These two are the labels a working system accumulates, and they are easy to conflate because both are records, both may go inside or outside the cover, and both are overlapped rather than replaced. They follow different acts. Under 28 TAC § 34.621 a service label is completed in detail and affixed AFTER ANY SERVICE. Under 28 TAC § 34.622 an inspection/test label is completed and affixed AFTER THE INSPECTION AND TESTING of a system. And where service or maintenance is performed under an inspection or test, the rule requires BOTH — an inspection/test label and, in addition, a service label completed and attached according to its own procedures.

The overlapping is deliberate and the rules say why. Approximately half an inch of the adhesive on the top back of each label should be used to attach it over the PREVIOUS label of the same kind, to permit viewing of the previous label and the MAINTAINING OF A BRIEF HISTORY. So a panel accumulates two stacks, and each stack is a chronology somebody can lift and read. That is also why the retention periods are minimums rather than expiry dates: service labels must remain in place for at least TWO YEARS and inspection/test labels for at least FIVE YEARS, after which a licensed employee or agent of a registered firm may remove them.

One condition applies to the inspection/test label alone and catches firms on new work. FOR A NEW INSTALLATION, AN INSPECTION/TEST LABEL MAY ONLY BE APPLIED AFTER THE SYSTEM HAS BEEN ACCEPTED BY THE LOCAL AHJ. Read alongside Chapter 8, that puts the labels in a sequence a firm cannot compress: the installation is inspected in stages, certified, and accepted locally — and only then can the blue label go on. A firm that tests a new system at handover and tags it the same afternoon has applied the label ahead of the acceptance the rule requires it to follow.