sentences:  Insulation on the bottom of floor systems or in the middle of wall systems, as is the case with caulking or paint based (soft) systems, will encourage more heat to travel through the sleeve and the penetrant, which can put more stress on the seal on the unexposed side.In the case of a thin (below 4") firestop mortar, there is also more potential hazard from tight annular spacing because metal expands during the fire, thus squeezing the firestop - only to rapidly shrink when hit with the hose-stream test, which can let water through, thus failing the H rating in Canada or the entire rating in the US, where hose-stream testing is mandatory.Such a failure may no longer be visible once the test assembly has reached ambient temperatures again.