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9665 S.W. TUALATIN-SHERWOOD ROAD PO BOX 100 TUALATIN OR 97068 PHONE: (503) 692-5460 FAX: (503) 692-1145

E-MAIL: sales@plasti-fab.comWEB: http://www.plasti-fab.com

COPOLYMER STOP LOGS

Stop logs were originally wooden planks that were set into a groove in a head wall, and stacked to vary the upstream water level. Today, most stop logs used in municipal and industrial projects are made of fiberglass, plastic, or a corrosion-resistant metal. Stop logs permit incremental changes in water level that are not possible using stop gates or slide gates. Plasti-Fab has been building stop logs for over 15 years. The Heavy Duty Copolymer Stop Log has a one-piece molded cover that totally encapsulates the internal structural steel matrix and has no seams, glued joints, or cut edges. Water and chemicals are completely sealed out. Plasti-Fab is the best choice, giving high quality log at a competitive price. Stop logs can vary in thickness from 1 inch to 6.5 inches or more, depending upon the width of the log and the expected head or water depth to be held back. Stop logs require individual handling, and for this reason are usually considered for lower use applications where they may remain in place indefinitely or where they can be installed briefly during annual maintenance. They do have some special advantages:

a. Stop logs require less lifting force than a large stop gate or slide gate.

b. They are less costly because an operator, stem, and associated hardware are not needed.

c. Stop logs are interchangeable. With careful design, a number of

openings can be built to share and optimize their use.

d. Stop logs can be designed to close off openings up to 20 feet wide.

e. Stop logs can range in height from 6 inches to 24 inches to more closely control water level. Common sizes will be 12 inches to 16 inches in height.

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Stop logs must be heavier than the buoyant force of the surrounding liquid or they will float. The weight of the stop log also provides the only seating force to seal between individual logs. This means all but the smallest logs will require some type of lifting device to remove them from the guide. Smaller logs, up to 3 feet wide, can be fitted with stainless steel lifting eyes, and can be raised by one or two people using lifting hooks. Large stop logs are fitted with stainless steel lifting pins that protrude from both sides of the log. A heavy duty lift beam with automatic latching mechanism is recommended for these applications. The lift beam will be raised with an overhead winch, davit crane, back hoe, or other convenient tool. GUIDES: Most stop log guides are fabricated using T-304 or T-316 stainless steel. However, in a few harsh environments or with the smaller stop log designs, a fiberglass guide may be used. Guide shapes will be similar to the Heavy Duty Titeseal gate, but the seal design has significant changes to compensate for the lack of a mechanical closure, i.e., no stem or operator. Guides are designed for embedding, surface mounting, or in-channel mounting. Embedded guides are either attached to the form work and encased with the wall pour, or they may be grouted into a pre-formed blockout at a later time. Surface mounted guides are anchored directly to the face of the wall, and a 1 inch grout base is used to permanently seal between the guide and the wall. In-channel guides are mounted and sealed in the same manner to the inside surface and floor of an existing channel. SEALS: This is NO published leakage standard for stop logs. Any written standard in specifications have been misapplied, usually from AWWA C-501. In order to satisfy these requirements, it was necessary to develop some entirely new seal designs. Plasti-Fab has the best stop-log seal designs available on the market today. All Plasti-Fab seals are made from virgin molded neoprene that is resilient, long-lasting, and has excellent compression-set characteristics. The seal between each stop long is achieved using a dual neoprene lip seal that is bonded and mechanically fastened to the top of each log. This lip or "alligator" seal gives a consistent, firm sealing surface across the entire width of the log, and the compressible lip supplies the flexibility to provide a positive seal. One log in each stack is designated to be the bottom log and is fitted with both top and bottom seals.

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To accomplish the more difficult job of sealing between the guide and each stop log, a special "labyrinth" seal was developed. This seal has two separate seating points for the stop log to seat against. It is mounted to each side of the channel, using a special stainless or FRP clamping bar, and can be easily removed and replaced if necessary. This custom seal can be activated with very low heads, and in actual testing has proven to be very effective. LIFTING BEAM: The Heavy Duty Lifting Beam is hot dip galvanized steel, and will be the same length as the stop logs it is designed to raise. The lift beam is supplied with self-latching swing hooks which engage the stop log lifting pins and hold the log firmly while it is being raised or lowered. In order to release the log, it must be seated on the stack or floor. When the log's weight is supported, the tag line can be pulled to release the hooks from the pins and the lift beam can be removed. STORAGE: When stop logs are not in use, they should be kept nearby in a storage rack of tome type to help protect the seals. Plasti-Fab has removed much of the potential for seal damage by placing the seals on the top surface of the stop log. Plasti-Fab offers several convenient storage rack designs. If no rack is available, then the logs should be set on the bottom edge of the log, or laid flat on their side on a flat surface with spacers in between each log. LOCATION: Water and wastewater treatment plants, fish hatcheries, CSO facilities, lagoons, flood control structures, diversion channels, sludge-drying beds, composting facilities, and wetlands. Stop logs also can be found in tank farms and industrial impoundment areas where vehicle access is required and isolation is difficult or impossible by any other means. WHY BUY PLASTI-FAB? 1. High corrosion resistance and long life under some of the worst "set and forget"

conditions found in treatment plants. 2. Copolymer Stop Logs give the engineer and contractor a real alternative to

other plastic stop log specifications.

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WHY BUY PLASTI-FAB? 3. Plasti-Fab has extensive design and application experience with stop logs.

a. Superior seal designs using superior seal material - neoprene.

b. Molded construction that totally encapsulates the internal support matrix. c. Ability to meet any specified deflection requirement.

d. Modern materials in lieu of redwood or cypress which is becoming scarce. e. If necessary to be competitive, Plasti-Fab will consider quoting aluminum and stainless steel stop logs.

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