MORE Conversations From the Professional Front Lines

[Raw Shark]

This has happened more than once?

First elbow that I know of, but this girl does a lot of sports and breaks herself all the time. It's like a skinned knee to her. She didn't even go to the doctor, which we had some words over. She had the next day off regardless, and then she went right back to work. I just help out because I don't want her making it worse by trying to lift the mop bucket or throw a punch or something.

[Purple]

What kind of superhuman can shrug off a broken bone? Like, I've made extra sure in my life to ensure I don't break as much as a nail. This woman must be something special.

[Raw Shark]

What kind of superhuman can shrug off a broken bone? Like, I've made extra sure in my life to ensure I don't break as much as a nail. This woman must be something special.

She is.

[Broomstick]

What kind of superhuman can shrug off a broken bone? Like, I've made extra sure in my life to ensure I don't break as much as a nail. This woman must be something special.

When I had my ribs busted I didn't go to the doctor for about two weeks. "Doc, my side hurts when I breathe", "Well, yeah, you've got at least one broken rib", "How can you tell without an x-ray?", "Well, there's that lump there where the bone is deformed..."

That rib still has a bend/kink in it 40 years later.

Maybe I should point out that one of reasons I didn't notice the broken bone is that rest of my body had been so badly beaten that pain had to fade somewhat before I started noticing localized points of pain, and having a concussion can also throw you off. There's about 3 days of my life I don't really remember.

Really, worst beating of my life, hope not to match or exceed it ever. So far so good.

It really is funny what you can ignore sometimes.

[SCRawl]

Apparently if you take 500 feet of schedule 40 pipe, put a 5hp motor and pump on the end of it, and drop it down a hole, you end up with a bunch of shredded pipe, a destroyed pump and a possibly fucked up well... Who knew?

Oh yeah, the guy selling the pipe. Maybe if you told him what you were going to do with the pipe you wouldn't have these problems. We have this amazing stuff now called steel, which is capable of handling the stresses of that application.

So this wasn't steel pipe, I take it. What was it, PVC? Sch40 just describes the thickness of the wall for a given OD, as you well know.

I'm thinking that if this was meant for drinking water, you'd need to use stainless steel pipe, which is really expensive, plus other stuff I probably haven't considered. On the other hand, asking PVC to handle that job was just a fool's errand, so you might as well bite the bullet once instead of having to pay for stainless pipe *and* the initial fuckup.

[Khaat]

Apparently if you take 500 feet of schedule 40 pipe, put a 5hp motor and pump on the end of it, and drop it down a hole, you end up with a bunch of shredded pipe, a destroyed pump and a possibly fucked up well... Who knew?

Oh yeah, the guy selling the pipe. Maybe if you told him what you were going to do with the pipe you wouldn't have these problems. We have this amazing stuff now called steel, which is capable of handling the stresses of that application.

Clearly the guy forgot the duct tape. It fixes everything, y'know! [/sarcasm]

[Simon_Jester]

It does seem like that would be the equivalent of daisy-chaining a couple of dozen drinking straws together and trying to draw water through them. If you're pulling hard enough to move a column of water five hundred feet long, you're presumably pulling hard enough to collapse the tube on itself.

[Elheru Aran]

Apparently if you take 500 feet of schedule 40 pipe, put a 5hp motor and pump on the end of it, and drop it down a hole, you end up with a bunch of shredded pipe, a destroyed pump and a possibly fucked up well... Who knew?

Oh yeah, the guy selling the pipe. Maybe if you told him what you were going to do with the pipe you wouldn't have these problems. We have this amazing stuff now called steel, which is capable of handling the stresses of that application.

So this wasn't steel pipe, I take it. What was it, PVC? Sch40 just describes the thickness of the wall for a given OD, as you well know.

I'm thinking that if this was meant for drinking water, you'd need to use stainless steel pipe, which is really expensive, plus other stuff I probably haven't considered. On the other hand, asking PVC to handle that job was just a fool's errand, so you might as well bite the bullet once instead of having to pay for stainless pipe *and* the initial fuckup.

Stainless steel? Maybe in Canada. As far as I know plastic is perfectly acceptable for the job here in the States. Of course, for a 500-ft hole, that's another story. It would depend on local codes, but black iron pipe would probably be considered fine for the job.

My parents have a well-- admittedly I'm pretty sure it's not 500 ft deep, they're less than a hundred miles from the coast so going that deep would probably be below sea level-- and it uses PVC. It also has an aboveground pump rather than submerged, which may make a difference.

[SCRawl]

Stainless steel? Maybe in Canada. As far as I know plastic is perfectly acceptable for the job here in the States. Of course, for a 500-ft hole, that's another story. It would depend on local codes, but black iron pipe would probably be considered fine for the job.

My parents have a well-- admittedly I'm pretty sure it's not 500 ft deep, they're less than a hundred miles from the coast so going that deep would probably be below sea level-- and it uses PVC. It also has an aboveground pump rather than submerged, which may make a difference.

That's the problem, isn't it? As Simon_Jester pointed out, how do you pull a 500' long column of water up a plastic pipe without it just collapsing under the vacuum pressure at the top? If we assume 1.5" sch40 pipe, that's 1.9" OD and .145" wall. That's a little over 1/8" of PVC to hold against that amount of pressure.

Perhaps if the pipe was fully primed before you started, i.e. no air gaps, it might survive, but as soon as you turn it off there will be an air gap at the top again. But we're getting into areas where I have no practical expertise, so it's entirely possible that I'm full of shit.

[Zeropoint]

You guys are half right. It's impossible to pull a column of water more than about 33.8 feet, even with a pure vacuum (well, the water would boil off the top of the column and you'd never get it lower than the vapor pressure for water at that temperature) because that's all that atmospheric pressure would support. To get more than that, the pump has to be at the bottom, pushing the water.

If we assume that the top of the 500 foot pipe was open to atmosphere, then we're looking at 500 ft / 33.8 ft per atm. = 14.8 atmospheres of pressure, or 14.8 atm * 14.7 psi/at. = 217 psi, which isn't THAT much. According to one manufacturer's specification page, 4-inch schedule 40 PVC is rated for 220 psi, and the ratings go up as the diameter goes down. That value is for 73 F, though, and the pipe needs to be de-rated if used at higher temperatures.

I obviously don't have all the information, and I don't know much about the proper construction of wells, but based on nothing but the numbers given, the customer doesn't sound like a complete idiot to me. Still, he should have done some checking on standards, codes, and best practices.

[phred]

So this wasn't steel pipe, I take it. What was it, PVC? Sch40 just describes the thickness of the wall for a given OD, as you well know.

I'm thinking that if this was meant for drinking water, you'd need to use stainless steel pipe, which is really expensive, plus other stuff I probably haven't considered. On the other hand, asking PVC to handle that job was just a fool's errand, so you might as well bite the bullet once instead of having to pay for stainless pipe *and* the initial fuckup.

Sorry I'm used to talking to people that know more about this sort of thing, yes it was PVC. The way most of the wells here are done is you put the pump and motor at the bottom of the pipe and drop it all down a 4 to 12 in wide hole in the ground. Most of the time we install them using either schedule 80 PVC for shallower wells, or galvanized steel if your going down more than 200'(60m) or so.

[Elheru Aran]

So this wasn't steel pipe, I take it. What was it, PVC? Sch40 just describes the thickness of the wall for a given OD, as you well know.

I'm thinking that if this was meant for drinking water, you'd need to use stainless steel pipe, which is really expensive, plus other stuff I probably haven't considered. On the other hand, asking PVC to handle that job was just a fool's errand, so you might as well bite the bullet once instead of having to pay for stainless pipe *and* the initial fuckup.

Sorry I'm used to talking to people that know more about this sort of thing, yes it was PVC. The way most of the wells here are done is you put the pump and motor at the bottom of the pipe and drop it all down a 4 to 12 in wide hole in the ground. Most of the time we install them using either schedule 80 PVC for shallower wells, or galvanized steel if your going down more than 200'(60m) or so.

The zinc from the galvanized pipe isn't an issue?

[Simon_Jester]

You guys are half right. It's impossible to pull a column of water more than about 33.8 feet, even with a pure vacuum (well, the water would boil off the top of the column and you'd never get it lower than the vapor pressure for water at that temperature) because that's all that atmospheric pressure would support. To get more than that, the pump has to be at the bottom, pushing the water.

If we assume that the top of the 500 foot pipe was open to atmosphere, then we're looking at 500 ft / 33.8 ft per atm. = 14.8 atmospheres of pressure, or 14.8 atm * 14.7 psi/at. = 217 psi, which isn't THAT much. According to one manufacturer's specification page, 4-inch schedule 40 PVC is rated for 220 psi, and the ratings go up as the diameter goes down. That value is for 73 F, though, and the pipe needs to be de-rated if used at higher temperatures.

I obviously don't have all the information, and I don't know much about the proper construction of wells, but based on nothing but the numbers given, the customer doesn't sound like a complete idiot to me. Still, he should have done some checking on standards, codes, and best practices.

The problem, I suspect, is that the water is sttarting out under considerable pressure with great force (five horsepower) being exerted on it in addition to that pressure.

So the pressure may be enough to burst the piping from the inside out (it probably doesn't resist pressure inside-out as well as outside-in). Alternatively, the forces being exerted might well strike any irregularity in the pipe or its interior with more force than this weak spot can withstand, again causing breakage.

*The nice thing about a word like "five horsepower" is that you can just imagine five big strong horses pulling or pushing on the object. This isn't an entirely accurate image, but it can give a concept of the amount of force involved and the amount of damage that can be inflicted if those forces are unleashed carelessly. And five big strong horses might very well be able to smash up a length of PVC pipe in all sorts of ways.

[Zeropoint]

Simon_Jester, your post was pretty much wrong from beginning to end. You've conflated the concepts of force, pressure, and power. You've failed to realize that pipe systems usually have a higher pressure on the INSIDE and that's what the ratings reflect. You've failed to grasp the relationship between pressure, column height, and gravity in a quasi-static fluid system.

[Elheru Aran]

I *did* think there was something wrong with the idea that it couldn't resist pressure from the inside out... otherwise you'd get hella more leaks.

About the only pipe system that doesn't have to deal with pressure from the inside is electrical conduit, and there's no liquids running through those. Conduit does appear to be thicker than your ordinary white PVC pipe, but I think that has to do with being a different type of plastic (could be wrong though).

[phred]

Its not just the pressure, there's also the torque from the motor and pump spinning every time it kicks on. I'm not entirely certain how the guy managed to install it.

I'm probably missing some parts of the story since it was a conversation that my boss was yelling over the phone.

[Simon_Jester]

Noted.

My physics is growing rusty, I fear, and fluid dynamics was literally never my strong suit.

Would someone actually mind explaining in detail what they believe is going on based on more detailed information? Just saying "you're wrong" is rather grating even if it is in fact correct. I would appreciate it if the people telling me I am wrong could use their superior knowledge to expand on this, that I may avoid future wrongness.

[phred]

The zinc from the galvanized pipe isn't an issue?

Not that I'm aware of. Usually if the well is feeding a residence there's a water softener and some filtration system between the well/storage tanks, and the house. Also a good portion of our business is agricultural, which usually comes with it own set of processes before the water gets out into the vineyards.

[Raw Shark]

YOUR DRIVER: We're going to have to detour. Dispatch is telling me I-25 is on fire.

IRISH BARTENDER: Fucking grand.

YOUR DRIVER: I'm not going to charge you for it.

IRISH BARTENDER: I appreciate that. I've been at work since ten this morning, and a girl in one of those hats threw up on the bar at eleven-thirty. I just want to get home and pour myself four fingers of whisky.

YOUR DRIVER: Yep. It's Derby Day, alright.

[Broomstick]

There I am, purchasing Passover matzo on clearance.

OTHER PERSON: I didn't know you were Jewish!

ME: I'm not.

OP: But... don't you have to be Jewish to buy those?

ME: Nope.

OP: Isn't there some sort or ritual or something?

ME: No - I mean, if you're eating a Passover meal, yeah, but outside of that no one gives a damn. The cracker police are not going to show up and ask for credentials. They're just really plain crackers. Jewish makers of these would be thrilled if they could expand their market to non-Jews.

[Raw Shark]

Well, there is some sort of ritual, but it's not like you need a Jew card to enjoy their cuisine, and (not to play into stereotypes here), I'm sure the manufacturers like money as much as any business people. I'm personally a big fan of blackberry Manischewitz, and cream cheese with lox on a bagel. Gefilte fish, not so much.

[Elheru Aran]

Matzo comes off as sort of a really big saltine cracker to me. Nice with some tomatoey-beefy veggie soup.

[Raw Shark]

Also, Purim is pretty fun. You basically spend the whole night doing shots, eating pastries, and toasting Mordecai while cursing Haman. Everybody gets shitfaced. It's great.

[Elheru Aran]

Heh, I'm reminded of something I said a while ago, people would all get along a bit better if they just ate more of each other's food...

[Broomstick]

Matzo comes off as sort of a really big saltine cracker to me. Nice with some tomatoey-beefy veggie soup.

Well...yeah, it really is a really plain saltine cracker. The ingredients are wheat, water, and salt (actually, I think the Passover ones are unsalted). Eating them with soup is a long-standing practice in this household. Or laying some slices of cheese over them. Or...well, anything you can put on or do with a saltine.

Thing is, with them going onto clearance I got about 8 boxes of them and as long as you keep them dry they don't go bad. At least not in any sort of meaningful time frame.