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.

January 16, 2001

Mr. R. Christopher Johnson
Managing Director
1300 Sumner Avenue
Cleveland, Ohio 44115-2851

Re: 1926.451, requirement that suspension scaffold power-operated hoists and manual hoists shall be tested by a "qualified testing laboratory;" Underwriters Laboratories Incorporated (UL) 1323 testing standard.

Dear Mr. Johnson:

This responds to your April 1, 1999, letter to the Occupational Safety and Health Administration (OSHA). You raise questions regarding OSHA's requirement, 29 CFR §1926.451(d)(13), (issued August 30, 1996), that power-operated and manually-operated hoists for suspension scaffolds be tested by a qualified testing laboratory. We apologize for the long delay in providing this response. You ask whether OSHA audits a laboratory's capability, experience and testing standards, and whether they must test hoists using the Underwriters Laboratories (UL) 1323 standard.


OSHA's scaffold standard, 29 CFR 1926.451 (Subpart L), does not define the term "qualified testing laboratory." However, in the Notice of Proposed Rulemaking for the scaffold standard, we stated that, "for a definition of 'qualified testing laboratory,' see newly revised Subpart K-Electrical" (page 42,687 of volume 51 of Federal Register, November 25, 1986). While it would have been better to have included a reference to Subpart K's definition in the final rule, the evident intent of the Agency was to apply Subpart K's definition in Subpart L. Therefore, a "qualified testing laboratory" under Subpart L is the same as that defined under Subpart K.

In 29 CFR 1926.449, Subpart K defines a "qualified testing laboratory" as follows:

A properly equipped and staffed testing laboratory which has capabilities for and which provides the following services:
(a) Experimental testing for safety of specified items of equipment and materials referred to in this standard to determine compliance with appropriate test standards or performance in a specified manner;
(b) Inspecting the run of such items of equipment and materials at factories for product evaluation to assure compliance with the test standards;
(c) Service-value determinations through field inspections to monitor the proper use of labels on products and with authority for recall of the label in the event a hazardous product is installed;
(d) Employing a controlled procedure for identifying the listed and or labeled equipment or materials tested; and
(e) Rendering creditable reports or findings that are objective and without bias of the tests and test methods employed.

Question 1: Does OSHA audit qualified testing laboratories to see if they are capable of testing scaffold hoists, and does OSHA investigate a lab's experience in testing hoists?

Answer: With respect to the scaffold standard, qualified testing laboratories are not routinely audited by OSHA. In enforcing the scaffold standard, OSHA would only investigate a laboratory's capability to test a hoist where that was an issue with regard to an employer's compliance with §1926.451(d)(13) that suspension scaffold hoists be tested by a qualified testing laboratory.

OSHA does have requirements, which include audits and qualifying criteria, for a laboratory that wishes to be considered a Nationally Recognized Testing Laboratory (NRTL). Those requirements are in 29 CFR 1910.7. However, there is no OSHA requirement that scaffold hoists used in construction be tested by a NRTL.

Question 2: Does OSHA ensure that the hoists are tested to the Underwriter's Laboratories (UL) 1323 standard, or inquire to what standard the hoists are tested?

Answer: The definition in §1926.449 of a qualified testing laboratory does not specify particular testing standards that must be used. However, in §1926.449(a), it does require that the laboratory "determine compliance with appropriate test standards...." [Emphasis added]. We consider an appropriate test standard to be any nationally recognized standard applicable to the equipment being tested. So, in the context of enforcing a construction employer's compliance with §1926.451(d)(13), where there was a question as to whether the testing laboratory used by the employer met the §1926.449(a) requirements, we would inquire as to what testing standard was used by the lab.

Question 3: Are any qualified laboratories located outside of the U. S., other than the Canadian Standard Association (CSA)?

Answer: We do not have names of any qualified testing laboratories outside of the U.S. However, a few of the U.S. NRTLs own facilities outside the U.S. CSA is the only non-U. S. NRTL to date.

[Note: See OSHA's
Nationally Recognized Testing Laboratory page for the current list of recognized NRTLs.]

Finally, you requested that §1926.451(d)(13) be amended to require that these hoists be tested in accordance with the UL 1323 standard.

We have not received any information indicating that the current standard is inadequate. If you have such information, we would be interested in reviewing it.

If you need additional information, please contact us by fax at: U.S. Department of Labor, OSHA, Directorate of Construction, Office of Construction Standards and Guidance, fax # 202-693-1689. You can also contact us by mail at the above office, Room N3468, 200 Constitution Avenue, N.W., Washington, D.C. 20210, although there will be a delay in our receiving correspondence by mail.


Russell B. Swanson, Director
Directorate of Construction

[Corrected 6/2/2005]