Best overall
Guardrail system
Passive. It protects everyone on the deck including the people who never read the JHA, and it needs no daily decision from anyone.
Notice
Guardrails vs safety nets vs PFAS
1926.501(b)(1) names three systems and treats them as interchangeable. On a real deck they are not remotely interchangeable — they differ in who they protect, what they cost to install, and how often they have to be re-proved. Here is the honest comparison.
Best for open structure
Safety nets
When there is no edge to rail and no overhead to anchor, a net is the only passive option left.
Best for short exposure
Personal fall arrest
One person, one task, one anchor — and the only system that travels with the worker.
Notice
The comparison, line by line
| Line | Guardrail | Safety net | Personal fall arrest |
|---|---|---|---|
| Type | Passive | Passive | Active |
| Protects | Everyone on the deck | Everyone above the net | Only the person clipped in |
| Key criterion | 200 lb at the top edge, no deflection below 39 in | Border rope 5,000 lb break strength | 1,800 lb maximum arresting force |
| Proof required | Built to spec, inspected | Drop test: 400 lb bag, 30 ± 2 in diameter | Inspection prior to each use |
| Re-proof interval | On damage | At install, relocation, major repair, and every 6 months in place | Every use |
| Vertical distance below net/anchor | None | Not more than 30 ft below the working level | Free fall ≤ 6 ft, deceleration ≤ 3.5 ft |
| Rescue plan needed | No | No | Yes — prompt rescue, 1926.502(d)(20) |
| Fails when | Someone removes a bay and forgets | Debris is left in the net | Someone does not clip in |
Passive beats active, every time
The single most useful distinction is passive versus active. A guardrail and a net keep working when the crew is tired, new, or in a hurry. A harness only works if someone decides to clip in, and keeps deciding to, on every trip across the deck.
That is why the sequence on a competent site is: rail it if you can, net it if you cannot rail it, and clip in only where neither will go.
Notice
Cost comparisons usually favour harnesses because they price the hardware and ignore the supervision. Supervision is the expensive part of an active system, and it is a recurring cost for the life of the job.
What nets actually require
Nets are the least-used of the three, mostly because their installation criteria are demanding. 1926.502(c) requires:
- Installation as close as practicable under the surface, and never more than 30 feet below it.
- A drop test at the jobsite after initial installation and before use, whenever relocated, after major repair, and at 6-month intervals if left in one place — a 400-pound bag of sand, 30 ± 2 inches in diameter, dropped from the highest working surface.
- A border rope or webbing with a minimum breaking strength of 5,000 pounds.
- Mesh openings no more than 36 square inches and no longer than 6 inches on a side.
- Materials and debris removed from the net as soon as possible, and at least before the next work shift.
That six-month re-test is what usually decides against nets on a long job — but on open steel with no anchor points and no edge to rail, they remain the only passive system available.
The combinations the standard allows
On low-slope roofing work 1926.501(b)(10) opens up options no other surface gets: any of the three conventional systems, or a warning line paired with a guardrail, a net, a personal fall arrest system, or a safety monitoring system. On a roof 50 feet or less in width, a safety monitoring system alone is permitted.
Warning lines go not less than 6 feet from the edge when mechanical equipment is not in use, under 1926.502(f)(1)(i). The monitor, under 1926.502(h), must be a competent person on the same walking surface, close enough to communicate orally, with no other duties that could take their attention away.
Warning
A monitor with a second job is not a monitor. 1926.502(h)(1)(v) is explicit: no other responsibilities that could take the monitor's attention from the monitoring function.