The centerpiece of any hockey arena, the ice surface has been completed at Toronto's Air
Canada Centre, the future home of the Toronto Maple Leafs and the Toronto Raptors. That is,
everything but the ice; that won't appear until February 20, 1999, when the Leafs play the
Montreal Canadiens.

The next day, the ice will be covered with a basketball playing surface asThe Raptors take on the Vancouver Grizzlies.

The whole idea behind creating an ice rink is to construct a huge block of concrete that will be colder than the freezing temperature of water. But at the same time, ensure that its underside does not freeze the sub grade.

The sub grade was first compacted before two lifts of clean washed sand were put down and rolled. Polyethylene pipes were buried in  the sand; these will contain heated ethylene glycol to ensure the sub grade does not freeze.

Then two layers of rigid insulation went down on top of the sand to also protect the sub grade.
 

Polyethylene slip sheets were placed on the insulation so that the freshly placed concrete slab which followed moved freely during curing.

But before the 150 mm of concrete was placed, the most difficult phase of the job was done:
an amazing amount of 32 mm diameter steel pipe for carrying cooling ethylene glycol to make
the ice more than 15 km was positioned and welded. Cimco's sales engineer David Sinclair
says steel pipe was specified over plastic because it results in a more efficient cooling
process.

"In terms of NHL rinks, this has the latest in terms of equipment technology," he says. For
example, plate and frame heat exchangers (which will chill the glycol before it goes to the
steel piping) were installed instead of conventional shell and tube heat exchangers which are
less efficient and more costly to maintain over the long term.

 Another difference: normally the steel headers which handle the supply and return of the
cooling glycol have trench covers. But at the Air Canada Centre, which will have other events
such as circuses, the headers are buried in the concrete. Sinclair says the final product is a
seamless floor.

More than 15 krn of cooling pipe for the ice rink floor was covered with concrete. The first sporting event is scheduled for Feb. 20, 1999.

The 216 m3 concrete pour for the ice rink floor was delayed until July  31 because of a strike by crane and heavy equipment operators. Just as the piping work could not be rushed, neither could the pour which took a little more than 8 hours. Says PCL's construction manager Ian Stewart, "This is one that you  want to try and pour slow and under perfect control. You only get one  shot to do it right."                                                                                               HCN