OSHA INSTRUCTION STD 3-10.4 OCTOBER 30, 1978

OSHA PROGRAM DIRECTIVE #100-84

TO: REGIONAL ADMINISTRATORS/OSHA

THRU: DONALD E. MACKENZIE Field Coordinator

Subject: 29 CFR 1926.451, Scaffolding

1. Purpose

The purpose of this directive is to clarify the application of 29 CFR 1926.451, Scaffolding, Construction standards.

2. Documentation Affected

This directive supersedes Field Information Memorandum #75-19 dated March 6, 1975.

3. Background

As the result of a request to clarify the application of 29 CFR 1926.451, the following is herewith forwarded:

a. 29 CFR 1926.451(a)(2)--Concrete block is not always an "unstable object" when used as a base for scaffolding. The circumstances and techniques under which it is used must be considered to determine its stability.

b. 29 CFR 1926.451(a)(3)--A brace is defined in 29 CFR 1926.452 (b)(3) as a tie that holds one scaffold member in a fixed position with respect to another member. The fact that a scaffold member has a place for a brace does not necessarily require that the brace be in place, if it interferes with the erection or stocking of the scaffold. This is only true if the scaffolding is capable of supporting four times the maximum intended load and meets the other applicable requirements of 29 CFR 1926.451. Also, the manufacturer's design specifications, particularly with respect to the lateral stresses involved, are an important aspect which must be considered in the decision to remove pieces of bracing.

OSHA INSTRUCTION STD 3-10.4 OCTOBER 30, 1978

c. 29 CFR 1926.451(a)(7) and (8)--A scaffold plank is considered a component of the scaffolding. As such, it must e capable of supporting four times the maximum intended load without failure (a safety factor of four). The fact that a plank might have a split in one end does not automatically mean that it must be removed from service, provided it does not otherwise create a hazard to the employees.

d. 29 CFR 1926.451(d)(4)--The standard requires scaffold legs to be placed on a foundation that is adequate to support four times the intended load of the scaffold. The standard does not require that base plates always be employed, but only when conditions necessitate their use. For example, the scaffold legs cannot be placed on a mud foundation without a base to prevent the legs from sinking into the mud.

4. Action

As in all cases, the determination of compliance or noncompliance depends upon the conditions the CSHO observes at the time of inspection. These four interpretations are meant as guidelines only.

5. Effective Date

This directive is effective immediately and will remain in effect until canceled or superseded.

Richard P. Wilson Deputy Director, Federal Compliance and State Programs