Tank Plate changing 1

[LuizSouza]

Dear Fellows,

We’ve a bidding in our gas processing plant for 4 firefighting water tanks, of course no roofs, the contractor winner proposes reduce the welding surface area by using large carbon steel plates than ones on the original designing.

Original: Plate is ¼” thickness x 7.87 ft x 11,61ft – #1 Ring.
Plates are ¼” thickness x 7.87 ft x 19, 68 ft – #1 Ring
Plates are 3/16” thickness x 4, 82 ft x 19, 68 ft – #2 Ring
And so on …

Contractor Proposal: All plates ¼” thickness x 7.87 ft x 11,61ft

Despite it’s more expansive for them.

Can anyone point some trouble? I want to accept, but I ‘d listen from you first.

Best Regards.

LuizSouza

 

[JStephen]

Normally in the tank building industry, (at least in the US), it is left entirely up to the tank contractor to choose the most economical plate sizes for construction. Contract documents for tanks do not usually require a minimum or maximum size of plate, or attempt to fix the final design of the tank.

A good bit of the cost of the finished tank is in the welding. If they can buy larger plates at a slightly higher price, they can quite likely offset that price by labor savings.

Normally, larger plates with less welding are considered an improvement in the finished product. Using 1/4" plate in lieu of 3/16" would be considered advantageous.

It's not entirely clear from your post how the final plate sizes will run. On larger tanks, 8' wide plates x 32' to 40' long are fairly typical. Exact lengths used will depend on the shop set-up and tank diameter.