We have conducted hydrostatic testing at our tank and now for insulation / cladding sheets hook up, we need to attach small attachments with welding.
Is that allowable as per code? Or do we need to conduct hydrostatic testing again?
As per API 650 you can weld the non-structural attachments to the tank even after hydrostatic testing.
Your case also appears to be the same. No re-hydro required.