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 sytem 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.

Qualifications
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 9§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.