subzero welding

Date 12-09-2009 22:47

I could have sworn this got deleted from D1.5, but I am obviously wrong, because it's still there.

If I were the authority in charge, I'd probably allow it as long as preheat requirements were met and so were weld quality requirements, and it didn't look like the welder was having a whole lot of difficulty.

Hg

By kipman

Date 12-10-2009 07:43

We run into this all the time. It basically forces you to build a temporary structure in the weld area. It's generally not seen as being a problem because we get better productivity that way anyway.
Mankenberg

By 803056

Date 12-11-2009 04:31

Kip has it correct. The standard allows the contractor to enclose the area where the welding is to be performed. As long as the amibient temperature is above zero, welding can be carried out. However, the requirements for preheat still prevails. If the temperature is below 32 degrees, the joint and surrounding material has to be preheated to at least 70 degrees (or higher for thicker sections) and maintained while welding is being done.

Best regards - Al

By welderbrent (*****)

Date 12-11-2009 14:40

To me, the important part is the ambient temperature in the work area, at least JUST AS important as the pre-heat, and in perspective to the way the question/comment was made. I believe the code makes that clear. I don't care if one doubles the amount of pre-heat that he uses, if the ambient temp in the area is not above zero, NO WELDING. That's the way I see it. Both conditions, pre-heat and ambient temp must be complied to.

I was taught years ago, get comfortable before you start welding, you will finish faster with a higher quality end product. That went for PPE, aids to make out of position work not wear you out fast, temperature in the winter and/or rain (repaired a lot of logging equip in the NW- LOTS OF RAIN, right Allan), and many other factors. Yes, they may slow down the starting arc, but they speed up the rest of the process especially if no one has to go back and fix bad weld.

Have a Great Day, Brent

By supermoto (***)

Date 12-11-2009 15:56

I don't know anything about API, but shouldn't you look at what API code tells you. Unless what your talking about is structural steel.

D1.1 doesn't tell you to make sure that the ambient temp. is 32 Fabove, but it tells you that the base metal needs to be 32 F above. It only talks about ambient temps to be above 0 F.

By spots

Date 12-11-2009 16:29

AWS D1.1 prohibits welding when the temperature in the area of welding is below 0 F.

If you look at the commentary (C 5.12.2) the reason behind this has nothing to do with metallurgy.

The prohibition is because the people that wrote that passage did not believe the man behind the hood could reliably make quality welds.

Does anyone know when this statement was evaluated last?

By kipman

Date 12-11-2009 22:45

Spots,
I have no idea when this issue was last looked at by the D1 committee. My guess however is that it will never be looked at again. There is no hue and cry from industry to change this provision so they will not spend time on it.
Regards,
Mankenberg

By Metarinka (****)

Date 12-11-2009 22:51

speaking from experience welding below 0 degrees is never comfortable, and you would have to be very cocky to think it doesn't lower quality.
Is there a need for a change?

By welderbrent (*****)

Date 12-11-2009 23:07

I realize there are some places that getting that temp to even come up to 0* is hard enough. And you must weigh in the reason the work is needing to be done, some emergency repairs are time sensitive.

BUT, if I take the time to build a shelter and rig up a heater, I'm going to try to get that temp up above 0* before I try to weld. I haven't been forced to work that cold very often and I am currently getting too old to even want to think about it. There's a good reason this old man owns a shop and got into inspections while living in AZ.

More to Metarinka's question, personally, NO. I don't think there is reason for a change. Another point to consider is the difficulty in keeping pre-heat in a member that is losing heat to the atmosphere because of the low ambient temperature. Depending upon the dimensions of the material and the ambient temperature, getting your weld area up to 32* or higher and holding it there will be a major challenge.

Just my two tin pennies worth.

Have a Great Day, Brent

By 3.2 Inspector (***)

Date 12-12-2009 08:09

I have been on a job where the temperature was -13F
We buildt a shelter around the hole unit and heated it up to around 50F

When they welded on towers and such, we applied pre-heat with the same equipment as for PWHT and raised our pre-heat temp by 120F
With even the slightest wind gusts, we had to cancel welding.

The worst part was that the bars started the non smoking crap during that winter :/
So we had to go outside when smoking after a nice meal, at that time of night the temperature had reached -22F

3.2

By Lawrence (*****)

Date 12-12-2009 12:30

I got up this morning and it was -13F

Burrr

:(

By 3.2 Inspector (***)

Date 12-12-2009 14:33

As we said, it is 2 inches cold :)

3.2

By Nanjing Date 12-19-2009 10:32

3.2 you smoke! how terrible and you frequent bars! I hope you do not chase after women as well.

Why do u refer to F and not C so everyone in the civilised world can have an inkling of what you are talking about.

By 3.2 Inspector (***)

Date 12-19-2009 12:09 Edited 12-19-2009 12:11

I both smoke, drink and chase women, sometimes all at the same time!
When the women chasing part fail, I drink some more :)

If you click on my name, you will see that I like women in garter belts in particular!

I was once told that this is an american forum and I should act accordingly.

3.2

By Nanjing Date 12-20-2009 05:51

Maintain the minimum preheat for the materials you are welding.

Simple!

10 words.. no more is needed to answer this question.

By spots

Date 12-14-2009 16:04

http://www.forengineers.org/cgi-bin/wrcbulletin/bulletin.pl?title=%22Welding%20Of%20Steel%20At%20Low%20Ambient%20Temperatures%22;author=;bulletin_nmbr=;abstract=;category=0;sort=title;start_search=Search;action=view;mode=1;page=1;id=98;.cgifields=sort

Welding Research Council Bulletin 86
Welding Of Steel At Low Ambient Temperatures

"... indicate that, provided proper precautions are taken, there is no absolute lower limit to the ambient temperature at which welding can be performed."

I will be purchasing a copy of this publication, more to follow.

By welderbrent (*****)

Date 12-14-2009 19:54

Spots, not sure what your point is exactly.

You started this thread by stating the D1.1 position on ambient temperature. You then stated a case where API jobs had been allowed to work below 0* by using higher pre-heat on the weld area. You finished by asking if anyone had ever gotten an engineer to do the same on a D1.1 job, i.e. raise the pre-heat and not be concerned about the ambient temp.

From this line of questions I conclude that you are looking for info concerning temperature restrictions for pre-heat and ambient temps on a code job, particularly D1.1, with API used as an example of an allowance that you know of given to complete a job.

Therefore:
1) I know of no such allowance ever being made under D1.1 (That is what you asked about)
2) As many have stated here, according to D1.1 you must take both factors into consideration. Both ambient temperature and work piece temperature must be within the code requirements of D1.1.
3) This can be accomplished by sheltering the work area and increasing the ambient temperature within the shelter, if needed, to get it above 0*F, and pre-heating the work members to the proper temperture for it's recommended pre-heat.
4) Note, if the temperature of the work members is below 32*F when welding is to commence it must be raised to 70*F (or more depending upon the material to be welded) and held there during welding operations, not just pre-heated to 32*F.
5) You asked for any and all opinions. Most here are based out of D1.1 as that is what many thought you were trying to find out, at least I did.
6) Having worked on logging equipment all over the NW, working for CBI on high elevation jobs in CO, NV, etc through the winter time, and working and hunting in the mountain areas of AZ, which does get below 0* occassionally, I don't care to try to complete quality work at those temps; My Two Tin Pennies Worth!!

Finally, the article you reference has little bearing on the case unless you can get an engineer to make a variance to the code for your job based upon the research it documents. IT IS NOT A CODE!! It does not alter the clear working conditions that D1.1 requires. You must also make certain of their official definition of 'ambient temperature'. It is not just the atmospheric air temperature at the job site. It is the air temperature within the general area where the work is being performed, which can be a much smaller region, especially if you build a shelter.

There are, within the quote you provided, a couple of other disclaimers here. Namely, "provided proper precautions are taken". What is that supposed to mean? And, "there is no absolute lower limit". That can mean that I can set the limit at 40*F if I so wish(or the engineer can if he so wishes). Or 20*. In other words, they aren't going to commit themselves on either side of a code declared Minimum Ambient Temperature Limit. Again, just my take on the wording in this one statement.

Now, if you want to send that to the D1.1 Committee and see if you can get them to change the Ambient Temperature requirements based upon this research, feel free. I, personally see no need. I don't think we are talking about that large of a volume of work that the change would effect. Plus, the Code is attempting to bring every possible factor (such as working temps), that can be altered to make the job of the welders more consistent and of good quality, into a controllable area of variables that will ALMOST gaurantee success.

Again, you asked for all opinions, so, Just My Two Tin Pennies Worth.

Have a Great Day, Brent

By HgTX

Date 12-14-2009 22:43

True enough, probably not a large volume of work.

My take on it, not that I have the authority to declare this, is that it shouldn't be in there. There are lots of reasons why someone would have trouble welding. Too cold, too hot, distracted by divorce, hanging at a weird angle to get to an awkward weld. It's not the code's place to determine under what circumstances welders can manage to get their jobs done, and it seems odd to single just that one out, especially because there's nothing magical about 0F. Someone else might not be able to function at +5F or +10F. You can't expect the code to protect you from this kind of problem. So you need to be able to keep an eye on things and be able to tell if someone can't handle it. And if you can do that, for whatever situation, then you don't need the code to help you out in this one very specific case.

Hg