At the approaches to the hazard, not on top of it - and one sign rarely covers a space with more than one entrance.

A sign in the middle of a wet floor is seen after someone has already stepped onto it.

Every route into the affected area needs its own warning.

Corners, doorways and the bottom of stairs are the positions where warning is needed earliest.

Signs should not themselves become a trip hazard or block an escape route.

In busy areas, physically restricting access with a barrier is more effective than any sign.

Because people learn to walk past them, and the warning has been discounted before the real hazard arrives.

A temporary sign works by being unusual. Permanence removes exactly that property.

Staff and visitors stop registering the sign type at all, not just that instance.

It also suggests the underlying hazard has not been dealt with, which is often the actual problem.

Where a hazard is permanent, a permanent fixed sign - or an engineering fix - is the correct response.

Storage that is convenient is the practical control, since signs left out are usually signs that are awkward to put away.

Symbols, supported by text - text alone excludes anyone who does not read that language.

Mixed-language workforces are the norm on most sites, and visitors have no site induction at all.

Symbol conventions, colour meanings and mandatory formats differ between markets, and some jurisdictions specify the exact graphic for a given hazard.

Multilingual signs are widely available and are worth specifying where the workforce is known.

Colour carries meaning independently of the symbol and is often the first thing registered.

A sign complying with one country's requirements is not automatically compliant in another.

By base weight, by shape, and by being placed out of the way of traffic.

Cone-shaped signs have a low centre of gravity and a wide base and are the most stable.

A-frames are more visible but present a large surface to draught and are knocked over more easily.

Weighted and water-fillable bases are used outdoors and in ventilated corridors.

Draughts from doors, ventilation and passing vehicles are the usual cause indoors.

Once it is down, the sign has become a trip hazard and stopped being a warning at the same time.

Folding flat, stacking, and being light enough to carry with other equipment.

A-frames fold and stack, which is their main advantage over cone signs.

Cone signs nest, which suits keeping several on a cleaning trolley.

Sign stands with interchangeable faces reduce the number of complete signs that have to be stored.

Weight matters because a sign that needs two hands does not get carried to the hazard.

Storage located where the hazard occurs, rather than in a central store, is what actually gets signs deployed.

For a minor short-lived hazard usually; for anything serious, physical restriction is the correct control.

A sign relies on being seen, read, understood and obeyed, and each of those can fail.

Barriers, belt units and physical closure remove that dependence.

Most safety frameworks place warning signs low in the hierarchy of controls, below elimination and engineering measures.

An open floor opening, a live electrical hazard or a fall risk needs a physical barrier rather than a warning.

Signs are appropriate where the hazard is genuinely minor and genuinely temporary.

Kept clean, legible and undamaged - a faded or dirty sign is not read.

Signs used in cleaning operations get wet and dirty constantly, which is exactly what obscures them.

Cracked and broken signs stop standing correctly and look neglected, which affects how seriously they are taken.

Ultraviolet exposure fades outdoor signs, and faded colours lose their coded meaning.

Replacement is inexpensive relative to the consequence of a warning not being seen.

Including portable signs in routine equipment checks is what keeps the stock usable.