How to set up the composite pipe access well? Inspection port layout specification

How to set up the composite pipe access well? Inspection port layout specification

In the buried composite pipe system of gas station, the maintenance well (operation well) is an important auxiliary facility of pipeline, which directly affects the convenience of daily inspection, maintenance and accident emergency treatment.

Setting position of 1. access well

The composite pipe overhaul wells of gas stations mainly include two categories: oil tank operation wells (load-bearing man-hole wells) and leakage detection wells. In practical engineering, load-bearing operating wells are usually set up above buried oil tanks to install submersible pumps, liquid level meters and other equipment and reserve maintenance space. According to the actual engineering case, a gas station with 4 double-layer oil tanks usually needs to be equipped with 8 anti-seepage operation wells and manhole covers (bearing), and equipped with water level observation wells in the tank area.

For the setting of pipeline ancillary facilities, other industry specifications can be used as reference: maintenance valve wells are usually set at important nodes (such as roads and rivers) and long-distance pipe sections where the pipeline crosses, with a spacing of about 0.5-1.0km; Exhaust valve wells are set at 600-800m intervals at pipeline uplift points and gentle pipe sections.

Layout Specification of 2. Inspection Port (Operation Port)

Refer to the regulations on inspection ports in the relevant drainage pipeline specifications, and in combination with the characteristics of the composite pipe system of the gas station, the inspection ports shall be arranged in accordance with the following principles:

1. Height and orientation of access port

The center height of the inspection hole of the operation well should be convenient for maintenance personnel to operate, and it is generally recommended to be about 1 m from the operation ground. The direction of the inspection port shall be oriented in a direction convenient for maintenance and observation, so as to facilitate daily inspection and troubleshooting.

2. Inspection well structure requirements

Pipeline inspection wells containing toxic and harmful substances such as oil products shall be of concrete or reinforced concrete structure instead of brick wells, so as to prevent oil leakage through brick cracks from polluting the soil and groundwater. The joint between the manhole cover and the well seat of the operating well shall be sealed, and the manhole cover shall not be allowed to prevent rainwater infiltration and oil and gas escape.

3. Anti-seepage and testing requirements

The leakage detection well is set at the lowest point or key node of the pipeline system, and the bottom surface of the well should be set with a slope (generally not less than 5%), which is sloped to the detection port or catch pit to ensure that any leakage can be found in time. In terms of anti-seepage requirements, water level observation wells and leakage detection wells in the tank farm should be considered together with the anti-seepage system in the tank farm.

Advantages of 3. finished operating wells

At present, in the reconstruction project of gas station, more and more projects adopt the finished anti-seepage operation well (load-bearing). The finished operating well has the following advantages: good overall sealing performance and high anti-seepage level; fast installation, no need for on-site pouring; strong load-bearing capacity of the manhole cover, which can meet the requirements of vehicle traffic. For gas stations using composite pipes, special sealing casing can be used for the connection between the finished operating well and the composite pipe to ensure reliable seepage control at the connection.

4. Summary

The installation of composite pipe maintenance wells shall be planned in combination with the pipeline direction, burial depth and oil tank location. The operation well spacing, inspection hole height and anti-seepage level shall meet the safety and environmental protection requirements. Selection of finished anti-seepage operation wells can greatly improve the construction efficiency and anti-seepage reliability.