Pipeline failure and maintenance-7

Release time:

2024-04-22

What are the underground operations during the inspection and maintenance of drainage pipes? Answer: there are several aspects of underground operation during inspection and maintenance of drainage pipeline.

(1) If it is required to go down the well for operation, the approval procedures must be fulfilled. The chief of the operation team (Group) shall fill in the "safe operation ticket for going down the well" and go down the well after being approved by the technical director of the maintenance team. For each down well task, the management personnel must check the pipe diameter, water depth, tide and sewage discharge of nearby users, and fill in the "down well safety operation ticket". The operation team (Group) shall do well in dewatering, ventilation, gas detection, lighting and other works of the pipeline before going down the well, and formulate protective measures to fill in the operation ticket. The personnel entering the well shall be trained in safety technology, and learn how to use first aid and protective equipment, lighting and ventilation equipment; when entering the well, there shall be two persons on the well for monitoring; if entering the pipeline, the monitoring personnel shall be added to the well for intermediate liaison, and the monitoring personnel shall not leave without permission. For the pipeline with diameter less than 0.8m, it is strictly prohibited to enter the pipeline for operation; the continuous operation time of each time when the operator goes down the well shall not exceed 1H; open fire is strictly prohibited for underground operation.

(2) During the underground operation of precipitation and ventilation, the management personnel of the pipeline operation team (Group) shall require the cooperation of related stations or installation of temporary water pumps to reduce the water level of the operation pipe section. Before entering the well, the working well cover and its upstream and downstream well covers must be opened in advance for natural ventilation, and the mud water shall be stirred with bamboo (wood) sticks to emit harmful gases. After natural ventilation of rainwater pipeline, if the detection results prove that the underground gas is still lack of oxygen or the concentration of toxic gas exceeds the allowable value, natural ventilation or artificial ventilation shall be continued during the underground operation to make the oxygen content reach the specified value and the concentration of toxic gas fall below the allowable value; after natural ventilation of drainage pipeline, if the concentration of explosive gas is still within the explosion range, it shall be underground During the operation, artificial ventilation must be adopted to reduce the explosive gas concentration in the pipeline to below the lower explosion limit; when artificial ventilation is adopted, the air volume of the ventilator can be generally calculated according to the average wind speed of 0.8m/s in the pipeline.

(3) Gas detection gas detection is mainly to determine the oxygen content of underground air and the concentration of common harmful gas; the oxygen content of underground air is generally not less than 19%, and the allowable concentration and explosion range of harmful gas are detailed in relevant regulations.

(4) Explosion proof lighting equipment shall be used for lighting and communication, and its power supply voltage shall not be greater than 12V; the illumination degree on the underground working surface shall not be less than 50lx. Wireless (mobile phone) or wired communication equipment should be used for communication between personnel in the well or underground instead of shouting or gestures.