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When working in a confined space, when the oxygen concentration is lower than how much, you can't use a filter gas mask.
General specification for filter gas masks

1 Subject content and scope of application

This standard specifies the classification, technical requirements, test methods, inspection rules, marks, packaging, transportation, storage and use requirements of filter gas masks.

This standard applies to filter gas masks (hereinafter referred to as masks).

This standard does not apply to respirators used in anoxic environment.

2 reference standard

GB2828 Sampling procedure and table for batch inspection counting (applicable to continuous batch inspection)

GB2829 Sampling procedures and tables for periodic inspection and counting (applicable to stability inspection of production process)

GB289 1 performance test method for filter gas masks

Test method for performance of filter gas mask cans

GB589 1 test method for impact protection

3 terminology

3. 1 Full-face mask

A cover near the head that covers the eyes, face, nose and mouth.

3.2 Half mask and half mask

Only the mask covering the nose and mouth can be closed. Also known as muzzle mask.

3.3 antivirus time protection time

Under the specified conditions, the poison mixture is introduced into the poison filter tank until the concentration of the permeated poison reaches the limited value.

4 classification

See table 1 for mask classification.

Table 1 Classification and composition of masks

kind

building blocks

Full-face mask, large canister, airway

Catheter gas mask

Full-face mask, medium-sized canister, airway

Full-face hood and small pot

Direct gas mask

Half mask, poison filter box

Note: the mass of the small pot does not exceed 300g; The mass of the filter box shall not exceed 200g; The mass of the medium-sized tank is 300 ~ 900 g; The mass of the large tank is 900 ~ 1400 g.

5 technical requirements

5. 1 basic component performance

5. 1. 1 mask

5. 1. 1. 1 The mask selected according to the regulations should fit well with the human face without obvious tenderness; The fixing system of the mask should have sufficient strength and elasticity; Components should be easy to replace.

5. 1. 1.2 The air leakage coefficient, actual dead space and visual field of the mask shall comply with the provisions in Table 2.

Table 2 Air leakage coefficient, actual dead space and visual field of the mask

full face mask

project

Big eye window

Binocular window

Half mask

Air leakage coefficient,%

0.005

0.005

five

Actual dead space, ml

250

280

185

Total field of vision,% >

70

65

-

Binocular vision,% >

55

24

65

field of vision

Visibility is reduced,% >

35

35

35

Note: When the door and nose cover is installed in the full-face cover, the actual dead space should be less than 180 mL.

5. 1. 1.3 The air tightness of the mask assembly is 1min, and the internal pressure drop is not more than 50Pa.

5. 1. 1.4 Airtightness of the mask exhalation valve The operation of the exhalation valve is airtight. When the pressure drops to-1 180 Pa, the negative pressure of the full-face expiratory valve will drop less than 590 Pa within 45 s, and it will take more than 20 s for the half-face expiratory valve to return to normal pressure.

5. 1. 1.5 The resistance of the mask to airflow shall meet the requirements in Table 3.

Table 3 shielding resistance Pa

full face mask

Half mask

Suction resistance