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Pop Quiz: 30 Questions About Scaffolding

By | Blog, OSHA Standards & Regulations, Scaffold Bracing, Scaffold Components, Scaffolding, Scaffolding Planks, Scaffolding Platforms | No Comments

CAN YOU ANSWER THIS?

It is somewhat surprising how creative workers can get when it involves scaffolding.  Just when it seems all the questions have been answered, along comes a question that raises an issue that was never addressed.  Challenge yourself to these questions and see if your answer agrees with the one given at the end of this article.

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Boards and Rails

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

A quiz that evaluates your understanding of the correct installation and use of supported scaffold platforms and fall protection.

How well do you know the mandatory standards that dictate how we are to build scaffolds?  Specifically, how well do you know the mandatory standards that counsel us in the proper design and construction of scaffold platforms and fall protection?  Let’s find out!

Here is a quiz to see if you know your stuff.  The answers can be found below.  The first set of questions is “true or false” while the second set is “fill in the blank.”  No cheating on this; try it first from memory and if you don’t get a perfect score see if you can find the correct answer in the federal OSHA standards.  And don’t look at the answers until you are done!

  1. All scaffolds need at least one platform to be a scaffold.
  2. The minimum width platform for a suspended scaffold is 24 inches.
  3. The maximum width platform for a two point suspended scaffold is 48 inches.
  4. A boom lift does not need a guardrail system.
  5. You can guess at the required strength of a fall protection anchor as long as it looks like it can hold 5,000 pounds.
  6. Plank used for a platform can be of any material and strength as long as it can hold four times the intended load.
  7. Aluminum plank cannot be used with steel scaffolding because of galvanic action.
  8. The minimum distance a solid sawn wood plank must overhang its support is 12 inches unless it is secured from movement.
  9. The height of a toprail above a scaffold platform is 42 inches, plus or minus 3 inches.
  10. You must wear personal fall protection equipment and have a guardrail system when working on a multi-point suspended scaffold.
  11. If you are wearing personal fall protection while on a tubular welded frame scaffold platform, you don’t need a guardrail if the platform is no more than 7 feet above the level below.
  12. Same question, different platform height:  If you are wearing personal fall protection while on a tubular welded frame scaffold, you don’t need a guardrail if the platform is no more than 12 feet above the level below.
  13. Toeboards are part of the guardrail system.
  14. If you know you are not going to fall, you don’t need fall protection while on a scaffold.
  15. You have to wear personal fall protection and have a guardrail on a mobile scaffold if you are going to ride it.

Answers to the True and False Questions:  1, True; 2, False; 3, False; 4, False; 5, False; 6, True; 7, False; 8, False; 9, False; 10, False; 11, Trick question—you don’t need fall protection because the platform is less than ten feet above the lower level — True; 12, True; 13, False; 14, Don’t you wish-False; 15, False, but then if you are riding it you like to tempt fate.

Fill inthe blank

  1. The maximum gap between platform units is ___________________ inches.
  2. The minimum toprail strength is ______________________ pounds.
  3. The height at which fall protection is required on scaffolds is _____________ feet.
  4. The minimum overlap for plank is _____________ inches unless the plank is secured from movement.
  5. The minimum width platform on a supported scaffold is _____________inches.
  6. Fall protection for scaffold erectors is determined by the _____________________ competent person.
  7. For a platform on a supported scaffold, the platform shall extend from the front _________________ to the _________________ supports.
  8. Designed personal fall protection anchors must have a safety factor of _____ to one.
  9. Scaffold Platforms shall be designed by a _________________ person.
  10. The maximum space between the edge of the platform to the guardrail system is _________________ inches.
  11. For normal use, if the front edge of the platform is no more than __________ inches from the work surface, it is not considered an open sided edge and does not need fall protection.
  12. The stamp on the side of a scaffold grade plank shall read: ________________________.
  13. If an 8’0’ long plank is not secured, the maximum cantilever past its support is _________inches.
  14. The maximum distance between guardrail posts on a scaffold is ___________ feet.
  15. When you hook off the lanyard of your personal fall protection system to the toprail of a scaffold guardrail system, the rail has to be able to support __________pounds.

Answers to Fill in the Blank questions: 16, one; 17, two hundred; 18, ten; 19, twelve; 20, eighteen; 21, employer’s; 22, uprights, guardrail; 23, two; 24, qualified; 25, nine and one half; 26, fourteen; 27, it shouldn’t read anything– there is no requirement; 28, twelve; 29, trick question—there is no maximum as long as the rails can support 200 pounds; 30, 200—your personal fall protection isn’t being used since you are behind the guardrail, you are just “storing” your hook!

Plank or Platform?

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Is it a plank or is it a platform?  Can a plank be a platform or can a platform be a plank?  When it comes to the working surface for a scaffold, these questions are common.  But they shouldn’t be.  It appears the confusion arises because the use of wood planks for scaffold platforms is commonplace.  Simply stated, wood planks can be used as a platform.  Therefore, wood planks can be a platform but a platform is much more than just wood planks.  To understand this, it is good to know that typical scaffold standards address two issues with scaffold platforms.  The first is the strength of the platform and the second is the construction of the platform.

A scaffold platform can be constructed from any material provided that the material has sufficient strength to support four times the load that will be put on it.  This ratio of four is the safety factor.  For example, if you want to put 1,000 pounds on your scaffold platform, your platform has to support 4,000 pounds.  That’s pretty simple assuming you know how strong the platform is and you also know the weight of the workers and materials you will be placing on the platform.  If you don’t know these two things, then you cannot determine if the platform is overloaded and consequently you will be in violation of the standard that requires a 4 to 1 safety factor.  I cannot help you with the load you are placing on the platform; it is impolite to ask people how much they weigh.  However, depending on what material you are using for the platform, I may be able to help with how much the platform can support.

If you choose Styrofoam for your platform you are out of luck—I don’t know the strength of Styrofoam.  If you choose a fabricated plank, like an aluminum hook plank or a laminated veneer lumber (lvl) plank, the manufacturer can tell you how strong their product is.  Of course, if you don’t know who the manufacturer is or the manufacturer hasn’t tested their product to determine the strength, you are once again, out of luck.  However, if you decide to use a solid sawn Southern Yellow Pine scaffold grade plank, for example, you are in luck!  I can provide you with a chart that shows the capacity.  Keep in mind that the U.S. federal OSHA standards do not require the use of Scaffold Grade plank but if you do not know how to calculate the strength of the plank you are using, you will have a very difficult time convincing anyone that you have a sufficient safety factor.  That’s why it is prudent to use a scaffold grade plank when using solid sawn lumber for your scaffold platform.

The second issue, the construction of the platform, is cleverly addressed in some standards by referring to the components of the platform as “platform units.”  While this is technically correct, it is reasonable to assume that the standard is talking about 2×10 wood planks.  Minimum standards require that scaffold users are provided with a platform that is safe, for example a platform which won’t become misplaced and dump the occupant to the level below.  The standards also want to eliminate hidden surprises such as cantilevered platforms that are inherently unstable, exposing the user to a potentially untimely demise.  The standards will normally specify the minimum overhang and maximum overhang for planks (platform units), the space between planks, and the distance not only from the work surface to the platform edge but also the maximum gap between the back edge of the platform and the guardrail system (assuming one is being utilized).  The bottom line to all this is to ensure that the scaffold has a safe, stable and complete platform.

The platform does not have to be 2×10 wood scaffold planks.  It actually can be Styrofoam.  It can be aluminum joists and plywood.  If you choose to use joists and plywood, how do the standards apply?  How do you take a standard that requires that “platform units” overhang their supports at least 6 inches and no more than 18 inches and apply it to a 4×4?  The answer is straightforward if one understands the intent of the platform standards:  If the platform is stable, it is safe.

While all this could be straightforward the reality is quite different.  There is no single set of standards.  Various governmental agencies have established their own specifications and they do not necessarily agree from one agency to the next.  For example, US federal OSHA specifies that the maximum overhang for a 12’-0” long “platform unit” is 18 inches, while the Army Corps of Engineers allows only 12 inches.  Go figure.  In California, the overhang can be as much as 18 inches, no matter what the length of the plank is.  Go figure.  Is there an explanation for these contradictory requirements?  I suppose there is but I am not aware of it.  I do know that varying requirements do not make it easy for scaffold erectors.

Is it a platform or is it a plank?  Or is it a platform unit?  12 or 18 inches?  What if it is 12 and a half inches when it should be 12?  Do you know the answer?

Fact or Fiction

By | Fall Protection, Guardrail, Resources, Safety Hazards, Scaffolding, Scaffolding Platforms | No Comments

Fall protection is a huge topic these days what with people falling down and falling from heights.  And since scaffolds are, by definition “any temporary elevated platform,” the issue of fall protection is significant, especially since most scaffold fatalities are due to falls from heights.  It doesn’t have to be this way.  Scaffold suppliers have this really cool product called a guardrail that when used properly, will keep you from falling.  And if you don’t like that, you can always use other stuff to keep from falling to your death.

As you may already know, there are basically two choices when addressing fall protection from scaffold platforms: a guardrail system and personal fall arrest systems.  While not specifically addressed in many safety standards, fall restraint can also be used as a form of fall protection.  Other options are available for fall protection from places like open sided floors and roofs, options that include safety nets, monitoring systems, warning lines and fall protection plans.  It should be noted that lots of safety folks don’t like some of those options since they require workers to behave and we all know that doesn’t always happen.

Experience has indicated to me that when it comes to fall protection, everybody is an expert.  I’m not sure if that is because people fall, making them instant experts, or they think it’s no big deal to “tie off.”  So let’s look at some of these issues and sort out the fact from the fiction.

  1.  Fall protection is required when you are more than 6 feet above the level below.  Fact and fiction!  It depends on the applicable code.  Codes require fall protection at heights ranging from 4 feet to 30 feet.  So find out what the rule is where you are working (or hanging around).
  2. Most workers on construction sites, both commercial and industrial, often use personal fall protection equipment.  Fiction.  Very few workers use personal fall protection equipment.
  3. Many workers wear personal fall protection equipment.  Fact.  Luckily very few workers use it.
  4. Anchors for personal fall protection systems must hold 5,000 pounds.  Fiction.  If the anchor is designed by a qualified person, it must have a safety factor of 2.
  5. If you hook your lanyard (the other end of the rope that is attached to your harness) to an anchor, the anchor must be designed.  Fact.  You cannot guess at the strength of the anchor; if the anchor is not part of a system designed by a qualified person (see #4) the anchor must hold at least 5,000 pounds.  Guessing is not allowed although it appears everybody does it.
  6. The maximum force on the body is limited to 1,800 pounds.  Fact.  This means you better not fall too far before your fall is arrested.  That’s a fancy way of saying that when you reach the end of your rope, the force on your body better be less than 1,800 pounds or there will be two of you.  Incidentally, if the force on your body is limited to 1,800 pounds why does the anchor have to hold 5,000 pounds?  After all, if you pull on one end of the rope with 1,800 pounds, doesn’t the anchor on the other end only have to pull with a force of 1,800 pounds?  Hmmmm-what’s with that?
  7. The 5,000 pound anchor requirement is based on extensive scholarly research and testing. Fiction.  It’s based on the strength of ¾ inch manila rope which is actually 5,400 pounds.  It was lowered to 5,000 pounds in the US federal construction standards to agree with the US federal general industry standards.  So much for science.
  8. You cannot free fall more than 6 feet.  Fiction (sort of).  You can free fall as far as you would like, according to a US federal OSHA Letter of Interpretation.  It’s just that when you get to the end of your free fall, the load on your body cannot be more than 1,800 pounds.  (Now you know how bungee jumping works.)
  9. 100 percent tie off is the same as 100 percent fall protection.  Fiction.  Anybody can do 100 percent tie off; just look at any construction site.  Workers tie off to all sorts of ridiculous stuff.  Like the guy that ties off to the step ladder he is on!  One hundred percent fall protection is easy for scaffold users, but not leading edge scaffold erectors.
  10. I cannot use a scaffold for an anchor.  Fiction.  Some scaffolds make very nice boat anchors.
  11. I can use a scaffold as an anchor.  Fact.  When designed by a qualified person (and perhaps a qualified Professional Engineer) a scaffold can be used as an anchor for a personal fall protection system.
  12. It is difficult to provide adequate anchorage for leading edge erectors and still comply with all the fall protection standards.  Fact.  It’s really tough to get a scaffold to hold 5,000 pounds.  It’s really tough to limit the free fall distance for erectors to 6 feet when they have nothing above them to tie to.  If we waived certain regulations for scaffold erectors, we would eliminate some of the excuses.  For example, is it really necessary for scaffold erectors to have an anchor that can hold 5,000 pounds?  Is it really necessary that the system have a 2 to 1 safety factor.  After all, as long as he/she doesn’t fall to a certain death have we not succeeded?  Something to think about.
  13. Horizontal lifelines are easy to install and use.  Fiction.  While they may be easy to install, they are not easy to use.  The problem with horizontal lifelines is that people never use them.  That’s right; they install them, and hook off but luckily never use them.  If they used them they would be terribly disappointed in the performance of the line.  There is a reason horizontal lifelines are to be designed by a qualified person.  Did you know that an anchor on a horizontal lifeline can see a load of 25,000 pounds if it is not designed properly?  What do you suppose that would do to the scaffold?
  14. All safety consultants and compliance officers are experts in fall protection design and installation.  Fiction.
  15. All scaffold users are experts in fall protection design and installation.  Fiction.
  16. All scaffold erectors are experts in fall protection design and installation.  Fiction.

So much for fall protection– I still think the easiest fall protection is:  Don’t fall.  But then perhaps there’s more fiction in that statement than fact!

Industrial or Commercial?

By | Resources, Scaffold Components, Scaffolding, Scaffolding Platforms | No Comments

Is it an industrial scaffold or a commercial scaffold?  That is the question that I am regularly asked.  And what is the answer?  Simply stated, I doubt there is a difference.  Now, before you industrial erectors get in a tizzy, there is no doubt that there is a difference in the application of the scaffold and the circumstances and environment where an industrial scaffold is used.  However, the physics, engineering, and safety are all the same.

So, is there a difference between industrial scaffolds, commercial scaffolds, and we may as well add maintenance scaffolds to the discussion?  I dare say that there is a difference.  Here is why I think so.  An industrial scaffold is normally used by trades that may never see a commercial project.  And so it is also true for commercial project scaffold users.  For example, I don’t think I have ever seen a stucco contractor working in an oil refinery.  But, on the other hand, I have seen a pipe fitter working in both a power plant and a high rise office building.  What makes the scaffold in each purpose different isn’t in the type of equipment but rather in its application to the specific situation.  Typically, systems scaffolds and tube & coupler scaffolds are a common sight at a refinery because these scaffolds provide the most versatility in reaching the desired location and elevation.  Conversely, frame scaffolds are the most common scaffolds on commercial sites because the congestion is so much less.  This is not to say the systems scaffolds are not seen on commercial sites; typically they are used on commercial sites due to their increased strength over frame scaffolds.  It is also true with tube & coupler scaffolds; you will find this equipment on commercial sites as auxiliary equipment that provides additional bracing for the primary scaffold.

The real difference, in my opinion, is in the procedural controls that have long been established at industrial projects that now are slowly expanding onto commercial projects.  The first example is the use of a tagging system.  As far as I know, this system began in refineries, chemical plants, power plants and other similar facilities.  It is based on a very tight control over the procedures that are in place at the facility.  And the tagging system works because of the tight controls.  Typically, the scaffold erector in an industrial plant also is responsible for the pre-workshift inspection of the scaffold.  Users of the scaffolds, besides having the training to recognize safety hazards on scaffolds, respect the tag and have been trained that if the tag is not current, the scaffold is not to be used.  Furthermore, the users understand that they (the users) shall not modify the scaffold; that task is left to the authorized trained and experienced workers charged with that work. And, obviously, if the tag is red the scaffold should not be used.  These kinds of controls, based on my experience, rarely exist on a commercial scaffold.

Another area where industrial scaffolds differ from commercial scaffolds is the platform.  The tendency at industrial facilities is to cover all openings in platforms with plywood, specifically the gaps that occur at scaffold legs and stairways.  Although the standards allow for these types of openings, industrial scaffold users prefer to have the gaps covered.  Such is not the case on many commercial sites where the gap between the main scaffold platform and say, the cantilever platform on the side brackets, is accepted and typical.  Next, due to the congestion at refineries, it is not uncommon to see multiple small platforms on a given scaffold.  Many of these platforms will be as small as 2 or 3 feet by 4 or 5 feet while on commercial sites the platform can be continuous along the entire face of the structure.

Access is another area where there is a difference, more because of the type of scaffold equipment being used than any other reason.  Since systems scaffolds are so prevalent in industrial environments, an attachable ladder is required (unless stairs are being used).  On commercial sites, where frame scaffolds are used, ladders will be omitted if the frame can be used for access.

Falling object protection is also addressed differently between commercial and industrial applications.  It is common for toeboards to be installed on all industrial scaffold platforms while commercial scaffolds may utilize alternative means of falling object protection including canopies and catch platforms.  Screens and barricades are common to both types of projects.

Finally, fall protection has notable differences between industrial and commercial scaffolds although there seems to be a merging of concepts in this regard.  It has been common in some industrial locations that all scaffold users utilize both guardrails and personal fall arrest equipment.  More importantly, scaffold erectors have been required to utilize personal fall protection, or at least “hook off” 100 per cent of the time.  That policy has now been adopted by general contractors in the commercial construction industry and we will see more companies insisting on 100 per cent tie off whether it is effective or not and despite it may not comply with the applicable standards and regulations.

So, as you can see, the scaffold is the same; it is only the application of the scaffold to meet the requirements of the customer and the restrictions of the site that makes industrial scaffolds different from a commercial scaffold.  Let’s face it—an injury or death is still an injury or death.  It doesn’t matter what type of scaffold it is; the scaffold has to be erected and used correctly no matter where it is.

Plank or Platform?

By | OSHA Standards & Regulations, Resources, Scaffolding, Scaffolding Planks, Scaffolding Platforms | No Comments

Is it plank or a platform that you stand on?  Is this a tough question?  Why is a concept so easy in theory so difficult in application?  The simple answer to the first question is that scaffold plank can be used to construct a platform.  For a variety of reasons, it gets complicated, or so it seems.

The Federal Occupational Safety and Health Administration, OSHA, describes a scaffold platform as a “work surface elevated above lower levels.  Platforms can be constructed using individual wood planks, fabricated planks, fabricated decks, and fabricated platforms.”  In an attempt to include the largest variety of products that can be used to construct a platform, OSHA refers to the various components as “platform units.”  While the experienced scaffolder will recognize that wood plank can be platform units, those not so knowledgeable will easily become confused since “platform unit” is not defined in the OSHA standards other than to say:  “Each platform unit (e.g. scaffold plank, fabricated plank, fabricated deck, or fabricated platform)” as a way of defining a platform unit.  The intent of the platform standards is to ensure a safe work surface for the scaffold user.  This means that the worker should expect a surface that has sufficient strength, doesn’t deflect too much, doesn’t have any big holes to fall through, and is relatively flat.

Having stated these expectations, where does that leave us when it comes to the specifics?  It depends on what you are using for “platform units.”  It also depends on the applicable scaffold standards.  Is it General Industry or Construction?  Let’s take a look at some of the things it takes to have a decent scaffold platform:

  • All platform units shall have a safety factor of four.  This means that if you are going to put 250 pounds on the platform unit, it has to hold at least 1,000 pounds before it breaks.
  • If you have a 2×10 plank, it has to be 4 times stronger than the load it will hold.
  • If you are using a platform unit as described above, in other words a 2×10 wood plank, a fabricated plank such as a laminated veneer lumber 2×10, or a fabricated deck (read that to be a hook plank) the space between units cannot be more than 1 inch.
  • If you are using solid sawn lumber for a platform unit, that is a plank cut out of a tree, it must be scaffold grade if OSHA General Industry standards apply, and it must have a 4 to 1 safety factor if OSHA Construction Industry standards apply.  (In Construction Industry applications, it does not have to be scaffold grade but the Scaffold Industry Association recommends that only scaffold grade solid sawn plank be used.)
  • You can use Styrofoam as a platform unit but you better make sure you have that 4 to 1 safety factor!
  • If you are using laminated veneer lumber, or other platform units fabricated from wood, again it has to have that 4 to 1 safety factor.
  • The minimum width of a scaffold platform, for most supported scaffolds, is 18 inches.  You can get by with less if you can show that you don’t have room to construct an 18 inch platform.
  • Platforms are to be “fully decked” between the front uprights and the guardrail system.  Great idea where a guardrail is being used.  I have no idea what that means when there is no guardrail.  Some people think that means the full width of the scaffold.  Suppose you have a nine foot wide (not long but wide) bay; does this mean the platform should be nine feet wide?
  • Platforms constructed with plank and plywood are legal, and safe too, notwithstanding an incorrect OSHA Letter of Interpretation that claimed one couldn’t inspect the plank if it was covered by plywood.
  • OSHA has a plank span chart in non-mandatory Appendix A of the Construction Scaffold standards.  You can follow this chart if you want.  Just make sure the plank you are using equals the strength used for the chart.  Of course, if your plank is stronger than what the chart is based on, then you can’t use the chart.  Get a qualified person to tell you what your plank can do.
  • Make sure you know what you are buying when it comes to plank.  Unscrupulous purveyors of scaffold plank have a tendency to overstate their products capability.  (If the deal sounds too good to be true, it probably is.)
  • If you choose to construct your platform with joists, such as aluminum beams, and plywood, make sure it is designed to support the intended load.  In other words, have a qualified person design it.
  • It is assumed that if platform units hang over their supports at least 6 inches they won’t fall off.  If you think your platform units may fall off, secure them so they don’t.
  • Don’t let your platform units hang over their supports too far as this will result in a diving board (also called a widow maker).  This is not good.  Unless you secure the opposite end, don’t let your platform units stick out more than 12 inches for platform units 10 feet or less in length or 18 inches for longer plank.
  • Overlap your platform units at least 12 inches unless you secure them.

Well, these are a few things to think about when you are installing or working on platform units.  Consult the OSHA, ANSI and SIA standards and codes for additional important information.  Remember this:  there is no back-up for a failed platform unit like there is for other scaffold components.  In engineering jargon, the platform has no redundancy.  If the platform unit you are standing on breaks you are history.  Some people suggest that the platform below will stop you.  Unfortunately, by the time you hit the deck below you will have built up enough energy to break that one too.  By the time you hit the ground you will have broken a lot of plank that you will have to pay for as soon as you get out of the hospital!  Don’t take chances on damaged product, misrepresented product, faulty product, or poorly placed product.  That’s what the standards say, in spite of the use of the term “platform unit.”