SILO

The silo is a structure which holds crops that were harvested at moisture contents of 50 to 65 percent and fermented. The crops most commonly ensiled in Georgia are corn and hybrid grasses. The entire plant is chopped into segments about 3/4 to 11/2 inches long and placed in the structure to ferment.

There are two basic categories of silos, trench and upright. Trench silos, also called bunker or pit silos, are oriented horizontally. Typically, they are dug into the side of a low hill, have a concrete floor and possibly concrete walls. The depth range from eight or ten feet and up. Silage is either dumped in from trucks or trailers or unloaded from forage boxes and then packed with a tractor or crawler for good fermentation and storage. The top is sealed by covering with plastic held in place by tires and sawdust After removing covering, the silage is removed with a loader for feeding. Some farmers without suitable equipment may still load the silage onto trailers by hand for feeding. The main dangers with these silos are the danger of a vehicle falling in, overturning the tractor used to pack the silage and collapse of the face during feeding.

Upright, or tower, silos are cylindrical structures usually 20 to 30 feet in diameter and up to 80 feet tall. The most common type of upright silo used in Georgia is built of concrete, has doors along one side enclosed by a metal chute and is rather open around the roof The forage is unloaded from the forage box to be blown up and into the silo by a large, PTO driven blower. Unloading is accomplished by a machine that removes the top layer of the silage and blows it out through the doors where it falls down the outside chute into a wagon or onto a conveyor for feedmg. There are several dangers with upright silos, including falls, electrocution, highly toxic gases and entanglement in the unloading and feeding equipment.

Oxygen-limiting silos, sometimes called airtight or sealed silos, are of metal construction and are intended to provide an oxygen-free environment inside. The forage is placed in the silo by the blower, but the unloader is located beneath the silage. Silage sloughs off the bottom of the column of feed and is removed from the structure by a conveyor. There is usually little need to enter an oxygenAimiting silo, except to service the unloader. However, there is the danger of falls on the outside and entrapment while working on the unloader.

During the fermentation period, nitrogen dioxide is released along with several less dangerous gases. Nitrogen dioxide is a highly toxic gas which can kill a person with only one breath. It is heavier than air and may be present in dangerous levels in the Silo, the chute and low areas near the base of the silo. The gas has an irritating, bleachAike odor and can be seen as a brownish colored gas in high concentration. Addition-al clues to the presence of N02 include brownish stains on buildings and equipment and dead birds at the chute.

Injuries to Expect

Injuries may include poisoning by N02 and/or oxygen deficiency as well as lacerations and fractures from entanglement and falls.

Rescue Procedures

· Shut off power to all equipment, uniess the silage blower is needed for ventilation purposes. Lock out electrical power to the unloader and any conveyors at the silo.

· If entry into the silo is required, wear the SCBA until it has been verified that there is no N02 present and there is sufficient oxygen. If N02 is present, ventilate the silo by running the forage blower or keep the SCBA on at all times. An extra SCBA or an oxygen supply must be delivered for the patient.

· Provide immediate medical attention if a person is found lying on the surface of fresh silage. Even if N02 levels are not excessive, a patient lying on the surface of the fresh silage may be exposed to dangerous levels of the gas. Lift the patient off the surface and provide oxygen.

· Wear a lifeline and harness. Always have an extra person monitor the rescue from outside the silo. Two-way radios will be needed for effective communication.

· If the patient is entangled in the unloader, tools must be hoisted using tag lines dropped down the chute or from the top of the silo. Reversing of the machine or partial disassembly may be required to free the patient.

· Secure the patient in a litter, backboard or body sling as appropriate. In most cases it will not be possible to remove the patient through the doors and to be lowered down the chute. Most likely, it will be necessary to lift the patient over the top of the silo to be lowered to the ground.

For over-the-top rescues, securely lash a sturdy ladder to the fixed outside ladder or the hands which hold the silo together. Ru the rope through a pulley or snatch block rigged to the top of the ladder. Drop one end of the rope to the rescuers inside and the other end to the ground.

Rig a second pulley or snatch block at the bottom of the silo directly under the ladder that is lashed to the top. Run the rope through this pulley and to members of the rescue team on the ground.

If the opening at the top is not large enough, enlarge it by cutting away the sheet metal or cut a new opening.

Pull the patient from the silo. The rescuer at the top can maneuver the backboard through the opening and can coordinate the rescue operation from that vantage point.

Tag lines attached to the back board or litter can be used to keep the patient from swinging or being blown about during the descent.