How to choose monitoring points for installing gas detectors in hazardous chemical tank areas?

Chemicals with dangerous properties such as flammable, explosive, toxic, corrosive, and radioactive properties are very likely to cause fires, explosions, and employee poisoning accidents during production, transportation, storage, use, and waste disposal, resulting in casualties, property losses, environmental pollution, and other adverse consequences. Each storage tank is a major hazard source. Therefore, gas detectors should be installed in hazardous chemical tank areas to monitor the concentration of toxic and harmful gases at all times to prevent disasters and accidents.

Principles for setting up combustible gas and toxic gas monitoring alarms in tank area environments

1. Places with combustible gas release sources, where the concentration of combustible gas in the air may reach 25%LEL during release, should be equipped with relevant combustible gas monitoring alarms.

2. Places with toxic gas release sources, where the concentration of toxic gas in the air can reach the maximum allowable value during release, and where there are personnel activities, should be equipped with toxic gas monitoring alarms.

3. Places where combustible gas and toxic gas release sources exist at the same time, should be equipped with combustible gas and toxic gas monitoring alarms at the same time.

4. In places where there are combustible and toxic gas release sources, only toxic gas monitoring alarms can be installed.

5. In places where combustible and toxic gases are released together, once released, when the concentration of combustible gas in the air may reach 25%LEL, and the toxic gas cannot reach the maximum allowable concentration, a combustible gas monitoring alarm should be installed; if once released, when the toxic gas in the air may reach the maximum allowable value, and the concentration of combustible gas cannot reach 25%LEL, a toxic gas monitoring alarm should be installed.

6. In general, fixed combustible gas or toxic gas monitoring alarms are installed. However, if there is no relevant fixed monitoring alarm or there is no condition to install a fixed monitoring alarm, or it is a non-long-term fixed production site, portable instruments can be used for monitoring, or sampling monitoring.

Determination of flammable gas monitoring alarm points

1. For flammable gas or flammable liquid storage tanks, a flammable gas alarm shall be installed every 20m~30m in the fire dike, and the distance between the monitoring alarm and the drain outlet, connection, valve and other places where materials are easily released from the tank should not be greater than 15m.

2.. For flammable gas or flammable liquid crane loading and unloading platforms, flammable gas monitoring alarms shall be installed according to the following regulations:

1. a) For small crane railway loading and unloading platforms, a monitoring alarm shall be installed every other parking space on the ground, and the horizontal distance between the loading and unloading port and the monitoring alarm shall not be greater than 15m;

1. b) For large crane railway loading and unloading platforms, a flammable gas monitoring alarm may be installed;

1. c) For car loading and unloading stations, the horizontal distance between the flammable gas monitoring alarm and the loading and unloading crane position shall not be greater than 10m.

Determination of toxic gas monitoring alarm points

1. When the toxic gas release source is in a closed or semi-closed place, the distance between each release source and the toxic gas monitoring alarm shall not exceed 1m;

2. When the toxic gas release source is in an open or semi-open place, the toxic gas monitoring alarm should be set on the leeward side of the main wind direction of the place, and the distance between each release source and the monitoring alarm should not be greater than 2m. If it is set on the upwind side, the distance between each release source and the monitoring alarm should not be greater than 1m.

Installation requirements for combustible gas and toxic gas monitoring alarms

1. The installation of combustible gas monitoring probes can be carried out by roof hanging, wall installation or pipe holding installation. It should be ensured that the installation is firm and reliable, and it should also be easy to maintain and calibrate.

2. The installation height of the combustible gas and toxic gas concentration alarm should be determined according to factors such as the specific gravity of the detection medium and the surrounding conditions. When the specific gravity of the monitored gas is less than that of air, the installation position of the combustible gas monitoring probe should be at least 0.5m above the leakage source; when the specific gravity of the monitored gas is greater than that of air, the installation position should be below the leakage source, but not less than 0.3m from the ground.

3. When installing the combustible and toxic gas monitoring probe, ensure that the sensor is fixed vertically downward.

4. Combustible gas and toxic gas detectors should avoid strong mechanical or electromagnetic interference, strong wind and dust and other natural pollution sources, and a clear space of not less than 0.3m should be left around them.