By Mike Giroux
If you go into any American city these days, you will notice larger buildings are being built and several other buildings in the city are being rehabbed, not only on the interior but also the exterior. Most of the time, when the renovations on the outside are being done, they are commonly using a suspended scaffolding system, more commonly called a swing stage scaffold.
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There are several methods of suspending a swing stage system on a building. The most common ways in today’s construction is by the use of roof hooks and outrigger beams. For the purpose of this article, we will only speak about a two- point anchor system. There are several other types out there in the real world, but we are just taking a small picture of swing stage scaffolding and expanding it so we can understand how it is rigged.
屋顶钩有两个不同的“口味”，并且两者都用于不同的应用中。钩子都在栏杆墙上使用，然后绑回建筑物或屋顶的实质物体或结构成员。第一类屋顶钩称为锻造钩。它是由一块温和的铁制成的，并被锻造成所需的形状和尺寸。（1）。在悬架端锻造一个环，在该悬架端附着脚手架绳，然后连接到马stirup上。钩子的另一端具有通过锻造孔连接的铁环，该孔用于钩子的绑带。关于锻造钩子，要理解的一个非常重要的事情是，它并非旨在处理与当今的电动秋千系统相关的力。它不符合所需的安全因素，因此只能用于绳索秋季保护锚或手动摆动阶段系统。这些钩子的尺寸开口范围为9至60英寸。
The second type of roof hook which is more commonly used is the flame-cut hook. This type of hook is acetylene-burned from a sheet of steel. It can be cut from different thicknesses and also different alloys. Unlike the forged hooks, these hooks are designed to handle the forces that may be associated with electric swing scaffold. These hooks are also much heavier than their counterpart forged hooks, therefore the practical application of these hooks only range from 9 to about 42-inches for their openings. (2).
无论您使用哪种类型的挂钩，都应在使用这些类型的锚固系统时遵守某些标准。首先，使用正确的钩子对适当的脚手架系统使用正确的钩子。请记住，锻造钩只能用于手动操作系统和绳索降落的保护。无论是手动还是电子，都可以在所有悬浮系统上使用火焰钩，因为它符合与这两个系统相关的所有必需的安全因子。其次，当我们使用钩子时，无论哪种类型，我们都需要保持钩子和栏杆壁之间的三个接触点。这些接触点是面部，钩的顶部边缘和钩的后边缘。（3）。钩子的直径由结构工程师在有执照的索具的帮助或建议下决定。最后，使用两点锚系统，我们需要使两个“侧面”相同。这是什么意思？ If I use as flame-cut hook on one side of the scaffold, I need to use the flame-cut hook on the second anchor point. I cannot use a flame-cut hook on one side and forged on the other side for an electronically operated swing scaffold. Remember, the forged type hook does not meet the safety factors for electric scaffold systems, therefore we must use the flame-cut hooks. Now we can use flame-cut on a manual system and the rope fall protection, but it would be more expensive and heavier to haul up. Again, we won’t be rigging these systems, but we should be aware of the type of materials and devices that are being used.
除了将屋顶钩用于锚固设备外，一些主钻机还可以使用称为栏杆夹的设备。（4）。这些夹具完全按照您的怀疑。它们夹在栏杆墙上，也被绑在一个实质的物体上。当索具使用这些夹具时，它们会出于某些原因而将栏杆填充：首先，因此夹具不会损坏护墙板，其次，因此它们可以获得尽可能多的表面接触。
Hooks and clamps are very easy to use and not very hard to bring up to the top of the roof. However, every building that we respond to does not have a parapet wall or the parapet wall is not structurally sound to use these devices. In this case, you will see another anchor system called outrigger beams. These beams may be made from steel or some type of aluminum alloy. They can come in either one-piece, spliced sections, or telescopic sections. These beams may be I-beams, H- beams, or even square or rectangular tube. (5). One-piece beams usually come in lengths of 12-20 feet and can be difficult to transport both to the job site and up to the roof through the building, particularly if the beam is made of steel and not an aluminum alloy. Aluminum -spliced telescopic sections usually come in eight-foot sections which can be assembled to reach 32 feet in length.
悬臂梁横梁都是由专业的人ufacturers and are designed by their engineers. Based on the situation, the building, and the manufactured system, the engineer will recommend how far the outreach should be and how much counterweight is needed to anchor the system. Depending on where you live and the requirements for outrigger beams, the counterweight could be heavier or lighter based on what governing body you use. In New York State, they require a 4:1 safety factor. However, the Occupational Safety and Health Administration (OSHA) requires a 4:1 factor or 1.5 times the stall torque value of the scaffold hoist used. Some stall torques could be 3000 lbf. Therefore, the New York State Code would use less counterweight than the OSHA Code. In this situation, they should follow the most stringent rule that applies. (see diagram 1A). However, after speaking to several master riggers for swing stage scaffold, I was informed that most manufacturers do not state their stall torque values. In this case, and in most cases, they use the 4:1 factor.
除了to the counterweights, the outrigger beam will also need to be tied back, just as like the roof hooks. The counterweights need to be labeled with their individual weight, must be made of essentially metal or concrete, a non-flowable material. This means that they cannot use sand, water, or concrete chips as a counterweight. Most counterweights are available individually in 50-pound plates. (6). The plates can be rigged in several fashions. They can slide onto the end of the beam, they can be suspended from a 5/16Th梁上的线绳，它们可以使用螺丝扣（7），也可以将两者的组合锚定。配重的方式确实取决于主钻机的理念，屋顶的布局，屋顶的结构组件以及梁本身的长度。
Just for our information, we should know if there is enough counterweight on the outrigger beam to make sure that if we do have an incident, we know that the whole system will not fall down on us and create a more serious situation, or create more of a problem for our victims. There is a very simple formula to find out how much counterweight is needed for the system. Regardless if the outrigger beams are steel or aluminum alloy, finding how much counterweight remains the same. If you look back at diagram 1A, you will see the formula:
CTWT= L x D1 x SF/D2
What this means is the counterweight (CTWT) is equal to the load times the length of the beam from the center front fulcrum to the end that is cantilevered. Then multiply that by the safety factor, which we said would be four unless a governing body has a more stringent safety factor. We then take that number and divide by the length of the beam from the center of the front fulcrum to the end of the beam. That will give us the total counterweights needed for that beam. This same formula would have to be done for the other outrigger beam. This formula is very simple and can be done very quickly to see if the counterweights on the beams are enough to hold the system in place while we perform a rescue. Common weight for counterweights on each outrigger beam is between 1,000-2,500 lbs.
Now I know there is a lot of technical information that may or may not be useful to us when it comes to a swing stage scaffold incident. The point here is that if we do have this type of emergency, we need to send someone to the roof to see if we have any failure in the rigging or counterweights or if it is due to the electric hoist on the scaffold. If we understand how things are rigged and works, we will be able to better help our victims. We can come up with a plan faster and act on that plan with more confidence.
I hope this gave you some insight into the workings of rigging swing stage scaffold. Whenever this type of emergency occurs, use all your resources on scene. These include the master rigger, workers, and foremen. Never be afraid to ask questions to these folks if you don’t understand. Remember, they are the experts in this field, use them to your advantage.
直到下一次，请保持安全并继续培训。
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迈克·吉鲁克斯（Mike Giroux）is a lieutenant and 19-year veteran with the Yonkers (NY) Fire Department. As a nationally certified Fire Instructor I and fire officer, he has taught all aspects of technical rescue for the Yonkers Fire Department, including rescue school, probationary school, and personal escape. He also teaches around the country as a Senior Chief Instructor for Wright Rescue Solutions, Inc. based out of Panama City, Florida. His specialties include high-angle rope rescue, confined space, and structural rope rescue. |
