I feel this question is asked to me ha ha , yes, I have done enough in insulation . And yeah, absolutely right. Perlite comes in granule (usually preformed pipe sections/block forms). If your piping need to be heat traced, I would suggest to go for Mineral wool even though it increases probability to corrosion. But be sure to take precaution. Using perlite wont be handy if tracers need be incorporated. Because you need a higher dia perlite preformed sections to incorporate the trace pipes, and on making the installation robust and tight with the bands, the chances for perlite breakage is very likely. So just go ahead with Mineral wool, but before that be sure to wrap the whole pipe accommodating the trace pipe with Aluminium or SS foil (depending on the temp) to create annular space and maximum tracing efficiency. Also it helps in avoiding direct contact between Mineral wool and pipe.
Cococa