Pipe spools are fabricated off site according to the
availability of engineering design information, the fabricator's
plant production capacity, etc. Individual tags denote that each
spool has unique properties and each has a designated
destination in the facility under construction as shown in the
project specifications. Spools are subject to inspection before
leaving the fabricator's plant. The outcome of the inspection
activity is that a spool will be found fit-for-installation with an
x% likelihood, and, thus, that there will be a problem with (100
- x)% of them. In the latter case, the fabricator must rework the
spool to rectify the problem, prior to shipping.