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Module 6 of 8 · 15 min

Wind, storms and weathervane mode: when the crane stops and how it is left at the end of the day

Free tower crane operator (licence) course: read the module, review with the questions and move on to the next one. At the end, a test and a PDF certificate.

Module 6 of 8 · Course contents

Wind is the tower crane's enemy: it increases the overturning moment, swings the load and, out of service, can bring the crane down if it is not left free to turn. The ITC sets concrete numbers.

Wind limits

  • Anemometer: intermittent warning at 50 km/h and continuous at 70 km/h (article 5.4).
  • The maximum wind speed allowed for working with the crane is 72 km/h, «or the one the manufacturer indicates, if lower» (annex IV, point 4). NTP 701 recalls that, when the anemometer sounds continuously, work stops.
  • With strong winds or an electrical storm nearby, work is interrupted, the manufacturer's measures are taken, the crane is left in weathervane mode and the power is cut at the main site board (annex IV, point 3).
  • The general rule of Royal Decree 1215/1997: the outdoor use of equipment lifting unguided loads must cease when weather conditions deteriorate to the point of endangering safety, with measures to prevent overturning (annex II, point 3.2.g).

What weathervane mode is

Leaving the jib free to slew so that it aligns itself with the wind and does not take the wind's push from the side. It is a safety device on the ITC's list (annex III, 6.10) and the anemometer stops sounding when the crane is in weathervane mode (article 5.4).

At the end of the working day (annex IV, point 5.1.2)

  1. Take the trolley close to the tower.
  2. Set weathervane mode: with a manual device, operate the lever; with an electric device, press the weathervane button.
  3. Press the stop button on the push-button panel.
  4. If the crane travels, fit the clamps that fix it to the rails.
  5. Cut the power at the crane's board and at the main board.

And at the start of the day, the first thing is to disconnect weathervane mode before operating the crane (annex IV, point 5.1.1).

Power lines and other cranes

  • If there are overhead power lines affecting the site, they must be diverted or de-energised; if that is not possible, barriers or notices (Royal Decree 1627/1997, annex IV, part C, point 10.c). Against high-voltage lines, NTP 701 recommends a safety clearance of at least 5 m, measured in vertical projection.
  • If two or more cranes overlap their working areas, measures must be taken to avoid collisions between loads or elements (Royal Decree 1215/1997, annex II, point 3.2.a). Siting with several cranes and the safety zone are part of the licence's theory syllabus (annex VI).
In practiceMid-afternoon the anemometer goes from beeping to a continuous sound: 70 km/h. You set the load down, take the trolley to the tower, set weathervane mode, stop and climb down. You do not wait «to see if it eases off» with the load hanging. And at night the crane is always left in weathervane mode, even if there is no wind.

Source: Real Decreto 836/2003, ITC MIE-AEM-2 del Reglamento de aparatos de elevación y manutención, grúas torre (tower cranes, consolidated text, in Spanish), article 5.4 and annex IV, points 3, 4 and 5.1.2 · Real Decreto 1215/1997, disposiciones mínimas de seguridad y salud para la utilización de los equipos de trabajo (work equipment, consolidated text, in Spanish), annex II, point 3.2 · Real Decreto 1627/1997, disposiciones mínimas de seguridad y salud en las obras de construcción (construction sites, consolidated text, in Spanish), annex IV, part C, point 10 · INSST, NTP 701: Grúas torre. Recomendaciones de seguridad en su manipulación (tower cranes: safety recommendations for their handling, 2005, in Spanish), wind and power lines

Module practice test

6 new questions, different from the final test. Tap an answer to see whether it is right, why, and which rule it comes from.

1. What is the purpose of leaving the crane in weathervane mode (puesta en veleta)?

2. Where is the trolley taken before putting the crane in weathervane mode at the end of the day?

3. If the crane travels on rails, what is fitted when it is left out of service?

4. What is the first thing done at the start of the shift before operating the crane?

5. If two cranes overlap their working areas, what does Royal Decree 1215/1997 require?

6. What safety clearance does NTP 701 recommend from high-voltage lines?

Course contents