A question about temperature

[derekmcd]

<p><BR/>Replying to:<BR/><DIV CLASS='Discussion_PostQuote'>My guess is Dr Rocket is correct, minor lung damage would occur almost imediately due to near vacuum inside the lungs. Keeping eyes closed would reduce eye damage.&nbsp;Holding one's breath might be helpful after the lungs were almost empty of air.&nbsp;I'll guess 5 minutes of hard vacuum would mean not even intensive care could prevent death&nbsp;within an hour. A pessure drop of 1/2 atmosphere in one second might produce death in about one&nbsp;more second. A sudden change is very damaging. &nbsp;Neil <br /> Posted by neilsox</DIV></p><p>I'm not sure how you could hold your breath after your lungs have had all the air sucked out of them.&nbsp; I proposed that they might collapse and thus protect the capillaries.&nbsp; As for the 5 minutes; In the link I provided earlier they mentioned tests on animal as being at about a 2 min max before they could no longer resuscitate them.&nbsp; I doubt humans would fair any better.&nbsp; With no one to help ya, you have less than 15 seconds to get yourself to safety before your ticket gets punched.&nbsp;</p> <div class="Discussion_UserSignature"> <div> </div><br /><div><span style="color:#0000ff" class="Apple-style-span">"If something's hard to do, then it's not worth doing." - Homer Simpson</span></div> </div>

 

[schmack]

<p>Hi guys,</p><p>&nbsp;I've seen one and two&nbsp;meter diameter&nbsp;<strong><u>steel</u></strong>&nbsp;pipes collapse on themselves from sudden pressure drops of 1atm (sometimes more). To the point where they look like a giant slippery slide or a tabogan flume. I imagine sudden exposure to vacuum to a human body would be fairly catastrophic. And fairly fast too. i can't see you lasting minutes.</p><p>&nbsp;</p> <div class="Discussion_UserSignature"> <p><font size="4" color="#ff0000"><font size="2">Assumption is the mother of all stuff ups</font> </font></p><p><font size="4" color="#ff0000">Gimme some Schmack Schmack!</font></p> </div>

 

[neuvik]

<p>Pressure under 1 atm is defined as a vacuum measured usualy in inches of mercury.&nbsp;&nbsp; That pipe must have been some really crappy steel.&nbsp;&nbsp; I'm assuming the inner diameter of the pipes is where you had the vacuum?&nbsp;&nbsp; The deformation is caused by the pressure of the atmosphere on the outside pipe; so if it was more than 1 atm on the inside and that was holding it all together, well, you need a new steel vendor.</p><p>&nbsp;</p> <div class="Discussion_UserSignature"> <p> </p><p><strong><font color="#ff0000">I don't think I'm alone when I say, "I hope more planets fall under the ruthless domination of Earth!"</font></strong></p><p><font color="#0000ff">SDC Boards: Power by PLuck - Ph**king Luck</font></p> </div>

 

[schmack]

Replying to:<BR/><DIV CLASS='Discussion_PostQuote'>Pressure under 1 atm is defined as a vacuum measured usualy in inches of mercury.&nbsp;&nbsp; That pipe must have been some really crappy steel.&nbsp;&nbsp; I'm assuming the inner diameter of the pipes is where you had the vacuum?&nbsp;&nbsp; The deformation is caused by the pressure of the atmosphere on the outside pipe; so if it was more than 1 atm on the inside and that was holding it all together, well, you need a new steel vendor.&nbsp; <br />Posted by neuvik</DIV><br /><br />It's to do with a phenomenon called "water hammer" and the collapse of the pipe is more because of the&nbsp;sudden drop in pressure, caused by the water moving and then stopping suddenly. I assure you, there was nothing wrong with the steel in the pipe. <div class="Discussion_UserSignature"> <p><font size="4" color="#ff0000"><font size="2">Assumption is the mother of all stuff ups</font> </font></p><p><font size="4" color="#ff0000">Gimme some Schmack Schmack!</font></p> </div>

 

[derekmcd]

<p><BR/>Replying to:<BR/><DIV CLASS='Discussion_PostQuote'>It's to do with a phenomenon called "water hammer" and the collapse of the pipe is more because of the&nbsp;sudden drop in pressure, caused by the water moving and then stopping suddenly. I assure you, there was nothing wrong with the steel in the pipe. <br /> Posted by schmack</DIV></p><p>I had water hammer issues my last house... damn was that annoying!</p><p>&nbsp;</p><p><font size="6">Bang!!!&nbsp;</font></p><p>&nbsp;</p><p>&nbsp;</p><p>&nbsp;</p><p>&nbsp;</p><p>&nbsp;</p><p><font size="6">Bang!!! </font> </p> <div class="Discussion_UserSignature"> <div> </div><br /><div><span style="color:#0000ff" class="Apple-style-span">"If something's hard to do, then it's not worth doing." - Homer Simpson</span></div> </div>

 

[neuvik]

<p><BR/>Replying to:<BR/><DIV CLASS='Discussion_PostQuote'>It's to do with a phenomenon called "water hammer" and the collapse of the pipe is more because of the&nbsp;sudden drop in pressure, caused by the water moving and then stopping suddenly. I assure you, there was nothing wrong with the steel in the pipe. <br /> Posted by schmack</DIV></p><p>&nbsp;</p><p>And it was a vacuum that caused it? &nbsp; I've heard of the transient forces rupturing a pipe.&nbsp; I could see if you just let the water hammer occur for a long time the vibrations would wear down the steel to the point of fatigue failure.&nbsp; Then it might look like it imploded. &nbsp; I'm sure in any analysis it would show the pipe first expanding as the waters kinetic energy is converted to potential energy, and as the pressure drops the much weakend pipe then collapses. </p> <div class="Discussion_UserSignature"> <p> </p><p><strong><font color="#ff0000">I don't think I'm alone when I say, "I hope more planets fall under the ruthless domination of Earth!"</font></strong></p><p><font color="#0000ff">SDC Boards: Power by PLuck - Ph**king Luck</font></p> </div>

 

[DrRocket]

<p><BR/>Replying to:<BR/><DIV CLASS='Discussion_PostQuote'>&nbsp;And it was a vacuum that caused it? &nbsp; I've heard of the transient forces rupturing a pipe.&nbsp; I could see if you just let the water hammer occur for a long time the vibrations would wear down the steel to the point of fatigue failure.&nbsp; Then it might look like it imploded. &nbsp; I'm sure in any analysis it would show the pipe first expanding as the waters kinetic energy is converted to potential energy, and as the pressure drops the much weakend pipe then collapses. <br />Posted by neuvik</DIV></p><p>Generally water hammer is the result of rapidly shutting off flow in a pipe.&nbsp; What happens is that the water in the pipe continues to move due to momentum and one gets some reflected compression waves moving&nbsp;back and forth with locally high pressures.&nbsp; It can be fairly severe.</p><p>I was involved in an investigation of a water hammer event a few years ago.&nbsp; It turned out that a pneumatic valve shut off a bit too quickly and started a water hammer.&nbsp; It ruptured the pipe, and destroyed a lot of equipment.</p><p>Oh yea, there was a bit of nitroglycerine in the pipe.&nbsp; And&nbsp;a few pounds more nearby.&nbsp;</p> <div class="Discussion_UserSignature"> </div>

 

[neuvik]

<p><BR/>Replying to:<BR/><DIV CLASS='Discussion_PostQuote'>Generally water hammer is the result of rapidly shutting off flow in a pipe.&nbsp; What happens is that the water in the pipe continues to move due to momentum and one gets some reflected compression waves moving&nbsp;back and forth with locally high pressures.&nbsp; It can be fairly severe.I was involved in an investigation of a water hammer event a few years ago.&nbsp; It turned out that a pneumatic valve shut off a bit too quickly and started a water hammer.&nbsp; It ruptured the pipe, and destroyed a lot of equipment.Oh yea, there was a bit of nitroglycerine in the pipe.&nbsp; And&nbsp;a few pounds more nearby.&nbsp; <br /> Posted by DrRocket</DIV></p><p>Wow...ahah. &nbsp; &nbsp;&nbsp; I'm know it from the maritime industry with either water and steam, but nitroglycerine?&nbsp; ahaha!</p><p>&nbsp;</p><p>&nbsp;Does/can the vacuum cause the deformation of the pipe?&nbsp; Or is it simply an illusion when the metal finial reaches fatigue failure(assuming that is the failure type responsible)? </p> <div class="Discussion_UserSignature"> <p> </p><p><strong><font color="#ff0000">I don't think I'm alone when I say, "I hope more planets fall under the ruthless domination of Earth!"</font></strong></p><p><font color="#0000ff">SDC Boards: Power by PLuck - Ph**king Luck</font></p> </div>

 

[DrRocket]

<p><BR/>Replying to:<BR/><DIV CLASS='Discussion_PostQuote'>Wow...ahah. &nbsp; &nbsp;&nbsp; I'm know it from the maritime industry with either water and steam, but nitroglycerine?&nbsp; ahaha!&nbsp;&nbsp;Does/can the vacuum cause the deformation of the pipe?&nbsp; Or is it simply an illusion when the metal finial reaches fatigue failure(assuming that is the failure type responsible)? <br />Posted by neuvik</DIV></p><p>I'm not quite sure what deformation you mean.&nbsp;&nbsp;Vacuum&nbsp;damage will be limited to the effect of the outside atmospheric pressure.&nbsp; That is likely to be rather low, unless the pipe has&nbsp;thin walls compared to the diameter.&nbsp; I think in most cases the damage is due to&nbsp;positive interior pressure created by the water hammer.&nbsp; In either case deformation will occur in accordance with applied stress, the&nbsp;resulting strain and the local strength of the material.&nbsp; I would anticipate the damage to be concentrated near joints or other discontinuities in the pipe, or more likely in corroded areas or&nbsp;delicate valve parts, again unless you are dealing with thin-walled pipe.</p><p>The example that I gave is a rather exceptional case.&nbsp; And most of the fluid involved was water.&nbsp; But a little NG goes a long way with water hammer.&nbsp; We did not have to worry about fatigue damage to the&nbsp;pipe, as the prompt effects were quite sufficient to cause us to have to replace the pipe in its entirety.&nbsp; Among other things.<br /></p> <div class="Discussion_UserSignature"> </div>

 

[neuvik]

<p><BR/>Replying to:<BR/><DIV CLASS='Discussion_PostQuote'>I'm not quite sure what deformation you mean.&nbsp;&nbsp;Vacuum&nbsp;damage will be limited to the effect of the outside atmospheric pressure.&nbsp; That is likely to be rather low, unless the pipe has&nbsp;thin walls compared to the diameter.&nbsp; I think in most cases the damage is due to&nbsp;positive interior pressure created by the water hammer.&nbsp; In either case deformation will occur in accordance with applied stress, the&nbsp;resulting strain and the local strength of the material.&nbsp; I would anticipate the damage to be concentrated near joints or other discontinuities in the pipe, or more likely in corroded areas or&nbsp;delicate valve parts, again unless you are dealing with thin-walled pipe.The example that I gave is a rather exceptional case.&nbsp; And most of the fluid involved was water.&nbsp; But a little NG goes a long way with water hammer.&nbsp; We did not have to worry about fatigue damage to the&nbsp;pipe, as the prompt effects were quite sufficient to cause us to have to replace the pipe in its entirety.&nbsp; Among other things. <br /> Posted by DrRocket</DIV></p><p>Thanks, you answered my question even with my poor communication of it.&nbsp;&nbsp;&nbsp;&nbsp;</p><p>&nbsp;</p><p>Figures you don't have to worry about the pipe carrying the NG failing to due fatigue. &nbsp; Simple transient force enough to make it go boom ehy? hehe. </p> <div class="Discussion_UserSignature"> <p> </p><p><strong><font color="#ff0000">I don't think I'm alone when I say, "I hope more planets fall under the ruthless domination of Earth!"</font></strong></p><p><font color="#0000ff">SDC Boards: Power by PLuck - Ph**king Luck</font></p> </div>

 

[_Simon_]

<p>Its nice to see that my question started some debate =)</p><p>I feel like a child compared to some of you guys and i generally concider myself a smart guy. Guess I&acute;m not afterall =)&nbsp;</p> <div class="Discussion_UserSignature"> </div>

 

[aphh]

<p><BR/>Replying to:<BR/><DIV CLASS='Discussion_PostQuote'>Its nice to see that my question started some debate =)I feel like a child compared to some of you guys and i generally concider myself a smart guy. Guess I&acute;m not afterall =)&nbsp; <br /> Posted by _Simon_</DIV></p><p>This was a very interesting topic. But I have to correct an error that I made on top of this page, pressure at 100 metres under water is 10 atm, not 100 atm.</p><p>Still considerable pressure and a frightening depth to work at. There is no quick escape from 100 metres deep.</p><p>Maybe that's why some astronaut(s) have said, that they feel more comfortable in space than deep under water.&nbsp;</p>