Scaffold or Shoring?

By David H. Glabe, P.E. / March 31, 2003

When is a platform a work deck and when is it formwork? This question is frequently asked during the process of erecting shoring equipment. A similar question is whether the equipment is scaffolding or shoring. Often the situation is misdiagnosed and the ensuing conversation concerning the application of regulations develops into a frustrating exchange of accusations.


Is there any significance to ascertaining the difference? Is the safety of the erector or user adversely affected? What role does the type of equipment have in determining the outcome? These are good questions that require answers.


The first step is to determine the basic difference between a scaffold and a shoring deck. As defined by the U.S. Federal Occupational Safety and Health Administration, OSHA, a scaffold is any temporary elevated platform and its supporting structure used to support workers and/or materials. A shoring deck, on the other hand, as described by the Scaffold, Shoring and Forming Institute, SSFI, is the sheathing, joists and stringers which act as the mold for liquid concrete. This mold is also commonly known as the formwork. These definitions surely indicate that there is a significant difference in the two definitions. So why the confusion? It begins with the fact the workers stand on both a “temporary elevated platform” and the formwork of a shoring deck. In essence, it appears that the shoring deck is a temporary elevated work platform.


Therefore, the second step is to look beyond appearances and perceptions to determine the purpose of the deck. Ask the basic question: What is this temporary structure for? Will this deck be used for workers to obtain access to their work or is this deck being used to support concrete. It doesn’t get any easier! If the deck is being used to support concrete, the workers are there doing work to the deck. If the deck is being used as an elevated platform, the workers are doing work from the platform.


The third step is to properly apply the standards. Here’s how it works. For shoring, use these US Federal OSHA standards:


For fall protection, 29CFR1926, Subpart M:

For access, use 29CFR1926, Subpart X:

For concrete and formwork, use 29CFR1926, Subpart Q.


For scaffolding, use these standards:


For fall protection, 29CFR1926, Subpart L;

For access, use 29CFR1926, Subpart L, unless you are using a portable or job built ladder, then use 29CFR1926, Subpart X;

For scaffold construction and use, use 29CFR1926, Subpart L.


What could possibly be the difference. The first is fall protection. Subpart M requires fall protection at 6 feet above the lower level. Subpart L requires fall protection at 10 feet above the lower level. This means that a scaffold platform must have fall protection once that platform is more than ten feet above the level below while a shoring deck requires fall protection at six feet. The second significant difference is in the safety factor. For scaffolding, the minimum safety factor is 4. For shoring and formwork, OSHA does not specify a safety factor although the American National Standards Institute, the SSFI, and others specify a range of safety factors of 2 to 4, depending on the component.


Keep in mind that it is not the type of equipment but rather the intended use of the equipment that determines applicable safety regulations. In other words, scaffold frames can easily be used as shoring. In this case Subpart M would apply for fall protection. Conversely, shoring frames used to support several plank for workers to use to access the top of a column would be scaffold and all the applicable scaffold standards would apply, including plank placement, access, safety factors, and fall protection. Just because the workers are standing on a tower normally used for shoring will not exempt them from the scaffold standards.


Perhaps the most problematic aspect of distinguishing between a shoring deck and a scaffold platform occurs at the work platform that typically surrounds the edge of the shoring deck. More specifically, how is the safety factor applied to the entire system? Those components supporting the work platform require a 4 to 1 safety factor while those components supporting the remainder of the deck typically require a 2 to 2.5 safety factor. Usually this is not of concern since the shoring is required to support loads that are much higher than those of a work deck. However, as with all scaffold and shoring designs, a qualified person will properly design the system.

Tags: Fall Protection Scaffolding Shoring formwork OSHA Standards & Regulations Resources

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David H. Glabe, P.E.

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