SpecTopics: “Cool” Facts about Cold Storage and Refrigerated Facilities

Refrigerated facilities are any buildings or sections of a building that achieve controlled storage conditions using refrigeration. Two basic storage facilities are:

1. Coolers that protect commodities at temperatures usually above 32°F.
2. Low-temperature rooms (freezers) operate under 32°F to prevent spoilage or to maintain or extend product life.

The conditions within a closed refrigerated chamber must be maintained to preserve the stored product. Specific items for consideration include:

• Uniform temperatures
• Effective relative humidity
• Effect of air movement on employees
• Controlled ventilation, if necessary
• Expected duration of storage

In the United States, the U.S. Public Health Service Food and Drug Administration developed the Food Code (Began 1997, current 2022), which consists of model requirements for safeguarding public health and ensuring that food is unadulterated. The code is a guide for establishing standards for all phases of handling refrigerated foods. It treats receiving, handling, storing, and transporting refrigerated foods and calls for sanitary as well as temperature requirements. These standards must be recognized in the design and operation of refrigerated storage facilities.

Regulations of the Occupational Safety and Health Administration (OSHA), Environmental Protection Agency (EPA), the U.S. Department of Agriculture (USDA), and other standards must also be incorporated in warehouse facility and procedures.

The five categories for the classification of refrigerated storage for preservation of food quality are:

• Controlled atmosphere for long-term storage of fruits and vegetables
• Coolers at temperatures of 32°F and above
• High-temperature freezers at 27 to 28°F
• Low-temperature storage rooms for general frozen products, usually maintained at -10 to -20°F
• Low-temperature storages at -10 to -20°F, with a surplus of refrigeration for freezing products received at above 0°F

Designing a facility with these standards involves also establishing your specific needs for your facility. Which will include your food storage requirements:

• Types of storage within the same facility (i.e. coolers, chillers, freezers, etc.)
• Size or quantities of food items as they are packaged or palletized
• Stacking and storage abilities for packaged or palletized food
• Number and location of shipping and receiving docks
• Utility spaces and adjacencies

A well-planned facility will need to minimize energy losses from moving products from one controlled environment to another through functional spaces.

However, planning the movement, storage and handling of food products is not the only concern for a refrigerated facility. The construction of the building and its envelope are also very important, especially for thermal and moisture movement.

Construction Methods
Cold storage, more than most construction, requires correct design, quality materials, good workmanship, and close supervision. Close cooperation between the general contractor, roofing subcontractor, insulation subcontractor, and other applicators increases the likelihood of a successful installation.

Enclosure construction methods can be classified as:

1. Insulated structural panel
2. Mechanically applied insulation
3. Adhesive or spray-applied foam systems

These construction techniques seal the insulation within an air and moisture tight envelope that must not be interrupted by major structural components.

Three methods are used to achieve an uninterrupted vapor retarder/insulation envelope:

1. The first and simplest is total encapsulation of the structural system by an exterior vapor retarder/insulation system under the floor, on the outside of the walls, and over the roof deck.
2. The second method is an entirely interior system in which the vapor retarder envelope is placed within the room and insulation is added to the walls, floors, and suspended ceiling. As with an exterior system, the moisture barrier is best applied to the outside of the enclosures. This technique is used where walls and ceilings must be washed, where an existing structure is converted to refrigerated space, or for smaller rooms that are located within large coolers or unrefrigerated facilities or are part of a food-processing facility.
3. The third method is interior-exterior construction, which involves an exterior curtain wall of masonry or similar material tied to an interior structural system. Adequate space allows the vapor retarder/insulation system to turn up over a roof deck and be incorporated into a roofing system, which serves as the vapor retarder. This construction method is a viable alternative, although it allows more interruptions in the vapor retarder than the exterior system.

The total exterior vapor retarder system is ideal due to having the fewest penetrations and thereby the lowest cost. Areas of widely varying temperatures should be divided into separate envelopes to retard heat and moisture flow between them.

Designing cold storage facilities involves a clear program for spaces, an understanding of the storage/handling needs for various food/temperature types and a well-designed building envelope.

To learn more about types of insulation, vapor control materials and other considerations, consult Carlisle Construction Materials’ guide – “The Cool Facts: A Guide to Refrigerated Facility Design, Operation and Maintenance”.  

For cold storage assembly specifications, transition details, and technical support, click here.