PRACTICAL. RESPONSIVE. EXPERT CONSTRUCTION ENGINEERING CONSULTANTS SINCE 1985
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Hoists

The Rise And Fall of Elevators

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Moving vertically on a construction project can be a challenge.  While stairs are normally available, it doesn’t make a whole lot of sense to use those to climb 50 stories unless you are interested in a lot of exercise!  Consequently hoists, elevators and lifts are frequently used to transport workers and materials between the various floors of buildings under construction.  In fact, rare is the project that doesn’t have some type of hoist for moving people and material vertically.

In the interest of making jobsites safe, the American National Standards Institute, ANSI, has developed numerous standards for use on jobsites, including standards for personnel hoists (elevators).  One of the standards which address the machines that move people vertically at construction sites is ANSI/ASSE A10.4-2007: Personnel Hoists and Employee Elevators on Construction and Demolition Sites.  Another standard is ANSI/SIA A92.10-2009: Transport Platforms.  Both of these standards address similar vertical transportation issues but in different ways.

“Personnel hoists and employee elevators” are utilized as the general carrier for workers on jobsites who want to travel between floors while “transport platforms” are more specific in their use.  Although each can be used to transport workers, a hoist is more adaptable to fast movement between floors where the interest is to get from one floor to another while a transport platform is more adaptable to a specific work environment.  In fact, the scope of each standard explains the difference.  A92.10 applies to “Transport Platforms that are primarily used as a tool of the trade to vertically transport authorized persons, along with materials and necessary tools, to various access levels on a building or structure for construction, renovation, maintenance or other types of work.”   [A92.10-2009: 1.1]  On the other hand, A10.4 “applies to the design, construction, installation, operation, inspection, testing, maintenance, alterations and repair of hoists and elevators that (1) are not an integral part of building, (2) are installed inside or outside building or structures during construction, alteration, demolition or operations and (3) are used to raise and lower workers and other personnel connected with or related to the structure.”  [A10.4-2007: 1.1.1]

Although these scopes may appear similar, there are subtle differences.  In the simplest explanation, a transport platform is more portable than a personnel hoist while a personnel hoist is more like a permanent elevator in a building.  The personnel hoist has doors, gates, cages, enclosures, counterweights and other devices not unlike a normal building passenger elevator while the transport platform is a stripped down model.  That is not to say that a transport platform is more hazardous; it’s just not as robust as a personnel hoist.

Each standard has specific requirements regarding the design and fabrication of the machine.  For example, wind loads, live loads, dynamic loads, overturning forces and inertia forces must be considered by the manufacturer.  Of particular concern for the erector is the connection of the machine to the building since improper and/or inadequate connections will lead to catastrophic failure of the entire system.  In other words, the erector better know what he/she is doing!

Keeping in mind that transport platforms are more portable than personnel hoists, the inspection criteria is different for each.  Transport platforms are treated more like scaffolding, that is, a temporary structure.  It is expected that the transport platform operator will visually inspect the machine each day before use.  The user shall “check the operating devices, brakes, emergency stops, the condition of all trailing cables, travel limit switches, guardrails, structural connecting mast ties, cables, guide rollers, and information plates, etc.” [A92.10-2009: 5.1.2.9]  Load test frequency for transport platforms is determined by applicable regulations (local and national) and the manufacturer.  For personnel hoists, “periodic inspections and tests of hoists shall be made at intervals not to exceed three months.” [A10.4-2007: 26.4.3]  Since personnel hoists are more complex and sophisticated in their operation than transport platforms, these inspections are more thorough than the transport platform inspections normally are.

As with all machinery, operators are expected to be trained.  For transport platforms, operators must be trained in all facets of the machine, including inspection, safety requirements, stability, allowable loads, the purpose of placards and decals, to name a few.  The obligations of the operator is not to be taken lightly as he is the individual who will ensure the safe use of the platform. Simply stated, this means that if you are not the operator, you are not allowed to operate the platform.  As a rider, you get to ride, not to operate.

For personnel hoists, they shall be “operated by a competent and authorized operator.” [A10.4-2007: 30.1]  Furthermore, the operators shall be “knowledgeable and capable of performing the duties outlined in the maintenance, operating and inspection manuals and are capable or recording such activity in their log.” [A10.4-2007: 30.3]   Normally, the personnel hoist operator is a designated driver who has no other duties while the transport platform operator may be doing other work once the transport platform arrives at the work location.

In summary, a personnel hoist is a sophisticated machine, similar in design and operation to a building elevator while a transport platform is a device that takes several workers to a work location with their tools and material.  The personnel hoist is truly an elevator, albeit a temporary one that will be removed when the project is completed, while the transport platform is much more temporary by being easier to erect, dismantle, operate and use; in other words it is more like a scaffold than the personnel hoist.

Do You Know Suspended Scaffolds?

By | Cantilever Beam, Hoists, Scaffolding | No Comments

Are you familiar with suspended scaffolds?  Do you know the difference between a suspended scaffold and a hanging scaffold?  Well, here’s a chance to show your friends and neighbors how well you know suspended scaffolds.  Take this quiz and see if you are the best of the best.

The answers are at the bottom of the page—no cheating!

 True or False

  1. ____A suspended scaffold is the same as a hanging scaffold.
  2. ____Outrigger scaffolds are one type of suspended scaffolds.
  3. ____You don’t need to utilize personal fall protection on a Multi-point Suspended Scaffold.
  4. ____Suspended scaffold users do not need any training if they are not operating the hoists on a suspended scaffold.
  5. ____Access is not required for a suspended scaffold.
  6. ____Counterweights for a cantilever beam can be ice or Jell-O.
  7. ____The safety factor for wire suspension ropes is at least 8.
  8. ____Counterweights cannot be used to stabilize outrigger beams on Mason Multi-point suspended scaffolds.
  9. ____Guardrails are not required on two point suspended scaffolds if all the occupants are wearing personal fall arrest   equipment.
  10. ___Guardrails or equivalent are required on Boatswains’ chair scaffolds.
  11. ___Outrigger beams secured directly to the roof do not require tiebacks.
  12. ___Suspended scaffolds shall be designed by a competent person and installed under the supervision of a qualified person, competent in scaffold erection.
  13. ___Vertical pickup means a rope used to support the horizontal rope in catenary scaffolds.
  14. ___Tiebacks only need to be one half the strength of the suspension ropes since they are there for back-up, not suspension.
  15. ___Sand can be used as a counterweight provided it is in a sealed strong metal container.

 

Now for the tough part, fill in the blank!

  1. When wire rope clips are used on suspension scaffolds, there shall be a minimum of ________ installed per connection.
  2. A stage rated for two workers or 500 pounds can support ________workers.
  3. Ropes shall be inspected for defects by a competent person prior to each ___________.
  4. Manually operated hoists shall require a _________crank force to descend.
  5. Wire rope clips shall be installed according to the __________recommendations.
  6. A two-point suspended scaffold is supported by _________ suspension ropes.
  7. Two-point suspended scaffold platforms shall not be more than ______inches wide unless it is designed by a ________person to prevent _________conditions.
  8. Suspension scaffold means one or more platforms suspended by _____ or other _______means from an overhead structure.
  9. The toprail of a suspended scaffold guardrail system must be able to withstand a force of at least ________pounds.

 

True or False Answers:

  1. False.  A hanging scaffold is constructed with rigid tubes while a suspended scaffold hangs from ropes.
  2. False.  Outrigger Scaffolds are a type of supported scaffold.
  3. True.  You need to install a guardrail system.
  4. False.  All scaffold users need training.
  5. False.  Proper access is required for all scaffolds.
  6. False.  The ice may melt and you might eat the Jell-O.
  7. False.  The minimum safety factor is 6.
  8. True.  The beams must be anchored to the supporting structure.
  9. False.  A guardrail system and PFE is required.
  10. False.  How do you attach a guardrail to a chair?
  11. True.
  12. False.  Suspended scaffolds shall be designed by a qualified person and installed under the supervision of a competent person, qualified in scaffold erection.
  13. True.
  14. False.  Tiebacks must be equal in strength to the suspension rope.
  15. True.  While not recommended, as long as the sand cannot leak out, it’s okay.
Fill in the Blank Answers:
  1. 3
  2. Depends on the weight of the workers.  You can put 5 on if they only weigh 125 pounds each.  Alternatively, if Bubba weighs 400 pounds, only he can be on it.
  3. Workshift.
  4. Positive.
  5. Manufacturer’s
  6. 2
  7. 36, qualified, unstable
  8. Ropes, non-rigid
  9. 100

The Magic of Hoists

By | Hoists, Resources, Scaffolding | No Comments

What connection do hoists have with scaffolding?  Can they be classified as scaffolds?  Hoists, after all, support workers and materials, as the scaffold definition specifies.  Typically, they are temporary, thus qualifying for another portion of the scaffold definition.  The hoist car has a supporting structure, thus qualifying with still another portion of the scaffold definition.  But are they really scaffolds?  The short answer is no.  The longer answer is still no. No matter how long you make the answer, the answer is still no.  A hoist transports workers and materials.  (View a hoist as a pick-up truck that drives vertically up and down the building and you’ll understand why hoists are not scaffolds.)

Hoists, just as scaffolding, are critical pieces of equipment on the modern jobsite.  Without them, it would be near impossible to economically construct a multi-story building.  The adjacent photo dramatically illustrates the importance of hoists on a jobsite in New York City.  Universal Builders Supply, who supplied the hoists for this project, did a fantastic job of demonstrating the versatility and importance of these machines.  Sure there is a crane on the job; but it can do only so much in a day.  And besides, cranes cannot easily transport workers.

Generally hoists can be cable supported or mast supported.  They can transport materials only or workers and materials.  They can be designed to be supported by a scaffold, they can be designed to be free standing, and they can be designed to be supported by the adjacent structure.  They can be single or multiple platforms or cars, and they are designed for a broad range of capacities.  They can be assembled by hand (if they aren’t very large), and they can be so large that a crane may be needed to erect them.  Without question, hoists are the workhorse of the project.

A mast supported hoist is an engineering marvel, similar to tower cranes and mast climbing scaffolds.  The mast supports the track or guideway for the hoist car and transfers the weight of the car and payload down to the base.  Obviously the base must support the load; reshoring for the base may be required.  If designed for it, a mast can be free standing for a certain height; otherwise, the mast is supported, or tied, to an adjacent structure to keep it from falling over.  These ties are structural ties, that is, the ties are a very critical part of the construction and must be designed and installed very carefully.  While the tie does not transfer any vertical loads to the adjacent structure, it does supply the lateral or sideway stability so the car load will be transferred through the mast.  The frequency of the ties is dependent on the design of the mast.  More frequent ties may result in a lighter mast.  Conversely, fewer ties means the mast must be more rigid and therefore more robust (you can’t get something for nothing!).  As with scaffolds, bracing is the key to the design and operation of a hoist.  Interior bracing in the mast provides the stiffness and components to keep the mast from bending too much while also providing the means to transfer loads down through the mast.

The next time you take a ride on a hoist think about what’s happening.  Transporting workers and goods vertically up the building is just as important as getting those workers and goods to the jobsite.  In fact, it can be much more difficult, once you think about it.  You can always take a side street to get to the job.  Climbing 50 flights of stairs however doesn’t sound like a very appealing alternative to taking a ride.

Can Hoists and Scaffolds Be Compatible?

By | Hoists, OSHA Standards & Regulations, Resources, Scaffold Components, Scaffolding | No Comments

Hoists and elevators are invaluable productivity enhancement devices used in project construction and renovation.  It would be impossible to complete today’s projects without hoists and elevators to move workers and materials vertically.  The Federal Occupational Safety and Health Administration, OSHA, and other agencies have standards that apply to the fabrication, installation, and use of hoists, elevators, and other similar devices.  However, understanding the standards that apply to the devices used to transport workers and materials is only a part of the picture.  Knowing how these devices interact with scaffold products is essential if safety is to be realized.

 

In a broad sense, vertical transport platforms can be generally classified in a manner similar to scaffolds.  The platforms can be supported by masts/columns or they can be supported by suspension ropes.  Within this broad categorization, many variants can be utilized to get the platform from the ground to where you want to go.  For example, an elevator in a 50 story building will be operated and supported by wire ropes while an elevator in a 2 story building will be operated by a hydraulic ram.  In other words, the one is supported by ropes while the other is supported by an adjustable column mounted on the lowest floor.  What does this have to do with scaffolding?  Well, nothing unless you decide to use the scaffold to support the hoist or elevator.  Then it can be pretty important to know what is going on.

 

Let’s look at mast supported hoists and elevators first. Keep in mind that there are very significant differences between material hoists and elevators used to transport humans.  However, the principle behind the operation of each is similar.  A mast or column supports the vertical load that is applied.  Depending on the design, the mast or column may also support the horizontal loads that will be applied to it.  What are these two loads?  The vertical load is the downward load that is a result of the weight of the car, the occupants, and the mast itself.  If this load is directly over the column or mast, there will be minimal horizontal loads.  On the other hand, if the car is cantilevered to the side of the mast, there can be a significant horizontal force that has to be restrained.  If the mast in question is attached to a building, for example, the hoist components, and the building, will restrain the forces.  If the mast however is attached to a scaffold, the scaffold had better be designed to handle those loads.  Since supported scaffolds are typically designed to support vertical loads only, a very qualified designer is required for these additional horizontal forces.  In fact, due to the potential complexity of the horizontal and vertical forces, some scaffold companies prohibit attaching large hoists and elevators to the scaffold.  This is not to say that it cannot be done; rather, these scaffold companies are very concerned about safe scaffold/hoist installation and use.

 

What about small hoists that transport material, such as scaffold components.  Can they be attached to scaffolds?  Sure, provided the scaffold is designed to support both the vertical and horizontal loads that will be imposed, not only by the hoist, but also by the materials that are being transported.  Impact loads also require consideration as the sudden starting and stopping of the machine can have an adverse effect on the ability of the scaffold to withstand the stresses.  If the hoist is mounted on the side of a scaffold tower the eccentric load caused by the hoist being outside the legs of the scaffold can produce significant forces that may exceed the capacity of the connection between the scaffold and the structure, resulting in cataclysmic results.  Consequently, the qualified designer must carefully consider all the forces that will occur and design accordingly.

 

Hoist platforms supported by suspension ropes typically apply only a vertical load to the supporting tower or apparatus.  These loads must be supported by the scaffold legs and just as important, by the members that directly hold the suspension ropes.  Again, a qualified person must design the entire structure, considering the impact, live, and equipment weight in the design.  The suspension cables must be strong enough for the loads and must be rigged according to the manufacturer’s recommendations.  Access gates and guardrail systems must be carefully designed into the scaffold so that there are no open sides or ends of the scaffold deck when the hoist platform is absent.  Lighting and signaling may also be a necessary part of the installation.

 

Even simple hand operated hoists can be disastrous in untrained hands.  The most basic hoist involves a rope that goes through a pulley supported by an arm attached to a scaffold leg.  Since these hoists have a very low load rating, you would think nothing could go wrong.  Unfortunately, workers can experience unwelcome results if they haven’t been trained properly.  The first tell tale sign that all is not right is a bent hoist arm.  Somebody hasn’t been told the load limit!  Next, the operator (the guy on the ground pulling on the rope) is standing a substantial distance away from the hoist, creating a potentially destabilizing horizontal force on the scaffold.  As the worker pulls and pulls, the load gets higher and higher and the horizontal force gets bigger and bigger.  About that time, the scaffold falls over and everybody is surprised.  The real surprise is that everybody is surprised.

 

If you are going to hoist materials or people, and you want the scaffold to support it, make sure you consider all the forces or you may find your vertical travel quickly becoming horizontal travel!

Well, Do You Know the Standards?

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

Last month we offered a quiz for you to take to test your knowledge of the OSHA scaffold standards.  Well, here’s the answers.  As you recall, it was suggested that the quiz be taken two ways, one closed book, the other open book.  The purpose was to simulate answering the questions in the field without any reference as opposed to having a source of information readily available.  Let’s see how you did.  Note:  The questions are in italics.

True or False

  1. A suspended scaffold shall be designed by a competent person.  False; a suspended scaffold shall be designed by a qualified person.  (If you don’t know the definition of a qualified person, look it up in the definitions of the scaffold standard.) (29 CFR 1926.451(a)(6)) and (29 CFR 1926.450–Definitions
  2. All suspended scaffolds must have at least a 3 to 1 safety factor.  False; all suspended scaffolds shall have at least a 4 to 1 safety factor. (29 CFR 1926.451(a)(1))
  3. Counterweights for suspended scaffolds must have a 4 to 1 safety factor.  True.  (29 CFR 1926.451(a)(2))
  4. Suspension ropes for suspended scaffolds must be steel.  False; while many suspension ropes are steel, the only requirement is that the ropes have a safety factor of at least 6 unless the safety factor is based on the stall load of the hoist being used.  In that case, the minimum safety factor is 2. (29 CFR 1926.451(a)(3 and 4))
  5. The material used to make suspension ropes for suspended scaffolds must be certified by the American Wire Rope Association.  False; it is the responsibility of the competent person to determine the adequacy and condition of the suspension rope. (29 CFR 1926.451(d)(10) and (29 CFR 1926.451(f)(3))
  6. Counterweights for suspended scaffold outrigger beams can be sand if it is in a sealed container.  True, provided you can guarantee that it won’t leak!  Solid steel counterweights, purposely manufactured for use with outrigger systems, with provisions for positive mechanical attachment, and the weight marked, are strongly recommended.  Furthermore, the counterweights must be “specifically designed as counterweights.” (29 CFR 1926.451(d)(3)(ii, iii, and iv))
  7. Masons multi-point scaffolds can use counterweights provided they are non-flowable material.  False; counterweights cannot be used with masons’ multi-point scaffolds.  Only direct connections can be used with masons’ multi-point scaffolds.  Furthermore, the direct connections for masons’ multi point scaffolds shall be designed by “an engineer experienced in such design.” (1926.451(d)(3)(i))
  8. Tieback cables shall be at least as half as strong as the suspension rope.  False; the tieback rope shall be equal in strength to the suspension rope. (1926.451(d)(3)(vii))
  9. Outrigger beams can never extend more than 48 inches beyond the fulcrum unless designed by a qualified person.  False; first, OSHA does not specify a minimum or maximum allowable cantilever length.  Second, all scaffolds shall be designed by a qualified person, regardless of the cantilever.  In other words, the cantilever can be any length but it shall be designed by a qualified designer (see Question # 1 above).  (29 CFR 1926.451(a)(6))
  10. Repaired wire rope can be used as a suspension rope if it has been repaired by a certified wire rope repairer.  False; is there such a thing as a certified wire rope repairer?  Repaired ropes (wire or otherwise) cannot be used as suspension ropes. (1926.451(d)(7))
  11. Ropes shall be inspected for defects by a competent person prior to each work shift. True.  (29 CFR 1926.451(d)(10))
  12. U-bolts can be used on scaffold suspension wire ropes provided they are tight.  False; U-bolts “shall not be used at the point of suspension for any scaffold hoist.”  (29 CFR 1926.451(d)(12)(v))
  13. There shall be at least three wire rope clips used on wire ropes at their connection points.  True.  (29 CFR 1926.451(d)(12)(i))
  14. Manually operated hoists shall require a positive crank force to descend.  True.  (29 CFR 1926.451(d)(17))
  15. Once the rigging system has been installed and inspected, it shall be inspected weekly unless the system has been overloaded.  False; “The ropes shall be inspected for defects by a competent person prior to each workshift and after every occurrence which could affect a rope’s integrity.” Besides, the rigging system should never be overloaded! (29 CFR 1926.451(d)(10))
  16. Personal Fall Arrest Equipment shall be used on all multi-point suspended scaffolds.  False; either a guardrail system or personal fall arrest system shall be used on a multi-point suspended scaffold.  (29 CFR 1926.451(g)(1)(vii))
  17. When vertical lifelines are used on a single level, two point suspended scaffold, the lifeline shall be attached to a secure location on the scaffold.  False; vertical lifelines should never be attached to a single level, two point suspended scaffold. (29 CFR 1926.451(g)(3)(i))
  18. Trained and experience workers do not have to use personal fall protection on two point suspended scaffolds if there is a guardrail system.  False; all employees on a two point suspended scaffold shall use personal fall protection and a guardrail system.  Training and experience alone do not stop falls!  (29 CFR 1926.451(g)(1)(ii))
  19. Suspended scaffold hoist operators need more training than other workers on a suspended scaffold platform.  True; if you are going to operate the hoist, you need to know how to.  If you aren’t going to operate the hoist, if can be argued that you don’t have to learn how.  (29 CFR 1926.454)
  20. While a good idea, a retrieval plan for dangling workers is not required on a suspended scaffold platform that is designed by a qualified person.  False; a qualified person has nothing to do with it.  If you marked true, you need some serious retraining! (29 CFR 1926.454 and (29 CFR 1926.502(d)(20))
  21. Platforms on two-point suspended scaffolds can never be more than 36 inches wide.  False; “Platforms shall not be more than 36 inches (94 cm) wide unless designed by a qualified person to prevent unstable conditions.”  (29 CFR 1926.452(p)(1))
  22. Welders working from a suspended scaffold should be concerned about special requirements for protecting the rigging.  True; Welding current can arc through the suspension wire rope and other strange things can occur.  (29 CFR 1926.451(d)(17)(i – vi))
  23. Suspended scaffold erectors do not have to use personal fall arrest equipment unless the building is more than 5 stories (48 feet) tall.  False; fall protection on all scaffolds, including suspended, is required at 10 feet (3.1m).  If you marked true, you really need retraining! (29 CFR 1926.451(g)(1))
  24. If u-bolts are used on suspension ropes, there shall be at least 4 so that there is a 4 to 1 safety factor.  False; there is no direct correlation between the number of U-bolts and a safety factor of 4.  Besides, U-bolts “shall not be used at the point of suspension for any scaffold hoist.”  See question # 12 above.  (29 CFR 1926.451(d)(12)(v))
  25. All suspended scaffolds, single, two-point, and multi-point, shall have a guardrail system.  True; single and two point suspended scaffold users shall also use personal fall arrest systems.  (29 CFR 1926.451(g)(1)(ii and vii))
  26. Outrigger beams used for a mason’s multi-point suspended scaffold shall be designed by an engineer experienced in such scaffold design.  False; specifically, the “connections shall be designed by an engineer experienced in such scaffold design.”  However, it’s a good idea to have the entire system designed by a qualified engineer.  See question # 7 above.  (29 CFR 1926.451(d)(3)(i))
  27. Suspension ropes shall be replaced if more than 6 randomly distributed wires in one rope lay are broken.  True.  (29 CFR 1926.451(d)(10)(iii))
  28. Only power operated hoists that support two or more workers require an overspeed brake.  False; both power operated and manually operated hoists “shall have a braking device or locking pawl which engages automatically….”  The number of workers on the scaffold has nothing to do with it.  (29 CFR 1926.451(d)(16))
  29. Manually operated hoists can “free-fall” if the operator is trained in this type of operation.  False.  Operator training has nothing to do with it.  Manually operated hoist shall not be allowed to free fall.  (29 CFR 1926.451(d)(17))
  30.  While erectors shall have special training, users of suspended scaffolds do not require specialized training on the use of suspended scaffolds if they are experienced.  False; while erectors shall have additional training on the proper installation of suspended scaffolds, users shall have training in the operation, use, inspection, and maintenance of suspended scaffolds, as required by the training standards and their employer’s requirements. Experience only counts if they have had proper training.  (29 CFR 1926.454)
  31. The SIA can provide erectors and users of suspended scaffolds with a recognized training program.  True.  Contact the SIA for more information: 818-610-0320.

 

Fill in the blank:

  1. All suspended scaffolds shall be inspected by a competent person. (29 CFR 1926.451(d)(10) and (29 CFR 1926.451(f)(3))
  2. A scaffold supported by a wire rope is classified as a suspended scaffold.  (29 CFR 1926.450-Definitions)
  3. When a u-bolt is used, the u-bolt shall be placed over the dead end of the rope.  (29 CFR 1926.451(d)(12)(vi))  Note:  U-bolts cannot be used “at the point of suspension for any scaffold hoist.  (29 CFR 1926.451(d)(12)(v))  Also see questions # 12 & 24 above.
  4. A minimum of  3 wire rope clips shall be used on suspended scaffold connections.  (29 CFR 1926.451(d)(12)(i))

 

This leaves us with the last question of the quiz:

  1. I think I got ________ of the questions correct.

 

If you got this one correct, congratulations!  If you got it wrong, watch out!  Here’s the reason.  Even if you answered 0 on question # 36 you at least realized you shouldn’t guess and/or make up some answer.  On the other hand, if you answered 36 and did not get all the answers correct, then you are misleading yourself and more importantly, misleading other employees.  Whether you’re an erector, safety director, enforcement officer, or scaffold user, it makes no difference; the standards should be cited correctly and accurately.  Thinking you are right when you are not will cause confusion at best, and injuries at worst.  Don’t take chances—know and understand the standards.

How Well Do You Know?

By | Hoists, Resources, Scaffolding | No Comments

How well do you know the minimum expectations for the construction and use of suspended scaffolds?  Take the following quiz two ways; first answer the questions without referring to any standards or regulations.  Second, answer the questions using any reference material you want.  In other words, take the quiz “closed book” and then take it again “open book.”  The correct answers will be in next month’s magazine so you have 30 days to answer the quiz!

 

True or False

  1. A suspended scaffold shall be designed by a competent person.
  2. All suspended scaffolds must have at least a 3 to 1 safety factor.
  3. Counterweights for suspended scaffolds must have a 4 to 1 safety factor.
  4. Suspension ropes for suspended scaffolds must be steel.
  5. The material used to make suspension ropes for suspended scaffolds must be certified by the American Wire Rope Association.
  6. Counterweights for suspended scaffold outrigger beams can be sand if it is in a sealed container.
  7. Masons multi-point scaffolds can use counterweights provided they are non-flowable material.
  8. Tieback cables shall be at least as half as strong as the suspension rope.
  9. Outrigger beams can never extend more than 48 inches beyond the fulcrum unless designed by a qualified person.
  10. Repaired wire rope can be used as a suspension rope if it has been repaired by a certified wire rope repairer.
  11. Ropes shall be inspected for defects by a competent person prior to each work shift.
  12. U-bolts can be used on scaffold suspension wire ropes provided they are tight.
  13. There shall be at least three wire rope clips used on wire ropes at their connection points.
  14. Manually operated hoists shall require a positive crank force to descend.
  15. Once the rigging system has been installed and inspected, it shall be inspected weekly unless the system has been overloaded.
  16. Personal Fall Arrest Equipment shall be used on all multi-point suspended scaffolds.
  17. When vertical lifelines are used on a single level, two point suspended scaffold, the lifeline shall be attached to a secure location on the scaffold.
  18. Trained and experience workers do not have to use personal fall protection on two point suspended scaffolds if there is a guardrail system.
  19. Suspended scaffold hoist operators need more training than other workers on a suspended scaffold platform.
  20. While a good idea, a retrieval plan for dangling workers is not required on a suspended scaffold platform that is designed by a qualified person.
  21. Platforms on two-point suspended scaffolds can never be more than 36 inches wide.
  22. Welders working from a suspended scaffold should be concerned about special requirements for protecting the rigging.
  23. Suspended scaffold erectors do not have to use personal fall arrest equipment unless the building is more than 5 stories (48 feet) tall.
  24. If u-bolts are used on suspension ropes, there shall be at least 4 so that there is a 4 to 1 safety factor.
  25. All suspended scaffolds, single, two-point, and multi-point, shall have a guardrail system.
  26. Outrigger beams used for a mason’s multi-point suspended scaffolds shall be designed by an engineer experienced in such scaffold design.
  27. Suspension ropes shall be replaced if more than 6 randomly distributed wires in one rope lay are broken.
  28. Only power operated hoists that support two or more workers require an overspeed brake.
  29. Manually operated hoists can “free-fall” if the operator is trained in this type of operation.
  30.  While erectors shall have special training, users of suspended scaffolds do not require specialized training on the use of suspended scaffolds if they are experienced.
  31. The SIA can provide erectors and users of suspended scaffolds with a recognized training program.

 

Fill in the blank:

  1. All suspended scaffolds shall be inspected by a _______________ person.
  2. A scaffold supported by a wire rope is classified as a ___________ scaffold.
  3. When a u-bolt is used, the u-bolt shall be placed over the ________ end of the rope.
  4. A minimum of ___________ wire rope clips shall be used on suspended scaffold connections.
  5. I think I got ______________ of the questions correct.

 

Taking this quiz “closed book” simulates actual jobsite conditions when you try to remember the regulations without any reference material at hand.  “Open book” testing simulates having the reference but perhaps not understanding the intent of the regulations.  Next month we’ll look at the answers to the questions.

STEEL, OR STEAL?

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

If the new currency issued by the US government is any indication, counterfeiting is big business. From a bogus airplane part to a phony Mickey Mouse, substandard fasteners to funny money, counterfeiting can occur anywhere, with all types of products. What about the scaffold industry? Can counterfeit products affect the typical scaffold user? The simple answer is yes. Counterfeiting can occur in several different ways, with a variety of different products.

 

Steel can be a prime source of counterfeiting. For example, bolts fabricated from inferior steel have been the cause of failures in various structures. Engineers are very concerned with the ramifications of faulty fasteners since failures due to these bogus fasteners are usually life threatening. It is difficult to spot faulty fasteners because the markings are identical to legitimate fasteners. In the scaffold business, these fasteners can wreak havoc on the safety of hoists, masts, machinery and other scaffold components. Consequently, it is imperative that you know your sources and that you are comfortable with your fastener supplier’s quality assurance program.

 

Steel used in the fabrication of frame and modular scaffold can be another source of counterfeiting. Steel counterfeiting can produce safety hazards in a variety of ways. One typical method is by outright fraudulent representation. The unscrupulous merchant will claim that the counterfeit product is exactly like a product produced by a legitimate manufacturer. In fact, the steel of the inferior product will not have the same strength as the legitimate item. Since the content of the steel cannot be identified by visual inspection, the unsuspecting user, assuming that both products are the same, will use the cheap imitation, only to have a failure that will cause serious injury or death. A twist on this concept is the manufacture of a scaffold frame or other component from steel that is not typical of a competing manufacturer but claiming that it is the identical product, including using the same name for the product. (That’s like building a car in your garage and saying that it’s a Ford!) The resulting confusion will produce potentially dangerous situations because of the strength reduction in the counterfeit product. Please note that this is not the same as producing an identical product and stating that it is comparable to that other product.

 

Another example of counterfeiting can occur with wood scaffold plank. To the untrained eye, all wood appears equal. Herein lies the trap. The unsuspecting consumer is told that the plank is scaffold grade when in fact it is not. Grade stamps are probably non-existent although the good counterfeiter will produce a bogus stamp so that the planks in question appear genuine. Obviously, once the planks are put into service, the window for disaster is opened and will not be closed until the entire inventory of plank is discarded. By then, injuries and death may have occurred. An easier trick, although not necessarily counterfeiting, is to place scaffold grade planks on the top and bottom of the bundle, filling the center with inferior planks. In either case, disaster lurks for the worker who relies on the inferior planks for support.

 

What can be done to avoid counterfeiting? With plank, solutions are somewhat easier than with steel products. Learn some fundamentals about the standards for scaffold grade plank such as the slope of grain, size of knots, and number of rings per inch. Purchase only from reputable suppliers, those who will provide references and legitimate documentation concerning their products. For steel, again deal only with reputable manufacturers who can verify the content of the steel and laboratory documentation of steel content. Reputable manufacturers constantly insist on steel content reports from the steel mills and frequently perform independent tests to insure the quality of their products. These steps verify the consistency of their products and provides the confidence that scaffold designers, erectors, and users require to ensure worker safety. Finally, above all else, the price might be the indication that something isn’t right. Purchasing plank at half the price may sound good but just as with other good “deals”, it might just be too good a deal. Be suspicious; you have the right, as buyer, to find out what you’re buying. And if that brand new scaffold frame is half the price of the competition, it just might be half the frame. Is it steel or steal?