We have had folks asking if we provide a break-away system
for street poles…
Although we officially do not provide a break-away system,
what we have found is that the alloy we use for our aluminum poles is often
considered a valid option.
In researching the subject here is some of the information
we have found:
1. Department of Transportation State of North
Carolina 1/26/2006
Subject: NCHRP 350 Compliance of Metalcraft 3” outer
Diameter 1/8” wall thickness, Alloy 6061-T6 Aluminum Tube Signs Supports
The signing section has reviewed the subject product and
found that it will provide adequate breakaway performance.
FHWA acceptance letter SS-15 documents Texas Transportation
Institute testing that indicates a thin-walled aluminum tube smaller than 4” in
diameter will provide adequate breakaway performance in strong soils…
This letter does not infer that this product will or must be
used by Department forces…
A follow up acceptance letter (SS 35) notes 3" & 4" w/ wall thicknesses of 0.125" can be found here-
2. U.S. Department of Transportation 8/11/2011 Federal Highway
Administration
Roadside safety devices should meet the guidelines contained
in the National Cooperative Highway Research Program (NCHRP) Report 350 if
tested prior to December 31, 2010, and the American Association of State
Highway and Transportation Officials’ (AASHTO) Manual for Assessing Safety
Hardware (MASH) if tested after that date. Requirements for breakaway supports are
contained in both of these documents and in AASHTO Standard Specifications for
Structural Supports for Highway Signs, Luminaries, and Traffic Signals.
Decision
The following system was found acceptable, with details
provided below:
Generic Aluminum support Pole 4-inch diameter with a 0.125
wall thickness
Findings
As noted in previous requests , the FHWA has previously
accepted a 6061-T6 aluminum pole in 3” as well as 4” diameter poles of the same
aluminum alloy with a wall thickness of
0.125 …Therefore, the 6061-t6 aluminum pole with 4-inch outside diameter and a
0.125 inch wall thickness remains acceptable for use on NHS under the range of
conditions originally tested, when such use is acceptable to a highway agency.
Upon request, Metalcraft can send along a Letter of
Certification with your order when you request our Aluminum alloy 6061-T6 poles
for your sign project.
