Toxic or combustible gas detection alarms in methanol tank farm?

Toxic or combustible gas detection alarms in methanol tank farm?


Toxic or combustible gas detection alarms in methanol tank farm? Recently a company in Jiangsu Wang Gong put forward such a question, in this small series here to explain to you.

Methanol gas is not included in the 10 toxic gases listed in Appendix B of the Design Code for the Detection and Alarm of Combustible Gases and Toxic Gases in Petrochemical Industry (GB50493), while methanol is listed as toxic gases in Table A.1 of the Code for the Setting of Detection and Alarm Devices for Toxic Gases in Workplace (GBZ/T223).

If methanol is treated as a toxic gas, the allowable concentration of short time exposure is 50mg/m3, the relative molecular mass is 32, and the alarm value is 35ppm. Treated with combustible gas, the lower explosive limit is 5.5%(V/V), and the alarm value is set as 25 LEL%, which is converted to volume fraction 5.5%*25%=1.375%=13750ppm, much higher than the upper toxic alarm limit of 35ppm.

According to the principle of "If the same gas belongs to both combustible and toxic gases, only gas physical examination (probe) detector should be set up", toxic gas detection and alarm should be considered first.

But in the actual work, how to choose also needs to be combined with the actual situation. For the existence of running leakage in the general factory area, the toxic gas detection alarm value is low, slightly leaked that alarm, every day is "Wolf", in order not to affect the production, the operator simply shut down the alarm, it will bring greater hidden dangers. Therefore, only when the leakage is well controlled, ppm alarm can highlight its role.

According to GBZ/T 233 toxic gas setting principle 4.1.1 "highly toxic/highly toxic gas must be installed" is not controversial, other toxic gas is "a large amount of discharge/easy to gather" occasions. It is recommended to comprehensively assess the risk level based on site conditions, meteorological conditions, operation modes of operators, and inspection frequency. Open type, good ventilation conditions according to the combustible setting is appropriate, and indoor, closed and semi-closed and other leakage gas is not easy to spread and personnel frequent places, should be set as toxic. Operators should be equipped with portable toxic gas detection alarms when sampling and inspection.

Wuxi Yong 'an Electronic Technology Co., Ltd. is not only gas detection alarm manufacturers, but also your use of gas detection alarm manufacturers.

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