With nearly 50 years' experience in conventional reinforced concrete pipe, box culverts, manholes, catch basins and grade adjustment rings, Munro Concrete Products Ltd. of Utopia, Ontario, recently seized a new opportunity: production of 72- and 84-in.-diameter prestressed concrete cylinder pipe (PCCP) for a 16-mile project.

Landing one of the largest manufacturing contracts for pressurized pipe in North America's recent history, however, required the company to establish a suitable production facility with overhead cranes that would provide precise material movement and reliable operation.

“The technology for producing the prestressed pressurized pipe wasn't a huge leap for us,” explains John Mokrzycki, Munro Concrete's director of operations. “But our timeline for getting things up and running was insanely tight. In just seven months, we designed the product and processes, built the factory and began production.”

Munro is manufacturing the pipe for a customer responsible for the installation of a water main between the regions of York and Peel in Ontario. The 16-mile pipeline is designed to carry drinking water, requiring the pipes to withstand 175 pounds of pressure and resist leaks to avoid contamination. Mokrzycki notes that as a contract of this magnitude might come up once every 10 years or so in North America, capitalizing on a rare opportunity warranted expanding Munro's product line.

SETTING UP SHOP

To accommodate pressure pipe production, Munro Concrete extended its existing 155,000-sq.-ft. facility. A significant component in equipping the 92,000-sq.-ft. addition was the technology to ensure precise product positioning; cranes that could be customized to fit specific facility requirements were found to offer the best solution. Demag Cranes & Components provided the cranes and engineering expertise. The base crane design and project execution were founded upon nearly 30 years of collaboration with North American concrete pipe equipment manufacturers, notes Demag District Manager Harry Lafferty.

Lifting capacity installed at the pressure pipe facility includes five production cranes, each spanning 75 feet and providing capacities of 50 tons, 20 tons and 3 tons. The company also purchased a 10-ton crane for use in its maintenance shop. In addition, Munro required a custom-built 65-ft. hoist to accommodate the 20-ft. length of its parts and the hook attachments. The system incorporates remote positioning and variable frequency drives on all production cranes.

“In order to maintain the pace with such a large project, coordination with Munro Concrete and the general contractor was extremely important,” Lafferty explains. “The installation of the cranes, runway rails and runway conductor systems, considering it was 65 feet from the floor level, was a challenge readily met by our installers. Everyone worked well together to meet the production start.”

PIPELINE PROGRESS

Munro Concrete produces 72-in. and 84-in. PCCP in 20-ft. lengths, 24 hours a day, seven days a week. During the production of a single piece of pipe, Demag equipment is used to move material nearly 20 times: from the steel cylinder shop to the core casting area, then from the prestressing and coating area to the maintenance shop. According to Mokrzycki, all cranes in the pressure pipe plant have radio remotes to enhance productivity and ensure safety. Using the remotes, operators can stand anywhere in the factory and precisely position the crane.

In addition, all the Munro production cranes have been equipped with variable frequency drives (VFD) to further enhance positioning accuracy and productivity. The VFD allows a crane's motor to operate 50 percent faster than normal at loads less than 75 percent of full capacity. As a result, lifting speeds are maximized and production can move more efficiently.

Unlike two-speed models, which provide only a slow speed for positioning and a high speed for traversing long distances, VFD-equipped models offer infinite speed control between zero and the crane's maximum speed. With VFD, operators can reduce load sway to further maximize production efficiency. Mokrzycki notes that operators in the core casting and prestressing areas report that, despite their size, the two 50-ton production cranes are the easiest in the factory to operate due to the VFD.

Munro Concrete began pressure pipe production in January and expects to complete the York-Peel order by November. — Demag Cranes, Cleveland, 440/248-2400, www.demag-us.com