January 6, 1992

Lawrence R. Stafford
Consulting Engineer
8 Gracemore Street
Albany, N.Y. 12203

Dear Mr. Stafford:

Thank you for your follow-up letter of November 19, concerning the status of your November 20, 1990 inquiry regarding the tie-in guides standards at 29 CFR 1910.66(e)(2)(iii)(a)(5) and (b)(6). Please accept our apology for the long delay in responding.

The Final Rules on Powered Platforms For Building Maintenance were published in the Federal Register, Volume 54, Number 44 on July 28, 1989. They became effective on January 24, 1990. As a result, OSHA Instruction STD 1-3.3 (issued November 1, 1982 and revised November 12, 1985) continues to be applicable only to existing powered platforms permanently dedicated to building maintenance and subject to the mandatory requirements at 29 CFR 1910.66 Appendix D. The guidelines at paragraph F.1.a. of STD 1-3.3 will be revised to be consistent with 29 CFR 1910.66(e)(2)(iii)(a)(5) and (6) standards. The revision will reference "minimum ultimate strength" to replace "minimum tensile strength." Also, the minimum ultimate strength required to transmit wind loads applied to the building anchor(s) will be emphasized. The minimum ultimate strength is based on a safety factor of four times the wind load applied in tension.

In your November 20, 1990 letter, you state: "The original engineering justification I submitted for acceptance of Intermittent Stabilization was based on only one (1) building anchor sustaining the load imposed by the translation of a two point suspended scaffold." Further, you state: "Two building anchors cannot share this load because the tie-in lanyards are designed to be installed in opposing directions, never in the same direction, in relation to the plane of the building." As such, you conclude: "The ultimate strength of each building anchor must be at least 600 pounds (272 kilograms), not 300 pounds (136 kilograms), because it is not possible for two (2) building anchors to share the scaffold translation load."

Although infrequently sharing the load equally, the building anchors may share the load unequally. As such, 29 CFR 1910.66(e)(2)(iii)(a)(5) applies to intermittent stabilization systems and 29 CFR 1910.66(e)(2)(iii)(B)(6) applies to button guide stabilization systems. When building anchors for an intermittent.

The blueprints forwarded by your letter are enclosed for your further use. We appreciate your interest in occupational safety and health. If we can be of further assistance, please do not hesitate to contact us.

Sincerely,



Patricia K. Clark, Director
Directorate of Compliance Programs