March 27, 2003 

 HSA-10/B114 

Mr. Howard Block

President

Welch Products, Inc.

205 South Garfield (PO Box Z) 

Carlisle, Iowa 50047

Dear Mr. Block:

In your March 17 letter to Mr. Richard Powers of my staff, you sent him a copy of a test 

report prepared by the Midwest Roadside Safety Facility, dated March 16, and entitled 

“Performance Analysis of Welch Products Recycled Rubber Spacer Block” and a CD 

showing the bogie test that was conducted with your product. You requested a ruling on 

the acceptability of your product, presumably for use with strong steel-post w-beam 

guardrail on the National Highway System (NHS). 

The Welch offset block is composed of approximately 40 per cent recycled rubber 

(natural and synthetic), 35 per cent carbon black, 11 per cent volatiles, and 5 per cent or 

less each of zinc oxide, ash, stearic acid and sulfur. Figure 9 in the test report shows the 

tested block to be 140-mm wide by 213-mm deep by 360-mm tall, with a 111-mm wide, 

9.5-mm deep routing on the field side to fit over the steel post flange. Testing consisted 

of two bogie tests in which a 992-kg bogie first impacted a standard routed timber block 

(Test WB-1) and then your block (Test WB-2), both of which were mounted between a 

W150 x 13.5 (W6 x 9) post and a short section of w-beam guardrail. The steel posts were 

set in a rigid foundation that prevented any rotation in the soil prior to failure at the 

ground line. In both tests, the posts did fail at the ground line with the blocks remaining 

essentially intact. It was noted in the test report that the Welch block compressed 

approximately 76 mm as the post yielded, leaving an effective depth of 127 mm. While 

this could increase the likelihood of a wheel snagging on a post under some impact 

conditions, the compression was maximized by the 90-degree impact angle and the 

rigidity of the post at the ground line. Since the FHWA has accepted (but discouraged) 

the use of nominal 150 mm x 150 mm wood offset blocks based on crash testing, we do 

not believe it is necessary to conduct a full-scale test of the Welch block at this time. 

Based on the results of the bogie test run using the Welch offset block, your product may 

be considered acceptable for use on the NHS with a strong-post w-beam guardrail when it 

conforms to the dimensions noted above, is composed of the same materials as the tested 

blocks, and is installed flush with the top of the post. As with all other alternative 

material offset blocks accepted for use on the NHS, this acceptance is based solely on the 

reported impact performance of the Welch block and is not intended to address the longterm performance or durability of the product. Field installations should be carefully 

monitored to verify expected performance and service life. 

If your block is or will be patented, its use on Federal-aid projects, except exempt, nonNHS 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. If you have any 

questions, please call Mr. Powers at (202) 366-1320.

 

Sincerely yours, 

 (original signed by Michael S. Griffith) 

Michael S. Griffith 

Acting Director, Office of Safety Design 

Office of Safety 

Enclosure

 
Sec. 635.411 Material or product selection. 

(a) Federal funds shall not participate, directly or indirectly, in payment for any premium or royalty on 

any patented or proprietary material, specification, or process specifically set forth in the plans and 

specifications for a project, unless: 

(1) Such patented or proprietary item is purchased or obtained through competitive bidding with equally 

suitable unpatented items; or 

(2) The State highway agency certifies either that such patented or proprietary item is essential for 

synchronization with existing highway facilities, or that no equally suitable alternate exists; or 

(3) Such patented or proprietary item is used for research or for a distinctive type of construction on 

relatively short sections of road for experimental purposes. 

(b) When there is available for purchase more than one nonpatented, nonproprietary material, 

semifinished or finished article or product that will fulfill the requirements for an item of work of a 

project and these available materials or products are judged to be of satisfactory quality and equally 

acceptable on the basis of engineering analysis and the anticipated prices for the related item(s) of work 

are estimated to be approximately the same, the PS&E for the project shall either contain or include by 

reference the specifications for each such material or product that is considered acceptable for 

incorporation in the work. If the State highway agency wishes to substitute some other acceptable 

material or product for the material or product designated by the successful bidder or bid as the lowest 

alternate, and such substitution results in an increase in costs, there will not be Federal-aid participation in 

any increase in costs. 

(c) A State highway agency may require a specific material or product when there are other acceptable 

materials and products, when such specific choice is approved by the Division Administrator as being in 

the public interest. When the Division Administrator's approval is not obtained, the item will be 

nonparticipating unless bidding procedures are used that establish the unit price of each acceptable 

alternative. In this case Federal-aid participation will be based on the lowest price so established. 

(d) Appendix A sets forth the FHWA requirements regarding (1) the specification of alternative types of 

culvert pipes, and (2) the number and types of such alternatives which must be set forth in the 

specifications for various types of drainage installations. 

(e) Reference in specifications and on plans to single trade name materials will not be approved on 

Federal-aid contracts. 

ENCLOSURE 2