By David H. Glabe, P.E. / July 31, 1999

Here are frequently asked questions concerning scaffolding, applicable standards and regulations.


What is a competent person?

By definition, a competent person is basically an individual who can identify a hazard and has the authority to take corrective action. While the competent person may not have the solution to minimize or eliminate the hazard, the competent person can consult a qualified person to get the solution.


Why should scaffolds be constructed under the supervision of a competent person?

There are at least two reasons. First, a competent person will have the knowledge to identify existing and potential hazards and have the authority to eliminate or minimize those hazards. Secondly, there is a law that says that all scaffolds shall be constructed under the supervision of a competent person.


What does “shall” mean in the Federal OSHA standards?

“Shall” means mandatory. In other words, “you gotta do it!”


Does Federal OSHA require all scaffold erectors be competent persons?

No. All erectors shall be trained and experienced; the supervisor shall be competent.


When is access required for a scaffold platform?

Access is required whenever the height between levels is more than 24 inches.


Can you climb out a window or off of a catwalk to access a scaffold platform?

Yes you can, provided the platform is no more than 24 inches above or below the point of access, and the platform is no more than 14 inches horizontally from the point of access.


Are guardrails required on all scaffold platforms more than ten feet above the level below?

No, but fall protection, either personal fall protection equipment, or a guardrail system, is required.


How strong does a guardrail have to be on a supported scaffold?

The toprail shall withstand 200 pounds in any direction except up on the rail, and the midrail must withstand 150 pounds in any direction except up at any point on the rail.


Do all supported scaffolds need a base plate?

Absolutely, unless the scaffold is a mobile scaffold in which case you shall use locking casters.


How wide does a scaffold platform have to be?

The minimum width of a platform is 18 inches unless you can show that an 18 inch wide platform will not fit in the space allotted. There is no maximum width of platform.


Do scaffold erectors have to always use personal fall arrest equipment?



Who determines if erectors must use personal fall arrest equipment?

The employer’s competent person determines in the erectors shall wear and use personal fall protection equipment.


Is it a good idea to use scaffold grade plank?

It is an excellent idea! The SIA strongly encourages the use of scaffold grade plank unless the plank being used has been designed for such use by a qualified person.


Can scaffold equipment of various manufacturers be intermixed?

Manufacturers discourage intermixing equipment because of the risk of incompatible equipment. The SIA approves of equipment intermixing only if the equipment is compatible. In other words, if you don’t know the hazards of intermixing equipment of various manufacturers, don’t do it.


Is it necessary to train scaffold erectors?

Yes; it is required by law.


Is it necessary to train scaffold users?

Yes; it is required by law.


Does Federal OSHA require all scaffolds to be designed by a qualified person?



Is continuous cross bracing required on all frame scaffolds?

No. While it is a good idea to install continuous bracing, and manufacturers recommend it, continuous bracing is not required provided proper bracing is installed. If you don’t know what proper bracing is, install continuous bracing.


Are clamp-on ladders considered “fixed” ladders and consequently must comply with Federal OSHA Subpart X standards?

No. Clamp-on ladders are a scaffold component and consequently are addressed in the scaffold standards, Subpart L. Clamp-on ladders are not fixed ladders.


How far above the platform should the ladder extend?

Unless there is a handhold such as an access gate panel or other hand grab, good construction practice suggests the ladder should extend above the platform about 36 inches. There are no Federal OSHA scaffold standards that specify a height unless a portable ladder is used. If a portable ladder (manufactured extension, fixed length, step, or job-built ladder) is used, the minimum height above platform is 36 inches unless the ladder is secured and a hand hold is provided.


When are toeboards required?

Toeboards are one form of falling object protection when there is a danger of injury to workers on lower levels of the scaffold. Other forms of falling object protection include canopies, barriers, screens, and catch platforms.


Who determines safe access for scaffold erectors?

The competent person makes the determination.


Is it okay to climb over the guardrail to access a platform?

Yes, although an access gate panel would make access a lot easier.


Federal OSHA requires for erectors that “hook-on or attachable ladders shall be installed as soon as possible as scaffold erection has progressed to a point that permits safe installation and use.” If the erectors are constructing a stair tower and installing the stair units as the tower is constructed, do the erectors have to install a ladder to be in compliance with the standards?

I would certainly hope not! Look at the intent of the regulation. Its intent is to protect the erector as best as possible. Stairs would provide that protection.

Tags: Scaffolding competent scaffolding Guardrail OSHA Standards & Regulations Resources scaffold standards

Previous Post CHECK IT OUT

David H. Glabe, P.E.

See what David H. Glabe has to say about construction engineering and the scaffolding industry.