why is it that D1.1 is limited to steels over 1/8 inch,,,,,but D1.3 is limited to steels equal 3/16 inch or less..........????
they are crossing over each other.......???????? i'm taking this from the 2002 D1.1 and the 98 D1.3.......have things changed....? is this right....???????
Okay, so there's a 1/16 of an inch crossover, big deal. In some instances a 3/16" thick fabrication may be better suited to D1.3 than D1.1. I guess I fail to see the impact of a 1/16" crossover in thickness. The code stipulated is an engineering decision, so they should know which is a better suit.
JA,
I've noted that too.
The biggest and best thing the two codes have in common is that they both have a Section 3 for pre-qualified procedures!
By CWI555 
Date 01-20-2007 18:02
Edited 01-20-2007 18:05
I don't know for sure, but I've always assumed that the the cross over thickness difference of 1/16th of an inch is to allow for cases were thickness range of the work pieces at hand are in the range between 1/8" and 3/16th.
For instance, if you have a disimilar thickness transition from 3/16" to 1/8" inch your covered if one of those drops below 1/8".
It seems to me if the code has a hard shift at any given point with no overlap it could cause lots of problems for the inspector and or engineer.
The project I'm on now has such a situation. The material is inbetween both codes, so the specs call for D1.1 in this particular aspect, but had it dropped below the limits of
D1.1 at a transition, they could have used D1.3 and been clean insofar as the code is concerned.
In short; I thinks it's meant to allow some flexibility. I don't know for sure on this one if I am correct, if anyone else knows different please inform.
D1.3 is for sheet steel applications.
D1.1 is for structural plate, pipe, and shape applications.
There is a cross over in available thickness of the above products in the 1/8 to 3/16 range.
Real easy answer, if you are welding on sheet steel in this range then use the D1.3. If you are welding on structural plate, pipe, or shapes in this range then use the D1.1.
What if you are welding 1-1/2 sch 10 pipe .109 wall?
The 1-1/2 sch 10 welds to 3-1/2 sch 10 for overhead sign structures.
trilon spans
In my opinion, neither D1.1 nor D1.3 would apply to the overhead sign structures you describe. That is not to say that your Engineer cannot specify either code, it's just that the criteria needs to be looked at very carefully.
From the scope of D1.3, "This welding code covers arc welding of structural sheet/strip steels,...". I interpret that as meaning it does not cover thin walled tube applications.
D1.1 only covers down to 1/8", so your application is outside D1.1. Then again how often is thin-walled pipe truely used in a STRUCTURAL application. Jon may be on the right track with the handrail question. Handrails are not considered structural elements.
The answer is use another code, maybe B2.1 for qualification. I believe there is also a standard from ASTM on handrails; however, I am not 100% on that recollection.
There is a new generation of "space-aged" structural designs coming out but as always the codes usually lags behind new industry trends. Typically codes want cutting edge processes or designs to develop some history of reliability before addressing them in the code. Maybe D1.1 will address ultrathin structural tubing in the future but not right now.
