A common failure point of mechanical insulation on cold (below-ambient) piping systems is
at the hanger locations due to compression of insulation subjected to inadequate support
or no insulation at all (thermal bridging). Symptoms include decreased thermal efficiency,
condensation, water damage below, corrosion under insulation (CUI) and mold growth.
Rigid pipe supports designed to handle the weight of loaded pipes, system movement/vibration
and preventing pipe stress or cracking are the solution but come in many different forms.
While the lowest-cost option are wood blocks with insulation protection shields (saddles),
wood is not recognized by ASHRAE because it will burn in plenum-rated spaces, absorbs
condensation (hygroscopic) and serves as a food source for mold growth.
Rigid closed-cell insulation types, such as cellular glass, phenolic foam, polyisocyanurate and
calcium silcate can be fabricated and installed with or without a vapor retarder and saddle
depending on the insulation manufacturer’s recommendation.

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