From what wind force does the outdoor use of work platforms become a risk?

A sudden gust of wind at 25 metres height can cause a work platform to tip over, even when the nominal load of the platform is not exceeded at all. Wind load acts in addition to the weight force of the person, tools and material and fundamentally changes the stability behaviour of the machine. For site managers who use scissor, articulating boom or truck-mounted work platforms in the open, the question of the permissible wind speed is therefore not a side issue but one of the central safety decisions before every outdoor assignment.

Mobile elevating work platforms are, in accordance with DIN EN 280, generally designed for a maximum wind speed of 12.5 metres per second – this corresponds to 45 kilometres per hour or wind force 6 on the Beaufort scale, colloquially referred to as "strong wind". At this wind force, whole branches are already moving and the use of umbrellas becomes difficult – a reference point that is easy to grasp for construction-site practice.

Important here is the restriction: 12.5 m/s is the design value most commonly used in the industry, but it is not a universal law. The actually permissible wind speed is model-dependent and must be looked up in the operating instructions of the respective machine. Some machines, in particular compact scissor lifts with a large wind-attack area when the platform is extended, may prescribe lower limit values. Anyone who relies blindly on the general guide value without checking the specific equipment manual takes an incalculable risk.

Since a precise anemometer is rarely to hand on construction sites, the Beaufort scale helps with a quick assessment on site. From wind force 4 (moderate wind, about 20 to 28 km/h), thin branches already move noticeably, which can lead to perceptible oscillations on work platforms at great height. Wind force 5 (fresh wind, 29 to 38 km/h) sets larger deciduous trees in motion. At wind force 6 (strong wind, 39 to 49 km/h, corresponding to around 12.5 m/s) the critical limit for most mobile elevating work platforms is reached. From wind force 7 (near gale) and upwards, the outdoor use of work platforms is without exception considered impermissible.

Anyone who works regularly in the outdoor area should not rely on their own feeling for the wind, but should make a local weather warning or a simple wind-measuring device a fixed component of the daily planning. Many modern construction-site weather stations deliver live values that can be directly compared with the Beaufort classification.

The stability of a work platform is determined by the interaction of dead weight, loading, outreach and wind-attack area. While the loading acts as a vertical force, the wind attacks the structure laterally – at the platform, at the boom and at the persons in the basket. For the calculation of the wind load, an attack area of 0.7 square metres per person is usually assumed, which flows into the stability calculation in addition to the platform area itself.

With articulating boom lifts, this effect intensifies with increasing outreach: the further the boom is extended laterally, the larger the lever arm becomes over which a lateral wind force acts on the tipping point of the machine. For this reason, many manufacturers prescribe lower permissible wind speeds at maximum outreach than in the basic position. Scissor lifts are less affected by this effect, since their lifting movement is purely vertical, but here too the wind-attack area increases continuously with the platform height.

When a Roto telehandler with a personnel basket is used as a mobile elevating work platform, in addition to the base standard DIN EN 280-1 the standard DIN EN 280-2 applies, which is specifically valid for work platforms with load-lifting attachments. Details on this are summarised in the guide on DIN EN 280. For the wind consideration, this means in practice: the dynamic load-moment control of modern equipment takes into account not only the pure basket loading, but also the current outreach and the angle of inclination – parameters that come under additional pressure with wind influence. Older equipment that only monitors the nominal load provides no differentiated feedback here and is to be treated correspondingly more cautiously with wind influence.

If the permissible wind speed is exceeded during use, the platform must be lowered without delay and operation stopped – regardless of how far the current task has progressed. Continuing to work "until the next break" is not a justifiable option, since wind gusts can lie significantly above the average value in the short term, even when the mean wind speed still appears to be within the permissible range. Site managers should define this stopping point already in the deployment planning, so that the decision at the concrete moment does not depend on the individual discretion of the operator under time pressure.

Wind speed and tip-over stability are not an isolated topic, but belong in every risk assessment that is prepared before the outdoor use of a work platform. In addition to the pure wind forecast for the day of use, this also includes the assessment of the surroundings: building edges, passages between high-rise buildings or open areas can generate local wind amplifications that lie significantly above the general weather forecast. Anyone who is unsure how wind load should systematically flow into their own risk assessment finds, in the guide on UVV inspection and equipment documentation, the organisational classification of which inspection and documentation obligations additionally apply for the respective platform type.

At permanently wind-exposed locations – for example on high-rise roofs, bridges or free-standing façades – it is worth taking a look at the wind-attack area already during the equipment selection. More compact diesel scissor lifts with a smaller platform area offer the wind less attack area than large models with extended platform extensions. Details on the available diesel rough-terrain scissor lifts are summarised in the corresponding guide. For articulating boom lifts, consultation with the Luibl Rental team on the specific wind class of the respective model is advisable, in particular for assignments with a presumably high outreach.

From what wind force must the use of a work platform be aborted? The limit value common in the industry is 12.5 m/s (45 km/h, Beaufort 6). The actually permissible value for the specific equipment is in the operating instructions and can be lower.

Does the wind limit value also apply indoors? No, the wind-load limit concerns exclusively outdoor use. Indoors, this hazard does not apply, although other factors such as draughts through open gates should be taken into account in individual cases.

How can I assess the wind speed on the construction site without a measuring device? The Beaufort scale offers practical reference points: if whole branches are already moving and the use of umbrellas becomes difficult, wind force 6 and thus the critical limit is usually reached.

Does the permissible wind speed change with the outreach of the platform? Yes, with articulating boom lifts the permissible wind speed often decreases with increasing lateral outreach, since the lever arm for the wind force increases. Manufacturer specifications are decisive here.

Does the same wind limit apply to Roto telehandlers with a personnel basket as to classic work platforms? Fundamentally yes, but the standard DIN EN 280-2 for load-lifting attachments additionally applies. The dynamic load-moment control of modern equipment indirectly includes wind influence via outreach and angle of inclination.

Questions about the right machine for wind-exposed places of use are answered by the Luibl Rental team during service hours Mon–Fri, 08:00–17:00.

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