Spec Check: Walk-ins

Walk-ins are extremely versatile pieces of foodservice equipment that are typically configured to meet operators' specific needs for refrigerated storage.

When purchasing a walk-in unit, timing can be critical because most orders require certain lead times. Also, on most projects, walk-ins require early installation. Proper installation is important too because it prevents air leakage, which can produce ice in walk-in freezers and moisture in walk-in refrigerators.

With average temperatures ranging between 34 and 38 degrees F for coolers and -10 degrees F for freezers, walk-ins can be as small as three feet by five feet or as large as 120 feet by 505 feet. The size of the unit that a foodservice operation needs will depend on how it uses the walk-in and on the restaurant's sales volume. For example, will the unit mainly store meat and other proteins, or will produce share the refrigerated space? Some operations strictly utilize smaller walk-in units as beer or keg coolers.

Not only do operators need to determine how much product they intend to store, they also need to consider how often staff will stock the walk-in, and that can depend on the number of food deliveries.

Maximizing the use of storage space represents another factor for operators to consider, and a number of variables can impact this effort. Although it may be tempting to specify a walk-in with more height (as opposed to a unit with a larger footprint) in an effort to conserve floor space, operators need to consider accessibility and safety issues. Also, if the higher areas are not fully utilized, the unit ultimately wastes money by cooling unusable space. Panel insulation also can impact storage capacity. For example, it takes eight inches of polystyrene to equal the insulation value of four inches of polyurethane.

Because walk-ins can store product that is already at desired temperatures and can also reduce temperatures of food items, the specific intended usage must be considered when specifying these units. This will impact the type and size of the refrigeration system. Items with a higher density and temperature may take longer to pull down to correct temperatures. In this case, a larger refrigeration system may be necessary to compensate.

Most walk-in refrigeration systems operate within a three- to four-degree window, and the amount of product stored will determine how often the refrigeration system runs. Pulling down the temperature of food items puts more stress on the refrigeration system and changes the unit's operation. Hot product also creates excessive steam in cold environments, producing moisture and changing the dynamics inside the walk-in.

The type of refrigeration system needed will depend on the walk-in's temperature requirements. For instance, operators can specify refrigeration systems for beer coolers to hold their frothy products at 31 to 32 degrees, which is close to freezing but produces the least amount of foam and the best yield out of a keg. Bakeries utilizing walk-ins may require low-velocity coils so big air blasts don't dry out dough. High-moisture items, such as fruit, require different refrigeration systems than dough. If an operator uses the walk-in to store raw chicken, which creates excessive moisture in the air, coated evaporator coils might be necessary.

Foodservice operators should also consider location when specifying a walk-in. These units not only have large footprints but can also function both inside and outside of the facility. Placement will also help determine ideal unit size and materials. Units that require frequent access are best located by the work area in order to reduce staff travel back and forth.

Indoor and outdoor walk-ins are basically the same, with the exception of the roofing material. Regulations for outdoor walk-ins typically require the structure and roof to withstand winds in the 110 to 120 mph range. Snow loads feature separate requirements that depend on the region. In addition, foodservice operators can choose outdoor roof membranes that will help reroute water. Other considerations for outdoor walk-ins include rubber roofs, cold weather compressor kits and condenser rain hoods.

Operators can choose from a number of interior and exterior finishes and construction materials. Although material finishes don't affect a unit's performance, the construction can affect durability. Stucco Galvalume is a popular finish because its embossed pattern helps hide scratches, dents and blemishes that occur over time. Other options include smooth or stucco stainless steel, galvanized steel, and stucco or smooth aluminum. Operators seeking more visibility inside the walk-in can choose white interior finishes, which help brighten the space. Heavy-duty wainscoting material and bumper rails provide added protection against damage from carts and other heavy objects.

The weight and frequency of traffic will help determine what type of flooring the walk-in unit requires. The use of heavily loaded carts or big shelves may require a reinforced or structural floor. It's important to note that standard walk-in floor construction is not designed for cart traffic, as wheels can cause floor material to come apart over time.

A common mistake in specifying walk-ins is installing the incorrect thickness of tile or floor overlays; these improper floor heights can cause problems with the overall construction. Higher-volume operations utilizing kegs should consider an aluminum diamond tread on the floors and portions of the wall. This heavier gauge will help reduce the risk of punctures, dents and damage. Walk-ins with floor panels generally require interior or exterior floor ramps for easier access.

Typically, freezers feature floors or insulated pads made of concrete. An operator installing walk-ins in a second-floor location, for example, as opposed to the ground floor, will need to make sure the cold air from the unit is not drawn through the floor into the first floor's ceiling.

Walk-in doors generally measure 26-, 30- or 36-inches wide, but operators can choose four- and five-foot hinged or sliding doors, too. If staff will use rolling racks or carts to transport product in and out of the walk-in, 30- or 36-inch doors tend to be the most suitable specification. If staff will use pallet jacks to bring product into and out of the space, five-foot doors will be needed. One common mistake operators make is specifying incorrect door swings, which can compromise a walk-in's storage capacity.

Doors are also an important consideration, as they receive abuse from day-to-day traffic. If a walk-in's door will be frequently opened and closed, a heavy-duty one may be necessary. Operations utilizing rolling carts, kegs and other heavier items that can damage walk-in doors can install kick plates, which help minimize dents. For high-volume operations, automatic closing devices like cam-lift hinges and positive door closers ensure that doors aren't accidently left open.

If it's necessary to see what's inside the walk-in or if it is being utilized as a merchandiser in a retail setting, glass doors should be considered. Strip curtains are another option and can help keep out unwanted outside air.

Walk-ins use either single- or three-phase electrical power, but larger units may require dedicated circuits and more amps.

Walk-in Options

There's an almost unlimited range of options available to customize walk-ins, which vary depending on the manufacturer. Here is a listing of popular add-ons.

  • Interior and exterior ramps
  • LED lighting
  • Electronic door-open/temperature alarms
  • View windows
  • Kick plates for doors and panels
  • Pressure-relief ports
  • Shelving
  • Heavy-duty or structural flooring
  • Vinyl-strip doors
  • Full-view glass doors
  • Anti-sweat modules for glass-door walk-ins
  • Rail-type wall protectors
  • Membrane and Galvalume roof packages
  • Electronic control systems
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