Belmont Farm Supply | Belmont, Ontario

Don’t forget the insulation

The ceiling height of the steel-constructed building is more than 36 ft (11 m). The concrete slab is 372 ft by 96 ft (113.4 m by 29.3 m). McRoberts says the customer felt that the most energy-efficient method to maintain a lower energy cost was to install a complete radiant floor system.

McRoberts has been a loyal REHAU user for about a dozen years and participates in the REHAU EDGE contractor rewards program. One of the perks for McRoberts is using his points to access the REHAU LoopCAD design software for his floor-heating projects. However, he sometimes taps the design folks at REHAU’s Toronto office to help with larger projects. For the 20,000 ft² (1,858 m²) Belmont Farm Supply fertilizer warehouse, REHAU’s Yajie Jiang did the pipe layout for IFH. 

The radiant system uses RAUPEX O₂ barrier piping in 3/4, 1, 1 1/4, 1 1/2 and 2-in. sizes; PRO-BALANCE 1 1/4-in. stainless-steel manifolds; 3/4-in. R20 connectors; and EVERLOC+ compression-sleeve fittings. More than 4 miles (6.6 km) of PEX was installed in the building, McRoberts notes.

“Instead of doing all the large diameter supply and return piping above, we did it all below ground with 2-in. and 1 1/2-in. oxygen-barrier piping with the fittings,” McRoberts explains. “Then we insulated all the piping with 1-in. foam insulation made for underground use.”

The next step was the placement of 2-in (5-cm) HotRockPanels expanded polystyrene panels that double as insulation and a piping-installation method. The 3/4-in. by 500-ft (152.4-m) loops were walked into place on top of the boards at 9-in to 12-in (23-cm to 30-cm) spacing — increasing the productivity of the IFH install crew — then connected to the manifolds, which were encased in REHAU’s premium stainless-steel cabinets to protect the system from the caustic environment. A 40% glycol solution runs through the PEX network.

The biggest challenge for IFH was the pit area. “There were two different areas on the project,” McRoberts explains. “In the pit area, we had to figure out how to get the piping from it up into a manifold. We did underground piping from the pit up to the manifold, like sleeves. Then we could pull all the piping up through the sleeves and into the manifold area.”

From the boiler room, all manifolds were supplied with 1 1/2-in. RAUPEX O₂ barrier supply lines, he adds. The longest supply lines were nearly 300 ft (91 m) from the heat source.

 “In each area of the manifolds, we installed floor sensor wells with PEX piping so we could insert our sensors in after the concrete was installed,” he says. “Before the concrete pour, the floor piping was pressurized to 100 psi to ensure there were no leaks under the floor, which also included the 1 1/2-in. and 2-in. RAUPEX O₂ barrier in-slab distribution piping with EVERLOC+ fittings. All this work was done on target to keep the project on schedule.”

In the mechanical room, two IBC SL-40-399G3 boilers are the heat source for the radiant heating system — providing nearly 800,000 Btu (234 kWh) of energy to maintain the required floor temperature, McRoberts notes. They are 95% efficient and, combined with the low water temperatures, will help reduce Belmont Farm Supply’s energy costs. Caleffi low-loss headers and a hydronic dirt separator provide hydraulic separation and protect the components.

A Taco 2400 series circulator distributes water to the five manifold stations. Webstone Isolation flange kits and Tekmar floor-sensing and pump controls round out the installed equipment.