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HRAI 112818 9During October, Alberta Municipal Affairs published Standata (14-BCV-019) providing a variance to National Building Code Regulation 9.36 that had increased under slab insulation requirements for radiant floor heating systems.

The increase had added significantly to the cost of hydronic systems, while only reducing heat loss by 1.27 percent according to Plumbing & HVAC magazine. One operator said it could increase the cost of the job by $8,000.

The requirement increased insulation from one inch or R-5 required by the CSA B214 hydronic installation code to R-16 or about four inches.

The variance requires RSI 0.88 or R-5 for a radiant floor heating slab in contact with the ground where the floor is fully below the frost line. And it requires RSI 1.32 or R-7.5 where the floor is above the frost line.

The announcement admitted that “…the current under slab insulation code provisions are excessive and jeopardize the availability of hydronic heating as an option…”