Matters Needing Attention in the Use of Combustible Gas Detectors
Once fixed-type detectors are installed in place, their positions are difficult to adjust. Based on years of practical experience, the following points should be considered during actual deployment.
① Identify all potential leakage points of the monitored equipment, analyze factors such as leakage pressure and discharge direction, draw a probe location layout drawing, and classify leakage risks into three levels: Grade Ⅰ, Grade Ⅱ and Grade Ⅲ according to the severity of leakage.
② Determine the diffusion direction of combustible gas in the event of a large-scale leakage according to the site layout, wind direction and other on-site conditions.
③ Establish a three-dimensional diffusion model of leaked gas by judging whether the gas density is higher or lower than air and combining with air circulation trends, then formulate an initial layout plan at the downstream of the gas flow. Finalize the installation plan after comprehensive evaluation, so that the required quantity and types of detectors can be calculated.
④ For areas with high risk of large combustible gas leakage, install one detection point every 10 to 20 meters in accordance with relevant regulations. For unattended small pump houses with intermittent operation, install a detector on the leeward side to guard against potential combustible gas leakage.
⑥ For locations with hydrogen leakage risks, install the detector on the horizontal plane above the leakage points.
⑦ For gases with density greater than air, mount the detector on the horizontal plane below the leakage points and take surrounding environmental characteristics into consideration. Special attention shall be paid to arranging monitoring points in areas prone to combustible gas accumulation.
⑧ In open environments where combustible gases diffuse freely with poor ventilation, the concentration of combustible gas in local air may easily approach or reach the Lower Explosive Limit (LEL). These positions are critical monitoring points that cannot be ignored. Analysis of on-site accidents shows that more than half of equipment failures are caused by improper installation and calibration. Therefore, it is necessary to clarify the precautions for correct installation and calibration to reduce malfunctions.
