November 23, 1987

David E. Hoberg, P.E.
DBM Consultants/Engineers
511 11th Avenue
South Minneapolis, Minnesota 55415

Dear Mr. Hoberg:

This is in response to your letter of September 22, 1987, concerning the potential hazards associated with the use of horizontal lifelines affixed to two-point suspension (Type T) powered platforms.

The circumstances you describe are of great concern. Our technical staff is currently evaluating the situation and a revision to the OSHA Instruction STD 1-3.3 CH-1 is in process. As you are aware, development and publication of a new standard is complex and this situation can not await such a resolution. Therefore, the revised OSHA Instruction will delineate safe options available to users of two-point suspension (Type T) powered platforms.

In response to your first question, it is not the intent of an OSHA Instruction STD to prohibit the application of a specific standard. In this instance, 29 CFR 1910.66(d)(8)(i) requires either attachment of a lanyard to a roof-secured (drop) lifeline or to a horizontal lifeline affixed to the platform.

Under paragraph F.1.e. of OSHA Instruction STD 1-3.3 CH-1, the final analysis and approval of any intermittent stabilization system rests with the responsible professional engineer. In situations where descent is along a bulbous (hammer head) type of structure, special provisions need be taken to prevent a vertical (drop) lifeline from inflicting an unstabilizing force upon the workers as they descend to lower and inner exterior surfaces. Therefore, to avert such hazardous forces, the horizontal lifeline is attractive, but as you point out, additional precautions are necessary.

In response to your second question, paragraph F.1.e.(3)(a) stipulates that a short lanyard and an automatic locking grab attached to the horizontal static line on the working platform be provided each employee. 29 CFR 1910.66(d)(8)(iv) recommends that the lanyard be 5 feet in length, therefore it can be concluded that the OSHA Instruction STD requires that a lanyard must be 5 feet or less.

As you are aware, ANSI A10.14 also recommends that lanyards be no greater than 5 feet and only 29 CFR 1926.104(d) limits lanyard length so as to prevent construction worker falls to no more than 6 feet. Test criteria for lanyards is based upon a 6 foot drop of a 250 pound weight as specified by ANSI A10.14. Therefore, fall heights of greater than 6 feet could result in stopping forces greater than the restraining capabilities of the safety system.

In response to your third question, the existing standard at 29 CFR 1910.66(d)(8) requires the alternative of a vertical lifeline for use with Type T two-point suspension powered platforms. Other alternatives which provide for greater of equivalent safety are also permitted under our policy for de minimis violations discussed by an enclosure.

As you are aware, the January 22, 1985, proposed revision of the powered platform standard at paragraph(f)(5)(ii)(m), page 2914, addresses this situation. Again, under our policy for de minimus violations, adherence with the proposed standard may be a de minimus violation when protection equal or superior to that provided for by the existing standard is assured by the employer. The requirements of the proposal should be a major consideration of the professional engineer in this circumstance.

Thank you for bringing this serious situation to our attention. If there are any questions, please feel free to contact Mr. Joseph Bode at 202-523-8031.

Sincerely,



Thomas J. Shepich, Director
Directorate of Compliance Programs