The Hockey Rink and Making Ice
The target dimensions of a hockey rink used for competitive play are 200 by 85 feet, with 11 feet from the boards to the goal lines and a corner radius of 28 feet, as spelled out in National Hockey League rules and incorporated at most hockey rinks. International hockey rinks are usually 15 feet wider; a generally accepted width is 98.4 feet or 30 meters.
For years, NHL rinks in Boston, Buffalo, and Chicago were a little smaller than the 200-by-85-feet standard—not a lot, but a noticeable difference—which created some controversy when the home teams were accused of building player rosters to take advantage of the smaller playing surface. Now, all professional rinks are the NHL standard size.
How Is Hockey Ice Made?
Making ice on an indoor hockey rink follows a process perfected after lots of trials and—yes—some errors. With the errors eliminated (such using too much water, or allowing it to freeze with an uneven surface), the path is clear to create consistently nice ice, particularly at the professional and highly competitive levels, such as international, collegiate/high school, and club hockey. Here's how nice hockey ice is made at indoor arenas:
Ice-making starts with a concrete slab. Freezing brine water/saline (salt water) or methanol is pumped through the slab to lower the concrete temperature to a flash-freezing point. (Brine water has a lower freezing point than fresh water, so the cold brine water lowers the slab temperature to the flash-freezing point, without the brine water freezing.)
Water is then pumped onto the slab in layers of about 2 mm each. After two of these layers freeze, white paint is sprayed over the ice surface in three more layers. The paint-and-water mixture freezes immediately, creating a blank canvas of ice on which all the markings such as the red lines, blue lines, face-off circles, goal lines, goal creases, the team's logo, and the like are painted. Not to worry—the paint is non-toxic, so when the ice is allowed to melt, it poses no environmental hazards.
Finally, freezing water is pumped over the ice till it reaches the desired 1-inch rink thickness and is hard enough to skate on.
Enter the Resurfacer
The ice hockey playing surface must be finished and prepared for play. For help with that job, rink technicians the world over can thank Frank Zamboni of California for the machine he built in the 1940s that now bears his name: the Zamboni, a commercial ice resurfacer machine; another is made by Olympia.
Before the invention of the Zamboni and other ice-resurfacing machines, preparing the ice was intensive, hand labor; it took a crew more than an hour to prepare, repair or refinish the surface for play. Refrigeration of the concrete slab has accelerated the ice-making process, too, so that it can be done in about 90 minutes, depending on the refrigeration technology used and how many are working on the rink preparation.
How Does a Zamboni Work?
A Zamboni resurfacer scrapes the ice surface clean using sharp blades underneath the machine carriage and sprays down warm water to take out the pits and gouges caused by ice skate blades, while flushing away any dirt.
That new layer of warm water freezes to form a smooth surface—or a resurface, in most cases. The job of resurfacing an NHL rink takes about six minutes, more or less, with two resurfacing machines working the ice, as required by the NHL. Resurfacing usually happens before the game, after warmups, between periods, and after a hockey game.
Zambonis range in price from about $10,000 for a tractor-pulled model to the low six figures for a fully-functional and self-contained machine. They are made in Paramount, California, where Frank Zamboni invented the machine, and Brantford, Ontario, outside of Toronto and coincidentally the boyhood home of hockey's "Great One," superstar Wayne Gretzky.
How to Make an Outside Ice Hockey Rink
Outside rink-builders use a heavy plastic liner (such as a pool liner) over a snow base or on the cold ground surface, on which the ice is allowed to form. Try to make this base as level as possible, for smooth skating and so the puck travels in a straight line.
A three- to six-inch lip border holds in the water; you can build up a lip by mounding snow under the liner edge or use PVC pipe for a border or build boards out of plywood and stake them into the ground before it freezes.
Once you have the base in place, pump water on top and let nature do the freezing, as long as you expect temperatures to be 20 degrees or lower for three consecutive days and nights.
How is Arena Ice
Nowadays in professional sports, arenas must be changed over from ice surfaces to hardcourt for basketball games or other uses like stadium concerts, a process that can take a couple hours to a day, depending on the number in the work crew.
In these cases, the side boards and Plexiglass safety barriers are removed, hauled away and insulated plywood sheets are placed over the ice. Presto change-o—pro teams can go from hockey face-off to basketball tip off or jump ball in a matter of hours, when the schedule calls for it.