Reach, Clearance & Turning Space

A body can occupy a space without being able to use it. The difference is reach - the zone within which a person can actually operate a control, grasp a handle, take a plate from a shelf or reach a tap. For a standing adult with full movement that zone is generous and easy to forget. For a seated wheelchair user, a short person, a child or someone with limited shoulder movement it is much smaller, lower and further forward, and it is the single most useful thing to understand about designing controls and storage.

Reach has two directions that behave differently. A forward reach - stretching straight ahead, over the edge of a worktop or towards a wall-mounted control - is limited both high and low: a seated person can comfortably reach neither too high above their head nor down near the floor, and any obstruction they must lean over, such as a deep counter, shrinks the reach further. A side reach - to a control beside them - is usually a little higher and easier, because there is nothing to lean across. As a rule of thumb, the safe, comfortable zone for anything a seated or short user must operate sits roughly between knee height and shoulder height - very approximately in the region of 400mm to 1200mm above the floor - though the precise figures are typical guidance to verify against your local standard, not fixed law.

> Put the things people must use - switches, handles, controls, everyday storage - in the comfortable middle band of reach. Leave the extremes for things used rarely or not at all.

The practical instruction is simple and powerful: the more essential a control, the more central it must sit in the reach zone. A light switch, a door handle, an intercom, a socket in daily use, the most-used kitchen shelf - all belong in that comfortable band. The top of a tall cupboard or a high window catch can sit outside it, because they are used seldom and can be reached with help or a pole. When a single height cannot serve both a tall standing user and a seated one, favour the lower position: it is reachable from the chair and only a small stoop for the standing user. The figure shows the seated reach envelope and where the comfortable band falls.

Reaching a surface is only half the problem; to use many of them you must get your body close, and that is where knee and toe clearance decides whether a fitting works. A wheelchair user approaching a basin, a worktop, a hob, a reception desk or a table needs somewhere for their knees and the front of the chair to go under the surface. Without that recess they can only reach the surface at arm's length across its front edge, which for a basin means leaning into it and for a worktop means being unable to work at it at all.

Two clearances work together. Knee clearance is the open height and depth beneath a surface - enough vertical room for the thighs and enough depth for the knees to slide in. Toe clearance is the space lower down, at floor level, for the footplates and toes. A vanity with a cupboard right to the floor, a desk with a modesty panel and a low rail, or a kitchen with continuous base units all destroy this clearance and turn a usable-looking fitting into one that cannot be approached. The fix is to leave a genuine open recess - no doors, no boxed-in pipework, no cross-rail at knee height - under at least one basin, one length of worktop, one section of counter.

There is a detailing trap here worth naming: exposed hot pipes and waste traps in that open knee space can burn or graze a seated user's legs, so where you open up the clearance you also insulate or shroud the pipework. Knee and toe clearance is a quiet, invisible provision - you cannot see it in a finished photograph - but it is the difference between an accessible basin and an ornament. Whenever you draw a surface someone must work at, ask the same question: can a seated person get their knees under it, and their toes below that? If not, it is a surface they can look at but not use.

People do not move through buildings as points; they move as bodies with width - and often with a wheelchair, a walking frame, a guide dog, a pram or a companion alongside. Clear width is the usable, unobstructed width of a route once you subtract everything that eats into it: door frames and open door leaves, skirtings, radiators, handrails, a badly placed bin or planter. The width that matters is not the width on the plan but the width actually left clear at the tightest point.

A useful mental model is that a route is only ever as wide as its narrowest pinch. A generous corridor with one doorway whose open leaf and frame reduce the clear opening below what a wheelchair needs is, in practice, a blocked corridor. As typical guidance, a single wheelchair user needs on the order of 900mm of clear width to pass along a route, while for two people to pass, or a wheelchair user and a walking person, you need appreciably more - often around 1500mm, or the same clear width provided at intervals. Treat these as figures to reason with and to confirm against your local standard, not as universal law.

> A route is only as accessible as its narrowest pinch point. Measure the clear width at the doors, not in the middle of the corridor.

Where a route cannot be kept generously wide throughout - a long domestic hallway, a narrow historic building - the answer is a passing place: a periodic widening, roughly the size of a turning space, where two people can pass or a wheelchair user can wait and let someone by. Set passing places within sight of one another so a user can see the next one before committing to the narrow stretch. The figure shows a corridor with its clear width dimensioned and a passing bay set into it. The same discipline applies to doorways in series, tight turns and thresholds: check the real clear width at every pinch, because that is where routes silently fail.

Somewhere along almost every journey a person must change direction, and a wheelchair user cannot simply pivot on the spot as a walking person does. They need a turning space - and giving it to them is one of the defining moves of accessible planning. The classic provision is a turning circle: a clear, level, unobstructed circle of floor within which a wheelchair can rotate through a full turn. A very widely used typical figure for that circle is about 1500mm in diameter, though the exact figure varies between standards and chair types and must be confirmed against your local code - larger powered chairs and mobility scooters need more.

Where a full circle will not fit, a T-shaped or three-point turn can work: a bay arranged so the user can go forward, reverse into the stem of the T, and come out facing the other way. It uses less area than a full circle but takes more effort and skill, so a circle is the more inclusive provision where space allows. Either way, the turning space must be genuinely clear - level floor, nothing overhanging it, no door swinging into it - because a circle drawn on a plan but crossed by a door arc or blocked by a radiator is not a turning space at all.

> A turning space is only real if it is clear, level and unobstructed - a circle a door swings into is not a turning space.

Turning spaces have to land in the right places: inside the entrance lobby, at the foot and head of a ramp, in the accessible WC, in the kitchen, at the end of a corridor, wherever a user must reverse or reorient. On plan they are easy to test - a simple 1500mm circle template you drop into every room and junction. If it fits clear, the space turns; if it clips a wall, a door or a fitting, you have found a barrier before it was built. The figure shows a turning circle set into a room with the door kept clear of it. Reach, clearance and turning together define the seated user's working envelope - and with that envelope understood, the next lesson strings these spaces into a continuous route.