Practical implications of working in freezer stores without proper protection
Why should the concept of “homostasis” be important to cold store managers? Homostasis is the human body’s optimum core body temperature which is 37.5 degrees Celsius. Since South African freezer stores are run at air temperatures of anything between minus 20 to 30 degrees C, it is important to know what effects such cold temperatures, including wind chill, have when a human’s core temperature is reduced below its optimum. The human heart, for example, tends to stop beating at a core temperature of around plus 20 degrees Celsius. Freezer store stock counts tend to become hopelessly inaccurate when core temperatures drop to 37Degeees C, only 0.5 of a degree below homostasis, and the incidence of forklift impacts will rise dramatically if drivers’ core temperatures drop by more than 1 degree C.
Forklift problems were one reason why I asked TCM forklifts to retrofit a heated cab to an existing reach truck at Freezerlink Cold Store in the early 1990’s. Drivers could be productive in the freezer stores for much longer, rack and product damage was significantly reduced as were stock discrepancies.
But heated cabs, which are now almost standard, don’t come cheap, and can add upwards of R300 000.00 to the cost of a vertical lift reach truck. As capital budgets are tight, Barpro has noticed a developing trend back to un-cabbed machines.
But volume throughputs made possible by heated cabs are now the norm, and drivers with no cabs are still expected to place and pick the same number of pallets per hour. As a result, they spend longer than they should in the freezer, core temperatures drop and damage to both racking and reach trucks tends to rise.
Ironically, it doesn’t help if a driver rigidly restricts his freezer time to 30 minutes before handing over to a second driver and warming up in the sun for the next half hour. This is because of something called “after drop.” when a driver emerges and starts to warm up, his blood supply, previously restricted from his arms and legs surges back. This can be a painful process, but the real problem is that the blood then returns colder to the heart and lungs, reducing core temperature. So after a 30 minute ‘’warm up’’ break, the driver’s core temperature has actually fallen, just as he goes back into the freezer. By the end of his shift, he is probably suffering from at least mild hypothermia unless wearing really good protective clothing.
Even Barpro’s European quality Delf freezer clothing is not a silver bullet here, as reach truck drivers suffer from 2 additional disadvantages. The act of driving doesn’t encourage the human body to create heat, in the same way as the moderate human activity required by say, stock picking. The driver’s sitting position also reduces blood circulation, so legs and feet get colder faster. We have advised several clients to consider special double thickness suits with a significant percentage of hollow fill fiber, as well as expensive boots with composite rather than steel toe protection, gloves and balaclavas. Incidentally, socks should be changed at least once a day as both hands and feet can perspire even in the cold, and damp cold feet are very uncomfortable.
In the longer term, even with the very best protective clothing, un-cabbed reach trucks will still need two drivers per shift. Apart from the reduced productivity, it can be very difficult, with two drivers per shift, to identify who misplaced pallets or hit the racking. In addition, on board computer terminals, essential for real- time warehouse management, are much more difficult to operate with open cabs. So, saving capital by removing heated cabs from reach trucks in modern freezer stores is probably not a good idea.