We are often asked what maximum wind speed a rope access tech can work at. Of course there is no quick answer.
Wind can be deceiving because you cannot tell if it is windy at height.
Besides a freak wind where a tech can be taken by surprise, there is another important element to consider: the wind chill factor.
Overall, the influence of wind is an important factor when working at height.
Determining if you can work on rope depends on:
• The project / industry.
Towers are bound to guidelines.
• Who you depend on.
If you need a crane for hauling or a boat for rescue bystand, they have limits.
• How high you are working.
Height has a definite influence.
• What you are doing.
If you are spray painting, you most likely don't want too much wind.
• Level of protection.
Can you work on the lee side or in a void? Wear goggles, ear plugs, wind proof clothing, etc.
• Wind factor versus cold
The Defence R&D Canada is world renowned for its research in influences of cold temperature on humans
The results are amazing, and the wind chill factor is a definite enemy when you are working at height due to the fact you are more exposed to higher wind speeds.
With so many influences, it almost seems impossible to determine at what wind speed you can work in.
It is safe to say that when a crane operator can't work, the rope access technician can't do his or her work when the crane is needed.
There are no set standards and, although the rope access technician is hanging safely, it is important to realize that other factors will weigh more heavily on decisions that affect the technician on the rope, such as:
A) Possibly tying the ropes off so the tech isn't picked up by the wind.
B) Can tools be used safely without flying all over the place?
In short, you can create a safe workplace if you take everything into account.
From our experience, the average cut-off limit is 35km/h - 10m/s. Keep in mind that it depends on what you are doing.
One of the many factors that cannot be forgotten is the wind chill factor, especially in the winter, when wind can cause the feeling of extreme low temperatures. Simply said, hands / fingers get numb due to the cold, and you need them to be able to operate the ropes...
To determine if you can work or not, we now know that there are many factors and you should keep an eye on on temperature and with whom you are working.
So, say you can work in ideal conditions up to 35km/h winds, the second thing to look at is the temperature. Given a -27°C temperature, you can still perform, as long as you are properly dressed.
Below are two tables, the first of which is from Environment Canada regarding wind chill temperatures versus speed; the second one is a table that translates the different ways often used to describe wind speed.
| Wind Chill Chart | ||||||||||||
| Tair (°C) V10 (km/h) |
5 | 0 | -5 | -10 | -15 | -20 | -25 | -30 | -35 | -40 | -45 | -50 |
|---|---|---|---|---|---|---|---|---|---|---|---|---|
| 5 | 4 | -2 | -7 | -13 | -19 | -24 | -30 | -36 | -41 | -47 | -53 | -58 |
| 10 | 3 | -3 | -9 | -15 | -21 | -27 | -33 | -39 | -45 | -51 | -57 | -63 |
| 15 | 2 | -4 | -11 | -17 | -23 | -29 | -35 | -41 | -48 | -54 | -60 | -66 |
| 20 | 1 | -5 | -12 | -18 | -24 | -30 | -37 | -43 | -49 | -56 | -62 | -68 |
| 25 | 1 | -6 | -12 | -19 | -25 | -32 | -38 | -44 | -51 | -57 | -64 | -70 |
| 30 | 0 | -6 | -13 | -20 | -26 | -33 | -39 | -46 | -52 | -59 | -65 | -72 |
| 35 | 0 | -7 | -14 | -20 | -27 | -33 | -40 | -47 | -53 | -60 | -66 | -73 |
| 40 | -1 | -7 | -14 | -21 | -27 | -34 | -41 | -48 | -54 | -61 | -68 | -74 |
| 45 | -1 | -8 | -15 | -21 | -28 | -35 | -42 | -48 | -55 | -62 | -69 | -75 |
| 50 | -1 | -8 | -15 | -22 | -29 | -35 | -42 | -49 | -56 | -63 | -69 | -76 |
| 55 | -2 | -8 | -15 | -22 | -29 | -36 | -43 | -50 | -57 | -63 | -70 | -77 |
| 60 | -2 | -9 | -16 | -23 | -30 | -36 | -43 | -50 | -57 | -64 | -71 | -78 |
| 65 | -2 | -9 | -16 | -23 | -30 | -37 | -44 | -51 | -58 | -65 | -72 | -79 |
| 70 | -2 | -9 | -16 | -23 | -30 | -37 | -44 | -51 | -58 | -65 | -72 | -80 |
| 75 | -3 | -10 | -17 | -24 | -31 | -38 | -45 | -52 | -59 | -66 | -73 | -80 |
| 75 | -3 | -10 | -17 | -24 | -31 | -38 | -45 | -52 | -60 | -67 | -74 | -81 |
Where Tair = Actual Air Temperature in °C
V10 = Wind Speed at 10 metres height in km/h (as reported in weather observations)
Notes:
• For a given combination of temperature and wind speed, the wind chill index corresponds roughly to the temperature that one would feel in a very light wind. For example, a temperature of -25°C and a wind speed of 20 km/h give a wind chill index of -37. This means that, with a wind of 20 km/h and a temperature of -25°C, one would feel as if it were -37°C in a very light wind.
• Wind chill does not affect objects and does not lower the actual temperature. It only describes how a human being would feel in the wind at the ambient temperature.
• The wind chill index does not take into account the effect of sunshine. Bright sunshine may reduce the effect of wind chill (make it feel warmer) by 6 to 10 units.
• Source: Environment Canada
| Wind speed table | |||
| Beaufort, BFT | m/s | km/h | mph |
| 2 | 2 - 3 | 6 - 11 | 4 - 7 |
| 3 | 3 - 5 | 12 - 19 | 7.5 - 12 |
| 4 | 6 - 8 | 20 - 28 | 12 - 17 |
| 5 | 8 - 11 | 29 - 38 | 18 - 24 |
| 6 | 11 - 14 | 39 - 50 | 24 - 31 |