Issue link: https://read.dmtmag.com/i/401422
WORLD FENCE NEWS • NOVEMBER 2014 • 69 We know how nerve-wracking it can be to install loops in a concrete pour; you have little to no control of the contractors pouring the concrete and one careless dig with a shovel can damage the loop and cause it to short to ground. Nobody is ever happy about cut- ting a loop into a new driveway! We have a few tips for installation in concrete pours to help prevent damage to the loop: Clearly mark the area of the loop with warning signs. We have a sample sign that can be downloaded off our web site (www. BDLoops.com) and placed around the area of the loop warning contractors to work carefully around the loop. After the loop has been laid out, pull the homeowner or build- ing manager aside and test the loop in front of them with a megohmmeter. Share the results and explain that the loop is fully operational, and have them sign the results. Explain that concrete crews have been known to damage loops and share with them the precautions you are taking with the warning signs. There is a sample megohm test signoff sheet that can be downloaded at www.bdloops.com/bdloops_down- loadsB.html. If possible, supervise the concrete pour and speak with the concrete crew about working carefully around the inductance loop. When laying a loop over rebar, offset the loop from the rebar pattern. To offset the loop simply lay the loop down so that the legs and corners of the loop do not line up with rebar. The less the loop that comes in contact with the rebar the more sensi- tive it will be. Run the lead-in through conduit and under the rebar. If you run the conduit on top of the rebar there is a chance that the loop can be stretched and damaged when the rebar is lifted into the middle of the concrete pour. View http://www.bdloops.com/ DB_ Instructions.pdf for visual dia- grams on how to run the lead-in under the rebar and offset the loop from the rebar pattern. If the loop is exiting the roadway into a garden bed, run the conduit 6" to 8" under the wood concrete forms. When the contractors remove the wood concrete forms they are not gentle, they use pry bars, crowbars, and shovels to dig them out. If you exit 6" to 8" under the wood concrete forms, the lead-in is much less likely to be damaged. Encase the loop in 3/8" semi-slit polyethylene pipe insulation. There are two advantages to doing this: it adds a small amount of protection against damage during installation, and it elevates the loop slightly off of the rebar which will make the loop a little more sensitive. We recently ran a variety of wires through our "shovel guillotine" (a shovel with a 6½" drop height and 6 lbs. of weight added to the blade) with and without semi-slit poly- ethylene pipe insulation. When the wires were covered with the insula- tion, enough of the impact was ab- sorbed that the outer jacket was rare- ly broken and the copper was never exposed. When the wires were not covered the jacket was almost always broken and many wires had their cop- per exposed, which would result in a failed loop/short to ground. The polyethylene pipe insulation will not protect the wire by itself, but it will add a layer of protection against a concrete crew that is working care- fully around the loop. To see the full details of the test visit www.BDLoops.com/bdloops_ lab.html. Polyethylene pipe insulation is available through big box stores like The Home Depot and Lowes in 6 ft. lengths, and can be special ordered in boxes of 90 pieces (540 ft). BD Loops is a manufacturer of preformed direct burial and saw-cut inductance loops for the gate, door, and parking industries. BD Loops has been in business for over 13 years and their products are available through over 350 dis- tributors in the U.S.A and Canada. BD Loops offers over 45 standard preformed loop sizes, all standard and custom loop sizes are ready to be shipped the same day. Visit www.bdloops.com and use the distributor locator to find a dis- tributor near you. If you would like to speak to Dickson, call BD Loops at 714-890-1604. Useful tools to protect loops in a concrete pour BY BRIAN DICKSON, GENERAL MANAGER, BD LOOPS THE LARGEST • THE STRONGEST THE BEST WARRANTY Proud to announce our newest driver! The Ultimate driver designed for the fence contractor is HERE! • Large 3-1/8" barrel • Full size hammer • Up to 1850 bpm • Includes 2" sleeve • 3 year warranty • Lifetime hammer YOU CAN CHANGE THE WAY YOU BUILD FENCE! 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