the air
flow of conditioning device and control gas humidity with thermometer.
7.10.5.3 Regulate gas flow through the filter; control test temperature according to
temperature of dry bulb in thermometer.
7.10.5.4 Slowly open the test medium generator device, regulate test medium
flowmeter to the position of the rectified concentration in advance and
simultaneously timing by stopwatch.
7.10.5.5 After finishing the test, close the test medium concentration control valve
and test medium generator device valve, continue to charge fresh air to blow wash
instruments for 20min.
7.10.6 Determination method for test medium concentration in mixed gas
7.10.6.1 Gravimetric method
Weigh mass of the test medium before and after test (to 0.01g); the test medium
mass concentration in mixed gas shall be calculated according to Formula (11):
100021 

Vt
mm …………………………………….. (11)
Where,
ρ -- Test medium mass concentration in mixed gas, in mg/L;
m1 -- Test medium mass before test, in grams (g);
m2 -- Test medium mass after test, in grams (g);
t -- Total time of test; in min;
V -- Total air flow, in L/min.
7.10.6.2 Chemical absorption method
Fill 25mL of absorption solution in two absorption bottles respectively; connect in
serial to test device, see Figure 13. Open valve and mixed gas is through the
absorption bottle in the speed of (50~100)mL, determine ventilation volume with
lower port flask and measuring cylinder or flowmeter. The gas volume through the
absorption bottle of each test shall be between (1.5~3.0) L. After finishing the test,
close the valve, take down the absorption bottle, transfer the absorption solution in a
triangular flask, determine the test medium mass in absorption solution by analysis
method and calculate the test medium vapor concentration in mixed gas according
to the volume of drainage water from the lower port flask.
colloidal sulfur and ferric sulfate, slight opalescence is permitted to exist; its
content shall be not less than 97.5%, hydrogen sulfide content shall not
exceed 0.2% and tranquilizer sulfuric acid content shall not exceed
0.3%~0.5%;
b) Standard silver nitrate solution: c (AgNO3) =0.02mol/L;
c) Sodium hydroxide standard solution: c (NaOH) =0.1mol/L;
d) Potassium iodide: analytically pure;
e) Ammonia: analytically pure;
f) Quantitative analysis indicator: weight 2g of potassium iodide and dissolve it
in 40mL of ammonia and 60mL of water;
g) Hydrocyanic acid vapor indicator through the filter: weigh 0.5g benzidine
hydrochloride, dissolve it in 250mL of hot water, add 10mL of 3% cupric
acetate solution and 40mL of 5% acetic acid solution to prepare into indicator
and store the indicator in a brown bottle for not more than 15 days; if the
indicator is found to be turned blue black in using, it shall be replaced.
7.11.1.2 Generating of test medium and determination of concentration
7.11.1.2.1 Boat type of bottle shall be adopted for hydrocyanic acid vapor
generating; boat type of bottle shall be put into 0℃ ice water bath.
7.11.1.2.2 Determination for hydrocyanic acid vapor concentration in mixed gas
Take gravimetric analysis as standard; simultaneously take chemical absorption
analysis method as comparison.
In chemical absorption analysis, take 50mL of sodium hydroxide standard solution
[cNaOH) =0.1mol/L]as absorption solution, add 1mL of quantitation indicator after
the absorption, drop with standard silver nitrate solution [c(AgNO3)=0.02mol/L] until
the solution is light-turbid as the endpoint. Hydrocyanic acid vapor mass
concentration in mixed gas shall be calculated according to Formula (13):
……………………………………… (13)
Where,
ρa -- Hydrocyanic acid vapor mass concentration in mixed gas, in mg/L;
c1 -- Amount of substance concentration of standard silver nitrate solution, in mol/L;
7.12.1.2 Reagent
a) Cyanogen chloride: colorless transparent liquid (pale yellow is permissible),
content is not less than 96%; hydrocyanic acid content is not larger than 4%;
hydrogen chloride content is not larger than 0.01%; without free chlorine;
stabilizer (sodium pyrophosphate) content is 0.3%~1.0%;
b) Standard silver nitrate solution: c(AgNO3)=0.02mol/L;
c) Standard potassium thiocyanate solution: c(KSCN)=0.02mol/L;
d) Sodium hydroxide solution: ω(NaOH)=5%;
e) Phenolphthalein solution: ω(phenolphthalein)=1%;
f) Peregal (polyammonia ethylene fatty alcohol ether) solution: 2%;
g) Nitric acid: analytically reagent;
h) Sodium bicarbonate: analytically reagent;
i) Pyridinium (pyridine): analytical reagent;
j) Standard iodine solution: c(1/2I2)=0.05mol/L;
c(1/2I2)=0.01mol/L;
k) Standard arsenic trioxide solution: c(1/4 As2O3)=0.02mol/L;
l) Starch solution: 1%;
m) Indicator:
1) Preparation of stock solution: add 40g sodium bicarbonate into 700 mL of
water, heat them till sodium bicarbonate if dissolved, add 250 mL of
pyridine and 50mL of 0.05 mol/L iodine solution at room temperature, it
becomes stock solution after being placed for 5d.during the stocking
process, the stock solution shall be inspected to guarantee the existence
of excessive free iodine.
Inspection method for the existence of free iodine: add (2~3)mL of stock
solution and 2mL of 1% starch solution into a test tube, in this case, the
solution shall turn blue.
2) Preparation with indicator: take 100mL of stock solution, add 20 mL of 1%
starch fluid, dilute them with water to (900~950) mL, instill standard
arsenic trioxide solution [c(1/4As2O3)=0.02mol/L] till blue disappears. Back
titrate it into blue with iodine standard solution [c(1/2I2)=0.02mol/L], and
concentration of mixed gas entering the filter with instrument, and make it meet the
requirements of Table 5, start the test.
7.12.2.3 Concentration determination of cyanogen chloride penetrating filter
Analyze the mixed gas passing through the filter with gas analyzer, determine the
concentration of mixed gas entering the filter with instrument, and that is the test end
point where it meets the requirements of Table 5.
7.13 Determination method for the protective time of benzene vapor
7.13.1 Chemical analysis method
7.13.1.1 Reagent
a) Benzene: analytical reagent;
b) Sulphuric acid: analytical reagent, ω (H2SO4) =98%;
c) Sodium nitrite: analytical reagent, dried at (105~110)℃;
d) Indicator: weigh 2g dry sodium nitrite, and dissolve them in 100mL of
sulphuric acid, only for the use on that day.
7.13.1.2 Generating of test medium and determination of concentration
7.13.1.2.1 Generating of test medium
The test is using evaporator (boat-shaped bottle) to generate benzene vapor, the
evaporator is placed in 35℃ thermostatic water-bath.
7.13.1.2.2 Determination for the concentration of benzene test medium in mixed
gas.
The concentration of benzene vapor in mixed gas shall be determined according to
the requirements of gravimetric method in 7.10. 6.1.
7.13.1.3 Determination method of benzene vapor penetrating filter
Add 20 mL of indicator into indication bottle, where the indicator turning from
colorless to yellow is the end point.
7.13.2 Instrumental method
7.13.2.1 Instrument
Gas analyzer: (0~35)mg/L; precision: 0.1mg/L;
7.14.2.2.2 Determination of ammonia concentration
Analyze the mixed gas passing through the filter with gas analyzer, determine the
concentration of mixed gas entering the filter with instrument, and make it meet the
requirements of Table 5, start the test.
7.14.2.3 Determination for the concentration of ammonia penetrating filter
Analyze the mixed gas passing through the filter with gas analyzer, determine the
concentration of mixed gas entering the filter with instrument, and that is the test end
point where it meets the requirements of Table 5.
7.15 Determination method for the protective time of hydrogen sulfide
7.15.1 Chemical analysis method
7.15.1.1 Reagent
a) Glacial acetic acid: analytical reagent;
b) Iodine standard solution: c(1/2I2)=0.02mol/L;
c) Standard potassium permanganate solution: c(1/5KMnO4)=0.01mol/L;
d) Standard sodium thiosulfate solution: c(Na2S2O3)=0.02mol/L;
e) Sulfuric acid solution: c(1/2H2SO4)=5mol/L;
f) Zinc acetate solution: weigh 2gzinc acetate and take 1mL of glacial acetic acid,
and prepare them into 100mL of aqueous solution with 100mL volumetric
flask;
g) Indicator: Take 4mL of standard potassium permanganate
[c(1/5KMnO4)=0.01mol/L] solution and 20 mL of sulphuric acid
[c(1/2H2SO4)=5mol/L] solution, and prepare them into 100mL of aqueous
solution.
7.15.1.2 Generating of test medium and determination of concentration
7.15.1.2.1 Generating of test medium
Adopt liquid hydrogen sulfide in steel bottle for gas supply.
7.15.1.2.2 Determination for the concentration of hydrogen sulfide test medium in
mixed gas
Chemical absorption analysis method is adopted for the determination for the
concentration of hydrogen sulfide in mixed gas.
7.15.2.2.2 Determination for the concentration of hydrogen sulfide
Analyze the mixed gas passing through the filter with gas analyzer, determine the
concentration of mixed gas entering the filter with instrument, and make it meet the
requirements of Table 5, start the test.
7.15.2.3 Concentration determination of hydrogen sulfide penetrating filter
Analyze the mixed gas passing through the filter with gas analyzer, determine the
concentration of mixed gas entering the filter with instrument, and that is the test end
point where it meets the requirements of Table 5.
7.16 Determination for the protective time of sulfur dioxide
7.16.1 Chemical analysis method
7.16.1.1 Reagent
a) Sulphuric acid: analytical reagent;
b) Iodine standard solution: c(1/2I2)=0.02mol/L;
c) Standard sodium thiosulfate solution: c(Na2S2O3)=0.02mol/L;
d) Standard potassium permanganate solution: c(1/5KMnO4)=0.01mol/L;
e) Starch solution: 0.5%.
7.16.1.2 Generating of test medium and determination of concentration
7.16.1.2.1 Generating of test medium
Adopt liquid sulfur dioxide in steel bottle, or adopt generating method to prepare
sulfur dioxide.
7.16.1.2.2 Determination for the concentration of sulfur dioxide test medium in
mixed gas
Chemical absorption analysis method is adopted for the determination of
concentration of sulfur dioxide in mixed gas.
Use 50mL of standard...
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