Considerations when working in wind
By Bill Smith30 March 2016
We can’t see it, but we feel it. It affects driving conditions and 5k race times and game-winning field goal attempts. It affects weather and whether or not planes can take off. And as readers of this magazine are almost certainly aware, especially in light of what happened in New York City in early February, it also affects crane operations.
I’m talking about wind, of course. Or more specifically, wind speed, which likely played a factor in the crawler crane accident in New York City. But wind hasn't just started becoming a factor in crane operations; it’s always been a factor.
I remember that back when I was operating a crane, there was a time when we were lifting and installing panels on the side of a building. There was a slight wind at play, only about 15 to 20 mph, if I remember right. The problem wasn’t the capacity on the crane – the crane had more than enough capacity for what we were lifting – the problem was that the wind was making it difficult to control the load. We had tag lines on the panels, and had to slowly swing them towards the workers, where they would grab the lines to stop the load. Many times the circular motion would jerk the workers as they tried to stop the spin.
Scenarios like the one I just described are what crane operators have to deal with many times on many jobs, almost every day. There are probably only a few days in a calendar year that there’s little or no wind in the forecast. This means that wind is very real, very common variable we have to deal with.
Understanding the invisible
To begin understanding wind, we to need to understand that it can have both a direct and indirect affect on cranes. Direct effects result in a change to the structural integrity or stability of the crane. Indirect effects refer to variables like the one I described earlier – how wind forces can cause a load on the hook to move suddenly, and without warning.
Both indirect and direct effects can have disastrous outcomes, which makes understanding how to work (or not work) with wind so important. To be absolutely clear, though, what I’m not saying is that cranes cannot or shouldn't operate in windy conditions. In fact, as many of you know, it’s quite the opposite: cranes are designed to work in wind and rated to withstand certain wind speeds.
Have you ever walked around the corner of a building and been blown away by the wind? I’m sure all of us have. Wind speed can be measured on one side of a building as too high to operate safely, and the opposite side of the same building can measure wind speeds that don’t pose a problem. Technically, a crane could be safely operated on one side of the building. But the question is: should you? Each jobsite, and each jobsite’s working conditions are different – lift directors and site supervisors take into consideration precautions for weather as one of the many variables to planning a safe operation. There is no one-size-fits-all rule that can guarantee success.
According to the OSHA Small Entity Compliance Guide titled, “Bad Weather Precautions”: “When a local storm warning has been issued, the competent person must determine whether it is necessary to implement manufacturer recommendations for securing the equipment. The competent person must adjust the equipment and/or operations to address the effect of wind, ice, and snow on equipment stability and rated capacity.”
OSHA also writes about load charts and wind speeds on their website.
Load charts do not generally take wind speeds into consideration. If the load chart or the operating manual does not have information on wind speeds and derating information, the crane manufacturer should be consulted. The procedures applicable to the operation of the equipment, including rated capacities (load charts), recommended operating speeds, special hazard warnings, instructions, and operator’s manual, must be readily available in the cab at all times for use by the operator. (See 29 CFR1926.1417(c)) The maximum allowable wind speed and derating information need to be posted conspicuously in the cab or on the load chart.
So what OSHA says is threefold:
- Load charts do not generally take wind speeds into consideration.
- The crane manufacturer should be consulted if the operating manual doesn't have wind speed information.
- Operating procedures, maximum allowable wind speeds, special hazards, warnings, and instructions need to be posted conspicuously in the cab.
As I refreshed my memory on OSHA verbiage, I found myself thinking about what a crane manufacturer might have to offer, so I reached out to Mark Krajci, product manager for all terrain cranes at Tadano America. I asked him for a list of five practical points to consider when it comes to wind, and here’s what he came back with.
Prior to a lift, you should anticipate and study the possible effects of wind on the load on the crane. The larger the load and sail area, the lower the wind speed the load can safely be lifted in. (There is a formula for this in every operator’s manual.)
- Prior to any lift, check the latest weather reports for possible high wind conditions and plan accordingly. The Site Supervisor, the Lift Director and the Operator all have a part in this plan.
- Always have access to and know where the Beaufort wind chart and deduction notes are located in the operator’s manual and load charts.
- It is essential that the crane be properly set up. Out of level cranes only get worse in high-wind conditions
- Never carry out lifting operations when the permissible wind speed has been exceeded. Know what this speed is, and, if equipped, use the anemometer.
Like virtually everything else pertaining to crane operations, understanding how wind affects a lift or a job or a workday is critical to ensuring safety and preventing accidents. Wind is one of those variables we can’t see, but that doesn't mean we can’t make it front and center each time we go to work.
In my experience, the most critical daily challenge from wind, as it pertains to crane operation, is how one goes about controlling a load. Wind affects many things in a crane lift, including the crane’s capacity, but even a slight wind makes it challenging for the operator to keep the load steady. Load drift, load spin, swinging the boom, and holding the load in place are all factors the operator has to adjust for, and work to control, when wind is present. Understanding the risk and preparing accordingly is the only way to truly mitigate adverse outcomes.
The NBIS Risk Management team proudly serves on the ANSI B30.5 standards committee, as well as the SC&RA Crane Safety Committee, providing regulatory guidance to members and policyholders regarding safe work practices. Talk to your insurance agent to Experience the Difference ™ our team of industry experts can have on your operations and insurance coverage. Call 1-877-860-RMSS or visit us online at www.NBIS.com.