4.2 Clearance distance

A fall arrest system needs sufficient space to stop the user before the person strikes the ground, a structure or another obstacle.

This space is commonly referred to as clearance distance.

Clearance distance is more than lanyard length

The required clearance distance may be affected by factors such as:

• lanyard length,
• deployment of an energy absorber,
• braking distance of a retractable type fall arrester,
• system elongation,
• anchorage position,
• the user's height and position,
• system movement,
• the safety margin stated in the manufacturer's instructions.

There is therefore no single clearance value that applies to all systems.

Clearance distance must be verified

Clearance distance must be assessed using the actual product and the intended use.

The manufacturer's instructions may specify different requirements depending on factors such as:

• direction of use,
• anchorage position,
• use over an edge,
• user weight,
• system configuration.

Clearance distance must therefore not be estimated or based on a general rule of thumb.

Important

A system may be correctly assembled and still be unsuitable if there is insufficient clearance to stop the fall.

Remember

Clearance distance must be verified using the manufacturer's instructions for the product or system – not estimated.