Wind chill and water pipes

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On Monday, January 6, 2014 3:32:18 PM UTC-5, Ed Pawlowski wrote:

It would help if you didn't edit out the pertinent part you're responding to and would at least answer the simple questions posed. I gave you two examples:
"The answer is both of them. At 0F, it's cold enough to freeze pipes. And depending on where the pipes are, they can be affected by the windchill. Again, just two examples:
A - Pipes are in a cabin with no heat. Do you think the cabin inside temp will be the same overnight as the temp drops without regard to what the windchill is? If the reported windchill was large, would you not agree that the pipes are going to be more likely to freeze?
B - Pipes in a drafty crawlspace. "
The temps that the crawlspace reaches on a cold night is affected by the windchill. So is the temperature that an unheated cabin will reach inside. With significant windchill they could reach temps overnight that they would not reach without windchill. It's that simple.

Why do you persist in only looking at the case where the outside temp is well above zero? Good grief. The question and context that started all this, again, was where the temp was ZERO and there was an additional 10 deg of winchill.

I thought maybe you'd have an answer, because you seem just as confused and unwilling to accept the fact that windchill does affect inanimate objects. Like him, you're stuck in a loop:
It has no effect, it doesn't matter, it can have nothing to do with pipes freezing. But then you say the only effect windchill has is to cool off inanimate objects faster.

No one said they can feel the number. Only that they can be affected by it too. Again, the drafty crawlspace, the unheated cabin.

It's not just a question of a bit faster. Again, on a night where the outside temp drops to 20F and the windchill is 0F, do you think the lowest temp of an unheated cabin is going to be the same as it is if the windchill was reported as 20F? That is a very realistic example where it makes a difference.
NOAA confused things with their

I don't see a problem with their definition. They did contradict themselves in answering the question. But even they say windchill affect pipess.
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On 1/7/2014 8:05 AM, snipped-for-privacy@optonline.net wrote:

No, they are affected by the wind, but not the windchill. Different things. You may not agree, but the definition of windchill factor was to tell a human how it is going to feel to the skin when outside. They can put a value on it. The wind may affect the rate of cooling in a draft, but it does not have the same numerical value and it can never go below the actual temperature.
You can make up any definition you want, but that does not change the real meaning.
Oh, you also ignore my example of a temperature of 35 degrees and a wndchill of 20 degrees. Will the pipes freeze? NO
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On Tuesday, January 7, 2014 11:22:34 AM UTC-5, Ed Pawlowski wrote:

The windchill is dirctly affected by the wind. You can't have one without the other. How hard is that to understand?
And the fact that you won't answer the very simple questions posed shows that you've lost the argument. I've answered ALL your questions, but you won't answer mine, which go to the core of the issue.
Here they are again:

Answer?
>

Anser?
Different

What it was created for and what it effects are two very different things. Ask NOAA, Weather Channel, University of IL, etc. They clearly say that the lower the windchill, the more likely pipes are to freeze.
They can

A value on an arbitrary scale. So what? Show us where the creators of the windchill said it doesn't have an effect on inanimate objects. NOAA among the others I listed as references say it does.
The wind may affect the rate of cooling in a draft,

I never said it could go below the actual temperature. Try responding in the context of the discussion. Did you even read it?
It was with a temp of 0F and a wind chill of -10F. Last time I checked those conditions are well below freezing on planet earth. What planet are you on?

I haven't made up anything or defined anything. Stop lying.

Wow! What a revelation! Maybe Stormin can weigh in on whether he thought his pipes could freeze when it was 35. He specifically said it was 0F with a windchill of -10F
Idiot.
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On Friday, January 3, 2014 6:21:03 PM UTC-5, Gordon Shumway wrote:

Which of course means that wind chill does have an effect on inanimate objects, in some cases. If you take an inanimate object like a brick that's at 70F and put it outside where it's exposed when the wind chill is 0F it's going to cool off faster than if you put it outside when the wind chill is 15F, even if the actual temperature in both cases is 20F. Once it's reached 20F, then it will have no further effect of any significance.
In the case of freezing pipes, I would say in many cases wind chill does matter, because any place that is drafty, or even an exterior wall, is going to be effected by the wind. The pipe in the wall could be colder on a night with a lower wind chill, even though the actual outside temp is the same.
It is impossible to get an inanimate object colder than ambient

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On Fri, 3 Jan 2014 16:02:50 -0800 (PST), " snipped-for-privacy@optonline.net"

No, no, no.

Yes, but the ambient temp in your example, is 20F. Wind chill does not have time in its' calculation.

You would be wrong. If it is going to freeze it may do it sooner but the pipe will not get colder than the ambient. Period.

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On 1/3/2014 7:55 PM, Gordon Shumway wrote:

SM: Yes, yes, yes.

SM: Might want to go back and research what wind chill is. It has to do with the heat loss as a function of time.

SM: So, the pipe is going to freeze sooner. That matters, as it will warm up tomorrow, and I don't want the pipes to freeze tonight.
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On Friday, January 3, 2014 7:55:21 PM UTC-5, Gordon Shumway wrote:

Of course it doesn't have time in it's calculation, which is irrelevant. A bucket of 75F water placed outside when it's 20F with a wind chill of 0F will freeze faster than it will when the wind chill is 17F. Therefore windchill does matter with inanimate objects, in some cases.

That's like saying the pipes will freeze if they will freeze. Sure, if you want to define ambient to be the temperature at the pipes. But who measures that? The point is if one hears that it's going to be 20F tonight, is there valid reason to be more concerned about pipes in an outside wall, a drafty crawlspace, etc freezing if the reported windchill is 0F versus 17F? The answer to that is yes.

Which shows that by ambient, you're using the outside air temp, which is what most people would be looking at when trying to decide it their pipes are going to freeze, because they have no way of knowing what the ambient temp at the actual pipe inside the wall is. Now, you're trying to change ambient into the temp at the pipes hidden in the walls, which no one would even know. It's simple. Whatever the reported outside temp is, the lower the windchill, the greater the possibility that pipes in an exterior wall, drafty crawlspace, etc will freeze.
Here's another question. If inanimate objects are not affected by windchill, then on a night when the outside temp is 20F, the same house is going to use the same amount of energy to keep it at 70F when the windchill is 0F as it does if the windchill is 17F?
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On 1/4/2014 9:12 AM, snipped-for-privacy@optonline.net wrote:

Let's change the parameters. Outside temperature is 35 degrees, but because of the wind, the weatherman says the wind chill factor is 29 degrees. Will the pipe freeze? No.
In your example you use an example of 17 and 0. The only difference that may have a minor effect is if the wind is actually moving the air away from the pipes. Many factors come into play on how the wind moves around the pipes inside the crawlspace. It does not determine if the pipes will freeze, on;y how fast. Rate of heat transfer is the only difference, the temperature never goes below ambient.

The big difference is how well sealed the house is. Radiational cooling difference will be minimal, but convection can be considerable.
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No, but it will cool faster. Wind chill is still relevant to inanimate objects, even above freezing.

...or the wall (and the pipes indirectly)

Right but that's not the issue at hand.

Well, wind chill has no bearing on radiation cooling.
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On Sat, 04 Jan 2014 23:01:32 -0500, snipped-for-privacy@attt.bizz wrote:

You would have been 100% correct if you had left off the word "chill."

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On 1/4/2014 8:37 PM, Gordon Shumway wrote:

YEP!!! Wind CHILL is an empirical determination of what happens to humans in cold wind. It's the same principle, but the NUMBER is relatively useless for freezing pipes in unspecified configurations. It is likely that lower wind chill number will be harder on pipes, for the same wind direction relative to the structure. How much depends.

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On 1/4/2014 11:50 PM, mike wrote:

Wind chill describes rate of heat loss of objects. Doesn't matter if they are living or dead. Ask the pilots in alaska, if wind chill is important when they land a plane in cold weather. Wind chill has a big effect on how long they can be there, before the oil is too cold to allow the plane to restart.
In the case of water pipes, it has a big effect on how fast they freeze. Which is the question of this thread.
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'Stormin Mormon[_10_ Wrote:

You have it exactly.
Wind chill affects the RATE of heat loss, not the temperature an object will cool down to.
If you put an inanimate object, like a cinder block, outdoors then it will cool down to the ambient temperature. The stronger the wind, the higher the wind chill, and the faster that cinder block will cool down to the ambient temperature, which is the temperature without considering wind chill.
People experience heat loss from their skin as the sensation "cold". The more rapidly heat is lost from the skin, the colder it feels to us. So, an outdoor temperature of -20 deg. F. can "feel like" an outdoor temperature of -30 deg. F. if there is a wind. The wind accelerates heat loss from the skin, thereby making it "feel" colder to us.
However, long story short, an inanimate object will never cool down to a temperature below the ambient temperature because of the wind. Lack of any wind will just mean that it will take longer for that inanimate object to cool down to ambient temperatures.
And, wind chill works in the opposite direction as well. If you defrost your fridge and put the ice outside on a warm summer day to melt, the stronger the wind, the faster that ice will melt. The less wind there is, the longer it will take that ice to melt.
--
nestork

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<...snipped...>

I would disagree with that somewhat. I believe that an inanimate object, say a cinder block for instance, if soaked in water and exposed to wind in low humidity, will reach a temperature somewhat below ambient until all the water evaporates.
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On 1/4/2014 11:29 PM, Larry W wrote:

Pipes don't have humidity, unless they're very leaky.
And that's the whole point of this pissing contest. Wind chill is a made up number based on empirical experiments on humans using measurements at the airport, looked up in a table, and posted on your TV screen.
The other way to get it is to calculate it directly from your own measurements inside your walls and that table lookup. But if you have those measurements, use 'em. Don't make up another number you don't need.
You can certainly imagine cases where wind blows directly on the pipes. If you live in a cold climate that's a no-no.
Right now it's 31F outside. My crawl space is at 54F. And it will be close to 55F next week and in June. And that's not by accident. The ground temp is very stable, and I don't let the wind blow under there.
Changing the subject... There's an experiment you can do. Turn off the water and wait several hours for it to stabilize. The water at different points in the system may be at different temperatures.
Take a small container, like the lid of a spray can and stick a thermometer in it. Turn on the water into the container. You can see the temperature change as water from different parts of the pipe reaches the spigot. There's a tradeoff. You want it to flow fast, so the temperature changes little along the way, but not so fast that the thermometer can't keep up. The further the distance, the less the accuracy.
I did the experiment a few weeks ago when we had record low temps around 15F. Water never got below 50F. And that happened just where it should have where the pipe goes thru an area closest to an outside wall.
When you want an answer, make a direct measurement on the thing you're measuring. Conditions at the airport aren't very direct when you have rivers and hills in between.
'Nother change of subject. My neighbor had his water meter changed. I got there late, so didn't see the start, but they put a collar around the pipe, pumped something cold into it to freeze the water so they could remove the meter. Way cool...
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On 1/5/2014 3:16 AM, mike wrote:

I've heard of electric operated "pipe freezer" for this. May also have been some eco friendly low boiling point suff like freon, or carbon dioxide.
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On 1/5/2014 2:29 AM, Larry W wrote:

different situation entirely. You are in swamp cooler territory.
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'Larry W[_3_ Wrote:

Yes, and I would agree, but the drop below ambient temperature cannot be attributed to wind chill, but to evaporative cooling.
When water evaporates, it absorbs heat. In this case, it would be absorbing heat from the cinder block, and that's what would cause the temperature of the block to dip below ambient.
Evaporative cooling is how a dog's tongue works to cool the blood of the dog, and therefore cool the dog down on a hot day.
--
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On 1/5/2014 1:43 AM, nestork wrote:

Will never cool below ambient, right? Or, a wet beach towel, hung from a line, or a media pad in a swamp cooler, or a wet forehead, under a brim of a hat.
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On 01/05/2014 07:28 AM, Stormin Mormon wrote:

Wow Stormy, you're knockin them outta the park this morning. ;-)
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