Aerial Lift or Mobile Scaffold?

By David H. Glabe, P.E. / November 1, 2010

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Why was this outdated standard used, you ask?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!

Tags: Scaffolding Aerial Lifts American National Standards Institute mobile scaffolds OSHA Standards & Regulations Resources scissor lifts

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