Amicable magnetism achieved

January 2011 » Web Exclusive » PROJECT CASE STUDY
Magnetically mounted cable/cable tray holding system solves invasive logjam for water district and wireless providers.

When the Olivenhain Municipal Water District (OMWD) in Encinitas, Calif., mandated a rehabilitative painting of its 10 million–gallon, 300-foot-diameter potable water tank, it gave advance notice of removal/reinstallation to the many cell phone companies that used the tank as a telecommunications hub for their antennas and cable trays. Since draining of the tank’s contents was required prior to epoxy coating and painting its interior/exterior steel, the cable trays for the transmission lines had to be removed prior to the process. The request stated that this was required and essential in order to not adversely affect the tank’s protective coatings and seals.

The OMWD, which covers 48 square miles of North San Diego County and serves approximately 68,000 residents, received delayed response and coordination with the carriers to reinstall the equipment. In fact, painting had already begun and the carrier’s welders weren’t able to replace the tray holders that run the cable up the legs, sides, and across the curvatures of the tank, thus rendering re-welding a non-viable option. At this juncture, OMWD’s Operations Supervisor Eric Phillips was faced with finding a non-invasive solution to advance the project’s timeline for completion ― fall 2010.

Magnetic solution
Phillips quickly sought council with the project’s construction manager, Chris Stump of Carlsbad, Calif.-based Broken Arrow Communications, to develop a solution for the application with Twinsburg, Ohio-based Metal & Cable Corp. Inc., which had expertise in non-invasive magnetic design configurations. The ensuing invention was the patent-pending Magnemount cable/cable tray holding system that presented a non-penetrating option to the welding and epoxy attachment methods that were delaying the project.

Designed to withstand winds as fast as 150 mph, the Magnemount system presented OMWD with a high-capacity magnetic solution to carry the cables and trays securely across and down the curvatures of the steel water tank. Most importantly, it presented no damage to the water tank’s interior/exterior surface, providing a fast, clean, onsite installation that allowed the flexibility to remove and attach at will, without welding.

The Magnemount passed independent stringent seismic and mechanical tests. An unlimited lifetime warranty also is given on all magnets and a five-year warranty on the complete Magnemount system.

System design
Designed to conform to the varying curvatures of steel water tanks via independently mounted magnets, the Magnemount system eliminated the need for Broken Arrow’s carrier installers to weld, cut cable trays, or add additional hardware to accept the arc of the tank. This was accomplished by placing one Magnemount cable/cable tray mount on each end of every length of cable tray. The final system leverages the originally patented Magnemount attached to 304 grade stainless steel Unistrut.

Furthermore, Stump worked with Metal & Cable Corp.’s President and Magnemount inventor David Klein to provide specific revisions to the system’s combination of magnets, hardware, and neoprene washers. According to Klein: “The adjustments involved using longer hex head cap screws (as long as 5 inches) so the cable trays can adjust further off the tank. These act like refrigerator leveling feet so the end of one tray can mate with the new end by adjusting the height of the acorn nut that supports the whole apparatus.”

Stump noted that the new configuration made it even easier for installers. “Once the Magnemount cable tray holders are placed on the tower, it takes no more than one minute to make adjustments, if necessary,” he said. “It also accommodates existing surface painting under the system on the water tower tanks and may eliminate the need to remove it during future painting processes.”

Conclusion
Broken Arrow completed the first installation of the Magnemount system for national wireless carrier Cricket Communications Inc. in August 2010, utilizing approximately 250 feet of cable tray and 100 Magnemount cable/cable tray holders in the installation. The OMWD also has required installers for all of the tank’s wireless carriers (including Verizon, Sprint, and T-Mobile) to incorporate non-weld systems; all are in the process of implementing and installing these systems to meet compliance.

According to OMWD’s Phillips: “This system is easy, flexible, maintenance-free, and eliminates permanent welding. Also, with multiple wireless carriers on the tank, it simplifies the logistics of coordinating whose tray goes where. Because the Magnemount is not a permanent weld, it simplifies the process. The adjustments can be made easily on-the-fly for repositioning them wherever they need to be placed.”

Broken Arrow’s Stump also noted: “The Magnemount system provides an outstanding alternative to welding, which is often not allowed by certain water districts. More importantly, this ‘magnetic solution’ allows for a much less invasive installation process, which provides cell phone companies with a viable option to present water municipalities who are averse to welding on their tanks. ”

The Magnemount cable/cable tray holding system, which passed independent seismic and mechanical tests, does not damage the water tank’s interior/exterior surface and provides a fast, clean, onsite installation with the flexibility to remove and attach at will, without welding.
The Magnemount system provided the Olivenhain Municipal Water District in Encinitas, Calif., with a high-capacity magnetic solution to carry cell phone company cables and trays securely across and down the curvatures of steel water tanks.

David Klein is president of Metal & Cable Corp. Inc. He can be contacted at david@metal-cable.com.


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