Strightness Tolerance

[greencircle]

Hi Guys,

Is there a standard some where on the Straightness on a aluminum street light poles. Iam looking to specify on my drawings for for various heights of poles.

Thanks
GC

 

[drawoh]

greencircle,

Is there any reason why there should be a standard on how straight lampposts are? I would guess that most of your requirement would be aesthetic.

--
JHG

 

[IRstuff]

There's got to be something that constrains it. What if the supplier produced a post that bent so far that the light was pointing sideways?

see table 3 in

http://bsl.lacity.org/downloads/business/bluebook2009r2.pdf

TTFN
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[IRstuff]

That one is actually loose compared to this one:

http://www.edmonton.ca/transportati...truction_and_Materials_Standards_Nov_2013.pdf

see also:

http://yzjyds.en.alibaba.com/product/871171900-212460658/Steel_street_light_poles.html

http://www.onemotoring.com.sg/publi...0.File.tmp/LTA_Street_lighting_Guidelines.pdf

http://www.ausgrid.com.au/~/media/Files/Network/Documents/NS and NUS/NS128.pdf

this has the spec buried in an Australian standard, presumably AS 2209 Timber Poles for Overhead Lines, or AS 4065 Concrete Utility Services Poles, or AS 4677 Steel Utility Service Poles

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[KENAT]

Well, if ASME Y14.5M -1994 is in force (which I suspect it may not be for something like this) then the size tolerance also controls form by default (rule 1/Taylor principLE).

However, I fear this isn't answering the OP's real question.

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[robyengIT]

in Europe we have attached Standard EN 40

 

[MintJulep]

The LA one has the straightness requirement defined as " At the discretion of the Inspector/Engineer."

 

[IRstuff]

"The LA one has the straightness requirement defined as " At the discretion of the Inspector/Engineer.""

Not sure which paragraph you are referring to, but the discretion phrase in:

"3. Straightness - At a frequency determined by the Engineer, Standards will be tested for straightness. Standards shall be sufficiently straight when in a vertical position such that the maximum deviation from a string line on the face of the Standard in a plane passing through the longitudinal axis shall not exceed the tolerance listed in Table II. At the discretion of the Inspector/Engineer, such tests may be conducted at the place of manufacture, or at the project site following erection."

applies to where/when the straightness is tested, and Table II, which points to Table III, is only discretionary for poles longer than 40 ft.

TTFN
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[3DDave]

I wonder how it worked when they were tree trunks, like the poles in my neighborhood are.

 

[greencircle]

Guys,

Thank you very much for sharing so many references. I now believe that its not only the straightness that I should be worried about, its the fabrication tolerance also. See attached picture of 2 poles. They both appear stright, except that one of them have the base welded slightly angle. So the whole pole is appearing tilted. I guess I should use 2 GD&T control.
1. Straightness control
2. Perpendicular control

In some applications, the perpendicular doesn't matter because there are leveling nuts. But in applications where there are no leveling nuts (Directly mount), the perpendicular does matter.

Thanks
GC

 

[KENAT]

2 things:

1. Do you understand the implications of 'rule 1' 'envelope principLE' 'Taylor principLE' or whatever you want to call it to your situation? Are your drawing dimensions etc. set up in a way to take advantage of it?

2. What is your process capability - just throwing straightness and perpendicular controls without understanding this (and of course functional requirements) may just increase the scrap rate.

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[greencircle]

Didn't know about it by this term. So I looked it up & found

http://www.cobanengineering.com/Geo...icTolerancing_FormTolerances-Straightness.asp

Yes, makes a lot of sense. In my case I should need to follow the shaft method. Good point KENAT, I can see how we could be rejecting some actually good parts.

 

[KENAT]

Just FYI, in future dimensioning and tolerancing questions may be better off in: forum1103

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[tbuelna]

That LA municipal standard was pretty specific in table V regarding bow/curvature vs. length for fabricated metal light standards. But it was not clear if table V just covered steel poles or if it also included aluminum poles.

I've never seen aluminum light standards used much in southern California. I've seen concrete light standards commonly used on residential and city surface streets, but most light standards over 25ft or so (highways and freeways) all seem to be fabricated steel. The unfortunate reality in southern California is that aluminum poles would likely be stolen and sold for scrap.

 

[IRstuff]

Given that the concrete straightness requirements from Table III are identical to those in Table V, I would think both aluminum and steel are covered by the former.

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[KENAT]

I seem to recall being told in a high school science class or some such that material selection may be impacted by propensity of Canis familiaris to relive himself on such utility poles and resultant corrosion issues.

However I've veered off topic sorry.

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