Cast-in-place concrete is a popular method of new construction. It can be cost-effective, efficient, and yield aesthetically pleasing results. The key to a successful cast-in-place concrete structure is always pre-planning. Here we will discuss the principles of horizontal concrete construction.
Locating columns, walls, and drawing the building lines is the easy part of starting any project. Then the hard stuff begins: what is the most efficient way to lay out the formwork? What is the desired formwork system? During what time of year will the construction take place? What type of hoisting equipment will be used? Who is going to install it? How must the project move? Are there specific details installers want to see? Asking these questions in advance of starting construction will save plenty of headaches down the road.
“The maximum span for this stringer is 5′-2 3/8”.” It is much easier for the installer to lay out 5’—10’—15’—20′. When shoring is laid out in CAD, do not be afraid to use the text override command. Round down to give more wiggle room. For example, a member may lay out to 5’-1 3/16” to clear a column, but override this dimension to simply say 5′. Let the field installers make minor adjustments, and keep the numbers simple.
The first pour is always the most anticipated since there are (typically) no overhead obstructions, there is a clean slab area only for the formwork subcontractor, and the material coming out is fresh. What happens after that first pour? How does the material get from the first pour to the fifth pour? The key is to know the system and to establish a material movement plan. If the only option of moving the material is with carts and forklifts, keep the shoring generously spaced to accommodate this movement. This may mean doubling or even tripling stringers, clustering shores, or any similar means of creating a clear pathway. Draw attention to these areas on the shoring plans to make sure they stand out. Material movement is fundamental for efficiency.
Moving material out of a stripped area is only part of the equation. Efficient formwork engineering also requires planning for post-pour activities. What types of hoisting and/or material movement equipment will be required by the stripping crew? What kind of reshore system is going to be used? What are the required quantities? Check if the shoring system can be used as the reshore system. Make sure the shoring will work at a taller height when the formwork is removed; this is a common mistake. If your existing shoring/formwork system is not going to be used as the reshore system, stage reshores under the shoring as it is erected. As the forms are stripped, the reshores are ready and available for use. The same can be said for hoisting equipment. Always trap a forklift or scissor lift where the project supervisor wants to start removing the formwork after the slab is poured.
Formwork weights are critical pieces of information, both for the designer and for the field personnel. Be sure to call out weights for panels and typical units of equipment, along with quantities. This will keep the guesswork to a minimum and help avoid those situations where the crane or forklift cannot pick up a given load, requiring the load to be broken down and restacked into smaller bundles.
Overall, the design of formwork will involve just as much scheduling and coordination as it will engineering. As with all other aspects of construction, planning is the key to success. Keep these tips in mind and your project will see an increase in efficiency and a decrease in your stress level.
It is difficult to imagine masonry construction without scaffolding. Prior to the advent of steel frame scaffolding, Bricklayer’s Square scaffolding was used to provide an elevated work platform for the masons to conduct their work. Starting in the 1930’s, steel scaffold frames slowly replaced the wood scaffolds commonly used by masons. Adjustable scaffolds, specifically designed for masons, became available in the 1970’s and the evolution continues today with mast climbers and other powered platforms being used by masons.
In spite of the variety of the equipment used by masons, several issues have persisted regarding the proper use and safety of scaffolds. The first issue involves the fall exposure that masons have while constructing a brick wall. The federal Occupational Safety & Health Administration, OSHA, standards recognize this issue and in 29 CFR 1926.451(g)(1)(vi) specify that “Each employee performing overhand bricklaying operations from a supported scaffold shall be protected from falling from all open sides and ends of the scaffold (except at the side next to the wall being laid) by the use of a personal fall arrest system or guardrail system.” While clear in its intent, there are still people who do not understand this. Simply stated, we allow the mason to be exposed to a fall hazard. That’s right, the mason can fall over the wall if he so chooses. However, any reasonable mason understands that if he leans over too far, he will fall over the wall! Typically, masons like to lay brick at waist high which means that the wall acts as the guardrail—problem solved. In those instances where the wall is lower, then yes, there is a fall hazard. But the hazard of trying to work through a guardrail system laying brick frankly is a greater hazard. Please note that only those who are “performing brick laying operations” are allowed to be exposed to the hazard. In other words, if you aren’t laying brick, you can’t be there.
The second issue involves the use of side and end brackets (commonly, and incorrectly, called outriggers). The normal use of these brackets is on the front of the scaffold, between the wall being constructed and the scaffold front leg. These brackets support the plank for the masons and are moved up in convenient increments as the wall increases in height. There’s nothing wrong with this installation. The problem is when masons install these brackets on the back of the scaffold and then used them as a landing or storage platform for brick and mortar. This is not good unless these brackets have been designed for that purpose. In fact, OSHA addresses this issue in 29 CFR 1926.452(c)(5)(iii) by emphatically stating that these brackets shall be used to support personnel “unless the scaffold has been designed for other loads by a qualified engineer.” The reason for this is that it is easy to overload the brackets and also easy to tip the scaffold over, nether prospect being very appealing to the mason. Keep in mind that the standard doesn’t say you cannot do it; if you would like to do it, hire an engineer who can help you.
The third issue that appears on occasion has to do with the material on the scaffold platforms. There is another OSHA standard, 29 CFR 1926.250(b)(5), that “Materials shall not be stored on scaffolds or runways in excess of supplies needed for immediate operations.” A quick read of this standard would suggest that a mason could have no more than a few brick or block on the scaffold at any given time. In fact, OSHA even issued a Letter of Interpretation that stated that all materials had to be removed from the scaffold at the end of the day. Fortunately, OSHA clarified this letter and stated that the hazards being addressed by this standard included falling objects and scaffold overload. OSHA concluded that since these potential hazards are specifically addressed in the scaffold standards, while leaving materials stored on a scaffold may be a violation of 29 CFR 1926.250(b)(5) it shall be considered a de minimis violation, one that carries no fines. Of course it is assumed that the mason will make sure the brick and block will not fall off the scaffold and the scaffold is not overloaded. This particular issue has appeared recently on jobsites where the Army Corps of Engineers regulations, EM 385, are enforced. As with all standards, it is important to know what the intent of a particular standard is and what hazard is being addressed. Once this is understood, it is much easier to resolve any issues regarding the storage of materials.
As long as we have brick and block walls, we’ll have scaffolding. Scaffolding has proven to be effective and safe, provided you know how to use it safely. Do you?
It’s been a long time since I first became involved in the business of scaffolding. My experience has included a lot of scaffolds, a lot of places and a lot of people. It has also included a lot of regulations. As a blossoming young engineer, I still recall asking by boss how OSHA fit into the design of scaffolding. Since federal OSHA was just a couple of years old at that time, he responded with a clearly stated: “I don’t know.” Forty years later, it appears that we still don’t know how OSHA fits into the design, construction and use of scaffolding. To be fair to federal OSHA, it doesn’t appear that any regulations, standards, codes or guidelines fit into the design of scaffolding. Now, before you get yourself all wound up, this may be somewhat of an extremely broad statement. But think about this: We have standards regarding fall protection and more specifically guardrail systems. In my research I have found guidelines regarding guardrails going back to the 1920’s, almost a century ago. And we still have people designing, constructing and using scaffolds without fall protection. If nothing else, we have consistency.
So what’s the problem? Is it poor enforcement? Is it poor training? Is it poor knowledge? Is it ignorance? Or maybe we just don’t care. Being a Professional Engineer, and accepting the responsibilities that go with the privilege, I am obligated to comply with the myriad of regulations, standards and codes that apply to the profession. Not to do so will result in the loss of my license and opportunity to earn a living. I don’t state this because I think I am special, but rather qualified professionals (degreed and licensed or not) accept the obligation that is or should be expected in the business. I don’t agree with all the regulations; for that matter I’m not really keen on any of the regulations—it certainly stifles constructive creativity. In fact, regulations are insidiously invading all aspects of our lives, resulting not only in a dumbing down of the industry but also in an erosion of expertise, efficiency, economy, and productivity.
Of course, those tasked with the enforcement of these regulations smugly point to the results of their policing actions. They publish yearly results of their efforts as if those efforts have any real effect on the industry. Frankly, the annual OSHA list of the top 10 violations has no relation to the degree of danger involved in the infraction. For example, scaffolds always show up in the top ten, suggesting that there is a real problem with safety in the industry. But is there a problem? Perhaps scaffolding shows up so frequently because infractions are easy to spot and the compliance officers haven’t been trained to evaluate where the real hazards are.
One of the favorite activities these days is the harassment of professional scaffold erectors (casual erectors, where the problems really occur, seem to be immune.) Statistics indicate that the death rate of professional erectors is extremely low, particularly when compared to the 80 annual deaths that occur with scaffold usage, the deaths in construction and more dramatically when compared with the approximately 37,000 people killed on the highways each year.
The situation is becoming so ridiculous due to what I think is a growing hysteria about safety and the lack of understanding of the actual hazards. Enormous amounts of time and energy are uselessly spent deciding whether a regulation has been violated instead of investing in the safe productive work that should be happening. How many times have you sat in a meeting ascertaining whether there is compliance with the regulations? How many hours have been wasted bickering about the nuance of a regulation instead of determining how to get the work done safely?
I am not advocating the abolishment of enforcement but something has to change. It is absolutely amazing how people think they are experts in erector fall protection, for example, and yet have never erected a scaffold in their lives. And yet we give them the authority and take it away from the people most affected. Furthermore, it is stunning to me how many government agencies, construction industry organizations, unions and engineering committees feel compelled to propagate more and more regulations, many applying to scaffolding, and yet do not even bother contacting the Scaffold and Access Industry Association or the Scaffold Shoring and Forming Institute for input. Are you aware that the American Society of Civil Engineers has a code regarding construction loads which includes specifications for scaffold loading? I didn’t think so.
I can sure complain about the problem but unfortunately I don’t have a snappy quick solution. We cannot abolish decent standards and codes nor can we abolish enforcement—those are needed for those employers and employees who just don’t get it. But we do need to abolish the politics in safety. Have you ever wondered why we chase after the employer but not the employee? Me too. Have you ever wondered why compliance officers don’t receive sufficient training for the task at hand? Me too. Have you ever wondered why so many designers and constructors erect scaffolds without having any clue as to what a safe scaffold is? Me too. Have you ever wondered why we allow the sale of scaffolding in this country without any idea of its load capacity? Me too. Have you ever wondered why safety consultants have such a poor understanding of the true hazards in scaffolding? Me too.
Forty years ago we were killing and maiming scaffold users. We’re stilling doing it today. And I still don’t know how OSHA fits into the safe design of scaffolding. However, I do know what a safe scaffold is. Do you?
I recall my first involvement with the Scaffold Industry Association, SIA, in the early 1980’s. I was impressed by the people who were genuinely involved in making the use of the scaffolding and related products safer. I also recall how I was railroaded into taking the minutes for council meetings! In fact, I was inducted (or abducted) into the role of scribe for the Shoring and Forming Council. You read that correctly. Back then there was a Shoring and Forming Council. There also was no Fall Protection Council, Aerial Lift Council, or Hoist Council. Over the years the focus of the association has changed, evolving into an organization that emphasizes the various forms of access for workers. Concurrently, shoring and forming slowly diminished in scope and involvement to the point that it is no longer represented in the SIA.
This doesn’t mean that there are no members who are involved with shoring and forming. It also doesn’t mean that there are no issues with the use of these products. In fact, there actually is more commonality between scaffolding and shoring than you might think. On the other hand, scaffolding is definitely not shoring and shoring is not scaffolding. For this discussion, we’ll leave wall formwork alone except for the fact that the work platform on a wall form is a scaffold and consequently the scaffold standards in federal OSHA 1926, Subpart L apply.
What are the common elements between shoring and scaffolding you may ask? Well, fall protection is a common element; access is a common element; falling object protection is a common element; and, capacity and strength are common elements. The significant difference between scaffolding and shoring is that a scaffold is a temporary elevated platform and its supporting structure used to support workers or materials or both. Shoring, on the other hand, can be a system of structural elements used to support the formwork for concrete (the Jell-O® mold that holds the liquid concrete). Shoring can also be a system of structural elements used to support existing structures such as buildings while repairs or modifications are being performed. Since shoring and scaffolding are different structures, different OSHA standards typically apply although there is overlap in a number of areas. That is where the similarities come into play and thus it makes sense that the SIA should consider resurrecting the Shoring and Forming council.
For example, fall protection for shoring erectors has the same issues as fall protection for scaffold erectors. For new concrete construction, the shoring equipment is always at the top of building (that is logical) and consequently, there is no convenient anchor above the erectors unless the Goodyear® blimp is in the neighborhood. Supported scaffolding can have the same issue. Interestingly enough, a review of the OSHA standards show that the Construction Industry fall protection standards are applied by OSHA through the use of Letters of Interpretation. Unfortunately, it is a circuitous route that attempts to apply the standards in creative ways so as to justify a desired outcome. The results are confusing requirements for shoring erectors to contend with during their work.
Access for both scaffold erectors and shoring erectors is an intriguing topic for those who attempt to apply inappropriate standards. OSHA considers shoring frames to be working surfaces and therefore fall protection and/or positioning devices are required. If these same frames are used as scaffolding, and they can be, then they can be climbed by the erectors. Confused yet? Wait—there’s more! Access for shoring can really be interesting. While the erector shouldn’t climb the frame because it is not a ladder but rather a working surface, the erector doesn’t need to comply with the ladder standards because his access continues to move while the shoring is constructed and the access requirements of 29 CFR 1926-Subpart X were never intended to apply to this work activity. Are you confused yet?
The final frustration is when the compliance officer or site safety employee can’t figure out whether you are working on scaffolding or shoring. Applying the scaffold standards to the erection of shoring is like trying to apply the fixed ladder standards to a scaffold attachable ladder—it doesn’t work.
The Scaffold Industry Association members have a wealth of experience and expertise that can be used to clarify the intent and application of the standards while making life easier and safer for both the erectors and users of temporary structures. Is it time to resurrect the Shoring and Forming Council? I think it is.
Generally there are two issues that determine if scaffolds are compatible; the first issue applies to the same type of scaffold of different designs or manufactured by different manufacturers. For example, a tubular welded frame scaffold manufactured by company A has a leg diameter of 1 inch while the tubular welded frame scaffold manufactured by company B has a leg diameter of 3 inches. Obviously, the 1 inch diameter tube would not fit onto the 3 inch diameter leg. This would make it incompatible. The second issue applies to different types of scaffolds. For example, can a tube & coupler scaffold, typically using tubes that are a nominal 2 inch diameter tube, be used with a systems scaffold that has the same diameter tube? Can this same scaffold be used with a tubular welded frame scaffold that has a tube diameter of 1-5/8”? These are legitimate questions for the scaffold inspector.
The Scaffold, Shoring & Forming Institute, SSFI, and manufacturers have guidelines about the matter. So does the Scaffold Industry Association, (SIA). The guidelines typically agree with the OSHA standards which succinctly sum it up: “Scaffold components manufactured by different manufacturers shall not be modified in order to intermix them unless a competent person determines that the resulting scaffold is structurally sound.” This means that scaffold components from different manufacturers can indeed by intermixed as long as the scaffold integrity is not compromised.
Here are factors that determine if seemingly different types of scaffolds are really compatible:
For tubular welded frame scaffolds, consider this:
For systems scaffolds, consider this:
For tube & coupler scaffolds, consider this:
This isn’t meant to be a complete list since there are many manufacturers with many products. The OSHA standards exist to ensure that intermixed equipment performs as anticipated. By requiring an evaluation by a competent person, the scaffold user will have a safe scaffold to use. If you are not comfortable determining the compatibility between scaffold components, manufacturers, materials, and scaffold types, don’t guess – contact a competent person and/or a competent/qualified manufacturer.
Should I be worried when I get on a scaffold? Should I be worried when I can buy a scaffold frame for less than half of what it costs from another supplier? Should I be worried when I don’t know the strength of the scaffold I get onto? Am I expected to know how strong the scaffold is that I am using? As a supplier should I know? As an erector am I required to know how strong the scaffold is? Should I worry about any of this? It seems to me that it would not be a bad idea to know whether the scaffold I am on will collapse before I get off it. It probably wouldn’t be a bad idea to know whether that extra stack of drywall will collapse the scaffold or merely overload it. Did you know that it is mandatory that you know how strong the scaffold is? Did you know that OSHA requires that you know how strong a scaffold is? And finally, did you know that what you don’t know might kill you?
Elsewhere in this magazine you will find an article about the manufacturing of scaffolding. The article describes the intricacies of manufacturing a scaffold product. There is a lot more to it than just a bunch of round steel tubes. Just because it is steel doesn’t mean it’s the right type of steel. Just because it is welded doesn’t mean that it is welded correctly. Once you read that article you should ask yourself the question: Why is this more complicated than I thought? It’s more complicated than you may think due to the simple fact that you expect it to work—all the time, every time. Scaffold users, whether they think about it not, expect the scaffold to work every time they climb up to an elevated platform. This isn’t like an automobile that may or may not start. You don’t get a second chance with a poorly fabricated scaffold. That’s why there are standards, regulations, specifications and procedures in place. Responsible scaffold manufacturers want to make sure the product they sell will work for you – all the time, every time. To do this, every participant in the manufacturing process must be responsible. In fact, this can be extended to the supplier who purchases scaffolding for the purpose of renting or selling it to the end user.
Lucky for some suppliers, some scaffold users are not sufficiently sophisticated to expect a quality product, or at least a reliable product. They don’t know that they are required to know how strong the scaffold is. It’s probably a good thing because too many suppliers, and for that matter manufacturers, don’t know how strong their products are or are not. Imitating an established design does not guarantee success. Relying on the competitor’s load data is a certain road to disaster. Thank goodness for a required high safety factor that protects the irresponsible manufacturer!
The Scaffold, Shoring & Forming Institute, SSFI, has developed a Standardized Testing Procedure so manufacturers can developed allowable load data that can be used by suppliers and users to confirm that the scaffold they are using isn’t overloaded. Too often, scaffold manufacturers don’t conduct the proper testing. For example, testing a scaffold frame one tier high will produce worthless data for a scaffold more than three frames high. Conducting only one test will also produce worthless data. Likewise, testing only one style of frame will not verify the capacity of a different style of frame. My experience indicates that way too many “new” manufacturers have no idea the SSFI Standardized Testing Procedure exists, much less that they are required to comply with applicable standards and codes. Unfortunately, if tests are conducted, they are conducted incorrectly, resulting in unreliable and misleading results. To add to the bad news, the tests are conducted by supposedly responsible testing labs that also are unaware of the proper protocol, resulting in a misleading validation of incorrect procedures and data. The final insult to the responsible manufacturer is the fraudulent misrepresentation of data. This is where one supplier or manufacturer uses the data of another manufacturer and merely changes the letterhead. It may be a clever way to appear legitimate but it won’t be too clever when someone dies because of it. Thank goodness for a high safety factor. Check out the OSHA standards: 29 CFR 1926.451(a)(1) and 1926.451(f)(1). 29 CFR 1926.451(a)(1) requires that your scaffolding have a 4 to 1 safety factor. If you don’t know how strong the scaffold is in the first place, how in the world are you going to be in compliance with this standard? 29 CFR 1926.451(f)(1) requires that you don’t overload the scaffold. Again, if you do not know the strength of the scaffold, you won’t be able to comply with the standard nor will you know if you are in danger of collapsing the scaffold. A simple question from an OSHA compliance officer will discover if you know the strength of your scaffold and whether you have had sufficient training. Should you be worried?
SAFETY IS MY GOAL
Have you ever noticed the bumper sticker on the pick up truck that roars by you at 20 miles over the limit? It says “Safety is my Goal.” Does that make sense to you? Kicking the football between the goal posts is a goal. Leaving a jobsite without injury is a goal. But watch out for the guy who says: “Safety is my goal.” To me that suggests that he plans on getting safe some day but he just hasn’t gotten there yet! Furthermore, how do you obtain safety? Do you buy it at the home improvement center on aisle 3 between the paint and toilets? Or maybe you can get it from the local scaffold supplier who has some extra safety lying around.
I think not. Safety isn’t a goal but rather a process. In the case of safety, the process is ensuring that the actions of people provide the result of no injuries or death. So, in the case of the speeding truck driver, while he is presumably encouraging safety by slapping a bumper sticker declaring his concern, his actions suggest otherwise. And so it is on the jobsite. If safety is the goal and not the process, stay away. Safety should be a way of working that results in a healthy safe environment. The process produces the result, and without the process you will never get the result. Think about it.
How often have you heard of this one? I want some of those OSHA approved plank. You can only have OSHA approved scaffold in this plant. Yeah, right. In scaffolding, OSHA doesn’t approve anything. That’s not their job. It’s your job to make sure you are in compliance with OSHA standards. In scaffolding, this means you have to understand your equipment, your regulations, and how you work. There is no substitute and there is no way around it. Another claim close to this is the one that says this product “complies with all applicable OSHA standards.” This actually is an accurate statement, for the manufacturer. In the case of scaffolding, the user is the one who has to ensure the product is being used safely (see above) and complies with the applicable OSHA standards. You obviously rely on the manufacturer to provide accurate information and a safe product, but that same manufacturer cannot control how you use the product. Therefore it is up to you. Look at it this way: An OSHA approved plank wouldn’t prohibit you from overloading it so what good would be the approval? Think about it.
100 PER CENT TIE-OFF
Have you ever been on a jobsite where there is a “100% tie-off policy?” You look around and everybody is tied off to something. All the workers are looking good. They are wearing harnesses and have lanyards, hooks, lifelines, retractables, and other assorted hardware. Some of these workers have so much stuff they look like walking hardware stores. And they’re tied off. Everybody is happy. The safety person is pleased and convinced the job is safe. The next time you go on to a jobsite, however, ask if the site has 100% fall protection. That’s right, 100% fall protection. Look around at what the walking hardware stores are tied to. Then you’ll realize that 100% tie-off doesn’t mean 100% fall protection. 100% tie-off is easy; 100% fall protection isn’t. Think about it.
SELF APPOINTED COMPETENT PERSON
It seems that we get “competent person” and being competent confused. OSHA has a definition for the competent person but has no definition for not being competent. Basically, a competent person is an individual who can recognize a hazard and has the authority to do something about it. On the other hand being competent suggests you have ability and qualifications. Not being the competent person and being incompetent are two entirely different things. But it’s amazing to me how many people think they can be competent persons when they truly are incompetent. Take for example, an incompetent individual who questions the decision of a competent person. If the incompetent person has authority without ability, look out. Think about it.
LOOK AT THAT GUY; WHAT AN IDIOT
How often have you been on a jobsite and you see someone performing an unsafe act (that’s a polite way of saying he’s doing something stupid that will result in injury or death). You shake your head and think to yourself: “Look at that guy-what an idiot.” Why do you do that? Why haven’t you stopped and talked him into stopping his unsafe act? Be polite, don’t tell him he’s an idiot, especially if he’s bigger than you. You just might see him do another unsafe act! But seriously, this guy is another human being, just like you, with family and friends. Just because you don’t know him doesn’t mean you don’t have to care. The day everybody starts thinking about their fellow workers in a concerned way will be the day the safety process (see above) takes a great leap forward and provides a result that will be awesome. And you don’t even have to think about that!
Did you ever wonder where the OSHA standards came from? For that matter, did you ever wonder where OSHA came from? How did the scaffold standards come to be? Did they always exist? Have you ever heard of Letters of Interpretation and Directives? You might be surprised at the answers.
The Federal Occupational Safety and Health Administration, OSHA, was created in 1970 when the United States Congress passed a law addressing workplace injuries and deaths. At the time, multiple rules, standards, and laws enforced by multiple agencies existed but were not consistently enforced. For that matter they weren’t very consistent or standard either. What was legal in one state wasn’t necessarily legal in another. What was seen as a safe work practice in Texas just might not be safe in Illinois. Statistics illustrated the state of affairs in 1970: Serious injuries and deaths continued to climb. The 91st Congress took action by passing Public Law 91-596 on December 29, 1970. This law required, in part, that employers shall:
“(1) Furnish to each of his/her employees employment and a place of employment which are free from recognized hazards that are causing or are likely to cause death or serious physical harm to his/her employees; (2) Comply with occupational safety and health standards promulgated under this Act.”
The law also requires that employees “shall comply with occupational safety and health standards and all rules, regulations, and orders issued pursuant to this Act which are applicable to his/her own actions and conduct.”
Passing the law was the easy part since safety can sometimes be rather subjective. What constitutes a safe place of employment? Your idea of a safe workplace may not agree with another’s opinion. To bring some consistency to the concept of safe workplace, the law also established an agency within the Department of Labor to develop standards that determined the minimum requirements for a safe workplace, and provide the enforcement to make the standards effective. Thus was born the Occupational Safety and Health Administration, OSHA. Also established at the same time was the OSHA Training Institute, OTI, to assist employers in providing training for employees.
How do you write regulations that everybody can agree on? First, you have to be real good at writing standards. Secondly, you have to make sure that the regulation, or standard, is applicable to the specific hazard and will not be misinterpreted. As a matter of fact, in a perfect world, no interpretation is required and everybody agrees on the meaning of the standard and the proper application of that specific standard. Too bad it’s not a perfect world.
Luckily, consensus standards and other rules existed prior to the establishment of OSHA. In other words, there was a foundation on which to build a system of mandatory standards. The American National Standards Institute, ANSI, had developed many standards prior to OSHA and for that matter, continues to develop consensus standards today. The ANSI standards are based on earlier standards and guidelines that were developed by insurance companies going back to the turn of the last century (that’s like a hundred years ago!) Scaffold standards can be traced back to the 1920’s when at least one insurance company issued guidelines for scaffolding and other construction activities.
The scaffold standards have evolved since 1971 when OSHA developed their first scaffold standard. In fact, in 1977 OSHA decided that the first scaffold standard could use some improvement and consequently started reviewing and rewriting the scaffold standard. This was a long arduous process but finally in 1996 the present standard was issued. However, as good as the present standard is, clarification is required from time to time, especially when attempting to apply the scaffold standard to s specific situation that doesn’t seem to “fit” any standards. This is where Letters of Interpretation come into the picture. Anybody can write to OSHA and ask for a Letter of Interpretation. Once the request is submitted, OSHA carefully reviews the standard and other available information to determine an interpretation that meets the intent of the standard. A letter is published and becomes enforceable just like the standard itself.
Directives are another tool that OSHA uses in conjunction with the standards. Directives are different than Letters of Interpretation. The purpose of the Enforcement Directive for Scaffolds, for example, is to give guidance to OSHA compliance officers for enforcing the scaffold standards. This directive is useful information and, just like the Letters of Interpretation, is available on the OSHA website, www.OSHA.gov.
So, is it a wonder that the OSHA scaffold standards are applicable to many scaffolds? Not really, once you realize that many people with a lot of expertise have been involved in the development of standards over the years and still are today. The Scaffold Industry Association, SIA, has been intensely involved in the development of many scaffold related standards since the association’s inception. Mr. Jerry Towse, first president of the SIA, recalls: “We (the SIA) were concerned when the first OSHA scaffold standards were issued because they inadequately addressed the industry’s concerns about safety. At that time, it was decided the association should be proactive in standard development.” This involvement includes the ANSI aerial lift standards, (the A92 series of standards), the ANSI scaffold standards, (A10.8), and the present OSHA standards. Like the SIA, the Scaffolding, Shoring, and Forming Institute, SSFI, has also been involved with scaffold standards since that association’s creation in 1960.
You may think the OSHA standards are deficient but I suggest this: try writing a standard or two. You’ll find out how hard it is to be precise yet broad enough to apply universally. You should be thankful to all the involved people who have selfishly contributed to the process.
s�_ae� (� For Tubular Welded Frame Scaffolds, for example, these are the differences:
This short dissertation illustrates the significant differences between the requirements of the two standards; use it to recognize that you cannot take the general industry standards and apply them to a construction industry application or use the construction industry standards in a general industry application. It is necessary to identify which standards apply for the specific application. And of course, no matter which standards apply, it is a safe scaffold that is required.
How much? No, not money, but how much can the scaffold hold? Have you ever wondered about that? If you have, that is not good for the simple and straightforward fact that if you are involved with the rental, sale, erection or use of scaffolds you are required to know the answer. That’s right; it’s in the federal OSHA standards. Look it up! Go to the training requirements and if you are a scaffold user, find 29 CFR 1926.454(a)(4) which succinctly states: (users shall be trained in) “the maximum intended load and the load-carrying capacities of the scaffold used.” If you erect, inspect and/or provide scaffolds for others, find 29 CFR 1926.454(b)(3) which requires you to know: “the design criteria, maximum intended load-carrying capacity and intended use of the scaffold.”
What is the intent of these standards? These standards are there to ensure that people like you and I use the scaffold in a safe manner, in a manner where we will never put more weight on the scaffold than it can safely hold. The standards are rather explicit in this regard. In fact, all parties involved with the scaffold have an obligation here. The designer must know what the scaffold is going to be used for and how much it is to support. The erector must know how it will be used so it can be built to accommodate the anticipated loads. The daily inspector of the scaffold must know not only how much the scaffold can support but also how much load is actually on the scaffold. And finally, the scaffold user must know the limits of the scaffold so he/she does not put any more workers or materials on the scaffold than it can safely support.
There are two types of loads. The first is the allowable load and the second is the actual load. The allowable load is determined by the manufacturer and as the name implies, is the load that you are permitted, or allowed, to place on the scaffold. On the other hand, the actual load is the load that you are going to actually put on the scaffold. For all scaffolds, the actual load must never be more than the allowable load. If the actual load is more than the allowable load it will be in violation of the OSHA standards and will collapse the scaffold at the worst condition.
Let’s look at the allowable load first. Where does it come from? It comes from the manufacturer of the scaffold. Responsible manufacturers will use the standardized test procedures developed by the Scaffold, Shoring and Forming Institute (SSFI). The manufacturer will test the scaffold to determine how much weight it can support at the time it collapses. Using the data from the tests, a safety factor will be applied to the test results and the allowable load is calculated. This is the load that the scaffold can be expected to support, provided the scaffold is erected according to the manufacturer’s guidelines and recommendations. This obviously includes the use of undamaged components, proper bracing and proper foundations. The allowable load will vary, based on the manufacturer, the type of scaffold (is it a frame scaffold, suspended scaffold or systems scaffold?), the material, and other factors. For example, a scaffold frame that is 3 feet high will hold more than one 5 feet high, assuming all other things are equal. Because of these variations, “one size doesn’t fit all.” Just because a scaffold frame from manufacturer A looks like the frame from manufacturer B doesn’t mean that it will carry the same load. You need to obtain the allowable load data from your manufacturer.
The second type of load, the actual load does not come from the manufacturer; it comes from you. If you are the user of the scaffold, it is your obligation to make sure you do not overload the scaffold. The actual load is comprised of three specific loads; the scaffold equipment load, the platform load, and the live load. The scaffold equipment load is the actual weight of the scaffolding equipment. This includes the vertical members, the horizontal members, the bracing, and any other components that are part of the scaffold structure. The platform load is the weight of the components used for the platform. This would be the plank or other materials that are used to construct the platform. The live load includes the workers, tools and materials that will be supported by the scaffold. The combination of these three loads makes up the actual load and can never be more than the allowable load.
What does all this mean? This means that all involved parties must discuss the use of the scaffold and the anticipated live load the scaffold must support. This also means that the user of the scaffold must control the amount of material and the number of workers that will be on the scaffold. Remember, the higher the scaffold, the less live load and plank levels it will support. Also, remember that a scaffold can be designed to support any actual load. It is up to the user to inform the designer of the requirements.