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T&P valves are never tested by homeowners because if you don't test them regularly (like they say in the manual) then do it once, it will probably leak. FOr catastropic failure scenarious, you'd likely blow one of many other parts of a house's plumbing before a pressure vessel would. Hell, the copper flex lines connected into to the supply and house would probably go before the tank would rupture. Not to mention cheap bathroom supply valves, crappy hoses, etc. This does not hold for very old heaters or heaters not so old but with atrocious water attributes, because those can have pinpoint failures from over pressurization and corrosion.
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# ? May 28, 2011 07:45 |
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# ? Mar 28, 2024 21:52 |
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Motronic posted:BLEVE "Big Loud Explosion, Very Exciting"
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# ? May 28, 2011 08:05 |
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DJ Commie posted:T&P valves are never tested by homeowners because if you don't test them regularly (like they say in the manual) then do it once, it will probably leak. FOr catastropic failure scenarious, you'd likely blow one of many other parts of a house's plumbing before a pressure vessel would. Hell, the copper flex lines connected into to the supply and house would probably go before the tank would rupture. Not to mention cheap bathroom supply valves, crappy hoses, etc. I checked mine last week. I was thinking about the rest of the system blowing first too. Do they have a non return valve?
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# ? May 28, 2011 08:08 |
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Boat posted:The water heater rocket worked pretty goddamn good though, and morons replace that overpressure valve all the time, because they're morons. Then all it takes is a broken thermostat.. Replace it with what? A metal plug? quote:The cylinder had been standing at one end of a ~20' x 40' laboratory on the second floor of the chemistry building. It was on a tile covered 4-6" thick concrete floor, directly over a reinforced concrete beam. The explosion blew all of the tile off of the floor for a 5' radius around the tank turning the tile into quarter sized pieces of shrapnel that embedded themselves in the walls and doors of the lab. The blast cracked the floor but due to the presence of the supporting beam, which shattered, the floor held. Since the floor held the force of the explosion was directed upward and propelled the cylinder, sans bottom, through the concrete ceiling of the lab into the mechanical room above. It struck two 3 inch water mains and drove them and the electrical wiring above them into the concrete roof of the building, cracking it. The cylinder came to rest on the third floor leaving a neat 20" diameter hole in its wake. The entrance door and wall of the lab were blown out into the hallway, all of the remaining walls of the lab were blown 4-8" off of their foundations. All of the windows, save one that was open, were blown out into the courtyard.
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# ? May 28, 2011 13:46 |
heat posted:Replace it with what? A metal plug? Who the hell would be that stupid? LN2 dewars vent fairly regularly when they are sitting there and if people were pulling from it or filling it you would think that someone along the way would have noticed the pressure relief valve and burst disc were missing. It takes a while to fill or pull from those and while doing so you are just stuck there looking at the head so somebody must have thought "hmm this isn't like the other dewars". I used to work at a semiconductor fabrication plant, using 12" wafers of single crystal silicon. Some of the failures were simply astonishing, both because the equipment was huge and complex and also because the wafers were super strong yet extremely brittle. I do not have any of my own photographs (trade secrets and whatnot) but I recall seeing a video (recorded by the camera inside the equipment) of a wafer which was undergoing a chemical treatment which used a high RPM spin to dry off the wafer. At 8k RPM the wafer simply disintegrated. The largest piece we found was about 10mm square. There was apparently a small 2mm long nick on the back of the wafer (we found it on the next wafer from the same batch) and that was enough. Stuff like this was comparatively rare when you thought of the numbers of wafers processed, but it was pretty much a daily occurrence because of the volume we dealt with. Oh and we routinely went double the maintenance intervals on the equipment so that may have had something to do with it. Once when recovering from a power outage (which is about the worst thing that can happen to a semiconductor fab) I saw someone place a cassette carrying 25 wafers on to a piece of equipment and press the button for the tool to run a small laser scanner up and down the cassette front to scan the cassette to check which slots had wafers in it (called indexing). Instead of extending the indexing reader (which is on the rear of the robot arm that picks the wafers up), the equipment extended the wafer pick up arm into the cassette, then moved that straight down breaking every single wafer in under a second. Only $14k worth of silicon down the drain... no big deal.
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# ? May 28, 2011 15:43 |
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So instead of reading the sticker on the outside, it just reached in and smashed everything? Clearly that robot didn't get it's coffee.
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# ? May 28, 2011 15:54 |
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CaptBubba posted:Who the hell would be that stupid? LN2 dewars vent fairly regularly when they are sitting there and if people were pulling from it or filling it you would think that someone along the way would have noticed the pressure relief valve and burst disc were missing. It takes a while to fill or pull from those and while doing so you are just stuck there looking at the head so somebody must have thought "hmm this isn't like the other dewars". Who knows, but judging from the guy who delivers LN2 to my lab I'm not exactly surprised. Not only does he ride in the elevator with the dewar, one day I caught him venting off hundreds of pounds of nitrogen, in a room the size of my bedroom, with the door closed. I got there just as the oxygen sensor started beeping and probably saved his life, meanwhile he had no idea that what he was doing was in any way dangerous.
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# ? May 28, 2011 16:06 |
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heat posted:Who knows, but judging from the guy who delivers LN2 to my lab I'm not exactly surprised. Not only does he ride in the elevator with the dewar, one day I caught him venting off hundreds of pounds of nitrogen, in a room the size of my bedroom, with the door closed. I got there just as the oxygen sensor started beeping and probably saved his life, meanwhile he had no idea that what he was doing was in any way dangerous. And this is the reason you don't currently have your very own dewar at home...
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# ? May 28, 2011 16:07 |
Godholio posted:So instead of reading the sticker on the outside, it just reached in and smashed everything? Clearly that robot didn't get it's coffee. Not quite. the indexer looks like if you made a devil horns thing with your hand. Laser on one "finger" and a receiver on the other. The wafers protrude a bit from the cassette opening so the indexer is supposed to run down the front of the cassette and as the wafers are passed the beam is broken and it marks that slot occupied. Instead of doing that the robot gave every wafer the middle finger. We left that piece of equipment until last to bring back up. Here's a diagram: 28 and 30 are the indexers and can move in and out to extend past the arm (they are shown halfway out) and 20 is the part that extends to pick up, or break, the wafer.
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# ? May 28, 2011 16:24 |
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JD Brickmeister posted:They were kind of able to do it by rigging a gun to shoot a hole in the bottom just as the tank started to bulge. It went maybe 60 feet, then started spinning because it didn't have stabilizer fins. Yeah...lame. I've shot a 1/2 full one with a .308 round from about 75 yards. It basically stays within 20 feet of where it was hit, but make a hell of a fireball for a very, very brief time. (this is hitting it in the middle at ambient temperature) Take my advice, you want to do this at more than 75 yards. But it's not terribly spectacular. Getting a safety valve to fail and the tank to BLEVE is the real horror show that you don't want to be within a 1/2 mile of.
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# ? May 28, 2011 16:26 |
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CaptBubba posted:Not quite. the indexer looks like if you made a devil horns thing with your hand. Laser on one "finger" and a receiver on the other. The wafers protrude a bit from the cassette opening so the indexer is supposed to run down the front of the cassette and as the wafers are passed the beam is broken and it marks that slot occupied. Instead of doing that the robot gave every wafer the middle finger. We left that piece of equipment until last to bring back up. Ah, I see. Thanks for the explanation.
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# ? May 28, 2011 16:38 |
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Boat posted:The water heater rocket worked pretty goddamn good though, and morons replace that overpressure valve all the time, because they're morons. Then all it takes is a broken thermostat.. I'm trying to figure out what causes the flash of light on the face of the water heater from the view of it popping at 2:10.
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# ? May 28, 2011 16:54 |
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Looks like the power cord sparking as it's ripped out.
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# ? May 28, 2011 17:04 |
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peepsalot posted:I'm trying to figure out what causes the flash of light on the face of the water heater from the view of it popping at 2:10. If you look close, there's 2 sparks. And there's also 2 heaters on your typical electric water heater. Looks like they wired power directly to the heaters. 240 can make a decent spark.
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# ? May 28, 2011 17:05 |
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peepsalot posted:I'm trying to figure out what causes the flash of light on the face of the water heater from the view of it popping at 2:10. The electrical connections shorting out since its rocketing off at that point.
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# ? May 28, 2011 17:14 |
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Beast Pussy posted:You say the check engine light is flashing in your VW? Passat or A4?
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# ? May 28, 2011 17:14 |
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heat posted:Who knows, but judging from the guy who delivers LN2 to my lab I'm not exactly surprised. Not only does he ride in the elevator with the dewar, one day I caught him venting off hundreds of pounds of nitrogen, in a room the size of my bedroom, with the door closed. I got there just as the oxygen sensor started beeping and probably saved his life, meanwhile he had no idea that what he was doing was in any way dangerous. I work in a lab at a gas manufacturing plant. The drivers that deliver our dewars and high pressure cylinders have no clue. I have no idea what is involved with passing hazmat for DOT is but some of the people that drive for us I wonder how they remember to breath. Our liquid filling personnel would never have let a dewar out of the building with plugs instead the proper pressure relief valves in place. They are extremely easy to spot. And even easier to spot when they are missing. As for the driver that was venting the dewar, why was he? And what is wrong with riding in the elevator with one? Even if the safety were to open you would only get a few seconds of gas being vented and not enough in volume to make the atmosphere oxygen deficient.
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# ? May 28, 2011 19:48 |
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Boat posted:The water heater rocket worked pretty goddamn good though, and morons replace that overpressure valve all the time, because they're morons. Then all it takes is a broken thermostat.. Wait, you're not supposed to replace that valve? Cause I test mine twice a year and replace it every couple, because it starts leaking.
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# ? May 28, 2011 20:17 |
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trouser chili posted:Wait, you're not supposed to replace that valve? Cause I test mine twice a year and replace it every couple, because it starts leaking. Replace it with a cap/plug, I think he meant, that way it becomes zero-maintenance
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# ? May 28, 2011 20:19 |
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Farside posted:And what is wrong with riding in the elevator with one? Even if the safety were to open you would only get a few seconds of gas being vented and not enough in volume to make the atmosphere oxygen deficient. I could imagine if the elevator were to coincidentally fail it could go south pretty quick. Probably much higher risk of dying on the drive over though.
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# ? May 28, 2011 21:17 |
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Induced mechanical failure behind the wheel. She parked it here and left.
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# ? May 28, 2011 21:48 |
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Well christ, BMW owners have an image to keep up, you know.
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# ? May 28, 2011 22:22 |
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Ridge_Runner_5 posted:Induced mechanical failure behind the wheel. She parked it here and left. Spike is a pretty powerful drink.
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# ? May 28, 2011 22:59 |
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Marux posted:Replace it with a cap/plug, I think he meant, that way it becomes zero-maintenance Yeah pretty much. Which reminds me, I have no idea why I didn't think to link this yet. It's not very car related, but hooooooly poo poo, there are some failures involved. Home Inspection Nightmares - some of this poo poo is unreal. A little preview: [/housechat]
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# ? May 29, 2011 01:20 |
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Some of that poo poo is ridiculous. The steps leading to the garage door caused a hearty chuckle.
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# ? May 29, 2011 01:53 |
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Wasn't there an entire GBS thread about that red spider thing. Did anyone ever work out what it was for?
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# ? May 29, 2011 02:41 |
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Boat posted:Yeah pretty much. Which reminds me, I have no idea why I didn't think to link this yet. It's not very car related, but hooooooly poo poo, there are some failures involved. Is that thing fake from what I am seeing their on the inside shot?
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# ? May 29, 2011 02:42 |
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dietcokefiend posted:Is that thing fake from what I am seeing their on the inside shot? I don't think it's fake, which makes it even worse!
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# ? May 29, 2011 03:09 |
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Farside posted:I have no idea what is involved with passing hazmat for DOT is but some of the people that drive for us I wonder how they remember to breath. Hazmat drivers don't inspect safety valves and such. They make sure they have a declaration of hazardous goods, a properly placarded truck, and the MSDS in the cab. The person who signs the Declaration of Hazardous Goods is required to inspect the cargo and prepare the paperwork, but I was never trained on examining safety valves. We just make sure the cylinder is UN certified and properly labeled by Haz Class, the cylinders are segregated and secured properly, and all the paperwork is complete and accurate.
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# ? May 29, 2011 04:52 |
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my1999gsr posted:Passat or A4? Passat wagon, forget the year. That blown up muffler was on a Jetta. Third times the charm so the next Volkswagen product to come in is probably gonna be a real doozy.
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# ? May 29, 2011 05:52 |
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Beast Pussy posted:Passat wagon, forget the year. That blown up muffler was on a Jetta. Third times the charm so the next Volkswagen product to come in is probably gonna be a real doozy. Hope you used G12 in that when you replaced the water pump, or it will coagulate and block some passages. It is not dexcool and the universal poo poo doesn't work. Trying to avoid another photo. VWs suck and are picky as hell.
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# ? May 29, 2011 07:46 |
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Farside posted:I work in a lab at a gas manufacturing plant. The drivers that deliver our dewars and high pressure cylinders have no clue. I have no idea what is involved with passing hazmat for DOT is but some of the people that drive for us I wonder how they remember to breath. He was venting the dewar because there was too much pressure in it; we get low pressure tanks that hook up to another dewar that stores cell lines. It's pretty funny if you hook up a tank with too much pressure, a dense liquid nitrogen fog streams out of every crack and opening. Riding with the dewar in an elevator is an extremely bad idea because it is a confined space: a few second of gas venting is PLENTY to make the atmosphere oxygen deficient, and the problem with oxygen deficiency is that you don't feel anything, you just pass out (into the pool of nitrogen on the floor) and then you die.
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# ? May 29, 2011 12:03 |
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Farside posted:have no idea what is involved with passing hazmat for DOT is but some of the people that drive for us I wonder how they remember to breath. It's a 35 question multiple choice test. If you can remember that you need to keep a bill of lading and MSDS with the truck at all times, that you need to put placards on all sides of the truck based on what's on the manifest, not put dangerous mixed loads right next to each other, and that you need to stop at RR crossings you're good to go. FYI, this is all you need for driving most radioactive material as well. As a long time hazmat technician for emergency response, I was horrified that this was all the driver's were expected to know to get the endorsement.
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# ? May 29, 2011 18:26 |
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Motronic posted:It's a 35 question multiple choice test. If you can remember that you need to keep a bill of lading and MSDS with the truck at all times, that you need to put placards on all sides of the truck based on what's on the manifest, not put dangerous mixed loads right next to each other, and that you need to stop at RR crossings you're good to go. Not like we are to be handling it. You want really mindless WTF, it's completely legal to haul nothing but batteries in a trailer without placards. 45,000 pounds of batteries is fine without markings, 1000 pounds of batteries with anything else, it's a hazmat load.
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# ? May 29, 2011 19:27 |
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Wet-cell car batteries are nothing but some ABS plastic, two lead types, some plastic matting, and sulfuric acid, which none are hard to mitigate. Spill/leak/burn is just acid and maybe some sweeping to do. Now that acid can combine with plenty of other things and do some awful poo poo, hence the mixed load consideration. It is an oversight regarding lithium-based and Nickel-based batteries, because those burning is an especially bad thing. They don't really leak.
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# ? May 29, 2011 19:45 |
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Motronic posted:As a long time hazmat technician for emergency response, I was horrified that this was all the driver's were expected to know to get the endorsement. You can probably thank shipping/trucking trade groups and their lobbyists for this.
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# ? May 29, 2011 19:58 |
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heat posted:He was venting the dewar because there was too much pressure in it; we get low pressure tanks that hook up to another dewar that stores cell lines. It's pretty funny if you hook up a tank with too much pressure, a dense liquid nitrogen fog streams out of every crack and opening. This all probably stems from various company policies through out the industry (the following are for my company), but the company you are getting your dewars from are morons (watch me put my foot in my mouth now. You don't work in the northeast do you?) 1. The driver should not be venting a dewar. His job is to deliver, thats it. If you were having a problem with the vessel, our cryogenics guys would come out and deal with it. 2. why the hell are they shipping you dewars w/o the properly rated safety to prevent the over pressure problem? Now it might be because I work around these drat things day in and day out but a dewar with a properly working safety venting off isn't going to fill an elevator car with enough gas to make an elevator car oxygen deficient. 5psi (max) vent at 1-2 seconds (max) from a 1/2" safety isn't going to kill you. Especially since most elevator cars aren't exactly air tight or with out their own ventilation systems. I will concede that there are different types of dewars and different types of safeties that you may be using that have different design characteristics than what I am used to. I work for a relatively small company compared to the big boys like airgas, linde, praxair etc. So my exposure to the vast array of vessels is comparatively smaller and as such everything I am saying may be moot. And because this is a mechanical failure thread here is my nitrous oxide pump tearing through its seals. Not very spectacular since its a low pressure pump but that liquid burns like a mother fucker if you get it on your skin. Edit: seems as though that I don't have permissions to access my partition on the company server from outside the network. I'll upload the video to youtube and post it later when I go back to work. Farside fucked around with this message at 03:57 on May 31, 2011 |
# ? May 31, 2011 03:52 |
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It's funny what people consider "low pressure." 4psi will rip most houses clear off their foundations.
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# ? May 31, 2011 15:05 |
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Nerobro posted:It's funny what people consider "low pressure." Well, that is low pressure. For 4 PSI to be able to do this, it needs a mechanical advantage. This is how lifting (air) bags work. Its not like a 4 PSI blast out of a 1/4 nozzle is some sort of death ray.
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# ? May 31, 2011 15:30 |
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# ? Mar 28, 2024 21:52 |
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I was using an extreme example. But pumping liquid N20 is going to be a 5-800psi pump. :-) I mean, that's low pressure if you're messing with 6000psi tanks of n2 all day long, but it's still amusing to hear it called low pressure.
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# ? May 31, 2011 15:39 |