Some questions regarding underground storage tanks at gas stations
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Dear sea friends, first of all, I wish you a happy New Year’s Day. I have recently been in charge of overseeing the installation work at a gas station. The loading ports, filling ports, and vent valves for all of the underground storage tanks there (for gasoline and diesel) are located on the manhole covers. Looking at the 2006 edition of the guidelines for gas station storage tanks, it shows that these components are also placed on the manholes. What is the purpose of this? Why can’t it be installed directly on the tank body? There is also the issue of corrosion protection for oil tanks – is it necessary to apply internal corrosion protection to gasoline tanks? Are there any regulatory requirements? I would appreciate your advice; thank you!
I’m familiar with gas stations, but not with their design. I thought placing it on the manhole cover would make maintenance easier, and it would also reduce the risk of leaks
The design of the manhole covers is primarily aimed at facilitating installation and maintenance; when repairs are needed, they can be removed easily! ! ! ! If it is designed on the tank body, it is inconvenient to remove on one hand, and it also has a certain impact on the strength of the tank body! ! Additionally, underground tanks at gas stations generally do not have internal anti-corrosion treatment; only external anti-corrosion protection (enhanced or super-enhanced level) is applied. For reference only! ! !
The device nozzles shouldn’t need to be removed, right? Also, what’s the purpose of removing it during maintenance? Please provide further explanation. Thank you
The design of the manhole covers is primarily aimed at facilitating installation and maintenance; when repairs are needed, they can be removed easily! ! ! !
It is for ease of maintenance; buried tanks generally have only a passage above the manhole, so the pipe openings are all located above the manhole.
For underground oil tanks in gas stations, all openings and connections should be located at manholes; these connections include the inlet pipe, outlet pipe, level gauge hole, sampling hole, and vent pipe. For ease of inspection, these pipes are fitted with flange connections at the manhole edges, allowing them to be removed entirely for convenient maintenance. Of course, since there are no devices inside the tank for the vent pipes and oil inlet pipes, they can be installed directly on the tank body. The oil outlet pipe requires maintenance sometimes due to the bottom valve (the same applies to the level gauge). Although vent pipes and oil inlet tanks can be installed on the tank body, the common practice is still to make openings at the manholes. After all, being able to see it makes one feel more at ease.
That’s right; a section of pipe is also fixedly welded to the manhole cover, with a flange on it. Other pipes coming in need to be connected to this flange as well as to the flange at the bottom, so that the manhole cover can still be lifted for easy operation. Stress will be generated on the tank, which is not good for it!
Underground storage tanks usually have one or two inspection openings per tank, which facilitates installation and maintenance; it’s convenient to have them grouped together. Alternatively, could the top of the tank be left completely open, with only a large cover placed near the ground level?
Since the fuel tanks at gas stations are buried underground, only manhole locations have operation wells. Manhole covers are installed for construction purposes and maintenance.