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.

September 23, 1993

Mr. Jerry LaPlante
McCrory Engineering, Inc.
2500 West Loop South
Suite 510
Houston, Texas 77072

Dear Mr. LaPlante:

This is in response to your April 23 letter to Mr. Gilbert Saulter, Dallas Regional Administrator requesting interpretation of the testing requirements under 29 CFR 1910.66 as they apply to powered platform installations permanently dedicated to building maintenance. Your letter was forwarded to the Directorate of Compliance Programs for response.

Inspection and testing requirements for the aforementioned installations are contained in paragraph (g) of 1910.66. In 1910.66(g)(1), inspection and field testing of these installations are required before being placed in initial service. Field testing is predicated on the limitation placed on the hoist. No hoist in an installation may be subject to a load in excess of 125 percent of its rated load. Periodic inspections and tests at intervals specified by the manufacturer, but not greater than 12 months, are required by 1910.66(g)(2) to determine that all parts of the installation equipment are in safe operation condition. Also, in compliance with 1910.66(g)(3), maintenance inspections and tests must follow procedures recommended by the manufacturer and be made every 30 days; or, where the work cycle is less than 30 days, such inspections and/or tests must be made prior to each work cycle.

In your letter you indicated that McCrory Engineering, Inc., has been testing power platforms and safety equipment on high-rise buildings for several years using a four to one maximum safety factor. The basis for this safety factor is not indicated. Normally a four to one maximum safety factor, based on yield strength, for example, is a design strength criterion. Loading to this extent is not required by the 1910.66 standard and so the associated testing procedures you requested would not be available from the Occupational Safety and Health Administration. Such loading could be characterized as destructive testing unless the tested component or installation is over-designed, for example, to extend its service life.

Please note that 1910.66(c)(3) requires that the building owner inform an employer of employees who are going to use a power platform installation that the installation has been inspected, tested, and maintained in compliance with 1910.66(g) and (h). By 1910.66(c)(2), this assurance must be based not only on 1910.66(c)(1) information requirements but also on all other relevant available information, including but not limited to test data, equipment specifications and verification by a registered professional engineer. The data from the testing described in your letter (and in paragraph 3 of this letter) must be considered by the aforementioned registered professional engineer verifying the safety of the installation as noted above.

Thank you for your interest in Occupational Safety and Health. If we can be of further assistance, please contact us.


Raymond E. Donnelly, Director
Office of General Industry
Compliance Assistance