Learning from the Manhattan Incident: Crane Safety
On Friday, February 5, one person was killed and three others injured when a 565-foot crane collapsed during rush hour in Lower Manhattan. The crawler crane was being lowered into a safe position when the accident occurred.* Although a very devastating incident, when considering the size of the crane, it’s a miracle more damage and fatalities didn’t ensue.
While cranes are an important asset, and often times a necessity, there are hazards involving all aspects of crane use on a construction site. We’ve outlines some tips to ensure you’re as safe as possible.
Preparing the Area
After ensuring a properly trained and authorized crew is selected, the next step is preparing the area where a crane will be used is important to ensure the job gets done safely and efficiently. Consider the following:
- Is the ground firm and level? Softer ground is ideal for a crawler crane, while a mobile truck crane works best on hard, dry ground. OSHA mandates that ground conditions must be drained and graded before a crane can be assembled and used. In addition, supporting materials (e.g., blocking, mats, cribbing) should be used.
- Can the crane safely rotate 360 degrees? Tower cranes and telescopic cranes often need to rotate in order to transport materials, so they need to be able to rotate a full 360 degrees. Make sure there are no power lines or buildings in the crane’s path.
- Is there adequate space for the outriggers? Studies have shown that as many as 50 percent of crane accidents occur because the outriggers are not properly used. Some cranes come equipped with outriggers for added stability and to provide the maximum lifting power. Many of today’s cranes have multiple outrigger positions to adapt to more ground conditions.
- Are access roads provided? Adequate access roads into and through the site are necessary for the safe delivery and movement of derricks, cranes, trucks, other necessary equipment, and the material to be erected.
Once a suitable site for the crane has been selected, work can begin.
Access and Egress
One of the most overlooked hazards when using a crane is simply getting on and off the equipment for assembly, disassembly and use. For example, lattice boom cranes require employees to walk on the boom sections to install and remove pins for assembly and disassembly, creating a hazard. Equipment made after Nov. 8, 2011, must be manufactured with built-in walkways for this type of crane. For equipment made before Nov. 8, 2011, the employer must provide fall protection for employees who are on a walking or working surface with an unprotected side or edge more than 15 feet above a lower level when assembling or disassembling a crane, and more than six feet when performing non-assembly or -disassembly work.
Equipment that is manufactured after this date must be equipped to provide safe access and egress between the ground and the operator work station(s), including the forward and rear positions. Walking and stepping surfaces, except for crawler treads, must have slip-resistant features, such as diamond plate metal, strategically placed grip tape, expanded metal or slip-resistant paint.
Materials often weight several tons, enough to crush just about anything it its path. Riggers must be qualified to perform any rigging work. Follow these tips to prevent accidents and injuries:
- Plan a rigging schedule to avoid rigging above or near areas where other work is being performed.
- Never exceed the maximum lifting capacity of a crane.
- Only use hooks with self-closing latches.
- Inspect straps and chains daily for defects:
- Nylon straps tear easily, so examine them for even the slightest fraying.
- Straps with knots in them can reduce the lifting capacity by up to 50 percent.
- Chain links can crack, stretch, twist or warp.
- Rope can get kinked or fray.
- Never leave materials suspended on a crane for extended periods of time.
Clearly, there are many hazards associated with using cranes on construction sites. However, they are an essential part of many construction projects and can be safe if everyone involved is properly trained.
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