MODEL A PRE-FORMED LOOP DETECTOR APPLICATION

Marlin Controls, Inc. offers the Model A Loop Detectors that are designed for installation into hot asphalt or under asphalt overlay.

 

ADVANTAGES: Wires sealed in rubber asphalt filled polypropylene conduit Completely tested prior to shipment:

• No splices.
• Shipped ready to install.
• Patented expansion / contraction joints.
• Direct burial in dirt / gravel or onto sub-base.Reduced maintenance cost.

SPECIFICATIONS

Loops shall be constructed from polypropylene conduit with 3/8" I.D. (9.5 mm) and 5/8" O.D (16 mm). Conduit shall be filled with hot rubberized asphalt which allows the loop to remain flexible once cooled, prevent incursion of moisture and set the turns of wire firmly in place. Loops shall have 5" (13cm) expansion / contraction joints at intervals along the loop to allow for movement of the pavement and to prevent breakage of the wire and / or conduit due to this movement.

Each expansion / contraction joint shall have a 9 inch (23cm) schedule 80 polypropylene cover slide to be placed over the joint.

The encapsulated copper loop wire shall be 16 gauge TFFN or THHN stranded single conductor wire with PVC insulation and nylon exterior jacket. (other gauges employed where called for). Loops shall have 4 turns. (additional or less turns where called for) Loop shall have one continuous wire through the loop head and lead-in to prevent loop malfunctions due to splicing. Lead-in wire shall be encased in a non-conductive 2250 psi (15.000 Kpa) flex hose constructed with a seamless extruded polyester fiber braid reinforcement and a non-conducive, seamless extruded urethane non-perforated jacket.

Fill lead-in hose completely with hot rubberized asphalt. Twist wires in all lead-ins a minimum of three turns per foot (30cm) for the entire length of the lead-in. Attach lead-ins to loop heads with a schedule 80 CPVC tee.