Does the weight of welds are included in the weight summary?

No. I suppose that could be included as an estimate, given some rule of thumb. Do you have something in mind?

Weight of welds is (almost) neglible) since a weld in a thick piece of ajoining plates (and pipes) needs a bevel prep on both surfaces, and the final result by any competent welder will end up as an almost smmoth surface. So, the net weight change is almost zero.

The only additional weight from welding would happen if a root gap exists between pieces, fittings, or plates: and that root gap should be very small anyway. (HP pipe joints should have a consumable backing plate or griout-out backing ring anyway: still, no net gain in weight.

What could help in a BOM is the total linear length of weld: how many feet (meters) of weld is required: That number can be used to directly get a cost additional factor, since the time for each pass of a weld is depend on length of the joints, not size of bead.

For tanks, the length would be the total length of all joints between plates (including head plates to wall plates for a flat roof or sloped roof tank).

I only want to be sure if the welds is considered in the output summary so that I can take into account in the unit price estimate. As you know, the roof plates has 38 mm over lap with two fillet weld and the bottom with one fillet weld, in case of shell, we always consider a butt weld with 3 mm root gap. Robert is right in mentioning that I have to know the total linear length of welds for cost estimate, but if we have to desmantle the existing tank, I have to add the weight of weld for labor cost.

Thanks.

TANK is not including weld material anywhere.

A good estimate of weight of weld metal is that it is approximately 1% of the tank plate dead load.