The Rooftop Unit Pick at the Unprotected Edge

1. No warning line along the west edge. The two workers guiding the RTU with tag lines are at an unprotected edge 48 ft above grade with nothing between them and the fall. This is the most serious observation on the roof and alone justifies stopping the pick.

2. Warning line 2 ft from the edge on the south side. The warning line provisions require the line to be erected a minimum distance from the roof edge - not less than 6 ft where mechanical equipment is not being used, and not less than 10 ft on the side parallel to the direction of equipment travel where equipment is being used. Two feet fails either figure. A line at 2 ft is a trip hazard that marks nothing.

3. The safety monitor has other duties. The safety monitoring system requires a competent person whose responsibility is to recognize and warn of fall hazards, and the employer must ensure the monitor has no other duties that could distract his attention. A foreman running the hoist and pulling conduit cannot watch six people at once; the system exists on paper only.

4. Harness clipped to a 1 in conduit stub. That is not an anchorage. Anchorages must support 5,000 lb per employee or be designed by a qualified person with a safety factor of at least two - a conduit stub held by two set screws will pull out under a fraction of that load. The worker's system also needs a rescue plan, since a suspended worker in a harness can lose consciousness in minutes.

5. Open roof hatch. A hatch is a floor opening; it needs a cover secured and marked, or a guardrail and toe board. Propping it open with no cover is a second, unrelated fall hazard in the walking path.

The system does not match the work. The low-slope roof provisions in the OSHA construction standard are written around roofing activities on roofs of limited slope and height. Setting rooftop units with a crane and pulling conduit are not roofing activities. They fall under the general rule for unprotected sides and edges 6 ft or more above a lower level, which permits guardrail systems, safety net systems, or personal fall arrest systems - a warning line combined with a safety monitor is not among the permitted options. With no parapet (the 39 in parapet exception is unavailable), every worker exposed to the edge needs one of the permitted systems.

This is the point most crews miss: the warning line on the roof is not a fall protection system at all for a mechanical crew. It is a visual boundary. It does not arrest a fall.

Before the pick resumes:

1. A guardrail system around the work area and the roof perimeter where the crew will travel - passive protection that protects everyone without training or attention.
2. If guardrail is genuinely infeasible at a specific point, personal fall arrest with engineered anchorages: a certified roof anchor, a mobile anchorage, or a tie-back designed and approved by a qualified person - plus a rescue plan and trained rescuers.
3. A written lift plan for the RTUs: crane position, radius, load chart, rigging, tag line handling, and the exclusion zone under the load.
4. A pre-task plan/JHA reviewed and signed by each crew member, and a competent-person inspection of the roof and the equipment before the first pick.
5. The roof hatch covered, secured, and marked.

Hierarchy of controls, applied: eliminate exposure (assemble or stage so no one approaches the edge), then guardrail, then nets, then personal fall arrest, with warning line and monitor last - and here, not permitted at all.

The decision is not close. Two days and $9,000 against a 48 ft fall: the direct cost of a fatality - investigation, willful or repeat citation exposure, defense costs, insurance renewal, schedule loss, and the human cost - exceeds $9,000 by orders of magnitude, and the indirect costs typically run several times the direct. Multi-employer citation doctrine means the general contractor is exposed for a subcontractor's hazard it knew about and controlled, and the walk-through observation puts that knowledge squarely on the record.

Exercise stop-work authority and say why. Stop the pick in writing, name the specific deficiencies, and require a written corrective action plan from the subcontractor before restart. The PM is not the person who waives a fall hazard; if the PM pushes back, escalate to the safety director and the executive in charge, and put the escalation in writing.

Mitigate rather than simply refuse. The $9,000 and two days may be reducible: rent a prefabricated guardrail system instead of fabricating one; set the RTUs from a crane position that keeps the crew out of the edge zone entirely; use a mobile anchorage for the conduit work. Give the PM a path to today's date that does not involve an unprotected edge - that is what turns a confrontation into a solution.

Cost and time responsibility. Fall protection is a means-and-methods obligation of the installing subcontractor under its subcontract and the site safety plan. The $9,000 and the two days are the subcontractor's to absorb unless the delay is attributable to the owner or to the GC's sequencing. Document that position in writing at the time of the stop, not at closeout.

The record: photograph the conditions, log the observation and the time of the stop in the daily report, issue a written notice to the subcontractor citing the safety plan and the applicable requirements, record the resumption with the inspection and signed JHA, and notify the owner and the insurance carrier as the contract requires. Verbal assurances that it will be fixed are not a basis for restarting a crane pick.