So, I'm new to this whole code and figuring out exactly what they are saying. I've been working in the wonderful north and have called it several days due to snow, ice, and just pure cold(-11 yesterday).
I was told by a friend that he thought there was something in AWS that specified temperatures and having shelter. After a bit of reading of table 3.2 I noticed a note at the bottom that referred me to Section 5, 5.12.2.
Seemed fairly clear on what they were saying but I guess not "crystal". I guess my question or questions are,
If it is say 20 degrees outside and the wind chill knocks it down below zero according to what AWS says does this mean I need to have a shelter around the weld area? It's currently 25 where I am at and the wind is kicking pretty good but not sure if it is below zero. I need to purchase a wind speed/temperature tool apparently! I understand pretty much all of what they say in that about snow, rain, yada, yada but the "atmospheric" temperature, wind chill factored in is where I am stumped. Armed with this knowledge at least we can go to the client when questioned about length of time on this job with our guns loaded sort of speak as they specified, "Welded to according to AWSD1.1 Standards".
Now, if it's 25 and the wind knocks the temperature down to 5 degrees or your feels like temperature is this considered acceptable? With proper preheat maintained at the weld area?
Steel we are welding is galvanized A36 and A500, process, SMAW, 7018 rods.
Thanks to all for any help in this. I'm sure I will be back with more questions as my quest for AWS CWI continues!
Shawn
Shawn,
Note #4: "when welding personnel are exposed to inclement conditions."
Personal opinion: NO. Wind speed/chill temp is not considered. But, if the inclement conditions make completion of a quality weld too difficult, stop. Put up a shelter. Just because the code does not specify something does not mean it cannot be used to promote that position anyway. The code is a MINIMUM.
The shelter would cut the negative impact of the wind both for work in general and wind chill for comfort to be able to weld better. Would not even need a heater to get the ambient temp to above 0° in the work area.
Pre-heat is a separate issue from ambient temp. First, the code distinguishes between ambient all over the geographical location (ambient environmental) and ambient in the work area (which may be inside a shelter consisting of the immediate work area).
Second, Once the Work Area Ambient temperature is acceptable then you can work on the Pre-Heat of the material. It must be at least 32°F unless required to be higher for thickness or grade of material. If material temp is lower than 32°F then it must be pre-heated to at least 70°F and maintained there during all welding.
Have a Great Day, Brent (BTW, temps in the high 70's here in Phoenix, low 60's at home in Prescott, was 60° when I left Phoenix this morning after my 12 hour shift last night)
I agree with Brent. The commentary with regard to 5.12.2 states that experience has shown that welders cannot produce optimum results when working in an environment where the temperature is lower than 0°F. Reference is made in 5.12.2 relative to the use of a heated structure or shelter to protect the welder, and the area being welded from inclement weather conditions. If the temperature in this structure or shelter provides an environment at 0°F or above, the prohibition of 5.12.2 is not applicable. Minimum preheat and interpass temperatures must be applied and maintained regardless of the environmental conditions inside the structure or shelter.
The only affect "wind chill" has on inanimate objects is to shorten the amount of time it takes for that object to cool.
For example
If the real temp is +10 and the wind chill is -10 The "work" will never move to a temperature below +10 no matter how hard or long the wind blows on it.
Sending warm thoughts your way :)
Lawrence is correct. Wind chill is a measure intended to be applied to humans only.
Thank you to all for the replies and education!
This is more in place to protect the welder and makes sense. I had a gust of wind blow me clean off the tower the other day. Blew me 5 feet off the tower, swung around to the opposite face. That's when I packed up my gear and said, "that's it, how's a guy supposed to make quality welds in that".
Thanks again to all!!
Shawn
I just dumped another bag of wood pellets into the ol' pellet stove. Can't expect to type a good report if I'm cold and my fingers are stiffer than a young man in a bordello.
I guess it is like welding in that respect. If the welder is cold and shivering, it is silly to expect a high quality weld.
Stiff breezes and cold winds increase the cooling rate of a weld as well as the welder. How many times do you see a welder using compressed air to hasten the cooling of a weldment? That's why radiators have fans to move the air past the cooling fins. A shelter or wind break reduces the volume and velocity of air moving past the weld and reduces the cooling rate so the weld metal cools more slowly. Back to basics; slow cooling reduces the tendency to develop undesirable microstructures. More supplementary heat is required to maintain the minimum interpass temperature if a stiff wind is blowing cold subzero air past the heated surfaces of the metal. Heat transfer is a function of the magnitude of the thermal gradients between the object to be heated or cooled and the gas moving past it.
It isn't rocket science; if one is standing in a cold wind and someone else is behind a wind break, it is pretty clear that the person standing unprotected in the stiff wind is going to get colder faster than the person shielded behind the windbreak. It is true whether the people are fully clothed or stand naked in a stiff breeze all else being equal. The difference between the weldment and the welder is that the welder has the added affects of evaporative cooling, but that is more pronounced if the welder is sweating. That isn't the primary concern when fully clothed (limits the rate of evaporation) and standing still in the cold of winter.
Best regards - Al
Topic American Welding Society Services / Certifications / AWS D1.1 Outside Temperature Clarification
