scissor lifts Archives | DH Glabe & Associates

Aerial Lift or Mobile Scaffold?

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

In the year 2000, at the turn of the century, the U.S. Federal Occupational Safety & Health Administration, OSHA, issued a Letter of Interpretation wherein it opined that aerial lifts known as scissors lifts (see illustration) are not aerial lifts but instead are mobile scaffolds.  The opinion was based on the fact that the revised OSHA scaffold standards for construction reference an American National Standards Institute, ANSI, standard that does not include scissors lifts.  This ANSI standard, known as ANSI A92.2-1969, was written in 1969, before the proliferation of aerial lifts that we have today.

Why was this outdated standard used, you ask?  Well, at the time the review of the original scaffold standard was initiated, A92.2-1969 was the ANSI standard that was applicable.  And since this was the only applicable standard, OSHA was required to work within the constraints of this standard to determine if scissors lifts were aerial lifts or not.  Since scissors lifts were not specifically mentioned in A92.2-1069, OSHA concluded that scissors lifts could not be included in the Aerial Lifts section of the revised standards.  However, OSHA also concluded that scissors lifts are scaffolds and therefore the other scaffold standards apply.  This includes 29 CFR 1926.451-General Requirements, and 29 CFR 1926.452-Additional Requirements for Specific Scaffolds.  Finally, OSHA concluded that since scissors lifts have wheels, they are Mobile Scaffolds and therefore must comply with 29 CFR 1926.452(w)-Mobile Scaffolds.  This interpretation of the standards relies on the accuracy of the assumption that scissors lifts are not aerial lifts and the assumption that scissors lifts are scaffolds.  Accepting these assumptions validates OSHA’s interpretation; not accepting these assumptions results in an entirely different conclusion.

I suggest an alternative interpretation to this dilemma since the industry generally recognizes that scissors lifts are aerial lifts and the Mobile Scaffold standards just don’t apply.  Here’s the argument:  The preponderance of information indicates that it was never intended for scissors lifts to be classified as Mobile Scaffolds.  A review of the preamble to the revised scaffold standards clearly indicates that the writers of the revised standard knew that additional ANSI standards existed: “OSHA recognizes that the A92 Committee has updated A92.2-1969 and has adopted other A92 standards which address technological advances and evolving safe industry practices regarding elevating and rotating work platforms.” (Federal Register, August 30, 1996, p 46095)  Furthermore, the writers also recognized the unique attributes of aerial lifts and the fact that they are just not the same as a typical supported or suspended scaffold.  How do I know that?  Besides stating in the preamble “…that the requirements of §1926.451 and §1926.452 do not apply to this type of equipment,”  the Scope and Application of Subpart L (29 CFR 1926.450(a)) clearly states that “The criteria for aerial lifts are set out exclusively in §1926.453 (Aerial Lifts) of this subpart.”  This exclusion is restated at the beginning of the General Requirements where it is confirmed that “This section does not apply to aerial lifts, the criteria for which are set out exclusively in § 1926.453.”  All this clarifies the applicability of standards but it does not necessarily clarify whether scissors lifts are scaffolds as described in § 1926.451 and §1926.452 or whether they are aerial lifts and consequently must comply with § 1926.453.  I believe the answer to this question exists within § 1926.453-Aerial Lifts and in the preamble for the revised standards.

1926.453-Aerial Lifts includes a note at the end of the section that points the reader to Non-mandatory Appendix C.  This appendix “lists examples of national consensus standards that are considered to provide employee protection equivalent to that provided through the application of ANSI A92.2-1969, where appropriate.”  Appendix C lists seven ANSI standards for aerial platforms, including ANSI A92.6-1990, Self Propelled Elevating Work Platforms. In case you are wondering, that’s the technical description for scissors lifts.  (See the illustration)  Furthermore, the OSHA writers explained in the preamble that “This Appendix is provided to serve as a guide to employers required to provide appropriate employee protection under § 1926.453, Aerial Lifts.  This Appendix reflects the proliferation of equipment-specific ANSI A92 standards since the adoption of ANSI A92.2-1969.”  Looks to me like a scissors lift is an aerial lift, not a Mobile Scaffold.

I can appreciate the constraints under which OSHA must operate.  The rulemaking process requires that the agency must comply with the legal restrictions that are in place to ensure that standards and regulations are not randomly (or intentionally) manipulated.  However, in this case, where it is clear in the industry that a scissors lift is an aerial lift, perhaps a little manipulation might be a good thing.  One last suggestion if I haven’t convinced you:  Read the Mobile Scaffold standards, § 1926.452(w)-Mobile Scaffolds and see how well they apply to a scissors lift.  The first standard requires that the scaffold “shall be braced by cross, horizontal, or diagonal braces, or combination thereof, to prevent  racking or collapse of the scaffold…Scaffolds shall be plumb, level, and squared.”  Does this make sense for a scissors lift?  How about “Where leveling of the scaffold is necessary, screw jacks or equivalent means shall be used.”  Or this one: “Caster stems and wheel stems shall be pinned or otherwise secured in scaffold legs or adjustment screws.”  And finally, “Before a scaffold is moved, each employee on the scaffold shall be made aware of the move.”  If you are operating the controls, do you talk to yourself?

The ANSI standard for scissors lifts, A92.6 is comprehensive, straightforward and very specific to scissors lifts.  Use this document.  You can purchase it directly from the Scaffold Industry Association at a very reasonable cost!

Cheap Paint

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

A friend of mine, when he first got involved in the aerial lift rental business, wondered why the aerial lift manufacturers used cheap paint on the guardrail systems.  Every time he rented a scissor lift, the paint was worn off the top of the rails when the unit was returned.  It didn’t take too long in the rental business however, for my friend to figure out that the paint was being worn off because the users were using the mid and top rails as platform supports.  In other words, the scissors lift users were improperly using the machine.  I have had the same experience; users often tell me it is the only way they can get the work done.  I even had one employer tell me that he tells his workers to use personal fall arrest equipment on scissors lifts so that when they climb on the guardrails, they are protected from falling.  Now there is a conscientious employer!  Amazingly enough, just the opposite happens with boom lifts (correctly known as “Boom Supported Elevating Work Platforms).  Sine there is a guardrail system around the platform or basket, some users assume that fall protection is provided, never considering the possibility of being launched out of the basket or platform due to a possible catapulting action.

Have users never thought about the consequences of using an aerial lift improperly?  There is the obvious consequence of falling from heights.  But what are some of the other consequences?  I dare say that we are now seeing the results of the misuse of aerial lifts.  Let’s consider the scissors lift, a versatile machine that mechanically raises and lowers a platform so the worker can access the work area quickly and conveniently.  The platform, typically no bigger than the wheel base of the machine, is lifted by arms that operate in a scissor like action.  The platform is stable with minimal sway and no redundant vertical motion once the platform is in position.  A guardrail surrounds the platform, protecting the worker from accidentally walking off the platform.  The guardrail system is always at the correct height, assuming the worker is standing on the platform and not cleverly standing on a bucket or other makeshift device to gain height.  Through the use of the guardrail system fall protection is provided.  Nothing else is required.  This guardrail system is the same as the guardrail system found at stadiums, auditoriums, bridges, balconies, decks and homes.  If this is an acceptable system at these facilities, why then do safety people and compliance officers insist that personal fall arrest equipment be used by scissors lift occupants?  Why are manufacturers installing anchors in scissors lifts?  What good is a platform that is 8 feet wide and 12 feet long when I am attached to an anchor with a lanyard that will only allow 5 or 6 feet of movement?  Frankly, it doesn’t make any more sense to “tie off” in a scissors lift than it is to tie off when I am standing on the balcony in my house.

But what makes this whole concept truly absurd is that the occupants tie off to the guardrail.  Let’s see, the guardrail can hold 200 pounds and if the occupant decides to fall, not only will he break the guardrail, but will probably bring the whole machine down on top of him, adding embarrassment to the injury.  Can this get any crazier?  Well yes, it can.

Let’s look at boom lifts.  The occupant hops in to take it up to do something quick, not thinking about the need for a personal fall restraint system.  That’s right, I said fall restraint.  We want you, the user, to stay in the bucket.  Utilize a long lanyard and you’ll feel like an astronaut, for six feet.  Then if you’re lucky, you’ll get left hanging around; if you’re not so lucky, you’ll bring the machine down on top of you.  Neither option is healthy.  Think about this: Who is the individual most exposed to the catapult action but doesn’t know it?  Who is the least likely to go through the effort of wearing a full body harness and short lanyard to move the machine only a few feet?  You’re correct if you said the truck driver.  She thinks that since the machine is only going onto the truck, there is no danger of falling.  On the contrary, there is a real likelihood that as the machine is driven onto the truck, it will tip and catapult the operator out of the basket, resulting in a real surprise at best, and a broken neck at worst.

Manufacturers are responding to all of this in a positive, constructive way.  Anchors are showing up on scissors lifts so that if you choose to wear fall restraint/protection, a suitable anchor is available.  Boom lifts are being designed to be more stable and capable of resisting flying occupants.  So, how do you know what to do?  It’s easy.  Read the manual that is located on the machine.  It will tell you amazing things that you may not know, such as what is required for fall restraint/protection.  Can it get any easier than this?  Get the training that is required before you operate an aerial lift.  And don’t do stupid stuff.

Finally, no thanks to all who have not used an aerial lift correctly.  You have managed to confuse a simple process to the point where perceptions and myths override common sense and personal responsibility.  Due to the misdeeds of a few, many are punished.  The Scaffold Industry Association has excellent information that you should have if you use aerial lifts.  Contact them; they’ll tell you all about it.

Adjustable Scaffolds–What is it?

By | Aerial Lifts, Fall Protection, Mast Climber, OSHA Standards & Regulations, Resources, Scaffolding, Scaffolding Platforms | No Comments

While scaffolds come in all shapes, sizes, and function, they can be categorized as supported, suspended or aerial lifts.  The American National standards Institute, ANSI, has defined an aerial platform as “a mobile device that has an adjustable position platform, supported from ground level by a structure.”  Scissors Lifts, Mast Climbers, and Boom-Supported Elevating Work Platforms (Boom Lifts) are examples of these machines.  While that may explain aerial lifts, what is the difference between supported and suspended scaffolds?  OSHA offers a rather detailed description for each but it can easily be explained this way.  A suspended scaffold is any platform supported by ropes.  That means all other scaffolds are supported scaffolds (if they aren’t aerial lifts).  In other words, a two point wire rope suspended scaffold really is a suspended scaffold.  However, a frame scaffold hanging off the side of a bridge, for example, is a supported scaffold, even if it is “suspended” over the side of the bridge.  While this example may be obvious, other scaffolds may defy easy categorization.

An Adjustable Scaffold is one of those scaffolds.  Which standards apply to this scaffold?  Is an Adjustable Scaffold a supported scaffold or is it a suspended scaffold?  For that matter, what is an Adjustable Scaffold?  By definition, an Adjustable Scaffold is “a scaffold structure with a manually elevating carriage that supports work and material platforms.”  What confuses the situation is that the platform on an Adjustable scaffold is supported by wire ropes.  This would mean that the scaffold is a suspended scaffold.  But not so fast; the wire rope is supported by rigid legs. That would make it a supported scaffold!  Looks to me like it’s both suspended and supported.  Well it is, sort of.  An Adjustable Scaffold is classified as a supported scaffold and here is why.  It is true that all Adjustable Scaffold platforms are supported by wire ropes.  However, unlike the typical suspended scaffold, Adjustable Scaffolds have an additional mechanism, a back-up system if you will, that supports the platform if the wire rope fails.  This mechanism includes a mechanical lever that prohibits the platform from falling very far, typically less than 12 inches.  Because this mechanism exists, the Adjustable Scaffold is not a true suspended scaffold.  That is, if the rope breaks, the scaffold platform will not crash to the ground.  Rather, it will only drop 12 inches, terrorizing the occupants but otherwise staying in the air and keeping them safe.




Adjustable Scaffolds are used almost exclusively by brick masons.  The ability of the platform to be slowly raised as the brick wall is constructed permits the top of the wall to always be at the optimum elevation for the mason.  One of the unique features of some Adjustable Scaffolds is the ability to free stand 28 feet high.  This allows the scaffold to be erected to the full height of a “big box” store (e.g. a Home Depot® or Wal-Mart®) without having to tie it to the structure.  This is a big advantage for masons in terms of efficiency and constructability.  For taller scaffolds, the masts must be tied to the adjacent structure, in compliance with applicable supported scaffold criteria.

As with all scaffolds, Adjustable Scaffolds must have proper fall protection.  This usually is a guardrail system that is installed when the scaffold is initially erected.  However, when the platform is being stocked by a forklift, and the guardrails are removed, the exposed employees must be wearing fall restraint or arrest equipment attached to a suitable anchor.  Since Adjustable Scaffolds are designed for masons, they can support substantial loads.  Consult the manufacturer for the capacity of the scaffold you are using.  Access can be provided by a portable ladder, stairs, a manufacturer supplied ladder or direct access.  Consult your manufacturer if you can use the mast of your scaffold for access.

Adjustable Scaffolds are Supported Scaffolds.  TheUSfederal OSHA standards that apply are the General Requirements, 29 CFR 1926.451, including the Supported Scaffold Criteria, 29 CFR 1926.451(c) which addresses scaffold stability and scaffold foundations.  Additionally, The American National Standards, A10.8-2001 has consensus standards that specifically address Adjustable Scaffolds.

Help, I’m Falling!

By | Aerial Lifts, Fall Protection, Mast Climber, OSHA Standards & Regulations, Resources, Scaffolding Platforms | No Comments

Fall protection for aerial lift operators and users, while straightforward in my mind, seems to be a mysterious phenomenon that bewilders the minds of many and produces myths worthy of aNew Yorkbest selling novel!  Fortunately, there is no need for it to be this way.  Admittedly, the Federal Occupational Safety and Health Administration, OSHA, standards that apply to aerial lifts can be a bit confusing, to say the least.  However, once explained, it becomes rather clear as to what is expected of aerial lift users.  Besides the standards, a more basic concept can be applied to fall protection for aerial lifts; that concept is, simply put, what’s the best way to keep users from falling?  You can’t get much more basic than that.  Let’s look at this concept first, and then look at the US OSHA standards to see why they are the way they are.


The American National Standards Institute, ANSI, has a number of classifications for the group of equipment known as aerial lifts.  In construction, the four most common types include “Boom Supported Elevating Work Platforms,” “Manually Propelled Elevating Aerial Platforms,” “Self-Propelled Elevating Work Platforms,” and “Mast-Climbing Work Platforms.”  On the jobsite, this equipment is also known as boom lifts, scissors lifts, and mast climbers.  The significance of all this is that boom lifts respond very differently to the requests of the operator than either the scissors lift or the mast climber.  The platform of a boom lift is supported by a single column type strut or beam.  This strut can be vertical, horizontal and any angle in between.  Scissors lifts, as the name suggests, have interlocking diagonal struts that allow the platform to raise and lower vertically directly above the base support.  Mast climbers, as the name suggests, has vertical struts/masts that allow the platform to raise and lower vertically by climbing the mast or masts.  The advantage of the boom lift is that the platform can go up and out, and in some cases, up, out, down and under, while the scissors lift platform and mast climber platform primarily only go up and down, similar to an elevator in a building.   These varying characteristics dictate the type of fall protection that is required.


The dynamic motion of a boom lift creates the phenomenon not unlike a catapult.  The boom can store sufficient energy during movement that it can literally launch the operator up and out of the basket.  Scissors lifts and mast climbers don’t develop this type of force and consequently is not normally a concern for fall protection.  What all this means is that on scissors lifts and mast climbers we want to keep the worker from walking/falling off the platform while on boom lifts we want the worker not only to be protected from walking off the platform but also from being launched from the platform.  This means the first line of protection on all lifts is the guardrail system.  For boom lifts it is also necessary to restrain the employee so he/she never leaves the platform.  A fall restraint system is required to do this.  Therefore, on boom lifts, not only is there a guardrail system to protect the employee but also an anchor to hook the fall restraint system to.  Please note that it is a restraint system, not a fall arrest system that is used.  We don’t want to have to catch you after you have been launched but rather to keep you from ever launching!


How does this approach to fall protection fit with the applicable regulations, you ask?  Well, first and foremost, comply with the manufacturer’s instructions.  These machines are sophisticated devices and the manufacturer is the authority on fall protection for his/her specific device.  The manufacturer may require more protection than I described above.  For example, scissors lifts may require the occupant to utilize personal fall arrest equipment attached to the specified anchor.  The manufacturer may require other safety devices that are not required by the OSHA standards.  If this is the case, you are expected to comply with those requirements provided they are more restrictive than the OSHA standards.  This brings us to the standards.


Aerial lifts are addressed in Subpart L of the Construction Industry Standards, specifically section 29 CFR 1926.453.  These standards are exclusive to aerial lifts.  (Note that the Scaffold General Requirements, 29 CFR 1926.451, do not apply to aerial lifts, as clarified in the first sentence of that section.)  Because OSHA standards cannot reference standards that are not in existence at the time of issuance, 29 CFR 1926.453 references ANSI Standard A92.2-1969 which was the applicable standard in 1986 when the revised scaffold standards were first proposed.  This 1969 standard does not reflect the multitude of machines that have been developed since then; unfortunately OSHA is stuck with this limitation.  Fortunately, OSHA recognizes this limitation and allows that equipment manufactured and used in compliance with more current standards will be recognized to be in compliance with 29 CFR 1926.453.  (See Non-Mandatory Appendix C of the OSHA Scaffold Standards for a list of those standards.)  This leads us specifically to Standard 29 CFR 1926.453(b)(2)(v) which requires that “a body belt shall be worn and a lanyard attached to the boom or basket when working from an [extensible or articulating boom platform] aerial lift.”  A note follows this regulation pointing out that a belt cannot be used for fall arrest but can be used for tethering.  Remember from the discussion above, that if you are properly anchored to the basket of a boom lift, you will never leave the basket and consequently will not be exposed to the forces of a fall.  It should be obvious from all this that if you do not anchor yourself properly you will leave the platform or basket and then we will have to catch you.  In that case you better be wearing a harness or you will probably kill yourself.  Bottom line, use short lanyards when using a boom lift so you never leave the basket.


Guardrail systems are used to keep workers from walking/falling off the platform or out of the basket.  Personal fall restraint is required to keep you in a boom lift.  Comply with the manufacturer’s recommendations no matter what type of aerial lift you are using; those requirements may be more restrictive than the OSHA minimum standards.  And a couple of final thoughts:  A 6 foot lanyard used with a restraint belt is a killer, a 6 foot lanyard used in a basket will still allow you to get launched; keep that in mind when you idly hook off so you “look good.”  And if you’re the truck driver loading the boom lift on the truck, watch out—you have a better chance than anybody of getting launched.