Inspection of self-contained air breathing apparatus before use

1. Turn on the air cylinder switch. The storage pressure in the cylinder is generally 18~30MPa. As the pressure in the pipeline and the pressure reduction system rises, the residual pressure alarm will sound.
2. Close the cylinder valve and observe the changes in the pressure gauge reading. Within 5 minutes, the pressure gauge reading should not drop by more than 2MPa, indicating that the high-pressure air tightness of the gas supply pipeline is good. Otherwise, the air tightness of each joint should be checked.
3. Through the lever of the supply valve, gently press the supply valve diaphragm group to slowly discharge the air in the pipeline. When the pressure drops to 4~6MPa, the residual pressure alarm should sound an alarm and continue to sound until the pressure gauge indication value is close to zero. Otherwise, the alarm should be recalibrated.
4. Check whether the pressure gauge is damaged and whether its connection is firm.
5. Check whether the medium-pressure conduit is aged, cracked, or leaking, and whether its connection with the supply valve, quick connector, and pressure reducer is firm and damaged. 6. Check whether the supply valve is flexible, whether there are any missing parts, whether the connection between it and the medium pressure tube is firm, and whether it is damaged. Check whether the supply valve and the exhalation valve match. Put on the exhaler, turn on the gas cylinder switch, and press the supply valve lever to put it in working state. When inhaling, the supply valve should supply air with an obvious "hissing" sound. When exhaling or holding your breath, the supply valve stops supplying air and there is no "hissing" sound, indicating a good match. If the supply valve still supplies air when exhaling or holding your breath, a "hissing" sound can be heard, indicating a mismatch. The ventilation resistance of the positive air exhalation valve should be checked, or the full-face mask should be replaced to meet the matching requirements.
7. Check whether the lenses, straps, annular seals, exhalation valves, and inhalation valves of the full-face mask are intact, whether there are any missing parts, and whether the connection position of the supply valve is correct and whether the connection is firm. The lenses and other parts of the full-face mask should be clean, bright, and free of dirt. Check whether the full-face mask fits the face well and is airtight. The method is: turn off the air bottle switch, take a few deep breaths, and suck out the remaining gas in the air respirator pipeline system. Maintain negative pressure in the full-face mask. Under the action of atmospheric pressure, the full-face mask should move toward the human face. If you feel difficulty breathing, it proves that the full-face mask and the exhalation valve have good airtightness.
8. Whether the air bottle is firmly fixed, and whether it is firmly and airtightly connected to the pressure reducer. Whether the shoulder straps and waist belts are intact, whether there are any breaks, etc.