Start with water, not with floors
Slips happen where a contaminant meets a smooth surface under a moving foot. Water is the contaminant nine times out of ten, so the fastest way to scope a site is to follow it. Where does rain come in? Where is the floor mopped during the day? Where do drinks get carried, where do people come out of showers, where does a cool room sweat? Mark each of those points on a plan. Those are your candidate locations.
Then split by surface
A location is one area of one surface type. If the wet route from the front door crosses stone, then a mat, then vinyl, that is two locations, not one. The mat itself is rarely tested. Different finishes of the same material also count separately: honed and polished granite in the same foyer behave differently when wet and need their own readings.
Count the transitions and the gradients
Falls concentrate where the body is already off balance: stepping off a mat, onto a ramp, onto the first tread of a stair, through a door. Any ramp, stair or landing on a wet route is a location in its own right. On a stair, the tread and the nosing are tested as one location unless the nosing is a different material.
Decide what to leave out
Dry internal areas away from any wet source can usually be covered by one or two dry floor friction tests as a sample, or left out entirely if the surface is carpet. Back-of-house areas nobody but staff use are lower priority than public ones, unless they are kitchens or wash-down bays, which are high priority regardless. Be honest about exposure: an area used by hundreds of people a day deserves its own reading; a store room does not.
Three worked examples
A commercial lobby
Front entry stone inside the door line; the same stone past the mat where it is dry; the lift lobby if the finish changes; the external steps or ramp; the end-of-trip shower area in the basement. Five locations covers the genuine risk in most towers.
A shopping centre
Each public entry, the food court floor, the fresh produce aisle of the supermarket if the centre is responsible for it, the base of each travelator or escalator, the public toilets, and any external walkway. A mid-sized centre lands between ten and fifteen locations, with the food court and entries on a more frequent schedule than the rest.
A primary school
Covered outdoor learning area, the walkway from drop-off to the classrooms, the student toilets, the canteen servery floor, the hall entry and any water play or pool area. Six to eight locations, tested in the holidays.
If you are still not sure
List the areas you know about in the booking form. We confirm the scope with you before the visit and adjust the price if it changes. The technician will also tell you on the day if an area you have not listed looks like it should be included, and you decide whether to add it.