WPS
Joints (QW-402)

QW-402.4
The deletion of the backing in single-welded groove welds. Double-welded groove welds are considered welding with backing.

w.r.t above I reviewed the WPS in my company, and I found that, normally for backing material it is written as...
Backing (Yes) Double V Groove (No) Single V Groove

In Single V Groove also, while doing the welding on the second side (after completing the welding on first side and completing back gouging from the other side), then why we can not say Backing (of weld metal) is available.

If in Single V Groove weld, we do not have acces for back gouging, then we can say that, there is no backing material available, but where we can back gouge the first weld, then that joint should not be considered "Joint with backing material".

In Single V Groove also, while doing the welding on the second side (after completing the welding on first side and completing back gouging from the other side), then why we can not say Backing (of weld metal) is available

Mac,

Because it's a single V groove weld. QW402.4

leem

This conversation / worry may be more complicated than is necessary. The variable is about DELETION of backing. If the WPS is qualified WITHOUT backing then in can OBVIOUSLY be used WITH backing.