Water Storage Tank Modifications 3

[CrazyHorse81]

Has anyone experienced modifying water storage tanks while keeping thier capacities under normal conditions (can't loose storage during fixes).

I have heard of scuba guys diving inside the tank and doing the fixes.

Some modifications may be tapping a new fitting into the side of the tank and running a discharge pipe to connect two tanks, or welding and re-painting certain bad spots in the tank...

Thanks in advance

 

[JedClampett]

I believe the tapping can be done entirely from the outside using the same techniques as hot tapping a pipe.
You could probably do the reinforcing from the inside. But the divers don't want the tank in operation to keep from being sucked into the outlet (I've heard stories). Plus, it's going to be very tough to coat. You could weld plates from the outside, but it's going to damage the coating on the inside.
Sooner or later the owner going to have to bite the bullet and figure out how to take the tank out of service. If the tanks are that critical, they should have some redundancy.

 

[semo]

Underwater work is extremely expensive and will not give the lifespan of draining the tank and doing it properly.

I don't know your situation; however, two things we have done in the past to maintain water service during tank repairs is the following:

1. Install a pressure relief valve on a hydrant, set it to maintain system pressure, and operate the plant 24/7. The excess water will be blown out the valve.

2. Rent a hydro-pneumatic pressure tank that will store some water and maintain the system pressure without operating the plant 24/7. Controls might need to be modified temporarily.

 

[bimr]

Nice post semo.

 

[CrazyHorse81]

I want to convince that two storage tanks aren't needed and that one tank will provide needed volume when one is being modified drained. Maybe the cost difference is the key to do so.

Thank you both