COMMITTED TO SAFETY AND VALUE ENGINEERING - SINCE 1985
Tag

fall protection anchors Archives | DH Glabe & Associates

Choosing the Correct Fall Protection System

By | Blog, Fall Protection | No Comments

While the construction and engineering industry does come with a certain amount of inherent risk, contractors can be proactive about safety on projects. OSHA sets strict guidelines regarding fall protection measures because falls are commonly responsible for serious workplace-related injuries and deaths. The National Safety Council finds that falls from height are the reason for the most non-fatal days of missed work. Keeping this in mind, contractors and engineers should ensure that all employees receive regular preventative training. Additionally, when working from any height, workers should be provided with the appropriate fall protection system.

Read More

Trust the Math for Your Eyes May be Deceived

By | Fall Protection, Resources | No Comments

 An inside look at why fall protection anchors must be tested

Fall protection!  When you put on your harness, tie off to a fall protection system, and step to the edge of the roof on a 20 foot tall building, do you know that you are truly safe?  Or is this maybe just a false sense of security that you have been lulled into?  Would you feel different if this were a 200 foot tall building?

As we all know, the components of a complete fall protection system are the user’s personal fall protection equipment and a suitable anchor or lifeline to connect it to.  If the system is properly designed, constructed and used, it will ensure that you will walk off the jobsite at the end of the day safe and sound.  As a user, you can only control the “use” aspect of the system so a great deal of responsibility is on you to ensure your own safety.  If you are a gambler, you can take your safety on faith.  However, those who do not want to rely on dumb luck need to know their fall protection system.

First, the simple stuff: your body harness and lanyard.  They should be purchased from a reputable source with readily available design and testing data from the manufacturer.  Utilizing your Fall Protection User Training, you should be able to perform a visual inspection of the equipment to check for damage or excessive wear.  If all looks good, you should feel comfortable that your personal fall protection equipment will do its job.

On the other hand we have the anchor portion of the system – this is not so easy.  You can look for visible signs of damage or corrosion, but the truth of the matter is that in most cases you have no idea what is behind or underneath the anchor itself.  It is in these areas where corrosion hides and maintenance tends to neglect.  The truth of the matter is that if the anchor was not designed and installed properly, no amount of maintenance can make it safe to use!  You may be thinking the anchor is fine and dandy because that steel beam over there is “big”, or that wall looks “solid” . . . there is no way that it won’t hold 5,000 pounds!  This may be true, but as you stand there looking at the “big” steel beam ask yourself this: what is holding the beam in place?  Okay there is a steel column at both ends, but what are they attached to?  If you don’t know, how can you really be sure that “big” steel beam isn’t going to follow you over the edge of the roof if you fall?

OSHA requires that all permanent fall protection anchors must be tested upon installation and be visually observed annually if they are to remain active.  The fact of the matter is that many property owners simply do not know about these requirements as many building anchors are used daily which have never been tested or inspected.  This puts you at risk of injury, and the property owner and your employer at risk of a hefty lawsuit if something were to go wrong.

We were recently involved in a project which involved the load testing of existing fall protection anchors around the perimeter of the mechanical penthouse.  The anchors were installed on the outside face of the brick veneer and consisted of a steel eye welded to the center of an 18”x6”x 1/8” thick steel plate.  The plate was bolted to the wall with two ½” diameter threaded rods and nuts at both ends.  On this particular structure, we could observe that the other end of the connection inside of the penthouse was identical to the connection on the outside.

Existing anchors outside of mechanical penthouse.

Existing anchors outside of mechanical penthouse.

 

Existing anchors inside of mechanical penthouse

Existing anchors inside of mechanical penthouse.

 

From the pictures above, you may be thinking it looks like someone clearly put some thought and effort into installing these anchors so they must have been designed and installed properly.  No rust is apparent and the wall appears “solid” . . . why do they need to be tested???  The reason we were asked to test the anchors is because someone didn’t feel like gambling as they prepared to hang off the side of the building and asked the correct question “can I get a copy of the latest testing and inspection reports?”  As it turns out there was no record that the anchors had ever been tested or inspected, and more disturbing that they may have never been designed either.  Fortunately in this case, the property owner and contractor were well aware of the OSHA requirements and requested the anchors be tested before use.

Armed only with a single architectural section of the penthouse wall, we felt it would be prudent to perform a structural investigation prior to performing any testing.  During this investigation we discovered that the two threaded rods were installed adjacent to the light gauge steel studs at most locations.  Running a computer modeled analysis of this configuration yielded results which confirmed that not only were the anchors not suitable for their intended use, but that testing them could potentially damage the building!

Since the existing anchors were determined to be inadequate, new anchors were designed and installed and the old anchors removed and/or taken out of service.  During the testing of the new anchors, we were asked to test one of the existing anchors in a location that a new anchor could not be installed due to equipment conflicts inside the building.  The test was halted at only 1400 pounds as the outside plate had already deflected ½ inch with this minimal load applied to it!

 

Picture during testing of existing anchor

Picture during testing of existing anchor.

 

The topic of fall protection anchors is cussed and discussed all the time, but we still have individuals who are either uninformed regarding the OSHA standards or they simply don’t care.  The anchor may look “big”, and that wall may appear “solid”, but the only way to know with certainty that it is safe is through proper testing and annual observation.  As a user, you need to be cognizant of your own safety and simply ask for the latest fall protection anchor testing or inspection report before you go trusting your life to it.  This will provide you with peace of mind, and you may educate someone else about the OSHA standards in the process which may save another life down the road.

The Quick Fix

By | Fall Protection, Resources | No Comments

Life is good when we get the quick fix! As children, our restless minds never want to work out the solution; just tell us the answer. Never mind how to get that answer. As adults, I’m not convinced our attitudes have changed much. Only the stakes have changed. We still strive for those easy answers, even if it is scaffolds or fall protection.

 

So goes fall protection for scaffold erectors. Give the erectors an easy solution and we don’t have to worry about the details. We don’t have to study the problem. We don’t have to gather the facts. We don’t have to work at the solution. We don’t have to recognize the laws of physics. In our search for the quick fix, we ignore the facts of the situation. We ignore the fact that fall protection for scaffold erectors is a very complex matter, not easily reduced to the quick fix.

 

Physics and engineering principles dictate the consequences of a fall and to achieve accurate results, we must consider all the forces that occur during a fall. The forces that develop due to a fall can be considered as either vertical or horizontal forces. The vertical forces are directed either up or down while the horizontal forces are directed either left, right, front, or back. The size, or magnitude, of these forces is basically determined by the height of the fall, that is how far the person falls before he or she is stopped. An example will demonstrate how the engineering principles are applied. Imagine that a scaffold erector is erecting a scaffold over a swimming pool. For some unknown reason, the erector falls, taking a dive off the scaffold platform into the swimming pool. I suppose it’s no big deal for the erector assuming there is sufficient water below and he is not tied to the scaffold. There are no substantial horizontal or vertical forces applied to the scaffold since he isn’t tied to the scaffold. The erector finds himself in the water and the scaffold remains standing. Let’s change the parameters a bit and you’ll see how things can change dramatically. Assume that we tied the erector to the scaffold because we don’t want him to get wet in case of a fall. When the erector takes a dive, he will be caught, after falling, by the lanyard that connects him to the scaffold. The erector may exert a horizontal force on the scaffold by pushing off, and the lanyard tied to the scaffold exerts both a vertical and a horizontal force due to the arc of the fall. Since nature likes everything in balance, there has to be a counteracting horizontal force and a counteracting vertical force. Depending on whether the scaffold is wide enough to act as a counterweight, or whether the scaffold is tied to a substantial structure, will determine if the horizontal forces are balanced. If we assume the scaffold is strong enough to support the vertical load of the erector and the fall, and the horizontal forces are balanced, the erector will remain suspended at the end of his rope. If the horizontal and vertical forces aren’t balanced, the erector will bring the scaffold down to the ground with him.

 

Substantial structures typically can provide substantial anchors. Conversely, non-substantial structures, such as scaffolds, can only provide non-substantial anchors. Keep in mind that laws based on the use of substantial anchors will not work for non-substantial anchors. In fact, standards written for construction workers exposed to falls from substantial structures may not work for scaffold erectors who want to use the scaffold as an anchor. It doesn’t get much simpler than that. The truth of the matter is that there is no quick fix.

 

Be careful though! Do not draw the conclusion that scaffolds cannot be fall protection anchors. Under the right circumstances, a scaffold can function as a suitable anchor. The trick is determining when that scaffold can be a suitable anchor. The current federal standards require that a qualified person determine a proper anchor because of the variables inherent in using a scaffold as a fall protection anchor. Sizable forces are generated when an individual falls off a scaffold. Depending on how the individual falls off the platform, or other scaffold member, will determine if both vertical forces and horizontal forces occur. Numerous tests have been done to show the adequacy, or inadequacy, of a scaffold to perform as an anchor. Since scaffolds typically can support vertical loads and forces well, a straight vertical drop can be easily resisted by the scaffold. Tests confirm this. However, once a horizontal force is introduced, things get complicated quickly. If the scaffold cannot resist these horizontal forces, the scaffold will fail. Tests also confirm this.

 

What does this tell us? First, don’t dive off scaffolds, especially if there is no water. Second, be sure you think about those horizontal forces. Fall protection tests on scaffolds may or may not include the horizontal force factor, depending on how the scaffold test is conducted. Scaffolds that are tall or massive may have sufficient counterbalancing weight while those scaffolds that are narrow or short, may not have sufficient counterbalancing weight. Therefore, the qualified person must consider a number of factors prior to using the scaffold for an anchor. More importantly, when conducting a test, or evaluating tests conducted by others, we must be careful that we aren’t too hasty in drawing conclusions. There is a very real danger in taking the results of one test and assuming it will work on all scaffolds, only to find that our assumptions are not only faulty but also pose a real hazard for the erector. Having said that, we must remember there is also danger in assuming that all scaffolds are inadequate anchors and erectors should never tie off.

 

The truth of the matter is that there is no quick fix. While scaffolds are versatile and adaptable, these attributes can also create complicated circumstances for fall protection. Technical solutions require technical tools and methods. We cannot ignore gravity nor can we ignore the laws of physics. We in the industry must recognize that realistic solutions will only come with realistic research, realistic analysis, and realistic expectations. To assume that there is a quick fix for fall hazards for scaffold erectors may result in a quick disaster. There is no quick fix.

 

ANCHORS

By | Fall Protection, OSHA Standards & Regulations, Resources | No Comments

Fall protection is a hot issue. Let’s face it – who wants to fall? The federal Occupational Safety and Health Administration (OSHA) clearly expects scaffold users to have some form of fall protection when on a scaffold platform above ten feet. Usually that protection is a guardrail system on supported scaffolds since it is a passive system, a system that requires little or no action on the part of the user to be effective. But what about users who choose to use personal fall protection systems that utilize harnesses, lanyards, rope grabs, vertical lifelines, and suitable anchors. Do users really appreciate the forces that are exerted on the individual components? What about erectors of scaffolding? When a safety officer, or for that matter, an OSHA compliance officer, requires erectors to be “tied off,” do they fully understand the ramifications of that request, especially as it relates to the anchor that is the key element of the protection system?

 

It is truly frightening to see what some individuals consider to be a suitable anchor. If it weren’t life threatening it would be comical. Unfortunately, if the individual who selects an anchor based on poor judgment, lack of expertise, and plain old misconception must use that poorly selected anchor, the experience may be truly unpleasant and even deadly! The fact is that workers, and more specifically erectors, are constantly directed and expected to utilize anchors that are inadequate and/or deadly. The selection of a suitable anchor for positive fall arrest is a serious decision that should never be left to amateurs. The look good theory of anchorage, whereby an erector ties off to a convenient location that “looks good” is an invitation to disaster.

 

OSHA, in Subpart L of the Construction Industry Regulations requires that non-designed anchors must be capable of supporting 5000 pounds. Designed anchors, anchors that are engineered, and are part of a complete fall arrest system, must have at least a two to one safety factor. Let’s face it; 5000 pounds is a lot of weight. Try hanging a large automobile from the next anchor you select and you’ll get a feel for what the regulations require. The next time you see a worker tied off to the guardrail of a scaffold, think about that automobile. Do you think the guardrail will hold it? (On the other hand, just think what an excellent anchor the automobile would make!) It must be remembered that the 5000 pound load is based on a maximum fall distance of 6 feet. What effect do you suppose a fall of 12 feet would have on an anchor, a situation that might occur if the scaffold erector is required to tie off at his/her feet. Hey – this stuff can get tricky.

 

I am continually amazed at how little people understand about this concept of fall protection and am continually impressed at how these forces are grossly underestimated. (I even underestimate it more than I would like to acknowledge.) The peculiar fact here is that when an unqualified individual requests that a worker “tie off 100 per cent of the time” this individual may in actuality be asking the worker to violate the OSHA regulations, and safe practices. It must be remembered that 100 per cent tie off is usually never 100 per cent fall protection. In fact, it takes quite a bit of work to guarantee 100 per cent fall protection. Most of the time scaffold erectors will never achieve it. That’s why training for scaffold erectors is so important.

 

What constitutes a good anchor? If a personal fall arrest system must be used, then choose the anchor carefully. The choosing must be done by a qualified person, a person who understands the forces that will be exerted on the anchor. Frankly, this person must know what he or she is doing. For vertical lifelines, the anchor ideally should be directly overhead of the user. This minimizes horizontal forces that may occur. If the anchor is welded, the welds must be designed so that they can handle the impact and possible tension loads. The welding must be done by a qualified welder. If the anchor is bolted, the bolts must be of adequate size, and must be properly secured. If an eye bolt is used, never rig the lifeline at a vertical angle to the bolt; the force exerted on the eyebolt must be in line (parallel) with the bolt to achieve maximum strength. If the lifeline is wrapped around a beam make sure that the beam connections to other structural components are adequate. Make sure the beam is adequate. It takes a qualified person to make that evaluation. If you’re thinking about tying to a scaffold, think about that automobile hanging there. Can the scaffold handle it?

 

If you think, after reading the previous paragraph, that no answers or good designs have been provided, you’re correct. Since the selection of an anchor can be so complex, it is impossible to present an anchor design to fit any occasion. The choice is yours: Have a qualified person specify the anchor, or somehow guess that the anchor you use will support 5000 pounds. The wrong choice may be hazardous to your health.