December 15, 2006
Refer to: HSA-10/LS-62
Mr. Robert Sik
Vice President
Akron Foundry Company
2728 Wingate Avenue
P.O. Box 27028
Akron. OH 44319-0009
Dear Mr. Sik:
Thank you for your letter dated October 12 requesting the Federal Highway Administration (FH\1/A) acceptance of a modification to your company's CS-300 breakaway cast aluminum transformer base for use on the National Highway System under the provisions of the National Cooperative Highway Research Program Report 350 "Recommended Procedures for the Safety Performance Evaluation of Highway Features."
You requested that we find the CS-300 base acceptable when used on a 10-1/2 inch diameter bolt circle, With the exception of the internal ear length used to bolt the base in place, the typical base assembly is identical to your previously accepted CS-300 transformer base. Attachment to the base at the internal. ears using standard round washers that lay 118.t or attachment using the previously accepted modified stack pack washer arrangement (1.8·58) \\ill provide full support when bolted in place.
We have reviewed the results of prior crash testing of the C8-300 base. which had been found acceptable when used with standard round washers on a bolt circle of 12 inches, and concur that this modification would have no significant impact on the breakaway performance of your company's transformer base. All appropriate conditions in the previous FH\VA acceptance letters dealing with Akron Foundry cast aluminum transformer bases continue 10 apply.Sincerely yours,
/original signed by /
John R. Baxter, P.E.
Director, Office of Safety Design
Office of Safety
