Frontline WLS16 Warning Line System

Watch: Frontline WLS16 in Action

What Sets the WLS16 Apart

System Components

The WLS16 platform separates the load-bearing stanchion from the cable hardware so you can spec the right length for the perimeter you need to mark. The stanchion ships fully assembled. Cable, flags, clips, and thimbles can be ordered as a kit with the stanchion or sourced separately.

Technical Specifications

Kit Selection

Order the stanchion alone if you already have compatible cable, flags, and end hardware. Otherwise, match the kit length to the linear footage of your warning-line perimeter, keeping in mind that stanchions can be placed up to 24 ft apart.

Compliance & Certification

Right Tool. Right Job.

How to Install the WLS16 in 7 Steps

The full procedure is in the WLS16 User Instruction Manual (Rev. February 2026). The condensed version below assumes a trained installer working on a flat, dry, low-slope surface at least 18 inches inside any fall hazard and at least 10 feet from any energized line.

1. Plan the perimeter. Lay out the warning line perimeter at least 6 ft from any unprotected roof edge (10 ft on edges perpendicular to mechanical equipment travel). Confirm the substrate is flat, dry, and free of gravel or slope.
2. Assemble the cross legs. Lay the bottom stanchion leg flat. Insert the supplied 1/2 in x 2 1/2 in hex bolt with washer and nut through the underside hole.
3. Stack the upper leg. Lay the upper stanchion leg over the bottom leg and the hex bolt so the cross is square, and the rubber pads contact the surface.
4. Drop in the post stanchion. Insert the post stanchion male tabs into the female openings on the upper leg. Hold the bolt from below and tighten with a 3/4-in hex socket or impact driver until the post stands upright.
5. Flag the cable. Run WLS16-CABLE316 through WLS16-FLAG markers spaced no more than 6 ft apart, using high-visibility flagging that stays legible from working distance.
6. Connect to stanchions. Thread the flagged cable through the warning line connection point at the top of each stanchion. Keep the lowest point (including sag) no lower than 34 in and no higher than 39 in from the walking surface. Posts no more than 24 ft apart.
7. Terminate the runs. At the start and end of each run, form a loop, seat a WLS16-THIMBLE inside it, and clamp with WLS16-CLIPS until firmly captured. Verify pulling one section does not pull slack from the next.

Inspection & Retirement

Warning line systems take incidental contact from tools, materials, and weather every day they are deployed. Routine inspection catches problems before they let a worker through the line at the wrong moment.

Pre-Use Inspection (Every Use)

Before each shift, confirm each stanchion stands upright at a true 90 degrees with the cross legs flat on the surface. Verify that the cable's lowest point is at or above 34 in and its highest point is at or below 39 in. Confirm visibility flags are present at intervals of 6 ft or less, including from the stanchion. Look for cracks, dents, deformed legs, missing bolts, missing rubber pads, and corrosion on any component. Confirm the perimeter is at least 6 ft from the unprotected edge (10 ft on edges perpendicular to mechanical equipment travel).

Competent Person Inspection (Minimum Every 6 Months)

A Competent Person, as defined in 29 CFR 1926.32(f), must perform and document a full inspection at least every six months. The inspection covers permanent deformation of any leg or post; weld integrity at the cross-leg joint; condition of the warning line connection point at the top of the stanchion; bolt tension on the 1/2-in hex assembly; label legibility; and any signs of unauthorized field modification. Log results on the inspection checklist included in the User Manual.

Inspection After Impact

If a stanchion has been struck, knocked over, dropped from height, or hit by mechanical equipment, remove it from service until a Competent Person inspects and clears it. Tip-force performance depends on the geometry of an undeformed cross-leg base.

Retirement for Damage

Retire any stanchion with cracked welds, bent posts or legs that will not sit flat, missing or torn rubber pads that compromise base friction, severe corrosion that has pitted the steel, or any deformation that prevents the post stanchion from seating fully vertical in the cross-leg openings. Retire any cable showing fraying, kinks, or damaged thimble terminations.

Cleaning and Storage

After exposure to rainwater, concrete slurry, paint, or construction debris, clean each component with mild soap and water and dry before storage. Equipment exposed to chemicals that cannot be removed with soap and water must be retired. Store disassembled or fully assembled in a clean, indoor, room-temperature space away from sunlight, rain, and chemical contaminants.

Frequently Asked Questions

Frontline WLS16 Submittal Documents

The following manufacturer documents are available for download to support procurement, safety planning, jobsite submittals, and Competent Person inspection records.