What is a Boom and How is it Used?
The function of a boom is to stop floating product while allowing water to flow. A boom has several parts, which are shown in the two diagrams below.
Floatation can be logs, timbers, Styrofoam floats, air-inflated fire hose or almost anything that floats.
· Freeboard is the part of the boom that is exposed above the surface of the water. The amount of freeboard will depend on the buoyancy of the flotation. To be effective, boom must have enough freeboard to keep contained product from washing over the boom. Wind will act on the freeboard to move and stress the boom.
· The skirt of a boom is the amount the boom extends below the water. The skirt acts to prevent contained product from washing under the boom. The deeper the skirt, the more effective it is. Deeper skirts increase the water current loading on the boom.
· The weight is what keeps the boom vertical in the water. Lead weights, chain in the bottom of the boom, or the mass of the floatation can all act as weight.
Boom performance is based on shape and angle of placement relative to the current. Cylindrical booms remain straighter in the water and can handle stronger currents, while flat booms are easier to transport and store. Boom must be set at a sharp enough angle to handle the present current and anticipated changes. Experimentation with boom angle may be necessary to prevent loss of oil beneath the boom.
Boom can be tied off to the shore or anchored to floating objects on the water. It is best not to tie boom directly to an anchor line, because the current will pull the boom under water. Anchor line must be of sufficient length to handle the current and tidal influence (usually 5 to 10 times the water depth). A sufficient number of anchors of an appropriate weight and type must be used.
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Boom can be placed in many configurations depending on the situation. Containment boom extends across a waterbody such as a river or brook, and is limited to slow waters. Collection boom is used to divert product to a convenient collection point. Access to the collection point must be considered. Deflection boom is used to direct product around a critical area.
This figure shows several methods of booming.
In an emergency, containment boom can be fabricated from almost anything that floats at least partially submerged and is resistant to oil or the floating chemical being contained. For example, fire hose can be used as a boom by capping the ends and filling the hose with air. It is helpful if at least one of the caps has a fitting for an air hose. Containment booming is ineffective in currents over 1 knot; boom deployed in rivers must be staggered to divert oil to a recovery point.
