OSHA requirements are set by statute, standards and regulations. Our interpretation letters explain these requirements and how they apply to particular circumstances, but they cannot create additional employer obligations. This letter constitutes OSHA's interpretation of the requirements discussed. Note that our enforcement guidance may be affected by changes to OSHA rules. Also, from time to time we update our guidance in response to new information. To keep apprised of such developments, you can consult OSHA's website at https://www.osha.gov.

February 1, 1999

Randall A. Tindell, ASP
Williams Power Company
7826 North State Hwy 95
Columbia, AL 36319

RE: The difference between maintenance and construction; scaffold inspection requirements; definition of periodicinspections

Dear Mr. Tindell:

This is in response to your letter dated March 6 to the Occupational Safety and Health Administration (OSHA) in which you asked for a written response to several questions you had discussed with OSHA. We apologize for the delay in responding.

We understand your questions to be as follows:

The difference between construction and maintenance
Question 1: There are two scaffold standards -- one for construction and one for general industry. What determines which standard applies -- the activity being performed, or the company's Standard Industrial Code (SIC)?

Answer: It is the activity to be performed while on the scaffold, not the company's standard industrial classification (SIC) code, that determines which standard applies.

Question 2: A valve is removed to install a test rig for maintenance and the valve is reinstalled when the work is completed. Is this a construction or maintenance activity?

Answer: "Maintenance" means keeping equipment or a structure in proper condition through routine, scheduled or anticipated measures without having to significantly alter the structure or equipment in the process. For equipment, this generally means keeping the equipment working properly by taking steps to prevent its failure or degradation.

In the activity you describe, a valve is removed so that a test rig can be temporarily installed to perform a maintenance activity. After the test, the rig is removed and the valve is either reinstalled or replaced with an identical valve. This would be considered a maintenance activity.

Question 3: If a valve is cut out and replaced, no matter what size it is, is this construction or maintenance?

Answer: The size of the valve and the complexity of the work are is not necessarily a factor in determining whether the activity is construction or maintenance. It would be a factor if, because of its size, the process of removal and replacement involves significantly altering the equipment that the valve is in.

Example No. 1: Maintenance
A common household water shut-off valve in a home heating system is removed and replaced. Its replacement is part of the routine maintenance of the system and removing and replacing the valve is done without making major alterations to the heating system. The removal and replacement of the valve would be considered maintenance.

Example No. 2: Construction
A 36 inch valve that is one of three major components in a processing system is removed and replaced. To do the job, 50 percent of all parts in the system have to be cut, unbolted, moved, or otherwise altered or replaced. Removing and replacing this valve would be considered construction because the valve constitutes a major portion of the equipment it is in and much of the rest of the system's parts must be moved or altered in the process of doing the job.

[Note: This letter has been amended and is presented here as historical content, for research and review purposes only and no longer represents OSHA policy. Additional clarification on this issue is available in the November 18, 2003 letter to Mr. Raymond V. Knobbs (Added 6/14/2004)]

Qualifications necessary to inspect scaffolds; how often is "periodic?"
Question 4: While using a scaffold for maintenance activity, is the visual inspection performed by the user, prior to use, sufficient for the periodic inspection requirements of the general industry standards.

Answer: Your question involves two issues: the required qualifications of a person who is responsible for inspecting a scaffold, and whether inspecting a scaffold prior to use meets the requirement that scaffolds be inspected periodically.

There are periodic inspection requirements for a number of different types of scaffolds. For example, there are periodic inspection requirements for welded frame scaffolds (§1910.28(d)(14)), mason's adjustable multiple-point suspension scaffolds (§1910.28(f)(11)), and two-point suspension scaffolds (§1910.28(g)(8)). These particular provisions do not specify qualifications that the person conducting the periodic inspection must have. However, the purpose of these inspection requirements is to ensure that the scaffold continues to be in a safe condition. For the employer to meet this obligation, the employee it assigns to do the inspections must have sufficient knowledge to recognize unsafe scaffold conditions and to determine if the scaffold continues to meet the applicable scaffold standard requirements. The employer may assign the periodic inspection task to one of its employees using the scaffold only if that employee has this level of knowledge. That employee must understand that a cursory look at the scaffold prior to use would not constitute an inspection -- an inspection requires a careful and critical examination.

For some types of scaffolds, a "competent person" must supervise the erection, installation or relocation of scaffolds. If an employee meets the requirements for a competent person for those purposes, that employee would also be qualified to periodically inspect those scaffolds.

What constitutes "periodic?"
These standards do not specify how often a scaffold must be inspected to meet the "periodic" requirement. The frequency will depend on factors such as the type of scaffold, site and weather conditions, intensity of use, age of the equipment, and how often sections or components are added, removed or changed. These kinds of factors will determine how quickly or slowly safety related faults, loose connections, degradation and other defects can be expected to develop.

"Periodic" means frequently enough so that, in light of these factors and the amount of time expected for their detrimental effects to occur, there is a good likelihood that problems will be found before they pose a hazard to employees.

Whether the frequency of scaffold inspection may be lowered to lessen radiation exposure
Question 5: While working in high radiation or highly contaminated areas in the nuclear industry, workers can be exposed to radiation doses while inspecting construction scaffolds before each work shift; (1) Can the inspection requirement be changed to periodic inspections? (2) Can the user-trained worker perform the inspection just prior to performing work?

Answer: When doing construction, 1926.451(f)(3) requires that a competent person inspect the scaffold and its components before each work shift and after any occurrence which could affect the structural integrity of the scaffold. If the worker will be exposed to a radiation hazard while performing the inspections required by the OSHA scaffold standard, the employer is required to protect the worker with personal protective equipment. The employer is not permitted to do fewer inspections than are required by the standard as a means of protecting the worker from the radiation hazard.

The employer may assign the task of inspecting the scaffold to a "user-trained worker" as long as that worker qualifies as a competent person under §1926.450(b). A competent person is defined as one who is "capable of identifying existing and predictable hazards in the surroundings or working conditions which are unsanitary, hazardous, or dangerous to employees, and who has authorization to take prompt corrective measures to eliminate them."

Thank you for your interest in occupational safety and health. We hope you find this information helpful. OSHA's requirements are set by statute, standards, and regulations. Our letters of interpretation do not create new or additional requirements but rather explain these requirements and how they apply to particular circumstances. This letter constitutes OSHA's interpretation of the requirements discussed. From time to time, letters are affected when the Agency updates a standard, a legal decision impacts a standard, or changes in technology affect the interpretation. To ensure that you are using the correct information and guidance, please consult OSHA's website at www.osha.gov. If you have further questions, please feel free to contact the Directorate of Construction at (202) 693-2020.


Russell B. Swanson, Director
Directorate of Construction

[Corrected 6/14/2004. Question numbers were added for reference purposes.] [Amended 9/4/2015]