By Andy Speier
Published Saturday, January 1, 2011
| From the January 2011 Issue of FireRescue
Look at any metropolitan skyline and you’ll see tower cranes. Such cranes run anywhere from 86 to 262 feet in height; when attached to a building, they can be more than 400 feet in height. Operators of these cranes work in a booth or cab located at or near the top of the crane. If they require medical assistance, you’ll need to access them via ladders and know how to extricate them from the cab.
There are two key personnel in tower crane operations: the operator and the bellman. The operator works in the cab and, due to the height and energy required to make the climb, they often stay in the cab their entire shift. The bellman works below and serves as the operator’s eyes for the operation.
The rescue and removal of a tower crane operator can be broken down into four phases:
- Hazard Identification
The hazards of crane rescue involve several areas:
- The site. Ask the site foreman or site safety person what type of work is being done at the site. Shut down any equipment that will interfere with your operation and safety.
- The crane. The bellman can tell you the crane’s height and distance from the departure point to the ground, and if there’s an auxiliary winch that you can use to haul your equipment up to the machine deck.
- The ladders. Climbing the crane will involve climbing up unprotected ladders, enclosed ladders or steep stairs. Carry and wear the appropriate PPE: an Aztec kit, a cow’s tail lanyard, a buck strap or a pick-off strap and a Class III harness with side-positioning rings. If climbing an unprotected ladder, you’ll need a cow’s tail or something similar so you can maintain a point of contact with the ladder. The ladder rungs are often greasy, so when climbing, don’t grab the rungs; use the beams, and wear gloves. This is especially important when climbing temporary ladders constructed on-site from lumber. Rungs can become loose; always verify that temporary ladders and bridges are secure.
- The climb. There are many sharp objects that can grab your clothing and equipment. Smacking your knee against a large bolt may make it difficult to complete your ascent. And make sure your equipment doesn’t hang past mid-thigh. Stow loose rigging gear in a backpack or fanny pack.
- Inside the cab. In an 8-hour period, the operator will empty their bladder several times. Be prepared to find bottles filled with urine inside the cab, which can become a trip hazard. Before entering the cab, get the patient’s name, age and, if possible, weight. This will help you to determine how you’ll extract them from the cab.
Access to the operator is through the top, the rear or the bottom of the cab. When working with a bottom-entry cab, rescuers must gain access to the top emergency hatch if the operator is unconscious. There’s no ladder to the top of the cab, so someone has to climb up the exterior using whatever hand-holds they can find. They should also bring some sort of tool to force open a rusty, bent access hatch. Once inside the cab, they’ll need to pull the operator off the seat so they can open the bottom hatch from the inside.
Newer cabs have top- or rear-entry access and more space, but remove any additional items, such as a small refrigerator, that take up valuable work space.
The newer, larger cabs have increased tempered glass surrounding the cab. The operator’s feet rest on steel crossbars with the glass below their feet. Their weight is on the steel bars, not the glass. As a rescuer, when you climb in front of the operator, you’re standing on this steel structure as well, and there’s not a lot of space between you and the glass. It’s very easy to turn and have a brake rack or carabiner contact the glass, which can shatter it. The bottom line: Be careful when working in the cab! Avoid having loose gear on your harness gear loops. Use a removable gear sling and remove it prior to entry, or carry your rigging gear in a harness pouch.
The crane operator’s controls are located in front of the seat and along the armrests. While attempting to move the patient from the chair, you may inadvertently depress the joystick, moving the crane. To avoid crane movement, shut off the power using the red button.
The operator’s seat can recline back far enough so that you can slide the operator head-first out of the chair. As the operator will more than likely not be wearing a harness, you’ll need to package them in something for extraction. An LSP Halfback or Spec Pak is an ideal tool to use because it can be used for lowering once the patient has been extracted. Note: If you anticipate hang times of more than 15 minutes, use the Spec Pack spreader bar designed for extended hang times.
With a top-entry access cab, you’ll need to rig a system that allows you to raise the patient and then convert the system to a lower. The secret to success: securing a change-of-direction pulley high enough above the cab so that it doesn’t interfere with the extraction. Consider the use of a pulley to deflect the line slightly to ensure a straight overhead pull. But check to see where the patient needs to be lowered to the ground. Will the deflection of the line help you, or will you need to change or move it? If you plan to slack or tension it, consider making the anchor of that pulley releasable. A load-releasing hitch or a set of fours (mini 4:1 MA haul system) can also work.
Cabs that have rear-entry access will be the easiest to operate from. There’s a small deck at the rear door but that area quickly gets crowded because the cab door opens out to give the operator more room in the cab. As with the top-entry cab, use a lowering system that runs through a high change of direction. This will allow you to remove all slack from the system prior to lowering. Vectoring may be helpful as well.
While one member secures the patient in an appropriate extraction device, other members of the team can start the rigging. Next, connect the patient to the rope system so that they’re moved from the cab to the deck and continue moving over the edge and on their way down.
Handrails that wiggle when you shake them are probably removable; removing them can save you the effort of lifting the patient over the handles. Tip: Whatever you do, don’t drop the handrails. And once they’re removed, all personnel operating on the deck or catwalk must wear a travel-limiting device.
Tower cranes are often found in congested areas. Ensure that all edge protection and any other equipment being rigged is secure. Have the drop zone below you cordoned off to prevent any dropped items from striking someone. Make sure any equipment attached to your harness or gear sling is properly attached.
Anchoring on a tower crane is relatively easy because there are many large steel cross braces and vertical steel members that are easy to wrap with a rigging strap or webbing. Running the mainline up through a high change-of-direction will reduce the awkward and difficult transition over the edge. If the belay line is anchored even with the belayer’s waist or slightly higher, it will help them work in a more comfortable position on the lower once the patient moves over the edge. Tip: The edge may be a sharp, so place a rope sleeve or canvas pad underneath the belay line as well as the mainline. Keep in mind that the bellman can rotate the crane if needed so that your patient ends up in a more ideal location.
- When lowering the patient to the ground, lock the crane in fixed mode, which is acceptable in winds up to 41 mph. For higher winds, the bellman will need to put the crane in weather vane mode.
- When rigging anchors on the crane, make sure that you haven’t tied off to something that’s designed to move.
- When climbing enclosed ladders, avoid carrying a large pack or gear bag, as it will be difficult to climb with it. When carrying equipment on a shoulder, sling it over your head, otherwise it will end up hanging off your wrist and you may drop it. If the access ladder allows, consider trailing a rope behind and pulling it up when you arrive at the machine deck. Think about what equipment you’ll need and keep resources available to carry it up if needed. Recognize that the equipment mules may not be available for much “heavy” work until they get a break, because climbing with a load of gear is hard work.
- Rigging the high change-of-direction anchor may involve the rigger climbing out onto the mast to get the anchor and pulley in the right location. This exposure may cause the rigger a bit of anxiety. Team leaders must know how much they can push their personnel, and team members must know their limits.
- It may be too time-consuming to have a second person physically climb and check another’s rigging. Therefore, once a task is completed, the rescuer should call to the safety officer on the deck and walk them through their rigging.
- Radios will be essential for communications, but they’re easy to drop, so secure them in pouches with strap enclosures. Consider taking several spare batteries with you.
- Will your mainline be long enough after it’s routed through a high change-of-direction pulley? Consider bringing a longer rope and/or additional ropes and tying them together. Your personnel should be proficient with knot passing so the patient doesn’t have to wait 10 feet off the ground as the crew realizes that they were close but not close enough.
- A tag line can be of benefit but it means carrying up an additional line. Depending on where you want the patient to end up and their position in relationship to the mast, it may be worth it. The tag line doesn’t have to be a 12.5-mm rescue rope. It can be a smaller-diameter rope, which will be lighter. You can even tie several shorter lengths together.
A Final Word
Crane rescues are inherently complex and difficult, made even more challenging because of their low frequency. With the proper training and preparation, you can ensure that you and your team extract the patient and get them to the ground where they can receive the medical help they need.
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