May 7, 1998
Refer to: HNG-14
Mr. Billy Atwood
Central Fabricators, Inc.
P.O. Box 930
Kosciusko, MS 39090

Dear Mr. Atwood:

In his April 7 letter to Mr. James H. Hatton, Jr. of my staff, Mr. Dean Alberson requested the Federal Highway Administration’s acceptance of a recycled plastic block manufactured by your company for use with steel post W-beam guardrail. This request summarized the results of pendulum tests that were conducted to demonstrate the impact resistance characteristics of your product. In subsequent letters dated April 13, 17, and 27, Mr. Alberson provided us with additional details concerning the material composition and physical dimensions of the blocks you intend to make.

We note that the block will be made from a mix that is 50% High Density Polyethylene (HDPE) and 45% Low Density Polyethylene (LDPE), with a maximum of 5% miscellaneous plastics. The tolerance on the HDPE and LDPE will be plus or minus 5%. The dimensions of the four blocks that were subjected to the pendulum testing are shown in Enclosure 1.

Based on our review of the information that you provided, we conclude that the Central Fabricators recycled plastic blocks made with the material composition that was tested and in one of the configurations shown in Enclosure 1 are acceptable for use with strong steel post W-beam guardrail on the National Highway System (NHS) when selected by a State transportation agency. 

This acceptance is limited to the impact resistance characteristics of the block only and is not meant to address the long-term effects of weathering or UV degradation. We assume that you will provide agencies considering the use of your product a written certification that the material composition will be the same as it was in the tested blocks and that you will address the durability issue as well.

Since your product is proprietary, its use on Federal-aid projects, except exempt, non-NHS projects, is subject to the conditions listed in Title 23, Code of Federal Regulations, Section 635.411, a copy of which is enclosed for your ready reference. Please call Mr. Richard Powers of my staff at (202) 366-1320 if you have any questions.

Sincerely yours,

(original signed by Dwight A. Horne)

Dwight A. Horne
Chief, Federal-Aid and Design Division