We have come across several incidents of frost heave recently in South African freezer stores.
So what is frost heave? It happens when water freezes under a cold store and pushes up the floor. There doesn’t have to be a lot of water and the temperature only needs to drop slightly below freezing point.
When water or moisture freezes it expands and the expansion has to go somewhere, which is up. As mobile racking requires a level floor, any frost heave is a major problem. I have seen freezer floors come up by almost 1 metre due to frost heave, and, the longer the problem is left, the worse it tends to get.
How do you prevent frost heave from happening?
Understand how your freezer store is designed to prevent frost heave and then make sure that these defences are working. Most freezer stores have heater mats. Know where the control panel is, make sure it is working, and check the temp under the heater mat on a regular basis.
If you use other methods like pumping warm glycol under the freezer floor, make sure that the glycol is flowing. UK freezer stores have flow indicators on each loop for this purpose.
If your store has air vents under the freezer floor, make sure these vents are not blocked. The 1 metre frost heave in the freezer store referred to earlier was caused when a new manager noticed that rats liked to use the under floor vent pipes, so, unaware of the dangers, he blocked the vents.
Remember, frost heave is very difficult to cure once the process has begun. And it doesn’t only happen in freezer stores. I have also witnessed an incident in a chill store……
Other things you can do to guard against frost heave
Get the electric heater mat supplier to check the mat’s performance on an annual basis.
Get a technician to take floor levels at the same time as he is doing the annual maintenance inspection. If this is done every year, you can quickly see any changes in floor level. If you do, don’t leave it but take action immediately.
Contributed by: James Cunningham, Managing Director, Barpro Storage SA
