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 25, 2003

Mr. Dan Wagester
Siemens Westinghouse Power Corp.
4400 Alafaya Trail
Orlando, Florida 32826-5032

Re: Whether 29 CFR 1926.251(a)(4) requires re-testing after disassembly/reassembly of special custom design lifting device

Dear Mr. Wagester:

This letter is in response to your faxed inquiry of August 20, 2002, and subsequent correspondence including fax, emails, and telephone calls with Mohammad Ayub and Michael Buchet of my staff. We understand you seek further clarification of the Occupational Safety and Health Administration (OSHA) proof-test requirements discussed in our August 15, 2002, letter to you. The issue relates to Siemens Westinghouse Power Corp.'s (Siemens) use of a special custom-design lifting accessory for erecting heat-transfer modules.

Prior Correspondence

As we indicated in our August letter:

[29 CFR 1926.251(a)(4)] specifically requires that custom-design lifting accessories must be marked to indicate the safe working load and proof-tested to 125 percent of their rated load prior to use [in construction].

The question raised in your latest communications concerns a custom-design "strongback" that was disassembled at the factory after marking and proof-testing. Your scenario includes having the strongback shipped to the construction project, reassembled and put to use without additional marking and proof-testing. We understand your question does not include (and we do not address) repeated disassembly, shipment/storage, reassembly and use cycles.

The strongback lifts one heat transfer module at a time. According to your September 11, 2002, e-mail, after putting a module in the strongback, you use the strongback to support the module for the remainder of the module erection sequence. The operation first entails righting the module and strongback from a horizontal to a vertical position. After righting the module the strongback is used to lift it and set it in place. Once the module is set in place workers disconnect the strongback and return it to the ground. The process is repeated to erect additional heat transfer modules.

According to your correspondence the strongbacks at issue are manufactured, marked and proof-tested to 125 percent of the rated load at the factory.

We understand that factory personnel disassemble the strongback for shipment to the field. Packaging for shipment includes laying the frames, sides, braces, etc. (major parts) flat. Your communications indicated that nuts, bolts, washers, pins, etc. (minor parts) do not travel with the strongback. The minor parts are replaced with similar parts during reassembly. At the construction site, workers under the supervision of a factory representative reassemble the strongback.

We have paraphrased your question as follows:

Question: Must the strongback be marked and proof-tested after its reassembly on site prior to use as a special custom design lifting accessory?


29 CFR 1926.251(a)(4) requires that:

Special custom design grabs, hooks, clamps, or other lifting accessories, for such units as modular panels, prefabricated structures and similar materials, shall be marked to indicate the safe working loads and shall be proof-tested prior to use to 125 percent of their rated load.

The purpose of this requirement is to ensure that the design and construction of a custom lifting device is sufficient to meet its intended load rating. Since you have already proof-tested the strong-back, its design and construction have been proven to meet the requirements of the standard. If sufficient steps have been taken to ensure quality control in re-assembly, there is no need for a second test and marking.

Therefore, the strongback need not be marked and proof-tested a second time before being used on the construction project if you ensure that its re-assembly meets all of the following requirements:

  • Reassembly is to manufacturer's specifications and follows manufacturer's procedures.
  • The strongback parts must be suited to the manufacture, disassembly, shipment, reassembly and use described. All re-used original parts are suited to the additional stresses of the disassembly and reassembly described in your communications.
  • All strongback parts are inspected for diminished capacity.
  • Quality control for the new minor parts used in the reassembly is at least equal to the quality control for the original minor parts.

In sum, field reassembly must be controlled to ensure replication of the original manufacturing process.

A designed reassembly in accordance with the above does not require the strongback to be re-tested. However, a re-test is required if repair or replacement of a part is found to be necessary due to breakage, damage, or evidence of diminished capacity. In that case there is a possibility that the stresses that caused the damage affected other parts. This was explained in a June 14, 2002, letter to Mr. Ron Pancari:



Question (2): Must Vogt-NEM's frames and other lifting accessories depicted in the submitted materials be proof tested and marked prior to use according to 29 CFR 1926.251(a)(4) after they have undergone repairs and replacements?

Answer: If a shipping frame or any other of the devices being discussed has been intentionally or inadvertently changed/modified, it essentially becomes a different custom design lifting accessory. Therefore, after it has undergone changes that affect its safe working load, including changes during your repair and replacement procedures, Vogt-NEM's lifting frames and other lifting accessories depicted in the submitted materials must be tested and marked according to §1926.251(a)(4) when they are to be used in a construction activity.

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