How many children fit on a carousel: capacity, age and places

At morning break a dozen children are standing round the carousel and all of them want to get on at once. The manual gives one figure to answer that: capacity up to 200 kg. The member of staff on duty has ten seconds to turn it into a decision.

Why makers state kilograms

The designer sizes the post, the central bearing, the arms and the foundation for a load, not for a number of heads. A three year old and a thirteen year old differ in mass by nearly three times, so „a carousel for eight children" would carry no technical information at all. Eight preschoolers come to about 130 kg, eight teenagers to over 350 kg, and those are two entirely different machines.

With rotating equipment there is a second factor that never appears in a catalogue: the mass is moving around an axis, so the bearing and the connections work under a varying load. The requirements for this group of equipment are in part 5 of EN 1176, among them the clearances between moving and fixed parts and the permitted speeds. The stated capacity applies to a carousel that is turning, not to children standing still on a platform.

The capacities of our four units

Dimensions, unit weight and foundation depth are confirmed on request before an order. We do not publish them on the product page until we have measured a unit from current production.

How many children that comes to

The conversion is simple: capacity divided by the approximate mass of a child of that age. The values below are approximations from growth reference data and within any particular group they can be several kilograms out in either direction.

The figures in the first row are theoretical, and that is where the usual misunderstanding sits. Eleven four year olds fit inside the mass limit but they do not fit on the platform in a way that gives each of them something to hold. With the youngest groups the constraint is surface area and the number of handholds, and the rated capacity is never reached.

The number of places is often the tighter limit

The cross carousel has four seats and that is a hard limit: a fifth child has nowhere to sit. Its 160 kg capacity meets that limit exactly at the top of its age range, because four twelve year olds already come to around 170 kg. That is why the unit is described for ages 3 to 12 rather than 3 to 14 like the round and disc versions.

On the round and disc carousels the number of places follows from the area of the platform and the layout of the handrails. We do not quote it as a fixed number, because it depends on whether children are standing or sitting and on how old they are. We confirm platform dimensions before an order if you need them for a design or a tender. The differences between the three structures are set out in the comparison of round, cross and disc carousels.

One adult changes the arithmetic

A supervisor weighing 75 kg takes up the same share of the capacity as three seven year olds. If they get on with two children, the carousel is carrying about 125 kg, and mostly at one point on the circumference, because an adult does not spread across the platform the way a group of children does.

The second issue is speed. An adult can push a carousel to a rate a child cannot reach with their own legs, and the standard limits speed precisely because on rotating equipment it is speed that sets the centrifugal force acting on a child holding on. A parent pushing the carousel and a parent jumping on to it are two different situations, and only the first is within what the unit is designed for.

What overloading actually does

A carousel does not break at 210 kg, because the structure carries a margin over the figure on the data sheet. Overloading works differently: it shortens the life of the parts that wear fastest anyway.

• The central bearing starts to run in jerks and to make noise, usually weeks before a repair becomes unavoidable.
• Bolted connections at the seats and handrails work loose faster, because they run under heavier vibration.
• The foundation can begin to move, if it was built to the minimum dimensions in the manual.
• The coating cracks where the stresses are highest, and corrosion starts from those cracks.

All four show up at the operational inspection, which EN 1176-7 puts at every 1 to 3 months. If the carousel stands somewhere teenagers or adults ride it regularly, set that interval at the short end of the range. The full inspection regime is set out in the piece on playground inspections.

Capacity and throughput are two different numbers

A head teacher usually asks not about capacity but about whether one unit will cover a break. That is a different calculation. With a ride of two to three minutes, a carousel manages four, maybe five rides in a quarter of an hour. At eight children a ride that comes to thirty or forty children per break, assuming the queue works smoothly, which with children it does not.

For a school of three hundred, one unit therefore means a queue for the whole of every break. Two units of different types solve that better than two of the same, because they separate the age groups instead of concentrating them in one place. The third number to plan around is ground: every unit needs 2 m of clear space around it, and no fence, bench or second unit may stand inside it. That is covered in the piece on the playground safety zone.

When the unit is there and nobody knows its capacity

On older sites it often turns out that nobody can answer the question of what the carousel is rated for, because the documentation went missing when the site changed hands. Start with the identification plate: it should be on the post or the frame and should give the maker, the year of manufacture and the standard. With those details the technical documentation can usually be reconstructed through the manufacturer. We reissue ours for equipment bought years ago, on the strength of the number from the plate or the invoice details.

If the maker no longer exists and nothing can be recovered, capacity is not something to guess from the look of a unit. The assessment of condition and permissible load is made by a technically competent person as part of the annual main inspection, and the findings go into the site file. Until that assessment, it is more sensible to work to a cautious limit than an optimistic one, particularly on a school site where twelve year olds are getting on.

Whether or not the documentation exists, it is worth putting the number of users and the age range on the site rules board. Parents and staff read the board, not a data sheet in a folder, so that is the only place where the information actually does any work.