4.2 Heavy Equipment You May Encounter at the Jobsite
Douglas Rupik, M.Ed., JIW
Identifying Heavy Equipment and Their Function
Equipment and machines have enabled us to increase our productivity as well as take on tasks that would otherwise be too big for us as individual welders. Never forget that just as these machines easily accomplish heavy tasks, they can also easily injure or kill you.
Heavy equipment can be categorized as:
- metalworking or metal forming, such as presses, punches, lathes, etc.;
- handling equipment, such as hoists and lifting equipment;
- aerial platforms and other access equipment; and
- earthmoving equipment
Safe Use of Handling Equipment
Cranes, forklifts, and hoists are so commonly seen and used on jobsites that it is easy to become complacent about safety when around them. However, injury and death can result from improper use of these types of equipment. In fact, as a result of accidents over the years, the government has increased training and credential requirements regarding who is allowed to operate and work with these machines, especially cranes, in construction. It is best to form good habits for working around these equipment and then continue with them for the entirety of your career.
Hoisting equipment is used to lift heavy loads from above and move them. Chain falls and cranes are examples of hoisting equipment. Lifting equipment, such as jacks and forklifts, is used to lift materials from below and then move them.
There is a temptation to use forklifts for both hoisting and lifting. But unless a forklift has the appropriate attachments to be used as a hoist, never hang loads below the forks.
Cranes appear deceptively simple to use, with overhead bridge cranes and jib cranes in shops being the easiest to use. However, you still need training to operate them safely. Misplaced confidence in one’s skills plus an overhead crane with a heavy load is an accident waiting to happen.
Before hoisting an object, answer two questions: How much does the object weigh, and where does the object need to be moved? The answers determine what crane and rigging need to be used. Do not allow the need for a job to be done in a hurry force you, and potentially the entire jobsite, into an unsafe situation. If the crane or rigging is not rated for the load, do not use it!
When you are calculating the load that can be applied to a crane, include the known weight of the object to be moved plus the weight of the crane’s hook and any rigging that will be used. If the weight of the object to be lifted is unknown, do not attempt to lift it. Instead, refer to the shipping information, blueprint, or manufacturer to determine its weight before proceeding.
When using a ground crane for hoisting, such as a crawler crane or boom truck, also include in your calculations how much the crane’s capacity is reduced by increased radius—that is, the further the load is moved away from the crane, the less capacity the crane has. To understand this idea, hold a bucket off the ground directly above your feet. How many bricks can you put in the bucket before you can no longer pick it up off the ground? Now try the same thing while holding the bucket with your arm extended away from your body. Just one brick in the bucket is likely challenging, but certainly fewer than when you lifted above your feet. Cranes experience the same challenge when lifting. Thus, a load that the crane may easily lift next to its base might just tip the crane over if it is swung further away.
Proper rigging—like materials of sufficient strength and size—must be chosen to secure loads before hoisting. A load that is rigged with undersized slings or rigged off-center may fall or swing uncontrollably while being hoisted, risking serious injury and damage to materials. Furthermore, proper signals to workers must be used when working with a crane operator.
Even when you are not directly working with a crane, you may still be in harm’s way. Always be aware of the cranes or other heavy equipment when they are on a jobsite. Never let the load of a crane pass over you, and if you see a load about to travel overhead, move out of its path. A shifting load or a sling that slips or breaks may drop the load on you, resulting in serious injury or death. Likewise, never get under a load suspended by a forklift or other lifting equipment.
Evaluating the ground beneath the crane is a component of hoisting equipment safety that is sometimes overlooked. It must be stable, level, and able to support the weight of the crane plus the load it is lifting. Will operators find out that there is a large sewer main under the crane only after it has collapsed?
In summary, working with cranes is dangerous and requires a lot of precautions. Much training is required before a person is certified or qualified to work as a rigger or signal person. Working with cranes without such training is an unsafe practice that must be avoided. Welders on jobsites should be alert around all hoisting and lifting equipment.
Safe Use of Aerial Work Platforms
There are generally two types of aerial work platforms: boom lifts and scissor lifts. Boom lifts can be telescoping or articulated, and scissor lifts can be designed for indoor or outdoor use. Aerial work platforms are usually self-propelled and powered by gasoline, diesel, propane, or electricity.
Basic safety practices apply to operating this equipment. Never disable or override safety features such as limit switches, do not operate them when the floor or ground is unstable or cannot support the weight of the equipment, and do not operate gas or diesel-powered equipment indoors or any site where exhaust fumes can accumulate to dangerous levels. Also, beware of and avoid high-voltage overhead power lines.
A fall arrest harness is usually not required to operate and use a scissor lift because it has railings and is relatively stable. However, a boom lift should never be used without wearing a fall arrest harness secured to the proper anchor point. The boom arm on a boom lift can act as a catapult if the equipment is driven over rough terrain.
Always use aerial work platforms according to the manufacturer’s recommendations. If you are operating one, be sure you are trained by your employer and follow site-specific safety rules. For instance, some employers or jobsites require the use of a fall arrest harness when operating a scissor lift, and some will not allow a scissor lift to be driven while the platform is elevated. Other employers may require a flagger or spotter on the ground when aerial lifts are in use. Be sure to understand and follow all jobsite safety requirements.
Working Safely Around Earthmoving Equipment
The most important thing to keep in mind when working on a jobsite with earthmoving equipment is that if the operator of the equipment is not aware of your presence, you may be in serious danger. Never walk behind a piece of heavy equipment in use. Always make eye contact with the equipment operator to be sure they are aware of your presence and then verify you have their permission before crossing their path of movement or operation. If the machine rotates and has a counterweight, do not approach from the operator’s blind side, as the counterweight may rotate and strike you, or crush you against a wall or other stationary object. This type of equipment should never be used for anything other than its intended use. For instance, an excavator bucket is designed for digging and not for use as an aerial work platform. It is also not intended to be used as a crane for erecting structural steel.
Always wear a high-visibility vest or clothing and other PPE on jobsites with earthmoving equipment. It is usually very noisy, so always protect your hearing with earplugs or earmuffs. Never cross red danger tape unless you are authorized to do so—likewise, do not enter an excavation that does not have appropriate shoring in place. Always follow employer or jobsite safety rules.
Attributions
- Figure 4.7: Street VX Wire Rope Hoist by Streetcrane is released under CC BY-SA 4.0
- Figure 4.8: Polipasto industrial by Ed9254 is released under CC BY-SA 3.0
- Figure 4.9: Grove Crane in Antarctica by Eli Duke is released under CC BY-SA 2.0
- Figure 4.10: O’Brien 5 Tonne Major Jib Crane by O’Brien Installations Limited is released under CC BY-ND 2.0
- Figure 4.11: Purso 6 by Matti Erikkilä is released under CC BY-SA 4.0
- Figure 4.12: 贝莉儿 NG 2015-04-19 (Unsplash 8Gg2Ne uTcM) by Danist Soh is released under CC0
- Figure 4.13: DCC03042011rvancopp by Rvancopp is released under CC BY-SA 4.0
- Figure 4.14: June 1, 2014 – Bring in the crane! by Washington State Department of Transportation is released under CC BY-NC-ND 2.0
- Figure 4.15: Hebebuehne Scissorlift by Smial is released under CC BY-SA 2.0 DE
- Figure 4.16: JLG 860SJ aerial work platform by High Contrast is released under CC BY 3.0 DE
- Figure 4.17: JLG lift 600SC p4 by Alf van Beem is released under CC0
- Figure 4.18: Genie Z-30-20N articulated boom lift by Grendelkhan is released under CC BY-SA 3.0
- Figure 4.19: Sailors operate a backhoe and an excavator by Official U.S. Navy Page is released under CC BY 2.0
- Figure 4.20: image released under the Pixabay License
- Figure 4.21: image released under the Pixabay License
- Figure 4.22: Work Development by City of Greenville, North Carolina is released under PDM 1.0
A hoist is a device used for lifting loads off the ground, usually by means of chain or rope wrapped around drums or pulleys.
Slings, clamps, or other equipment used to secure a load to a hoisting line or hook.