Because it physically obstructs the route rather than relying on someone reading and obeying a warning.

A sign depends on being seen, understood and complied with, and each of those can fail.

A belt across a corridor has to be actively stepped over or unclipped.

That moves it up the hierarchy of controls from warning to restriction.

It also makes the boundary of the affected area unambiguous.

For a minor short-lived hazard a sign is proportionate; for a route that must not be used, a barrier is.

Belts clip to an adjacent post, a wall receiver or a fixed point, and posts link into a continuous run.

Multi-belt posts allow runs to branch or turn corners from a single position.

Wall-mounted cassettes anchor a run to a fixed structure without a post.

One person can set up and take down a substantial run in minutes.

That speed is a large part of why they are used for cleaning and maintenance work.

Runs should include a controlled point of entry rather than forcing people to step over.

Limited by belt length and by the sideways pull on the end posts - too long or too tight and the line collapses.

A belt under tension pulls the posts at each end inward.

Weighted bases resist that, but only up to a point.

Intermediate posts break the run into shorter spans and are the practical answer.

Belts should be pulled taut enough not to sag but not tensioned hard.

Manufacturers state maximum span and recommended base weights for their systems.

Yes, and printed belts combine the restriction with the explanation.

Do not enter, cleaning in progress and closed for maintenance are common printed messages.

That saves people having to work out why the route is closed, which reduces the temptation to duck under.

Plain belts restrict and leave the explanation to a separate sign.

Belt colour also carries meaning independently of any printing.

Custom printed belts are widely available for site-specific messages.

The retraction mechanism - a belt that will not retract fully or that snaps back is the usual complaint.

The spring cassette is the wearing part and is not usually serviceable.

A belt that retracts at speed is a genuine injury risk to hands and faces.

Slow-retract mechanisms exist specifically to address that and are worth specifying.

Belt edges fray and printing wears, which reduces legibility.

Bases and posts are usually the durable part and outlast several cassettes.

No - a belt restricts a route, it does not protect against a fall or an impact.

Around an open floor opening, a lift shaft or a live edge, a physical guardrail with structural performance is required.

A belt will not arrest anyone who trips into it.

It also gives no protection against a vehicle or moving plant.

Guardrails, hard barriers and covers are the appropriate controls for those hazards.

Belts are for controlling pedestrian routes, and used within that scope they work well.

Cleaning and maintenance work, closed stairwells and aisles, queue management and temporary area closures.

Cleaning in public buildings is the largest single application.

Retail and warehouse aisles closed for stock work or repairs are another.

Stairwells and escalators taken out of service need unambiguous closure.

Queue management uses identical hardware with different belts and messages.

Because the same stock serves both, it can disappear into non-safety use - worth allowing for when deciding quantities.