When installing the heat shrink sleeve (any heat shrink sleeve applied to a steel pipeline) preheating the steel is going to be required. The purpose of preheating the steel is to be sure the interface between the adhesive sealant of the shrink sleeve and the steel pipe (and factory applied coating) achieves the required bond-line temperature. This bond-line temperature is the temperature at which an actual BOND occurs. It varies from product to product, generally depending on the specific adhesive sealant that is being used.
So, what is the tip?
Any installer (and inspector and end user) MUST be sure that the installer is heating all 360 degrees of the pipe. It is NOT sufficient to simply preheat the top of the pipe; or the side of the pipe. Every side of the pipe; everywhere that the shrink sleeve will be in contact with the pipe; must be properly preheated to at least the minimum installation temperature. This includes the BOTTOM of the pipe which is very often overlooked.
So, tip#1: Make absolutely certain that the installer is preheating (and checking the temperature) at all points of the pipeline. They need to check the top, the bottom, the sides, the plant applied coating and the bare steel. Without the proper preheat temperature, you can be certain that the heat shrink sleeve is not going to perform as you are expecting -- or as the data sheet says it well.