Foamed-in-place urethane, laminated urethane, polystyrene, 4″, 5″ or 6″ panels, many construction differences.
Many walk-ins are similar. Once erected they look a lot alike. Almost all school applications use 4″, polyurethane insulated walk-ins, either foamed-in-place or laminated. These are slightly more expensive than the other types, but may produce energy savings and be more durable. When specifying, look into the manufacturers door construction to be sure it will withstand normal school usage. Several manufacturers reinforce the doors to prevent sagging and warping of the doors over time. Walk-in boxes may be ordered as freezers or coolers, either independent of each other, or as “combination” units, where the two units share a common wall.
Galvanized panels are more subject to corrosion and discoloration than aluminum panels. Units that are to be installed outside must have a covering over the roof, usually made of a polyvinyl material. This is necessary to prevent water seepage into the box. Walk-ins come in all shapes and sizes and heights. Be sure to specify at least 7’6″ high. This is an overall height. If conditions allow, an 8’6″ height is better. The interior will be 8″ smaller allowing for the floor and ceiling. Also, the refrigeration coils will hang down into the box, potentially interfering with shelving. There are significant differences in refrigeration. They can either be mounted inside or outside. Usually, they are mounted outside. This removes the noise and heat from the kitchen. Also, there are “hermetic” and “semi-hermetic” types. Hermetic is usually less expensive but may be more costly to service.
You must know the overall size that the walk-in must be: length, width and height. You must know the voltage and phase of the electricity available. A drain line must be nearby to drain the water from the unit during the defrost cycle, although this may be done electrically. The floor surface should be flat and level. If this is to be a replacement box, the supplier must know if the existing box is on the floor or in a pit.
Several things must go right for a proper walk-in installation. One of the most important is the installer. If the box is not erected properly, you will be dissatisfied with it FOREVER. Be sure to bid these units to qualified dealers that have extensive walk-in construction experience. ALWAYS put into your specs that “it is the responsibility of the successful bidder to take final measurements, on-site before ordering”. It is a good idea to require the bidders to inspect the area BEFORE bidding, to insure that no changes will be required after bidding.
There are over 100 manufacturers of walk-in equipment. When deciding on a prime spec or approved alternates, ask the dealer salesperson or the rep for references of their equipment in school foodservice applications. Do not be misled by “they are all alike”. They are not.
There are also lots of available options, like ramps, windows in the doors, white prepainted ceilings for better light diffusion inside the box, fluorescent lights, kick plates on the doors to minimize damage from carts, digital alarms and more. Some of these make the box much more user friendly. Be sure of your options before specifying.