Cold stores are not only the most costly to build and operate they also pose special handling and health and safety issues. Energy is the big cost bug bear, typically accounting for up to 25% of running costs, and so that places strong emphasis on choosing the correct mix of racking types to strike the right balance between storage density and selectivity at the design stage.
Mobile racking, which allows forklift drivers to open a selected aisle without dismounting, is a popular choice owing to its high storage density, and while there is an access time delay handling rates in certain circumstances can be moderately high. Admittedly, it is almost three times more costly than conventional APR (adjustable pallet racking) but the latter rarely provides the lowest operating cost in cold stores and we much remember the impact that spacewasting APR has on high initial building costs. An alternative to high density mobile racking is the much cheaper drive in/drive through racking but drawbacks here are higher accident rates and poor selectivity. Other, static dense racking solutions include doubledeep, flow-through racking, pushback and satellite storage. To help buyers through the complexity of racking choice the UniCarriers Logistics Analyser uses simulation to design and calculate the best balance between density and selectivity.
It should go without saying that cold stores have one potentially huge risk that ambient stores don’t have. This is defective cold storage and poor management.
Nevertheless, disasters occur. In the first decade of this century a certain UK 3PL lost £3 million of frozen peas through a meltdown. In other countries, like India, losses from cold storage of potatoes could be as high as 38- 45%, mainly due to poor air circulation and resultant wide variation in spatial distribution of temperatures and humidity. It is vital, therefore, that every precaution is taken to prevent power loss.
The health of the workforce inside the cold store should be given high priority. Working in low temperatures can be uncomfortable and lead to different illnesses that may affect performance. Accepted practice calls for cold store workers to take a 15-minute break every hour outside the store. Given that would pose operating difficulties for forklifts, where the recommendation is that they be kept inside the cold store, and that batteries should be brought to them, it makes sense to equip the forklifts with heated cabs. However, if frequent ingress and egress are unavoidable efforts should be made to make stays inside as short as possible and the stays outside as long as possible so that the truck temperature never falls below 0 deg C.
Careful consideration should be given to the choice of forklift operations inside the cold store. Reach trucks were the favoured choice with heated cabs but owing to their requirement for a minimum aisle width of 2.6 mt such a choice has adverse implications for high initial building costs and energy costs, especially if APR is used throughout. A more spaceefficient, cab-equipped articulated forklift will work in aisles down to 1.6 mt wide and these are now eating into reach truck cold store market share.
Keeping cold temperatures constant can be helped with proper attention to doors. When conventional sliding doors open, warm air rushes in and denser air escapes, causing ice build-up on the floor and higher power bills. Fast-acting, insulated roller doors would be a better choice but another solution relies on using conveyor tunnels like an airlock. Tests show that energy savings justify the cost of this approach.
Since they generate heat inside cold stores, lighting should not be overlooked. LED lights would be a good choice because they generate less heat and so less cooling is needed. Their longevity and minimum maintenance are two more assets.