July 9, 1979

MEMORANDUM FOR:     GROVER WRENN

FROM:               Jerry L. Purswell

SUBJECT:            Interpretation of 1926.500(d)(1)--Use of Steel Band in
                    Guardrails

In response to your request, the conditions under which metal banding would suffice as material for constructing guardrails in compliance with 1926.500(d)(1) are as follows [Paragraph 1926.500(f)(vi)]:

(a) The metal banding must be smooth enough to prevent injury while performing its intended function. Therefore, the edges must be rolled with a sufficient radius to prevent injury, wrapped with a suitable material to protect the edge, or otherwise shielded.

(b) The band must meet the criterion of "minimum" deflection. This has been stated in an existing Program Directive as being no more than 3 inches over a span of 8 feet with a 200 pound load applied.

(c) The band must withstand a 200 pound static load in any direction.

Combining requirements (b) and (c), the Compliance Officer should reject any system, whether it be metal or wood rails, cables or metal bands, if it deflects more than 3 inches in a span of 8 feet with a 200 pound load applied in any direction.

I suspect that we have the metal banding problem now because we have not enforced the requirements adequately in the past when systems employing cables were introduced. I seriously doubt that any of the cable systems I have seen used around the District would meet the strength-deflection requirement.