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Rink Ice-Out Melt and Floor Warm-Up Calculator

Ice-out looks like a day of doing nothing and it is not. The sheet in the default form weighs a hundred and one thousand pounds and holds fifteen million Btu of melting to be done, and once it is water it has to leave through a drain that takes it at a fixed rate. Then the floor has to come up, and the floor has a speed limit that somebody else set. This works all three so the calendar is not a guess.

Only read when the selector above is set to a measured area.
The average off your last survey, not the target. Sheets finish a season thicker than they started.
Some crews saw the sheet into blocks and take it out on a loader rather than melting it. Whatever you haul is heat and drain time you do not pay for.
From your own probe. Legitimately below freezing, and the page expects that.
From the property table you work from, or a core you cut and weighed.
From the property table you work from.
From the property table you work from. It is most of the answer.
Whatever you are actually using and can account for — building heat, air handling, blowers, open doors on a warm day. Bringing the floor up with the refrigeration plant is the refrigeration contractor work and this page gives no procedure for it.
Measured, not the pipe size. A floor drain that has been under ice all season rarely runs at its rated figure on day one.
From the floor drawings.
From the mix design or the floor documents.
From the property table or the floor documents.
From the floor sensors if you have them. Negative and below-freezing values are legitimate here.
The limit your engineer or your floor contractor sets for this floor. This page has no limit of its own and does not know whether yours is right.
Rink Ice-Out Melt Calculator — Water, Heat and DrainBuildFigure

The three jobs, in order

Take 1.40 in of ice over 16,327 square feet. That is 1,905 cubic feet, and at 57.2 lb per cubic foot it weighs 108,956 pounds. Warming it from 20 °F to freezing takes 0.49 x 12 = 5.9 Btu a pound, or 640,659 Btu. Melting it takes 144 Btu a pound, or 15.7 million. The melting is 96 per cent of the heat and none of it moves a thermometer.

At 400,000 Btu/h that is 40.8 hours of melting. The same ice becomes 13,056 gallons of water, and a drain measured at 40 gallons a minute takes 5.4 hours to swallow it. The two run together, so the sheet is clear after the longer one — 40.8 hours here, and the drain is not the problem.

The floor is the long pole

A 5 in slab over that area is 6,803 cubic feet at 145 lb per cubic foot, which is 986,000 pounds. At 0.21 Btu per pound per degree it takes 207,000 Btu to move the whole floor one degree. Bringing it from 22 °F to 55 °F is 33 degrees and 6.8 million Btu, which at 400,000 Btu/h is 17 hours of heat — but a 2 °F per hour ramp limit puts 16.5 hours on it, so the two are nearly matched and the heat governs by half an hour. Change the ramp to 1 °F per hour and it doubles to 33 hours and the limit takes over.

Why anyone hauls ice out

Sawing the sheet into blocks and driving them out on a loader skips the melting entirely, and the melting is the expensive part. The trade is labour, machinery on the floor and somewhere to put a hundred thousand pounds of ice. The haul field in the form lets you split it: haul half and both the heat and the drain time halve with it.

What this cannot know

It cannot tell you how fast your floor may be warmed. That is a number from the people who designed and built it, and the field exists to hold theirs. It has no view on how you put heat into the building, and it deliberately says nothing about doing any of it with the refrigeration plant, which is the refrigeration contractor's work in a room this page has no business describing.

Questions people ask

Why is the total not just melt time plus drain time?

Because water starts leaving as soon as ice starts melting. The two overlap, so the sheet is clear when the slower of the two finishes, not when both have run end to end. The page reports each and then takes the longer.

Can I speed it up by warming the floor at the same time?

In practice ice-out and floor warm-up run into one another, and how much they overlap depends on the building. The page keeps them separate and adds them, which is the conservative reading. If your floor is genuinely coming up while the last of the ice is going, your calendar will beat this number.

What ramp limit should I use?

Whatever your engineer or floor contractor specifies for your floor. There is no general figure and this page will not offer one. If nobody has given you a limit, ask for it before you start rather than picking one.

Is hauling the ice out cheaper than melting it?

It depends entirely on your labour, your equipment and where the ice goes, none of which this page knows. What it can tell you is exactly how much heat and drain time hauling saves, which is the input to that decision rather than the answer to it.

Why does 1.4 in of ice make only 13,000 gallons?

Because ice is lighter than water. The 1,905 cubic feet of ice weighs 108,956 pounds, and that weight of water is only 1,746 cubic feet. Ice always gives back less water volume than it occupied, which is the same eight per cent that made the sheet deeper than the floods that built it.

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