Global Steel, Inc.

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Global Steel, Inc.
1435 N. Cascade Ave
Colorado Springs, CO 80907
Phone (719)634-1300
FAX (719)634-0366
globalsteel@aol.com

Potato Storage

The Global Steel Potato Storage facility consists of an arched standing seam metal building, concrete foundation, urethane foam insulation, and a CPU controlled air system.  The standing seam arched building is comprised of a series of metal arches, each formed into a continuous piece of metal and placed from ground to ground, thus eliminating lap seams in the metal arches.  Additionally, the use of  the standing seam eliminates the need for bolts.  This construction makes it virtually impossible for the arched building to develop water leaks. Another benefit the standing seam arched building offers results from the building's unique shape.  Since the arch shape closely matches the angle of repose of the potato pile in storage, side wall pressure on the building is reduced.

Concrete is used both in the foundation and in the grouting of the building.  Global Steel places a small amount of extra masonry sand in the concrete for easy finish.  Since the end of the arched panels are grouted into the final pour of concrete, it is necessary to have a good "cream" on the surface to produce a good seal.  This method provides just that seal.

Urethane foam insulation in the United States is rated at 7r per inch.  Urethane foam, a closed cell structure, is a two part petroleum product that mixes at the tip of the applicating gun.  It then expands 32-1 and cures within approximately one minute.  Once cured, the urethane foam is inert.   In these storage facilities, Global Steel uses a Class A urethane foam with a flame spread of 25 and a 2 lb. density.

The CPU controlled Air System is a state of the art atmospheric control system.  This feature is critical to the potato storage unit the system regulates the temperature and humidity inside the storage facility.  However, optimum performance of the ventilation equipment is enhanced by quality storage management.  If the storage unit is managed properly, potato temperatures should vary less than one degree from the top to the bottom of the potato pile.  Additionally, a high relative humidity is achieved through the use of humidifiers. The high humidity aids in minimizing potato shrinkage throughout the duration of the storage season.  Some of Global Steel's customers have indicated that they have incurred less than three percent shrinkage during a storage season.  These impressive results relate to the  proper storage methods implemented in conjunction with the use of the CPU driven control panel.

Proper management of the storage begins when the potatoes are placed in a pile within the storage unit and go through a 10-day to two week suberization.  After the potato pile has had time to stabilize and heal, the temperature is dropped approximately one degree at a time until the desired storage temperature is realized.  The temperature is then maintained at this level throughout the storage season.  During the very cold months of winter, the volume of humidification used is reduced or the humidifiers are turned off to eliminate free moisture or condensation on the top of the potato storage ceiling and  potato pile.  The volume of water placed through the humidifiers is related to the temperature variations between the outside and inside of the storage.  While it is not uncommon to see beads of moisture on the ceiling of the storage facility, if the humidity becomes too high this moisture begins to form droplets and puts “free moisture” onto the potato pile, which may begin breakdown in the pile.  A well managed, controlled atmosphere commodity storage will eliminate the presence of "free moisture" which begins breakdown in the pile.  The Global Steel Potato Storage will maintain the quality of the potato by providing adequate air movement and high humidity in an airtight building.

Storage periods of up to 8-9 months are not unrealistic with the use of the CPU air system and proper management.  Storage time can be lengthened even further by placing ice in the air plenum near the end of the storage season.  It is imperative that the potato pile not be allowed to rise in temperature during this time.  Although the ice will not lower the temperature of the potato pile, it will assist in maintaining the temperature of the potato pile to achieve an even longer storage period.  Additionally, some potato storages utilize mechanical refrigeration units to lengthen the storage season.

The basic potato storage bay , which measures 60 ft. wide by 160 ft. long, is attached to a fan house or mixing chamber.  Return air or fresh air enters the mixing chanber and is redistributed through the air plenum.  The air plenum consists of a series of lateral ducts running under the potato pile, delivering the humidified air through the potato pile at a metered rate.

The Global Steel Potato Storage is just one of the innovative products Global Steel offers using the Arch Machine Metal Building System.  Global Steel will not only construct the storage facility but also offers training on proper management of the building in conjunction with the CPU controlled air system.  Global Steel's expertise in this area has provided  it a competitive edge in the marketplace.