Polyethyene Pipe Insulation
Can using pipe insulation in a concrete pour help protect the loop wire from damage?

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Purpose:

Observe and record if 3/8” semi-slit polyethylene pipe insulation adds protection against shovel strikes.

Hypothesis:

The polyethylene pipe Insulation will add a small amount of protection against shovel strikes.

Materials:

  • Shovel Guillotine with the following measurements:
  • Shovel with 6lbs attached to blade and 6 ½” of drop height.
  • Pin release to ensure drop height is consistent.
  • Guide to center objects under the blade. 
  • BD Loops Direct Burial Loop Wire
  • BD Loops Saw-Cut Loop Wire
  • BD Loops Direct Burial Lead-in Wire
  • Brand X Loop Wire
  • Brand Y Loop Wire
  • 3/8” Semi-slit polyethylene pipe insulation
  • Camera for documentation purposes

Procedure:

The shovel guillotine has a pin release to ensure that the blade is dropped from the same height for each test. Each wire type is encased in the semi-slit polyethylene pipe insulation and placed in a guide at the bottom of the guillotine. The pin is pulled and the shovel falls down on the encased wire.

This test is done twice for each wire type and the results are recorded.
Then each wire type is tested without the pipe insulation. The wires are placed in the guide at the bottom of the guillotine. The pin is pulled and the shovel falls down on the unprotected wire. This test is done twice for each wire type and the results are recorded.

Results:

Wire Type

BD Loops
Direct Burial Loop Wire

BD Loops
Saw-Cut Loop Wire

BD Loops Direct Burial Lead-In Wire

Brand X
Loop Wire

Brand Y
Loop Wire

W/ Insulation
Test 1

Jacket Scratched
No Short
(Img A)

Jacket Pierced
Insulation Intact
No Short
(Img B)

Jacket Dented
No Short
(Img C)

Jacket Dented
No Short
(Img D)

Jacket Dented
No Short
(Img E)

W/ Insulation
Test 2

Jacket Dented
No Short

Jacket Pierced
Insulation Intact
No Short

Jacket Dented
No Short

Jacket Dented
No Short

Jacket Scratched
No Short

W/O Insulation
Test 1

Jacket Dented
No Short
(Img F)

Jacket Pierced
Insulation Pierced
Short
(Img G)

Jacket Pierced
Insulation Intact
No Short
(Img H)

Jacket Dented
No Short
(Img I)

Jacket Pierced
Installation Pierced
Short
(Img J)

W/O Insulation
Test 2

Jacket Pierced
Insulation Intact
No Short

Jacket Pierced
Insulation Intact
No Short

Jacket Pierced
Insulation Intact
No Short

Jacket Dented
No Short

Jacket Pierced
Installation Pierced
Short

 

Conclusion:

The 3/8” polyethylene pipe insulation absorbed some of the impact of the shovel strike. When the wires were covered with insulation the shovel strikes never resulted in exposed copper (short to ground).  When the wires were run through the test without the additional insulation 50% of the shovel strikes resulted in pierced jackets, and 30% of the strikes resulted in exposed copper (shorts to ground).

What this means, BD Loops comments and Overall Conclusion:

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.

In our testing we found that when the wires were covered with the semi-slit polyethylene pipe insulation enough of the impact was absorbed that the outer jacket was rarely broken and the copper was never exposed. 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 carefully around the loop.  

To best protect a loop in a concrete pour a variety of tactics should be used, including warning signs, test result signoff sheets, communication with the concrete company, and more. To learn more about how you can protect your loops in a concrete pour visit the Education and More section of our website: www.bdloops.com.

Semi-slit polyethylene pipe Insulation is available through big box stores like Home Depot and Lowes in 6ft lengths, and can be special ordered in boxes of 90pcs (540ft).

 

BD Loops is an assembler of preformed direct burial and saw-cut inductance loops for the gate, door, and parking industries. With over 13 years in business the quality of our loops is unparalleled. BD Loops products are available through over 350 distributors throughout the USA 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. The company has several letters of recommendation testifying their professionalism and design, and is a member of the following associations: AFA, IDA, NAFCA, NOMMA, IPI, CODA and IMSA. Use the Distributor Locator to find a BD Loops distributor near you.

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