scaffold erectors Archives | DH Glabe & Associates

The Wind Sucks

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An explanation of the effects that the wind has on a scaffold that is wrapped or enclosed with a tarp, shrink wrap, plastic or other cladding.

As you well know, the wind blows.  Have you ever considered that instead, perhaps the wind sucks?  As one construction superintendent said to a friend of mine: “Don’t tell me about the wind; I’ve been around wind all my life!”  And from there, it’s easy to assume that that experience makes him an expert.  And if this superintendent is an expert on wind, then I suppose we all are experts on the wind since we have the same experience.  Logical conclusion perhaps, but the facts indicate otherwise, particularly with scaffolds in general and specifically with enclosed scaffolds, that is scaffolds that are wrapped with a tarp, screening or other enclosure material.  As we approach another winter season where the temperature goes the wrong way from warm for many areas of North America and the winds have a tendency to blow (or is that suck?) ill will on many scaffolds, we will once again experience the disappointment of scaffolds falling due to an overzealous sucking (or is that blowing?) wind.

I’m impressed with the courageous attitude certain scaffold erectors, and users, have when challenging the wind.  This personal fortitude too often, and unfortunately, is founded on a lack of understanding of the power and dynamics of the wind.  My experience indicates that luck, mostly bad, is involved with many wrapped scaffolds and not courage as some may assume.  Worse yet, some scaffolders just think that you cannot design for the wind, just that you’ll be lucky or unlucky, that building scaffolds is a roll of the dice.  Feeling lucky today?

Believe it or not, the force of the wind can be calculated and a scaffold can actually be designed to resist the wind.  To do this, an understanding of the wind speed, wind pressure, and other factors is required.  And yes, the wind blows and sucks.  If you don’t think so, look at a scaffold that is wrapped in plastic; in some areas the plastic is pushing into the scaffold and in other areas the plastic is pulling away from the scaffold.

It appears that there is some confusion by the ill-informed that the various scaffold standards regarding tying supported scaffolds to an existing structure are instructions on how to adequately design and erect a scaffold so it doesn’t fall over in the wind.  For example, a common requirement specifies that supported scaffolds be tied to a structure at intervals not to exceed 26 feet vertically and 30 feet horizontally.  This is a minimum requirement and it is not based on the wind but rather on the stability of the scaffold.  Therefore, to assume that tying the scaffold into a building every 30 feet horizontally and every 26 feet vertically is adequate is just plain dangerous unless your scaffold and the tie can hold the wind load.  For most areas of North America the load on the tie can be well above 15,000 pounds at that spacing.  Your #9 wire and 16 penny nail just isn’t going to hack it!  But wait, can the load actually be that high?  Yes it can.  Here are a few facts to consider:

  • The design wind speed for most areas of North America is 90 mph;
  • You only need one gust at 90 mph to bring down the scaffold;
  • To determine the load on a scaffold tie, the wind speed must be converted to pounds;
  • Formulae actually exist for doing this conversion;
  • The American Society of Civil Engineers (ASCE) has developed a procedure for wind design;
  • The higher you go on the scaffold, the stronger the wind becomes;
  • The shape of the scaffold has an effect on the wind pressure;
  • The shape of the structure has an effect on the wind pressure;
  • Where the scaffold is relative to adjacent structures has an effect on the wind pressure;
  • Geography affects the wind pressure;
  • Time of year affects the wind pressure design;
  • Project duration affect the wind pressure design;
  • Scaffold importance affects the wind pressure design;
  • The pressure on the enclosure at the corner of a scaffold can be twice what it is in the middle of the scaffold;
  • The pressure on the enclosure at the top of the scaffold can be three times what is in the middle of the scaffold (This would mean the upper corner is the most vulnerable);
  • Fully enclosed versus partially enclosed scaffolds have an effect on wind pressure and tie loads;
  • Feeling lucky has no positive effect on the wind pressure.

Christopher Columbus, and others before and after him, figured out the advantages and disadvantages of the strength of the wind.  It’s not necessary for you to experiment—North America has already been “discovered.”  If you want to get a general, and I mean general, idea of how much force a wind has, do this:  Multiply the wind speed, in miles per hour, times itself, (in other words, square the wind speed) and then times 0.00512.  Take this answer and multiply it times 780.  This will give you the force, in pounds, on a tie spaced at 26 feet by 30 feet.  Pretty exciting, huh?  As an example, take a wind speed of 45 mph.  The tie load = 45 x 45 x 0.00512 x 780 = 8,087 pounds.  Double that for the ends of the scaffold and triple it for the ties at the roof line.  This is serious stuff: get a qualified person to design the enclosed scaffold for you unless, of course, you’re feelin’ lucky.  And finally, remember that if the wind is blowing out of the northeast, it’s sucking from the southwest.

Is This Fall Protection?

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

It’s time to take a serious look at how fall protection is regulated in the scaffold industry.  I have addressed this issue in the past with no apparent effect since nothing has changed.  There is no doubt that fall protection, particularly personal fall arrest equipment, has made tremendous advancements over the last ten years or so.  Harnesses, attachment hardware, ease of use and comfort are positive indicators that fall protection manufacturers have achieved impressive successes.  While this has helped the scaffold erector and user, the regulations that were written more than a decade ago have not kept pace with the reality of the situation.

Frankly, nobody is behaving.  Not the scaffold erectors, not the scaffold users, not the safety managers, not the compliance officers.  Basically all of us.  The bottom line is that selective enforcement of the fall protection regulations has replaced consistent regulatory enforcement.  This is not all that bad if you’re the one that can call the shots.  If you aren’t that person, you may be in trouble.  Before I suggest a solution, a review of the regulations is required to identify the dichotomy of the situation.

The federal OSHA regulations, (state regulations are similar) require that an individual using personal fall arrest equipment comply with certain requirements, designed to ensure that the use of personal fall arrest equipment is effective in minimizing injuries and preventing deaths.  These original requirements include:

  • Limiting the force on your body to 1,800 pounds;
  • Limiting the free fall to 6 feet (Since the original requirements were issued, OSHA determined that the free fall could be more than 6 feet but the force on the body still could only be 1800 pounds maximum);
  • Limiting the deceleration distance to 3.5 feet;
  • Not allowing you to hit the level below;
  • Using an adequate anchor. This anchor must be 2 times stronger than the load experienced or 5000 pounds if the anchor is not designed.

If my experience is any indicator, nobody complies.  Furthermore, nobody is enforcing all of these standards.  Let’s face it, when a general contractor requires 100 per cent fall protection, either it’s not happening or they aren’t complying with the regulations listed above.  Sure, the contractor is adamant about everybody be connected to something but will it really be in compliance if the errant employee chooses to fall?  And if the employee were to fall, do we really care if he/she is in compliance as long as this employee is able to go home to spouse and family?

Here’s the solution.  Wave the personal fall protection for scaffold erectors.  That’s right; give erectors an exemption on the above requirements.  This will eliminate the constant battle between the safety folks and the erectors.  Sure, if an erector falls while tied off to the scaffold, he may damage the scaffold.  If she is wearing a shock absorbing lanyard, chances are that the force on the scaffold will be considerably less than the 1,800 pounds and no where near the 5,000 pounds.  Of course, the flip side of this is that the erector cannot argue that fall protection is impossible because a 5000 pound anchor cannot be found.  The erector doesn’t need one.  Nobody else needs a 5000 pound anchor either.

For users, the situation is not similar.  I do not advocate waiving the rules for these workers.  Passive fall protection, such as guardrail system, is typically available for scaffold users and is effective.  If personal fall protection is required, suitable anchors can be located, either by constructing scaffolds to support potential fall forces, or choosing anchors that are outside the scaffold.  Employers must continue to train their employees in fall hazard recognition and to advocate proper fall protection.  For scaffolds, this would require complying with the regulations–all of them.

My proposal is this:  Waive the 5,000 pound regulation for scaffold erectors.  Waive the regulation limiting the free fall distance for erectors.  This will legally permit scaffold erectors to tie off at their feet.  Require all scaffold erectors to wear harnesses whenever they are elevated, with the understanding that they are to “tie off” when they are in a stationary mode.  Require that all scaffold erectors utilize shock absorbing lanyards and/or retractable lanyards that help minimize the fall forces on the body.  Allow the competent person to permit the leading edge erectors to work without fall protection, similar to leading edge steel erectors.  Waive the regulation for deceleration distance.

Is this industry up to the challenge of providing reasonable solutions for scaffold erectors?  Is OSHA willing to recognize the reality?  Are we willing to do what is right for the erector and user of scaffolds?  I think we are.  Prove me right.  What do you think?  Send your opinions to the editor;  I want to know if this is a reasonable approach.  If you don’t think this is reasonable, suggest an alternative solution; constructive criticism is good, complaining is bad.  I’m waiting to hear from you.

Is it Possible?

By | OSHA Standards & Regulations, Resources, Scaffolding, Uncategorized | No Comments

Is it possible for scaffold erectors to comply with the Federal Occupational Safety and Health Administration (OSHA) standards for both fall protection and scaffold erection?  I think not.  Here’s why.


Federal OSHA requires that scaffold erectors use safe personal fall arrest protection, if it is feasible to do so, as determined by a competent person. This is what happens in a perfect world.  I say a perfect world because, in the real world, expectations don’t necessarily agree with the standards.  OSHA compliance officers, company safety managers, scaffold erectors, and yes, consultants, typically have very different ideas about erector fall protection and the applicability of the fall protection and scaffold standards.  The confusion begins with the strength requirements specified in the OSHA Fall Protection Standards, Subpart M.  In addition to other requirements, Subpart M specifies the minimum standards for the use of fall protection equipment.  The standards specify that all systems, designed or undesigned, must limit the force on the body to 1,800 pounds (ouch) and the freefall distance to 6 feet.  Additionally, undesigned systems require that the anchor strength must be at least 5,000 pounds.  That is a lot of pounds. The scaffold has to be real special to handle that kind of load and of course, most scaffolds cannot handle that much force on its components.  (It is still a mystery as to how anyone would know that an anchor could hold 5,000 pounds if it is not designed, or at least analyzed!)


Unfortunately, lots of folks think, or at least assume, that most scaffolds can support a 5,000 pound load.  Typically, the scaffold erector gets forced into “tying off” to the scaffold because a safety officer requires it.  Never mind the scaffold can’t support the 5,000 pound load.  For the safety officer, this isn’t normally important as long as the erector is tied to something so it looks good.  Assuming the erector doesn’t fall, anyone observing the situation could conclude that tying to the scaffold is a good thing and assume that the erector’s actions are not only safe, but also are in compliance with the standards.  Therein lies the problem.  By tying off to the scaffold, the erector is probably violating the fall protection standards since the scaffold cannot handle the 5,000 pound anchor load.  Should he be cited?  Maybe we should ask if he is safe.  Assuming that the scaffold is properly built and in accordance with good construction practice, it just might be able to support him if he falls.


How can this be, you might ask?  If the erector is wearing a shock-absorbing lanyard, and his freefall is less than 6 feet, the force on the scaffold will be approximately 900 pounds.  (Before all you fall protection people and engineers jump all over me for this seemingly gross assumption, please note that I said a “properly built” scaffold.)   Nine hundred pounds is a lot less than 5,000 pounds.  Unfortunately the erector is not in compliance with the standards because a qualified person didn’t design the fall protection anchor.  According to the standards, an undesigned anchor must support a falling load of 5,000 pounds.  Since the erector appears to be out of compliance, should he be cited?


But wait a minute.  Where’s the hazard?  If the erector is exerting a force of 900 pounds on the scaffold, and the scaffold can support that load, what’s the problem?  None, except the anchor wasn’t designed and consequently the erector is in “technical” violation of the standards.  If the scaffold doesn’t collapse, and the erector is not in harm’s way, can this be a bad thing?  I doubt it.  This however does bring us to the issue at hand; it’s time to waive certain fall protection standards for erectors.


Rather than continue this argument that scaffolds cannot be used as anchors because they don’t comply with the fall protection standards, it is time to recognize that scaffold erectors have special requirements that are not met with the existing standards.  If we are to pursue the idea that we need to provide additional protection for erectors, beyond better training and skills, then the standards must be modified to reflect that approach.  If contractors, safety officers, consultants, and compliance officers continue to insist that erectors tie to scaffolding, then its time to grant a permanent variance to the fall protection standards.  There is no way that using scaffolding as undesigned anchors will ever be compatible with the fall protection standards, as they are written.


I suggest that OSHA work with the scaffold industry to enforce the regulations that are critical to the elimination of hazards.  The existing standards specify that the competent person determines the fall protection for erectors.  This would include leaving the decision about fall protection with the competent person and waiving certain fall protection standards.  Specific training, for erectors, compliance, and safety workers, would be necessary to ensure that only the applicable standards are enforced.  Of course, there will be an increased responsibility for the competent person to ensure that the best protection is provided for the erectors.  But then, there is nothing wrong with this.  Its time that erectors recognize, while they may be special, are not above the standards.  In turn, OSHA needs to recognize that the work of the scaffold erector is neither correctly addressed by the present standards nor correctly enforced by compliance officers.


Until the standards are modified to reflect current safe practices, those individuals charged with safety must recognize that compliance with one standard may result in the violation of other standards.  Furthermore, safety officers and erectors must recognize the application of one standard doesn’t permit the violation of other standards without repercussions.  That is the dilemma.  It’s time to do something about it.  Do you agree?


Note:  This article consistently referred to erectors in the masculine: “he/him”.  Why are there no female scaffold erectors?

Would You Pass?

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Do you remember the last time you took a test or quiz? Do you remember how many questions were on that test? Do you remember how you felt before you took the test and after you took the test? Were the questions true and false? Perhaps they were multiple choice or even fill in the blank. Then of course, there were the essay tests and worse yet, tests with problems. Those always seemed the toughest. What was a passing grade? Was the test graded on a curve?


For most of us, its probably been awhile since we took a test, any kind of test. But, imagine that tomorrow you are going to take a test involving scaffolding. It really doesn’t matter what type of scaffold, but assume it’s a scaffold familiar to you. After all, we don’t want to make this test any harder than its going to be. In fact, let’s start with a quiz, of say twenty questions. The questions will be mainly fill in the blank although the test administrator may give you a couple of multiple choice questions and perhaps some true and false questions. The topics will include the OSHA standards, common sense, work habits, and general knowledge. How do you think you will do?


Now imagine that a bigger test will be given, call it a final exam. This final exam will consist of a mind boggling 7000 questions! Most will be fill in the blank, but certainly there will be several problems that have to be solved and even some essay questions to answer. Finally, the test administrator may choose to give you some oral questions, (that is, you have to tell the answer; you just can’t write it down.) While this exam may now seem impossibly difficult, there are two more criteria. First, the test administrator, at the administrator’s discretion, may arbitrarily decide what is the correct answer, based on his or her own opinion and not necessarily on fact. Second, and this will be difficult to accept, but you must get all the questions correct. One question wrong and you fail the exam.


Ridiculous you say, and besides, what does this have to do with scaffolding. The final exam just described can be any large scaffold project, one involving 7000 components. The quiz would be a small project involving just a few pieces. As we all know, or should know, not installing all the pieces may result in an unsafe or unstable scaffold that could fail. Missing just one of the hundreds of OSHA regulations could result in failure. Keep in mind that in the scaffold section alone, there are over two hundred regulations applicable to scaffolds. While all these regulations may not apply to your scaffold, it really doesn’t matter. Miss just one of the applicable regulations, and you failed the exam. The essay questions, particularly the verbal essay questions, occur when an individual responsible for safety, the exam administrator, asks you what you know about scaffolds, regulations, and training. Answer any of that wrong, and you just flunked. If the administrator knows little about the subject, it probably doesn’t matter; the administrator can arbitrarily change the answer to the question. In some cases, you flunk just because your actions appear to be suspicious.


Finally, just when you think you might have survived this incredibly tough exam, you’ll be asked about your previous education and training. If you can’t answer that to the satisfaction of the administrator, you still fail even if you passed the rest of the exam. This is tough stuff. You’ll have to go back and get retrained. Incidentally, it is not required for the exam administrator to be trained in the subject matter. He or she only has to know how to give the test.


The next time you are involved with a scaffold, whether it’s the selling, renting, erecting, or designing the scaffold, think about the grading system. If you send workers out to erect scaffolds, think about the rigorous exam they must take today, and every day. Have you given those erectors the knowledge, skill, and training to pass the test with a perfect score? Do you have the knowledge, training, and expertise to determine the competency of your fellow worker? If you are the administrator of the test, are you qualified to give the test and are you qualified to grade the test? Is it possible to grade “on the curve” without compromising safety? Is it possible to accept the fact that a perfect score everyday, on every exam, is not realistic and never expected in any school? While incorrectly constructed scaffolds subject the user to hazards, do all imperfections in the scaffold result in serious injury or death? If not, why do we demand a perfect score? On the other hand, if any imperfection is critical, its time to recognize the importance of skilled workers. This includes the erector, the user, and equally important, the safety officer responsible for ensuring the safe construction and use of scaffolds. To be effective, the test administrator must know more than the test taker.

It’s a Wrap!

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It’s that time of year when cold weather scaffold users start wrapping scaffolds in enclosures for weather protection and warmth. Since wrapping a scaffold in an enclosure seriously changes the forces that are applied to scaffolds, the installation of such systems must be carefully designed and executed.


Conditions vary greatly across North America and it is impossible to provide specific instructions for enclosing a scaffold. Why is this? Many factors affect the forces that occur when a scaffold is wrapped. These factors include:


• Height of the scaffold

• Length of the scaffold

• Width of the scaffold

• Shape of the adjacent structure

• Location of the structure and scaffold

• Proximity of other adjacent structures

• Terrain

• Local weather conditions

• Material used for the enclosure

• Scaffold loads

• Tie location


In spite of the variables, some general observations can be made. First and foremost, typical tie design and spacing probably will not work. While the Occupational Safety and Health Administration, (OSHA), specifies maximum permissible vertical and horizontal tie spacing in its’ standards, it must be remembered that these are minimum standards and only provide stability to the scaffold; this minimum tie spacing does not provide strength against wind forces. Typically, the ties used on an enclosed scaffold should be designed by a qualified person who is familiar with the forces that occur. Many times, erectors casually assume that “doubling up” the ties is sufficient. This assumption can lead to disastrous results.


Second, the choice of fabric used for enclosures will affect the scaffold and ties in a variety of ways. For example, vibration is very significant due to the buffeting of the wind and can loosen expansion anchors that are used to hold the ties. The choice of enclosure material also affects the scaffold. A stiff enclosure fabric, securely fastened to the scaffold, will produce less vibration than a flexible material such as plastic sheeting.


Third, the method used to tie the enclosure to the scaffold will affect both the tie design and the forces on the scaffold. Generally, there are two approaches that can be used to design a wrapped scaffold. The first method, generally uneconomical and counterproductive, assumes that the enclosure will release from the scaffold at a certain wind speed, minimizing the chances that the scaffold will pull away from the structure and fall over. In this design, the connection between the enclosure and the scaffold is such that it will either break or release the enclosure once the wind exceeds a certain velocity. The assumption is that a design such as this will minimize the number of ties required to restrain the scaffold. This can be a very dangerous approach, especially if an uninformed user modifies the enclosure connection. How far the enclosure flies and where it lands upon completion of the flight should be of concern to the scaffold erector! The second design method assumes that the enclosure is adequately secured to the scaffold. The restraint system is designed to support the scaffold and enclosure as one unit. A much preferred method of design, the scaffold and enclosure will continue to provide protection and access throughout the project.


What are the forces? Can a standard wire tie handle the load? As stated earlier, it is impossible to accurately state the loads on a wrapped scaffold without a specific analysis of the scaffold. However, various wind forces can be described so that you have an idea of the forces that can be generated. If the wind speed at the project is 20 mph, the basic force in the middle of the scaffold is approximately 1 pound per square foot. If the wind picks up to a 40 mph breeze, the load increases to 4 pounds per square foot. At a 60 mph breeze, the force increases to 9 pounds per square foot. Using the OSHA standards as a reference, the force on the tie, at 20 miles per hour, would be 800 pounds. Applying the 4 to 1 safety factor, the tie would be designed for 3,200 pounds. At 60 miles per hour, the force on the tie would be minimum 7,020 pounds. Applying the standard safety factor, the tie must be designed for at least 28,000 pounds. You would need quite a bit of wire to handle that kind of force. Keep in mind that these forces have not taken into consideration the factors that will increase the load substantially, in some cases doubling the load. These increases in forces occur at corners, roofs, and other areas where the wind is affected by other structures or the surrounding terrain.


Wrapping scaffolds should not be taken lightly. Qualified scaffold designers should be consulted before erecting the scaffold. Your safety, and the safety of your fellow workers, demands a proper design.


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

Previous articles have discussed various portions of the new OSHA regulations that address scaffold use and erection, including the new requirements that specify that a competent person evaluate each scaffold erection project for the feasibility of providing erectors with safe access and fall protection. On what basis does the competent person make that evaluation?


What historical data exists that can assist the competent person in recognizing hazards that occur during the erection process. Does any data exist that tells us the high risk age bracket? Does any data exist that tells us the level of training that is most effective for erectors? Does any data exist that tells us the minimum level of expertise that can be expected to return the maximum level of safety? Does any data exist that tells us what subject matter should be taught to erectors? Does any data exist that tells us the techniques and methods that should be utilized by erectors? Does any data exist that tells us what erectors were doing at the time of an accident? Does any data exist that would tell us what NOT to do? Do manufacturers have any data that would improve the safety for the erectors? Does the Scaffold Industry Association have any data that would help members improve the safety of erectors? Does OSHA have any data that would help members improve the safety of the erector?


Some time ago the Scaffold Industry Association (SIA) conducted a survey of its’ members to determine how many members were getting injured or killed while erecting scaffolds. The results, as described in last month’s newsletter lead article, suggested that erector falls were “almost non-existent” and that most injuries “happened on the ground or by inexperienced and/or untrained workers.” It is a fact that this survey was unscientific and flawed in that it did not include data that was available but not used, data that indicates that “professional” erectors do indeed get injured and killed. Additionally, data from the Occupational Safety and Health Administration, National Institutes of Health, and others, would indicate that there is a problem with erectors not staying on the scaffold where they belong. For example, OSHA claims that 11% of scaffold fatalities are erectors. What were these erectors doing at the time of the fall? Was the fatality due to a fall? What experience did the erector have? What could be done to eliminate or minimize the hazard in the future? Would fall protection equipment have helped? Could the scaffold been used as an anchor? Would using the scaffold as an anchor jeopardize the safety of other workers on the scaffold?


Lots and lots of questions but very few answers. From my perspective, it would appear we are reacting emotionally to a very serious subject. It has been said that when we have no facts we are driven by emotion and that is exactly what is occurring with this issue. Those in favor of 100% tie off are either ignorant of the very complicated forces that occur or choose to ignore these facts. Those in favor of no fall protection for erectors are either ignorant of the opportunities that exist in many circumstances or choose to ignore those opportunities. Can either side be criticized when none of us have the facts? Further complicating the situation is the litigious nature of the business and the risks that are associated with making a wrong decision. It’s no wonder that manufacturers are adamant about using a proper anchor and discourage the use of scaffolds as anchors. And yet, owners, contractors, safety officials, and compliance officers, blind to the inherent dangers that may exist, demand fall protection that generally results in the erector violating 1926.502(d). (That’s the requirement that non designed anchors support 5000 pounds.)


What possibly can be done with this issue? It is no secret that scaffold erectors daily tie off and are still able to erect or dismantle a scaffold. The question is, and this is a big question, what level of safety does the erector have? Is he/she at a greater risk because he/she is tied off to the scaffold? Has the hazard exposure for fellow workers increased because of this? What happens during a fall. Test results illustrate the complexity of the subject; sometimes the scaffold works as an anchor and sometimes it doesn’t. I sure hope all of you choose an anchor that works but frankly, guessing is a risky business. Why not try a scientific approach since it’s doubtful a regulatory approach will be fully effective. Imagine the success if the erector’s competent person can make an evaluation based on historical data, research, and even testing. I don’t know about you but I would be a lot more comfortable if I had more information – and I design anchors. I am convinced that the facts will solve the mystery and the competent person’s decision will be respected. This industry has the obligation, and OSHA has an obligation here also, to do the research to get these facts. We have an obligation to the erector and we have an obligation to the competent person to get this information. It’s encouraging that the SIA is working on a fall protection plan and this is a good start. Beyond that we need to continue searching for better methods, training, and techniques. Give me the facts – just the facts!