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                Safety Eligibility Letter B-192
  
  **Hardware Type:**
            Longitudinal Barriers and Bridge Rails
                          **Code:**
            B-192
                          **Date:**
            05/29/2009
                          **Testing Criteria:**
            NCHRP 350
                          **Manufacturer:**
            BWW Enterprises
                          **Device Description:**
            Diamond Block TL-3
                          **View PDF:**
            b192.pdf (142.78 KB)
    
    Safety Eligibility Letter B-192

		
			 
			**Download Version**PDF [143 KB]
			
			DOT logoU.S. Department of Transportation**Federal Highway Administration**
			1200 New Jersey Ave. S.E.Washington, D.C. 20590
			May 29, 2009
			In Reply Refer To:HSSD/B-192
			
			Mr. Robert Williams
            	President, BWW Enterprises, Inc.
                5733 South Dale Mabry Highway
            Tampa, FL  33611
           	Dear Mr. Williams:
            This letter is in response to your request for the Federal Highway Administration (FHWA) acceptance of a roadside safety product for use on the National Highway System (NHS).
          Name of  system:BWW Enterprises Diamond BlockType of  system:W-Beam Guardrail Offset Block, 8-inchTest Level:NCHRP Report 350 TL-3Testing  conducted by:Midwest Roadside Safety FacilityDate of request:March 4, 2009You requested that we find this product acceptable for use  on the NHS under the provisions of the National Cooperative Highway Research  Program (NCHRP) Report 350 “Recommended Procedures for the Safety Performance  Evaluation of Highway Features.”
          **Requirements**Roadside safety systems should meet the guidelines contained  in the NCHRP Report 350. The FHWA  Memorandum “Identifying Acceptable Highway Safety Features” of July 25, 1997,  provides further guidance on crash testing requirements of longitudinal  barriers.
          **Description**The Diamond Block is comprised of approximately 97.65  percent recycled high density polyethylene plastic, 1.25 percent chemical  blowing agent, 1 percent carbon black, and 0.1 percent UV stabilizer.  It measures approximately 7.5 inches x 4.6 inches x 14.5 inches tall  with a recess on the back to accommodate the face of the guardrail post. The voided design of the block is seen in the  drawing which is enclosed for reference.  The block’s weight is in the range of 5.8 to 5.9 pounds.
          **Crash Testing**The Midwest Roadside Safety Facility conducted two bogie  vehicle tests using standard steel guardrail posts held rigidly in a test  foundation. One test evaluated the  performance of a standard routed wood blockout, and the other evaluated the  Diamond Block (named EXUL-1 during the testing phase). In both cases the bogie vehicle impacted a  short length of w-beam rail mounted on the face of the blockout. In the wood blockout test the 2190-pound  bogie impacted the test article at 20 mph.  In the test of the Diamond block the 1817-pound bogie impacted the test  article at 23.0 mph.
          Based on the results of the crash tests, no significant  differences were observed between the performance of the wood and plastic  spacer blocks. Both blocks displayed  similar levels of permanent damage after impact. Analysis of the high-speed video showed that  the plastic block remained firmly attached to the post during the impact with  the router gripping the front flange of the post until it was overridden by the  bogie vehicle. No concerns were observed  with regards to the dynamic performance nor the structural integrity of the  plastic blockout when compared with the wood.  In addition, the force vs. deflection curve for the Diamond Block test  was cross plotted against component testing using results from two previously  FHWA accepted plastic blockouts. The  results of this comparison showed that the Diamond blockout displayed similar  force vs. deflection behavior to previously accepted designs.
          **Findings**Therefore, the guardrail offset block described above and  detailed in the enclosed drawing is acceptable for use on the NHS under the  range of conditions tested, when such use is acceptable to a highway agency.
          Please note the following standard  provisions that apply to FHWA letters of acceptance:
          This acceptance is limited to the  crashworthiness characteristics of the systems and does not cover their  structural features, nor conformity with the Manual on Uniform Traffic Control  Devices.
          		Any changes that may adversely influence  the crashworthiness of the system will require a new acceptance letter.
                Should the FHWA discover that the  qualification testing was flawed, that in-service performance reveals  unacceptable safety problems, or that the system being marketed is  significantly different from the version that was crash tested, we reserve the  right to modify or revoke our acceptance.
                You will be expected to supply potential  users with sufficient information on design and installation requirements to  ensure proper performance.
                You will be expected to certify to  potential users that the Diamond Blocks furnished have essentially the same  chemistry, mechanical properties, and geometry as the EXUL-1 that was crash  tested for acceptance, and that w-beam guardrail using the Diamond Block will  meet the crashworthiness requirements of the FHWA and the NCHRP Report 350.
                To prevent misunderstanding by others, this  letter of acceptance is designated as number B-192 and shall not be reproduced  except in full. This letter and the test  documentation upon which it is based are public information. All such letters and documentation may be  reviewed at our office upon request.
                The Diamond Block is a patented product and  considered proprietary. If proprietary  systems are specified by a highway agency for use on Federal-aid projects,  except exempt, non-NHS projects, (a) they must be supplied through competitive  bidding with equally suitable unpatented items; (b) the highway agency must  certify that they are essential for synchronization with the existing highway  facilities or that no equally suitable alternative exists; or (c) they must be  used for research or for a distinctive type of construction on relatively short  sections of road for experimental purposes.  Our regulations concerning proprietary products are contained in Title  23, Code of Federal Regulations, Section 635.411.
                This acceptance letter shall not be  construed as authorization or consent by the FHWA to use, manufacture, or sell  any patented system for which the applicant is not the patent holder. The acceptance letter is limited to the  crashworthiness characteristics of the candidate system, and the FHWA is  neither prepared nor required to become involved in issues concerning patent  law. Patent issues, if any, are to be  resolved by the applicant.Sincerely yours,
						Signature of David A. Nicol
						David A. Nicol, P.E.Director, Office of Safety DesignOffice of SafetyEnclosures U.S. DEPARTMENT OF TRANSPORTATION

**Federal Highway Administration**

1200 NEW JERSEY AVENUE, SE

WASHINGTON, DC 20590

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