Announcement

Collapse
No announcement yet.

Welding in confined space

Collapse
X
 
  • Filter
  • Time
  • Show
Clear All
new posts

  • Welding in confined space

    I got asked to do a job inside of a tank on a trailer to hauls sand. I've done it before in the past without any kind of safety precautions but those days are over. The job is ****ty and I'm taking a risk by smoking out such a small area, depleting my oxygen and intensifying the harmful dust that is normally released when welding and grinding.

    The client is more than happy to provide a proper environment for me to go inside safely (a trained rescuer to watch and the proper equipment to get me out if need be) The thing is, I know of a couple guys who are trained for this as well, in fact they do it for a career. They are firefighter/emts.

    My idea is this, if I purchase or rent all the needed gear and hire someone to be my watcher, I can perhaps make a small additional profit off the overall job and then I get to have better control over the equipment used and the person watching over me. I feel much better having a friend with firefighter credentials watching my back than some joe blow truck driver who took the coarse one weekend.

    Does anyone see any liability issues with me hiring my own guy to watch me vs having the paying customer provide the trained personel?
    sigpic

  • #2
    welded inside tanks alot and never had anyone sit and watch the hole for me .just get a respirator and blower vent and you should be good to go.if your really worried about the dust just hose the tank out before you work in it .all tanks need to be cleaned before you go work in it anyway so really there shouldn't be any dust to worry about. if you choose to enter an uncleaned tank then your on your own. all tanks should be ventilated before you enter because of dead air inside.

    Comment


    • #3
      Alternatives

      Since it is a confined space, you probably need a watcher by law. But I would rather have better air in the tank than a slightly more skilled watcher.

      Consider buying a blower to pump in fresh air, and therefore expel the dust and toxins. This one is somewhat small, but they make bigger units.

      http://www.selfretractinglifeline.co...uct-combo.html

      You did not say what you were doing to keep the toxins out of your lungs. In the extreme case, you could carry a tank of air like a scuba tank. But you could wear a mask that delivers fresh air from a pump located outside the tank. Or wear a battery pack and a blower with filters on your belt, a PAPR, which is what I wear when doing a lot of grinding. The PAPR respirators are rated as 10 times better than a conventional respirator, and the alternatives would deliver even cleaner air.

      So I say, invest in better air, not in better watchers.

      Richard
      Syncrowave 200, Millermatic 211, Victor torch, Propane forge....

      Comment


      • #4
        If you only have this one job to do with these conditions, I would let the client supply the men and equipment. If you have a long term project then you might consider having your own man watch and equipment. One problem with hiring someone for this is that it is a mind numbing job to sit outside an entranceway for hours a day. It takes a special kind of person to do that seemingly easy task for any length of time and still remain alert to your situation which may change without much warning.

        Comment


        • #5
          Well in addition to my watcher I intend to have ventilation fan, co2/o2 monitor and all that other good stuff.

          My question relates to whether or not its a good idea for me to provide all the nessesary equipment and trained personnel for this job or if i should let the customer be responsibile for all that. In a liability perspective that is.

          I think I would prefer to get into owning my own vent fan, rescue tripod, scbas etc and rent them back to the customer for use during a confined space job. More $$ in my pocket which i think is fair compensation for having to do such ****ty work.
          sigpic

          Comment


          • #6
            I imagine a sand tanker has a hole in the bottom to vent thru, I would have fan to vacuum the stale air out the top. Some care is in order but there is no sense in over thinking it.
            In a liability perspective that is.
            I am not sure where the liability is here, you are the one inside the tank.

            Comment


            • #7
              There are a couple kinds of liability, product and worker, you are a contractor so pretty much most any safety issues are up to you. I spose if they provide the material and tools in some kind of agreement then there could be possible recourse for you to sue them. I like a hand,,, if its vented not much of an issue but would want someone to check on me once in a while, explain they are not to enter the vessel for any reason and if you are passed out call 911, other reason is to hand me tools, nothing makes that job more difficult than to have to crawl out for every little thing. Way back in the day a good helpers responsibility was to keep shoving cans of cold Bud in the hole.

              Comment


              • #8
                I have done them where I had hole in bottom to let heavier gasses out and reach in with wire feeder, lots cleaner and tried to do very little grinding if possible.

                Comment


                • #9
                  Originally posted by tommy2069 View Post
                  welded inside tanks alot and never had anyone sit and watch the hole for me .just get a respirator and blower vent and you should be good to go.if your really worried about the dust just hose the tank out before you work in it .all tanks need to be cleaned before you go work in it anyway so really there shouldn't be any dust to worry about. if you choose to enter an uncleaned tank then your on your own. all tanks should be ventilated before you enter because of dead air inside.
                  You guys ever here of OSHA?

                  There's a lot of bad advise flowing in this thread and the worst example is quoted above.

                  If you should have an unlucky experience in that tank you are DEFINATELY not on your own. There's an army of bureaucrats and attorneys just itching to sue evert one in sight for your untimely demise.

                  Get a qualified hole watch and an air monitor at the very least
                  Miller Diversion 165
                  1966 Bridgeport Mill
                  Leblond 15x 35 Regal Servoshift lathe
                  Solberga SE 1425 Drill Press
                  Bigass Bandsaw
                  Hydraulic press
                  small surface grinder
                  Belt sander
                  Tons of grinders and hand tools
                  Knife edge Balancing rollers
                  Heat and AC in the garage

                  Jags and racing Triumphs

                  Comment


                  • #10
                    You have not stated if you will be stick or mig welding, but I choose stick over mig because you can see the smoke as it leaves your "negative vented" tank. If you mig, you can't see the Argon/CO2 in the air and still might effect your performance. Argon/CO2 is not a contaminant, it is a gas, and thus is not filtered by most respirators. Plus the time between rods will give more time for the fan to draw out the smoke.

                    I also use to be a volunteer firefighter and EMT, and I am a very good rock climber, and with that said, I do a lot of things that I shouldn't. I also weld inside a lot of 10,000 gal tanks w/ 14" diameter holes with many impellers inside, plus at 145 degrees. So I do stupid things, but I also don't let anyone else do it since they might not get back out.

                    The biggest things about working inside tanks are:

                    1) Oxygen
                    2) Your ability to get IN/OUT (in an emergency, after 4 hours of work)
                    3) Air born contaminants
                    4) Ability to work safely inside (no moving parts/lock out & tag out, no pinch areas)

                    If you answer no to any of these, it is better to pass the job.

                    Comment


                    • #11
                      Your safest bet would be a respirator with an air supply to it, next best thing would be a blower to supply air, and one with a hose that you can put right by your weld to suck the gases out. At work, we use birdcage blowers, stick a hose on the end of it, you get a blower. Stick the hose into the side of it, you get vacuum.

                      Comment


                      • #12
                        Originally posted by Sberry View Post
                        Way back in the day a good helpers responsibility was to keep shoving cans of cold Bud in the hole.

                        This is why I like being the boss.... send everyone home at 5:00 and work till 11:00 but throw away the evidence before morning.

                        Comment


                        • #13
                          Sand

                          You said the truck was used to haul sand. I would note that sand is not usually considered a toxic material, like a chemical. Yes, the dust is not good for you. Any good filtering system will take care of the dust. We are not talking about exotic chemicals with unknown effects.

                          If you think about getting inside a tank, the issues are:

                          Adequate oxygen or fresh air blown into the tank.

                          Toxic fumes, which most filters will not filter out. Carbon Monoxide is one of those fumes, of course.

                          It seems to me that an ordinary respirator, a fan to blow fresh air into the tank, and a watcher would be adequate.

                          I know that some people worry about the welding Argon or CO2 displacing oxygen. Typical CO2 or argon flow rates are around 20 cubic feet per hour, and a tank that is 20 by 8 by 8 feet is 1280 cubic feet. Let's assume that you weld 4 hours of actual arc on time. That is 4 times 20 cubic feet per hour, or 80 cubic feet. Even if the tank was sealed shut, 80 cubic feet vs 1280 feet is 6 percent of of the volume of the tank. You are not going to pass out if the percentage of O2 in the air is 20% instead of the usual 21%.

                          Granted if the space is very small you could perhaps displace enough oxygen to be a problem, but I think if you do the calculations you can see that the welding gas is a very small percentage of the air in the space.

                          Further, these confined space fans pump out roughly 1000 cubic feet per minute, not 20 cubic feet per hour. 20 cubic feet per hour is 0.3 cubic feet per minute. 0.3 vs. 1000? You would be hard put to measure the difference with fancy instruments.

                          Yes, confined spaces can be risky, but the risk is what is in the tank before you get into it, not the welding gas itself. If for some reason the tank was low on oxygen before you got into it, that would be a problem. But if you hook up a 1000 cfm fan for a few minutes before you get into the space, that should completely change the air.

                          To me, the key is that the tank was used to haul sand, not nasty chemicals.

                          Richard
                          Syncrowave 200, Millermatic 211, Victor torch, Propane forge....

                          Comment


                          • #14
                            Air compressors aren't for breathing air, but are a nice way to blow accumulated smoke etc out of a small space quickly. I'd drop my air hose into the tank where it would be handy.

                            Comment


                            • #15
                              I was the guy writing confined space permits as well as hot work for this type of job in the refinery. Yes get a hole watch. Get a monitor for LEL just in case something gets in there like Argon gas in the bottom displacing the air. We used air movers to suck out the air and bring in fresh air. Also tie a rope or use a harness with a tripod if necessary the rope can be used for rescue if the hole is in the side. Don't do it alone for sure. And make sure the hole watch doesn't leave or stand 35 feet away blabbing to someone else. Just my thoughts...Bob
                              Bob Wright

                              Comment

                              Working...
                              X