Maybe a little OT- Close call

Hi...

might be a little OT but ......Thought I would share a close call I had on the jobsite. I am a rig welder of about 24 yrs in Canada and was working at a refinery ... At the present I was welding a 6 inch sched 40 pipe flange to a 90* elbow. I set up the flange and elbow on the back of my welding truck on a "spinner" so that I could roll weld the joint. I had a coffee going on the deck of my truck that morning , I had laid the bead and hot pass and was minding my own buisness working away.

Meanwhile, aproximately 150 yards from me there was another outfit doing a hydrostatic test of a 8 inch pipeline we had "welded out" (finished) a few days prior. The test was completed and they were about to "Dewater" the pipeline (Drain it of the water used for the test). An engineer asked what the testers were going to do with the water used for the test and they said they normally just let it run on the gound etc..... as it was just local well water. The engineer said in no way would he have a bunch of water laying about for a few days around the refinery and he wanted the water trucked out with water trucks. They said no problem and brought in water trucks to load and haul the water away. The pipeline the trucks hooked up to was comming down a very long (1/4 to half a mile) sloping hill so the "head pressure" of an 8 inch pipeline must have been pretty high. One truck in question had hooked to the pipeline and was taking a load. Then the pipeline gave the truck a burst of air that was in the line followed by a rush of water combined with the head pressure. The top of the truck was blown off. I must admit I did hear a low sounding whoosh but wasn't about to stop a weld as I was laying a cap with a 3/16 X

7018 welding rod and wanted the weld to look uniform. I figured I would take a look after finishing the weld. What I didn't see or know about was that a sched #40 -4 inch pipe about 14 feet in length had been blown off the top of the truck and was a very "small stick" in the air as they told me later it probably went 300 feet in the air. What I didn't know was that it was comming down in the vacinity of my welding truck and I was welding off the back of it!. They started screaming and yelling at me. I forgot to mention that I was using a Lincoln Classic 3D ........with the "D" meaning deisel. I wouldn't have heard anybody yelling that far away. So I am welding away and am about three quarters away around the 6 inch pipe and "KERBANG" .....The pipe landed on my truck cab and welding machine. The impact of the pipe conecting with the truck broke the arc I was welding and thank God , because as I lifted my helmet in shock I was hit with a wave of deisel fuel....The missle had ruptured the fuel tank on my welding machine. I looked down at my hot weld and saw it starting to smoke like crazy so I ran like hell in case it ignited and I would have gone up with it. Luckily it didn't ignite and my truck and equipment was saved. The whole outcome of that was about ten thousand dollars worth of damage to my welding rig and nerve damage to me as I now lift my helmet when I hear funny noises. The oil Company was very good about the incident. They just said 'Whatever it takes to fix that truck...send us the bill and we'll look after it"....and they did... I just thought I would share this close call I had... Regards...Jim
Reply to
Jim & Lil
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Did they cover the cost of new pants as well? Lucky.

mj

Reply to
michael

Wow. Gave me the shivers just reading it. Will you be shopping for a reeeeally heavy-duty hard hat now? :-)

Wayne

Reply to
wmbjkREMOVE_THIS

Hey Jim,

I guess you know that there are "water hammer pumps" that work on exactly that principle. The head of water running down free-flow in a pipe is valved shut rapidly (flapper valve), and the inertia of the water creates a VERY high pressure which is then diverted to transport water to where-ever it is desired. Usually up hill of course, but sometimes just laterally.

Another scary welding story, only with three fatalities. A pipe-fitter and two-man welding crew were to weld a new "T" onto a low pressure water source, just outside a gate valve on a water- tank. The T already had a shop-welded flange to suit the existing valve flange, but some of the rest of the pipe-work was to be cut and set on site to suit. Friday afternoon of a long week-end, the crew bolted the T tight onto the old valve, and then cut the pieces for the rest of the job, and tacked them in place, then ran a light pass around all the joints. 5 o'clock, off home for the long week-end. Tuesday morning, they come back and start right off running heavy beads from two welders. But apparently over the weekend, the new pipe had partially filled with water from the apparently leaking existing valve. The two welders created enough heat that before the second passes were completed the whole thing got such steam pressure that one end of the T blew off and killed one welder when it hit him, and scalded the other two so bad they died. Uggg.

So, glad you're safe. Nearly one of the "never knew what hit him" stories.

Take care.

Brian Laws> Hi...

Reply to
Brian Lawson

So . . . what would "head pressure" be on an 8 inch pipeline full of water sloping uphill/downhill for say 1/2 mile. Would it be, say 75% of (2640 x

1/2 pound) ?? This based on 8/12 = .75 and water pressure being around 1/2 pound per foot, and 2640 feet = 1/2 mile Can someone confirm this.

Bob Swinney

Reply to
Bob Swinney

1 psi for every 2.31 feet of elevation, half mile at say 10% slope would be well over 100 psi. A lot less pressure could still be exciting with 8" pipe.

Wayne

Reply to
wmbjkREMOVE_THIS

And there would be well over 50,000 pounds of water in that 8" pipe. LARGE mass in motion.

Reply to
Brian Lawson
0.03612 psi / per inch of Water column. 2640 x 12 x .03612 = 1144 psi. That's for 1/2 mile vertical displacement. Downward slope doesn't matter, vertical head does.

Mike Eberle> So . . . what would "head pressure" be on an 8 inch pipeline full of water

Reply to
mikee

YIPES! Thank God it was off by 5 feet, eh!?

Tim

-- "I have misplaced my pants." - Homer Simpson | Electronics,

Reply to
Tim Williams

My rule in general is that a close call means that you are doing something wrong. In this case, your hands were clean, how could you expect something going on 300 feet away to affect you? The error was on the other end, sounds like somebody turned a valve wide open when it should have just been cracked open. Sort of an odd way to drain a pipeline, I imagine a big valve was involved, something bigger than a two inch hose.

I always want to learn from mistakes, whether somebody gets hurt or not.

richard

Jim & Lil wrote:

Reply to
Richard Ferguson

My rule in general is that a close call means that you are doing something wrong. In this case, your hands were clean, how could you expect something going on 300 feet away to affect you? The error was on the other end, sounds like somebody turned a valve wide open when it should have just been cracked open. Sort of an odd way to drain a pipeline, I imagine a big valve was involved, something bigger than a two inch hose.

I always want to learn from mistakes, whether somebody gets hurt or not.

richard

Jim & Lil wrote:

Reply to
Richard Ferguson

My rule in general is that a close call means that you are doing something wrong. In this case, your hands were clean, how could you expect something going on 300 feet away to affect you? The error was on the other end, sounds like somebody turned a valve wide open when it should have just been cracked open. Sort of an odd way to drain a pipeline, I imagine a big valve was involved, something bigger than a two inch hose.

I always want to learn from mistakes, whether somebody gets hurt or not.

richard

Jim & Lil wrote:

Reply to
Richard Ferguson

My rule in general is that a close call means that you are doing something wrong. In this case, your hands were clean, how could you expect something going on 300 feet away to affect you? The error was on the other end, sounds like somebody turned a valve wide open when it should have just been cracked open. Sort of an odd way to drain a pipeline, I imagine a big valve was involved, something bigger than a two inch hose.

I always want to learn from mistakes, whether somebody gets hurt or not.

richard

Jim & Lil wrote:

Reply to
Richard Ferguson

Close counts in horseshoes and is much better than a bull's eye in this instance, thankfully! Gerry :-)} London, Canada

Reply to
Gerald Miller

The only thing you really need to know is the vertical head. But, depending on how big the air bubble was, there could also be a bit of hydraulic hammer involved, and that can be quite spectacular. I wonder if the water was going into the tanker faster than the air could escape, and it built up air pressure inside the tank? That's the only way I can think of for the top of the tank to go 300 feet in the air.

Jon

Reply to
Jon Elson

Very lucky man, In South Australia last week (late Feb 2004) A welder was working in a building at a quarry on a conveyor when it collapsed & killed him. Only know what I read in the papers, he only started there earlier this year.

Reply to
Ian Sutherland

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