Temporary Grain Storage (continued)

AE-84 (Revised), August 1998

Separate Bin Walls

Steel bin rings

Round bin rings can be conveniently and economically erected to provide emergency grain storage. Two or three steel rings from round grain bins can be set on an existing floor. Anchor the bin rings as recommended by the manufacturer.

Round plywood bins

Plywood bins, 4 or 8 feet deep and 10- 37 feet in diameter, can be made by nailing plywood sheets and 2 x 4 nailers into a long strip and bending to form a circle (Figure 3). Fasteners and nails are critical to keep the bin from bursting.

Figure 3. Round plywood bin. (26KB b&w Image)

Use at least 3/8" plywood with at least a 24/0 span rating. The recommended method for fastening plywood sheets together is shown in Figure 4 and Table 6. Usually it is a joint that fails, not the plywood sheet itself. If in doubt about plywood strength, wrap the bin with cable, hoops or at least No. 9 wire.

Figure 4. Nailing schedule for round plywood bins. (20KB b&w Image)

Movable wood grain walls

They are built of plywood and lumber, are self-supporting, and can convert all or part of a building to grain storage.

Figure 5. Details of self-supporting portable wall. (17KB b&w Image)

Figure 6. Other grain walls that have been used. (24KB b&w Image)

For structural adequacy, follow these specs:

1. Lumber grade is No. 2 or equivalent Douglas Fir structural light framing, or joists and planks. Compare the allowable bending stress of the wood.
2. Place the 4 inch edge of the wale next to the stud.
3. Select plywood with a span rating of 42/20 Ext. Or, use 5/8 CDX plywood if of Douglas Fir, Southern Pine, or other group 1 or 2 species. Plywood of Group 3, 4, or 5 species must be 3/4 inch thick.
4. Place face grain of plywood across the supports.
5. Wale supports carry a heavy vertical load from the tie rods. Glue wale supports to studs with a construction adhesive; add two 3/8 inch lag bolts/stud.
6. Ties are 32 inches apart and are sized for heavy wheat. Steel cable or strand, or threaded rods, may be used instead of strap ties. Install thimbles in cable ends. Select turnbuckles, and cable if used, for adequate strength.

Silos

Concrete silos generally need to be reinforced and weather proofed to hold grain. Table 8 shows suggested hoop spacing for concrete stave silos. Check construction recommendations with silo manufacturer as newer silos use stronger materials. A weather tight roof and chute plus foundation drainage are essential.

An aeration system should be installed to cool the grain and prevent moisture migration. Provide about 1 square foot of vent in the roof for each 1,000 cfm of airflow. Conventional silage blowers should not be used to fill the silo because they cause too much grain damage. Silos must be unloaded from the center to aviod structural damage.

Commercially Available Temporary Grain Storage

Units are available through some farm supply stores and grain equipment suppliers. These units vary in construction. Polyethylene sheeting, reinforced-fiber sheeting, wire mesh, wood or metal panels for holding the grain are usually used. Repairs, freight, erection, and site costs need to be included when getting estimates. Some units are reusable.

Various forms of plastic sheeting are available to be used with grain piled on the ground to prevent rain and wind loss. Usually the covering will need repair or replacement after one season of use. Rodents, birds, chewing insects, sharp hooves or claws, gunshot, etc. can cause leak problems. Some suppliers have a mesh or fishnet type of fabric draped over the plastic covering to help hold the plastic sheeting in place. (Suppliers include Raven Industries, Sioux Falls, SD 605/336-2750 and LeMar Industries Corp., Des Moines, IA 515/266-7264.)

Figure 7. Sidewalls on this type of storage are reinforced with wire mesh and used to support walls 4 feet to 6 feet high. Covers can be reinforced plastic sheeting. Bins are filled with augers. (Suppliers of this type include: B & W Mfg Co., Columbus, NE 402/564-3032 and Thompsons, Melita, Manitoba 204/522-3241.) (33KB b&w Photo)

Figure 8. Round tubes of plastic about 8 feet in diameter have been developed for silage storage. Limited experience with these for dry grain storage has been satisfactory. Consult with manufacturers for their up-to-date experience. Special filling equipment or technique will be needed. (34KB b&w Photo)

Suppliers include:

Ag-Bag International, Warrington, OR — (800) 334-7432Kelly Ryan Equipment Co., Blaire, NB — (402) 426-2151
Sioux Automation Center, Sioux Center, IA — (712) 722-1488
Versa Corporation, Austoria, OR — (800) 837-7288

Bins Formed Using Bales

Large round bales can be used to form a circular bin wall. With a 5-foot grain wall depth, there is a force of about 115 pounds of force on each foot at the bottom pushing the bale outward, so they will likely need to be restrained by wrapping with a cable. Plastic along the inside of the bales is recommended to help keep grain from leaking out and to prevent water from entering. Peak the grain so it flows onto the top of the bales to form a smooth top. The plastic or tarp should drape over the top of the bales, so the water flows to the outside of the bales.

Outside Piles

If you must pile the grain outside on the ground, drainage is crucial. The pile should be on high ground and the earth crowned under the pile. Place plastic (6 mil) on the ground to keep ground moisture from wetting the grain.

Plastic or tarp covering the pile will reduce wetting by rain and snow and minimize damage by wind and birds. The top surface should be smooth to aid in drainage. The cover should carry the water away from the piled grain to prevent wetting the grain. Condensation under the plastic may cause problems unless it is controlled with aeration. Move airflow under the plastic to carry the moisture away. Drainage tile under the plastic has been used as an air intake duct when the aeration fan exhausts air from the bottom of the pile. The ability to cool the grain by aeration improves the storability of the grain. Run the pile north and south to allow the sun to dry off the sloping sides.

Erect a fence to keep animals off the pile. Nearby trees aid wind protection but can also be a home for birds and might result in snow drifting on the pile.

Storage Capacity

The quantity of grain in piles can be estimated using Table 9. Formulas for calculating the volume of common shapes are shown in Figure 9.

Average filling angles for some types of grain are shown in Table 10.

Figure 9. Areas and volumes. MWP-13, 1988. 1.244 ft³/bu. (11KB b&w Image)

Management of Temporary Grain Storage is Extremely Important

Check frequently for heating, sweating, moisture accumulation and general condition of grain and the bin. Exposed grain pile tops get trampled on, windblown and damaged by moisture. Temporary plastic coverings are loosened by temperature changes, changing winds, ice, animals and vandalism. Walls can suddenly burst open from extra pressure caused by wetted grain. Hoops, bands or other types of wall reinforcement can fail.

Cooling the grain with aeration is vital for proper storage. Cool temperatures minimize mold growth, limit moisture migration, and control insects. An aeration airflow rate of about 1/10 to 1/5 cubic feet per minute per bushel is recommended for dry grain.

Operate aeration fans until piled grain temperatures are uniform and equal to the average outdoor temperature or near freezing.

Temporary grain storage is for less than 6 months. Grain should be moved to permanent storage before warm spring weather that can aggravate the poorer, temporary storage conditions. Stored grain is the result of a season's work — it deserves as much attention in storage as it took to produce it in the first place.

The mention of specific companies here is not an endorsement.
This is done for illustrative purposes and reader convenience.
Omissions were not intended and additional information is welcome.

[ BACK ]

[ Introduction ] [ Using Existing Buildings ]
[ Separate Bin Walls ] [ Silos ] [ Commercially Available Temporary Grain Storage ]
[ Bins Formed Using Bales ] [ Outside Piles ] [ Storage Capacity ]
[ Management of Temporary Grain Storage is Extremely Important ]

AE-84 (Revised), August 1998