October 22, 1992
Refer to: HNG-14/SS-31
Mr. Nick D. Calvi
Allied Tube and conduit
16100 South Lathrop Avenue
Harvey, Illinois 60426
Dear Mr. Calvi:
Thank you for your October 5 letter to Mr. James H. Hatton, Jr., regarding acceptance of your company's 64-mm (2 ½-inch), 12 gage single post set in a 76-mm (3-inch), 7 gage anchor as meeting the breakaway requirements adopted by the Federal Highway Administration (FHWA). You referenced previous FHWA acceptance letters for single and dual square steel tube sign supports set into anchors and/or sleeves of various gages installed in strong and weak soils.
We have reviewed the test reports of various perforated square steel tube sign supports and find that the Allied 64-mm, 12 gage post set into a 76-mm, 7 gage anchor should perform comparably to the previously accepted signpost systems of similar dimensions, and is acceptable for use on Federal-aid highway projects, if requested by a State.
Our acceptance is limited to breakaway characteristics of the system and does not cover its structural features. Presumably, you will supply potential users with sufficient information on structural design and installation requirements to ensure proper performance. We anticipate that the States will require certification from Allied that the hardware furnished has essentially the same chemistry, mechanical properties, and geometry as that used in the tests of your company's other signpost/base systems, and that it will meet the FHWA change in velocity requirements.
Lawrence A. Staron, Chief
Federal-Aid and Design Division
Geometric and Roadside Design Acceptance Letter Number SS-31