Wind and aerial work platforms: wind limits and machines for indoor and outdoor use

In short: most outdoor aerial work platforms are designed, under EN 280, to work in wind speeds up to 12.5 m/s (45 km/h), measured at platform height. Indoor-only machines are rated at 0 m/s and must never be used outdoors, even on a calm day. Wind gets stronger with height, speeds up between buildings and pushes on everything in the platform. Always check the rating on the data plate and in the manual of your machine and, if the wind picks up, lower and stow the platform.

Wind is one of the most underestimated conditions when working with aerial work platforms. On the ground it may feel like a breeze, but several metres up, against a facade or in a gap between two buildings, the same wind can be well above what the machine is designed for. In this guide we explain why wind matters, what the limits are, how to measure it, which machines are suitable for indoor and outdoor use and what to do when the wind picks up.

Why wind is dangerous on an aerial work platform

When the platform is raised, the wind pushes on the platform, the people, the tools and the structure itself (scissor stack or boom). That force acts far from the ground and adds to the weight of the load in the platform, which reduces the machine's stability margin. In strong wind the platform can sway, functions become harder to control and, at the limit, the machine can overturn.

• Exposed area: the larger the surface the wind can catch (platform, people, materials, panels), the greater the force. That is why you must never increase the platform area with boards, banners or sheets.
• Height: wind is stronger at height than at ground level. IPAF notes that at 20 m the wind speed may be 50% greater than at ground level.
• Gusts: a sudden gust can push the platform against a structure or unsettle the machine, even when the average wind speed is below the limit.
• Funnelling: between tall buildings the wind is channelled and speeds up, and moving out of the shelter of a facade can expose you to an unexpected gust.

What EN 280 says: 12.5 m/s outdoors and 0 m/s indoors

The European standard EN 280-1:2022, which covers the design of mobile elevating work platforms (MEWPs), requires the manufacturer to include wind loads in the stability and structural calculations of machines used outdoors. According to IPAF, the maximum design wind speed in EN 280 is 12.5 m/s, applied horizontally to the structure, the platform, the occupants and the equipment. The standard also has an informative annex on machines used in wind speeds above 12.5 m/s; in that case the permitted value is stated by the manufacturer.

Machines designed for indoor use only are not calculated for wind. They are therefore rated at 0 m/s and marked for indoor use only. The wind rating of each machine is shown on the data plate and next to the platform control station, as well as in the operation and safety manual.

The Beaufort scale: how to recognise the wind

The Beaufort scale classifies wind in forces from 0 to 12. The 12.5 m/s limit falls within force 6 (strong breeze), which ranges from 10.8 to 13.8 m/s. The values in the table are average speeds measured 10 m above open, flat ground, according to MeteoSwiss. Visual signs help you notice that the wind is rising, but they are no substitute for an anemometer.

Note that with a force 5 wind at ground level, the wind at the platform may already be above 12.5 m/s, because wind increases with height. In practice, if large trees are swaying or you can hear wires whistling, it is time to measure carefully or to stay on the ground.

How to measure wind correctly

• Use an anemometer. The most practical option is a handheld anemometer carried in the platform, so you measure at working height. Some machines and sites have fixed anemometers.
• Measure at platform height, not on the ground. The machine's rating refers to the wind at the platform. Measure again once elevated and every time you change position.
• Count the gusts, not just the average. If gusts are getting close to the machine's limit, do not go up, or come down. A gust above the limit is above the limit.
• Check the forecast before the working day. The Portuguese weather service (IPMA) gives the 10-minute average wind speed in km/h and classes 36 to 55 km/h as strong wind. A strong wind forecast is already close to or above 45 km/h and, at height, the wind is stronger still.
• Look at the site. Tall facades, corners, gaps between buildings, openings in industrial buildings and passing high-sided vehicles can create gusts that the forecast does not show.

Indoor and outdoor machines: JLG examples

The JLG range includes indoor-only machines, machines that work indoors and outdoors with the same limits, and machines that allow fewer people or less load outdoors. Some examples, based on JLG specification sheets and the JLG sales manual:

The ES1932 shows the rule clearly: the same scissor lift that carries two people in a warehouse can only carry one outdoors, because two people increase the area exposed to the wind. If the job is outdoors and needs two people in the platform, choose a machine that allows it outdoors. See how to choose between indoor electric scissor lifts and rough terrain scissor lifts, between an electric scissor lift and a vertical mast lift and when a spider lift makes sense.

"Indoor" really does mean indoor

An indoor-only machine must not be used outdoors, even on a day with no wind. JLG and IPAF point out that there is also wind in buildings under construction, in warehouses with doors open and in hangars. If the building has open loading bay doors, unfinished walls or strong draughts, treat the site as outdoors and use a machine rated at 12.5 m/s.

Signs, panels and loads in the platform: the sail effect

The wind rating is calculated for the normal platform, people and equipment. Anything that increases the exposed area acts like a sail and can make the machine unstable, even with wind below the limit.

• Never attach banners, advertising boards or tarpaulins to the platform, not even temporarily.
• Panels, sheets, glass and cladding boards catch a lot of wind. Only carry them if the manufacturer allows it, with approved accessories and within the limits in the manual.
• Accessories such as panel carriers, glazing carriers or painting covers can increase the wind area and may have their own limits. Check the manual or ask the manufacturer.
• Do not add extra mesh or covers to the platform that the manufacturer has not approved.

Wind tunnels between buildings

In urban areas wind behaves differently from the forecast. Between tall buildings the air is channelled and speeds up, eddies form at corners, and a facade can shelter the platform right up to the moment it rises above the roofline or swings past a corner. IPAF highlights these funnelling and shielding effects, as well as the slipstream from aircraft and from lorries near motorways.

• Survey the site before starting and identify gaps, corners and openings.
• Measure the wind at the most exposed point where you will be working, not just at the starting point.
• Watch out for movements that take the platform out of shelter, such as rising above the roof or slewing the boom away from the facade.

What to do when the wind picks up

1. Stop work as soon as the wind approaches the machine's limit or you feel the platform swaying.
2. Lower the platform to the stowed position with smooth movements. On booms, follow the stowing sequence in the manual.
3. Do not drive with the platform raised in windy conditions.
4. Secure or remove loose materials from the platform and the work area.
5. Do not go back up until the measured wind, including gusts, has clearly dropped below the limit.
6. Report it to the site manager and record the stoppage.

With wind above the limit, the machine must stay stowed. If there is a thunderstorm, follow the instructions in the manual and do not stay in the platform.

Planning and responsibilities

Wind should be part of the plan for work at height, not a last-minute decision. In Portugal, Decree-Law no. 50/2005 states that work at height should only be carried out when weather conditions do not put the safety and health of workers at risk, that work equipment should only be used in conditions for which it is suitable, and that self-propelled equipment may only be driven by properly qualified workers. Read more about what the law requires for work at height.

• When preparing: choose a machine with the right rating for the site (indoor or outdoor), check the forecast and set the stop limit in advance.
• On site: have an anemometer available, assess wind tunnels and sheltered areas and check the machine's data plate during the pre-use check.
• During work: the operator measures and decides to stop when the wind approaches the limit. The site manager should back that decision.
• Training: operator training, such as IPAF training (PAL card), covers wind hazards and site assessment.

Need help choosing the right machine?

We are the official JLG dealer in Portugal. We help you choose the right platform for indoor work, outdoor work or both, whether you need new JLG machines or aerial work platform rental. You can check the JLG manuals to confirm the wind rating of your machine.

If you have questions about the data plate or the condition of a machine, request a technical inspection from Trapézio de Prismas or contact us.