October 12, 2004
Refer to: HSA-10/WZ-77
Mr. Peter Speer
Bunzl Extrusion Tacoma Incorporated
3110 70th Avenue East
Tacoma, Washington 98424
Dear Mr. Speer:
This is in response to your letter of February 27, 2001, requesting modification to the Federal Highway Administration (FHWA) acceptance of your company's T3B Plastic Type III Barricades as crashworthy traffic control devices for use in work zones on the National Highway System (NHS). We initially accepted this barricade in our letter to you dated June 29, 2000, and numbered WZ-39. That letter also accepted modifications that used perforated square steel tubes (PSST) as the vertical and horizontal elements of the barricade frame. We subsequently accepted this barricade with lightweight warning lights and modified supporting legs (acceptance letter WZ-63 dated December 6, 2000). You have now requested that we find this barricade acceptable for use on the NHS under the provisions of National Cooperative Highway Research Program (NCHRP) Report 350 "Recommended Procedures for the Safety Performance Evaluation of Highway Features" with the following modifications to the upright supports:
2 each 50 x 50 mm x 5 mm thick A-36 steel L-channel uprights when used in conjunction with either of the accepted PSST or angle iron support legs.
2 each 38 x 38 mm x 3.5 mm thick hot-rolled high carbon steel L-channel or angle uprights when used in conjunction with either of the accepted PSST or angle iron support legs.
The T3B Barricade is a plastic, lightweight, portable Type III barricade. The T3B 25.4mm x 210mm hollow plastic barricade panels are made from a specially formulated polyolefin plastic, and the vertical uprights are 44.5-mm square thermoplastic tubing extrusions. The support legs are 14 ga, 50.8-mm square perforated galvanized mild steel tubing. One 150-mm tall PSST stub is welded to each support leg, and the vertical uprights are inserted into them. Testing of your 2438-mm (8 foot) wide version of this barricade was discussed in our letter WZ-39. The fasteners used were 7.94 mm (5/16") bolts with Nylock nuts and steel washers to attach panels to the uprights. As an alternative, PSST upright frame elements have been found acceptable.
|Barricade foot||14 ga PSST or Qwik-punch||2 x 2 x 60 inch w/ PSST Stub||12 lb|
|Upright, first option||6 gage A36 L channels||2 x 2 inch||12.2 lb|
|Upright, second option||10 gage hot rolled high carbon L channels||1.5 x 1.5 inch||7.6 lb|
|T3B 8-inch panels||Thermoplastic||¾ x 8 ¼ x 96 inch||5.25 lb|
Successful crash tests of steel-framed Type III barricades have typically used Telespar-type perforated square steel tubes or hot-rolled high-carbon steel L-channels ("angle iron"). You requested angle iron uprights of A-36 steel or hot-rolled high-carbon steel. The successful test of the "generic" type III barricade (covered in acceptance letters WZ-6 and WZ-54) used high-carbon steel. Our acceptance letter WZ-40, dated June 6, 2000, reported on the Illinois L-Channel Type III Barricade which used angle iron of A-36 steel. As a result of this successful test of a generic state design, we find your use of A-36 angle iron uprights acceptable.
A type III Barricade fabricated from Davidson Plastic/Bunzl Extrusion hollow horizontal rails (maximum 1220 mm (4 feet)) and:
2 each 50 x 50 mm x 5 mm thick A-36 steel L-channel when used in conjunction with either of the accepted PSST or angle iron support legs, or
2 each 38 x 38 mm x 3.5 mm thick hot-rolled high carbon steel L-channel or angle when used in conjunction with either of the accepted PSST or angle iron support legs,
will be acceptable for use as Test Level 3 devices on the NHS under the range of conditions tested, when proposed by a State.
The conditions stated in our previous letter on the T3B barricade (WZ-39) remain in effect. Barricades fabricated from plastic upright elements may be too flexible when used with a sign panel and not be used unless crash tested.
Please note the following standard provisions which apply to FHWA letters of acceptance:
(Original Signed by John R. Baxter)
John R. Baxter, P.E.
Director, Office of Safety Design
Office of Safety