Engineered Fall Arrest vs. Fall Restraint: Which Does Your Site Actually Need?
We see a lot of sites that are over-engineered. Someone specified a full personal fall arrest system — harness, shock-absorbing lanyard, rated anchor, rescue plan, the works — when a simple fall restraint setup would have been cheaper, faster to deploy, and arguably safer because it prevents the fall entirely.
Restraint vs. arrest is one of the most consequential decisions in fall protection design. Here is how we work through it with our clients.
The definitions
A fall restraint system uses a fixed-length lanyard attached to an anchor that prevents the worker from physically reaching the fall hazard. The worker simply cannot get close enough to the edge to fall. A fall arrest system allows the worker to reach the edge — or even fall over it — and then catches them with a shock-absorbing lanyard or self-retracting lifeline within a controlled deceleration distance.
Restraint is preventive. Arrest is reactive. Both are valid; they solve different problems.
When restraint is the right answer
Restraint is preferable any time the work area is large enough that you can keep workers a safe distance from the edge with a fixed lanyard. Typical examples: HVAC service on a low-slope roof with a single perimeter, perimeter-only PV maintenance, mechanical work near the center of a building.
Restraint is dramatically simpler than arrest. You do not need a rescue plan that can deploy within minutes (because there is no suspended worker), you do not need 5.5 m of clear fall space, you do not need a shock-absorbing lanyard, and your anchor strength requirement drops because there is no dynamic loading event.
When arrest is the only option
Arrest becomes necessary when the work geometry forces the worker into the fall zone. Typical examples: edge work on a steep-pitch roof, work on the leading edge during construction, tower climbing, work inside a confined space with overhead access only, work on irregular structures where restraint geometry is impossible.
If you choose arrest, you have inherited every requirement that comes with it: 22.2 kN anchor strength per worker, full body harness, shock-absorbing connector, documented rescue plan, sufficient fall clearance, and a trained rescuer on site or within a defined response time.
The decision flowchart we actually use
Our internal flowchart for new client sites is short:
- Can you eliminate the fall hazard entirely (guardrail, parapet)? If yes, do that first.
- Can you keep workers out of the fall zone with a fixed lanyard? If yes, design for restraint.
- Do workers have to be in the fall zone to do their job? If yes, design for arrest.
- Is there enough clearance below the anchor for a 5.5 m fall arrest event? If no, redesign with an SRL or move the anchor.