At what wind force does outdoor use of aerial work platforms become a risk?
A sudden gust of wind at a height of 25 metres can tip over an aerial work platform, even if the rated load of the platform has not been exceeded. Wind load acts in addition to the weight of people, tools and materials and fundamentally changes the stability of the machine. For site managers using scissor, articulating or truck-mounted platforms outdoors, the question of the permissible wind speed is therefore not a minor matter but one of the central safety decisions before every outdoor job.
The standard value: 12.5 metres per second as the industry benchmark
Mobile elevating work platforms are generally designed to EN 280 for a maximum wind speed of 12.5 metres per second. This corresponds to 45 kilometres per hour or force 6 on the Beaufort scale, commonly referred to as a "strong breeze". At this wind force, whole branches are already moving and using an umbrella becomes difficult: an easily recognisable reference point for practice on site.
The important restriction is this: 12.5 m/s is the design value most commonly used in the industry, but not a universal law. The actual permissible wind speed depends on the model and must be checked in the operating manual of the machine in question. Some machines, especially compact scissor lifts with a large wind-exposed area when the platform is extended, may specify lower limits. Anyone who relies blindly on the general guide value without checking the specific machine manual is taking an incalculable risk.
The Beaufort scale as a practical classification tool
As a precise anemometer is rarely to hand on site, the Beaufort scale helps with a quick assessment on the spot. From force 4 (moderate breeze, around 20 to 28 km/h), thin branches already move noticeably, which can cause perceptible vibrations on aerial work platforms at great heights. Force 5 (fresh breeze, 29 to 38 km/h) sets larger deciduous trees in motion. At force 6 (strong breeze, 39 to 49 km/h, corresponding to around 12.5 m/s), the critical limit for most aerial work platforms is reached. From force 7 (near gale) upwards, outdoor use of aerial work platforms is considered impermissible without exception.
Anyone who regularly works outdoors should not rely on their own feeling for the wind, but should make a local weather warning or a simple wind gauge a fixed part of daily planning. Many modern site weather stations provide live values that can be compared directly with the Beaufort classification.
Why wind load affects stability differently from payload alone
The stability of an aerial work platform is determined by the interaction of its own weight, payload, outreach and wind-exposed area. While the payload acts as a vertical force, the wind acts laterally on the structure: on the platform, on the boom and on the people in the basket. To calculate the wind load, an exposed area of 0.7 square metres per person is usually assumed, which is included in the stability calculation in addition to the area of the platform itself.
With articulating boom lifts, this effect increases with outreach: the further the boom is extended sideways, the greater the lever arm through which a lateral wind force acts on the machine's tipping point. For this reason, many manufacturers specify lower permissible wind speeds at maximum outreach than in the stowed position. Scissor lifts are less affected, as their lifting movement is purely vertical, but here too the wind-exposed area increases continuously with platform height.
Roto telehandler in basket mode: additional standard requirements
If a roto telehandler with a personnel basket is used as an aerial work platform, the standard EN 280-2, which applies specifically to platforms with load handling devices, applies in addition to the basic standard EN 280-1. Details are summarised in the guide to EN 280. In practice, this means for wind assessment: the dynamic load moment control of modern machines takes into account not only the basket load but also the current outreach and angle of inclination: parameters that come under additional pressure in windy conditions. Older machines that only monitor the rated load do not provide differentiated feedback here and should therefore be handled with greater caution in windy conditions.
What to do if the limit is exceeded
If the permissible wind speed is exceeded during use, the platform must be lowered immediately and operations stopped, regardless of how far the current task has progressed. Continuing "until the next break" is not an acceptable option, as gusts can briefly be well above the average value, even if the mean wind speed still appears to be within the permissible range. Site managers should define this stop point in the job planning so that the decision at the critical moment does not depend on the individual judgement of the operator under time pressure.
Wind load as part of the risk assessment
Wind speed and stability are not an isolated topic but belong in every risk assessment carried out before an aerial work platform is used outdoors. In addition to the wind forecast for the day of use, this includes assessing the surroundings: building edges, passages between high-rise buildings or open areas can cause local wind amplification well above the general weather forecast. If you are unsure how wind load should be systematically included in your own risk assessment, the guide to periodic inspection of work equipment and machine documentation explains the organisational framework and which inspection and documentation requirements also apply to the platform type concerned.
The right machine for wind-exposed locations
At permanently wind-exposed locations, such as high-rise roofs, bridges or free-standing facades, it pays to consider the wind-exposed area when choosing the machine. More compact diesel scissor lifts with a smaller platform area offer less surface to the wind than large models with extended platform decks. Details of the available rough-terrain diesel scissor lifts are summarised in the relevant guide. For articulating boom lifts, it is advisable to consult the Luibl Rental team about the specific wind class of the model concerned, especially for jobs with expected high outreach.
FAQ: wind speed and stability of aerial work platforms
At what wind force must the use of an aerial work platform be stopped? The usual industry limit is 12.5 m/s (45 km/h, Beaufort 6). The actual permissible value for the specific machine is stated in the operating manual and may be lower.
Does the wind limit also apply indoors? No, the wind load limit applies only to outdoor use. Indoors this hazard does not apply, although other factors such as draughts through open doors should be considered in individual cases.
How can I estimate wind speed on site without a measuring device? The Beaufort scale provides practical reference points: if whole branches are already moving and using an umbrella becomes difficult, force 6 and thus the critical limit has usually been reached.
Does the permissible wind speed change with the platform's outreach? Yes, with articulating boom lifts the permissible wind speed often decreases as lateral outreach increases, because the lever arm for the wind force becomes larger. The manufacturer's specifications are decisive here.
Does the same wind limit apply to roto telehandlers with a personnel basket as to conventional aerial work platforms? In principle yes, but the standard EN 280-2 for load handling devices also applies. The dynamic load moment control of modern machines takes wind influence into account indirectly via outreach and angle of inclination.
Questions about the right machine for wind-exposed locations are answered by the Luibl Rental team during service hours, Mon–Fri, 08:00–17:00.