Interesting Optical Effect with PVC drain pipe
RFI-EMI-GUY
In my house attic, I have several 4 inch white PVC vent stacks which are
simply white PVC drain pipe extending from the wall headers through the
attic and the roof. On the roof, these are covered with lead flashing to
prevent water from getting inside the house. I have been doing a lot of
work in the attic, and have noticed that these pipes "glow" quite
noticeably as a result of the sunlight outside. As this often happens
when the sun is at the horizon and thus at an angle below which direct
coupling into the pipe would be possible, I am very curious as to the
reason that the visible infrared portion is so much more visible than
white light spectrum. Has anyone else noticed this? What is going on?
--
Joe Leikhim K4SAT
"The RFI-EMI-GUY"�
"Use only Genuine Interocitor Parts" Tom Servo ;-P
John Larkin
<Rhyo...@NETTALLY.COM> wrote:
>
>In my house attic, I have several 4 inch white PVC vent stacks which are
>simply white PVC drain pipe extending from the wall headers through the
>attic and the roof. On the roof, these are covered with lead flashing to
>prevent water from getting inside the house. I have been doing a lot of
>work in the attic, and have noticed that these pipes "glow" quite
>noticeably as a result of the sunlight outside. As this often happens
>when the sun is at the horizon and thus at an angle below which direct
>coupling into the pipe would be possible, I am very curious as to the
>reason that the visible infrared portion is so much more visible than
>white light spectrum. Has anyone else noticed this? What is going on?
Visible infrared?
Jonh
RFI-EMI-GUY
:Visible infrared?
Maybe I meant "near infrared". Indeed it is red and very warm light.
Jonh
Eeyore
RFI-EMI-GUY wrote:
> (snip)
> :Visible infrared?
>
> Maybe I meant "near infrared". Indeed it is red and very warm light.
Presumably the optical pass-band of the PVC.
Graham
RFI-EMI-GUY
What I am seeing seems to contradict the PVC spectral absorption curve.
See link:
http://www.infraredheaters.com/page12.htm
castleb...@att.net
"RFI-EMI-GUY" <Rhyo...@NETTALLY.COM> wrote in message
news:49fd38eb$0$21120$9a6e...@unlimited.newshosting.com...
Where can I get a replacement bead condenser.
Bob
RFI-EMI-GUY
Joerg
>
> In my house attic, I have several 4 inch white PVC vent stacks which are
> simply white PVC drain pipe extending from the wall headers through the
> attic and the roof. On the roof, these are covered with lead flashing to
> prevent water from getting inside the house. I have been doing a lot of
> work in the attic, and have noticed that these pipes "glow" quite
> noticeably as a result of the sunlight outside. As this often happens
> when the sun is at the horizon and thus at an angle below which direct
> coupling into the pipe would be possible, I am very curious as to the
> reason that the visible infrared portion is so much more visible than
> white light spectrum. Has anyone else noticed this? What is going on?
>
White PVC sticking out the roof? 4"? Wow. White PVC usually becomes
rotten from UV pretty quickly. If it isn't painted it begins to turn
brown within 2-3 years in our area. After some more years you can
sometimes crumble it by hand.
--
Regards, Joerg
http://www.analogconsultants.com/
"gmail" domain blocked because of excessive spam.
Use another domain or send PM.
Jim Thompson
>RFI-EMI-GUY wrote:
>>
>> In my house attic, I have several 4 inch white PVC vent stacks which are
>> simply white PVC drain pipe extending from the wall headers through the
>> attic and the roof. On the roof, these are covered with lead flashing to
>> prevent water from getting inside the house. I have been doing a lot of
>> work in the attic, and have noticed that these pipes "glow" quite
>> noticeably as a result of the sunlight outside. As this often happens
>> when the sun is at the horizon and thus at an angle below which direct
>> coupling into the pipe would be possible, I am very curious as to the
>> reason that the visible infrared portion is so much more visible than
>> white light spectrum. Has anyone else noticed this? What is going on?
>>
>
>White PVC sticking out the roof? 4"? Wow. White PVC usually becomes
>rotten from UV pretty quickly. If it isn't painted it begins to turn
>brown within 2-3 years in our area. After some more years you can
>sometimes crumble it by hand.
Same here. Generally all above-ground stuff around here is done in
ABS (or metallic pipe).
...Jim Thompson
--
| James E.Thompson, P.E. | mens |
| Analog Innovations, Inc. | et |
| Analog/Mixed-Signal ASIC's and Discrete Systems | manus |
| Phoenix, Arizona 85048 Skype: Contacts Only | |
| Voice:(480)460-2350 Fax: Available upon request | Brass Rat |
| E-mail Icon at http://www.analog-innovations.com | 1962 |
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Joerg
> On Sun, 03 May 2009 10:51:21 -0700, Joerg
> <notthis...@removethispacbell.net> wrote:
>
>> RFI-EMI-GUY wrote:
>>> In my house attic, I have several 4 inch white PVC vent stacks which are
>>> simply white PVC drain pipe extending from the wall headers through the
>>> attic and the roof. On the roof, these are covered with lead flashing to
>>> prevent water from getting inside the house. I have been doing a lot of
>>> work in the attic, and have noticed that these pipes "glow" quite
>>> noticeably as a result of the sunlight outside. As this often happens
>>> when the sun is at the horizon and thus at an angle below which direct
>>> coupling into the pipe would be possible, I am very curious as to the
>>> reason that the visible infrared portion is so much more visible than
>>> white light spectrum. Has anyone else noticed this? What is going on?
>>>
>> White PVC sticking out the roof? 4"? Wow. White PVC usually becomes
>> rotten from UV pretty quickly. If it isn't painted it begins to turn
>> brown within 2-3 years in our area. After some more years you can
>> sometimes crumble it by hand.
>
> Same here. Generally all above-ground stuff around here is done in
> ABS (or metallic pipe).
>
That's how our vents are done (and not 4"). Probably a code requirement,
or at least it should be, just like the code prescribes protruding
lengths so the vents aren't plugged by a snow pack.
RFI-EMI-GUY
> RFI-EMI-GUY wrote:
>>
>> In my house attic, I have several 4 inch white PVC vent stacks which
>> are simply white PVC drain pipe extending from the wall headers
>> through the attic and the roof. On the roof, these are covered with
>> lead flashing to prevent water from getting inside the house. I have
>> been doing a lot of work in the attic, and have noticed that these
>> pipes "glow" quite noticeably as a result of the sunlight outside. As
>> this often happens when the sun is at the horizon and thus at an angle
>> below which direct coupling into the pipe would be possible, I am very
>> curious as to the reason that the visible infrared portion is so much
>> more visible than white light spectrum. Has anyone else noticed this?
>> What is going on?
>>
>
> White PVC sticking out the roof? 4"? Wow. White PVC usually becomes
> rotten from UV pretty quickly. If it isn't painted it begins to turn
> brown within 2-3 years in our area. After some more years you can
> sometimes crumble it by hand.
>
Read the above again, the part sticking through the roof is covered in
lead flashing as is standard practice.
RFI-EMI-GUY
AS usual the topic veers far away from the question asked :{
Joerg
Up to the top in lead? Wow, haven't seen that yet. I wouldn't do that
either though because it'll get hot.
But yes, PVC can "glow" if it isn't very thick.
Don Klipstein
RFI-EMI-GUY wrote:
>Eeyore wrote:
>>
>> RFI-EMI-GUY wrote:
>>
>>> (snip)
>>> :Visible infrared?
>>>
>>> Maybe I meant "near infrared". Indeed it is red and very warm light.
>>
>> Presumably the optical pass-band of the PVC.
>
>What I am seeing seems to contradict the PVC spectral absorption curve.
>See link:
>
>http://www.infraredheaters.com/page12.htm
The PVC curve shown is only shown for wavelengths longer than 2
micrometers.
What you are seeing is certainly much shorter wavelength, likely not far
from 700 nm (one common definition of boundary between visible and IR).
My experience is that if white light from sunlight or tungsten is turned
to a warm-looking red by a non-red object, what I see is wavelengths
from around 590-600 nm through the low, maybe mid 700's of nm.
- Don Klipstein (d...@misty.com)
Jasen Betts
> RFI-EMI-GUY wrote:
>>
>> In my house attic, I have several 4 inch white PVC vent stacks which are
>> simply white PVC drain pipe extending from the wall headers through the
>> attic and the roof. On the roof, these are covered with lead flashing to
>> prevent water from getting inside the house. I have been doing a lot of
>> work in the attic, and have noticed that these pipes "glow" quite
>> noticeably as a result of the sunlight outside. As this often happens
>> when the sun is at the horizon and thus at an angle below which direct
>> coupling into the pipe would be possible, I am very curious as to the
>> reason that the visible infrared portion is so much more visible than
>> white light spectrum. Has anyone else noticed this? What is going on?
>>
>
> White PVC sticking out the roof? 4"? Wow. White PVC usually becomes
> rotten from UV pretty quickly. If it isn't painted it begins to turn
> brown within 2-3 years in our area. After some more years you can
> sometimes crumble it by hand.
if it's loaded with TiO it'll last several decades exposed.
Martin Brown
If it is bright enough, and the sun is plenty bright some people can see
out almost to 780nm IR. Beyond that you need a CCD camera (they will
easily see the 820nm IR from a TV remote as bright).
Wavelengths out past 700nm are faint and do not necessarily look red so
much as grey but they are detectable by a dark adapted eye in some
individuals. You can sort of cheaply emulate the effect by making a pair
of googles with unexposed black slide film. After your eyes dark adapt
the scene comes back into a false colour view not unlike Kodak IR film.
A CD spectroscope will allow you to reference the wavelength against a
red LED.
NB it is dangerous to look at the sun with an IR long wave pass filter.
The visible light is mostly blocked so with the iris wide open looking
at the sun even for a short time can do real damage. There are no pain
receptors in the eye you don't feel anything until much later.
Regards,
Martin Brown
Joerg
Contractors typically use the cheapest stuff they can get. Made in China.
Charlie E.
You are probably just seeing internal reflection, as in a waveguide,
of those wavelengths down either the body or the interior of the
pipe...
Charlie
Charlie E.
<notthis...@removethispacbell.net> wrote:
>RFI-EMI-GUY wrote:
>>
>> In my house attic, I have several 4 inch white PVC vent stacks which are
>> simply white PVC drain pipe extending from the wall headers through the
>> attic and the roof. On the roof, these are covered with lead flashing to
>> prevent water from getting inside the house. I have been doing a lot of
>> work in the attic, and have noticed that these pipes "glow" quite
>> noticeably as a result of the sunlight outside. As this often happens
>> when the sun is at the horizon and thus at an angle below which direct
>> coupling into the pipe would be possible, I am very curious as to the
>> reason that the visible infrared portion is so much more visible than
>> white light spectrum. Has anyone else noticed this? What is going on?
>>
>
>White PVC sticking out the roof? 4"? Wow. White PVC usually becomes
>rotten from UV pretty quickly. If it isn't painted it begins to turn
>brown within 2-3 years in our area. After some more years you can
>sometimes crumble it by hand.
Around here, it takes considerably less time than that. The pipes I
ran to my pools solar heater were quite dark within a year, even the
ones by the pumphouse that are mostly in the shade!
Charlie
Rich the Cynic
>
> In my house attic, I have several 4 inch white PVC vent stacks which are
> simply white PVC drain pipe extending from the wall headers through the
> attic and the roof. On the roof, these are covered with lead flashing to
> prevent water from getting inside the house. I have been doing a lot of
> work in the attic, and have noticed that these pipes "glow" quite
> noticeably as a result of the sunlight outside. As this often happens
> when the sun is at the horizon and thus at an angle below which direct
> coupling into the pipe would be possible, I am very curious as to the
> reason that the visible infrared portion is so much more visible than
> white light spectrum. Has anyone else noticed this? What is going on?
Duh. They're light pipes.
I'd put something over the top of them to keep birds from putting their
nests there and plugging them.
Good Luck!
Rich
Rich Grise
> On Sun, 03 May 2009 10:51:21 -0700, Joerg
dramatically minimize the "glow", but how's black ABS's UV susceptibillity
vs. white PVC?
Thanks,
Rich
Rich Grise
Wouldn't that be TiO2?
Thanks,
Rich
Rich Grise
So, how is Chinese PVC different from "domestic" PVC (if there is any such
thing any more)? I'd have assumed that PVC is PVC.
Thanks,
Rich
Rich Grise
Is there anything over the top of the hole, like a shroud? If not, then
it's pretty obvious, like those SS skylights.
Thanks,
Rich
Rich Grise
>>>
>>>> RFI-EMI-GUY wrote:
...
>>>>> am very curious as to the reason that the visible infrared portion
>>>>> is so much more visible than white light spectrum. Has anyone else
>
That's because the question is so stupid.
What the hell is "visible infrared?"
Thanks,
Rich
Rich Grise
> Eeyore wrote:
>> RFI-EMI-GUY wrote:
>>> (snip)
>>> :Visible infrared?
>>>
>>> Maybe I meant "near infrared". Indeed it is red and very warm light.
>>
>> Presumably the optical pass-band of the PVC.
>
What time of day?
Thanks
Rich
Rich Grise
> (snip John Larkin's attribution)
> :Visible infrared?
>
> Maybe I meant "near infrared". Indeed it is red and very warm light.
>
If it's visible, then by definition it's not "infrared".
Hope This Helps!
Rich
Joerg
AFAIK there is stuff mixed in to provide UV stabilization and so on. We
have some 10ft lengths of very old PVC pipe, plus elbows and whatnot in
the garage from the previous owner of the house. Wherever I used some of
that it took forever to blacken or never blackend. Sometimes you end up
with two tees in a row, same location. After 2-3 years one is
brownish-black, the other almost as white as new. Guess which one is the
new tee?
Spehro Pefhany
wrote:
Nah, there's virgin and there's regrind, and recycled plastic crap (in
varying percentages of each). There's LOTs of different additives, to
improve extrudability, placticizer to make it flexible, heat
stabilizers, UV stabilizers, fire retardants, etc.. Some years ago
Taiwan makers were making window blinds from extruded PVC with a lot
of UV stabilizer (as you might expect)-- only problem was that it was
lead, and the blinds slowly disintegrated under sunlight, yielding
lead-bearing dust. There's also potential health problems with some
fire retardants, which have been banned already in Europe and maybe in
North America too by now. Some of the smelly flexible PVC (like
swimming pool liner smell) is as much as 30% plasticizer chemicals.
But most PVC pipe, IME, is made domestically because it's cheaper to
turn the silos full of powder into bulky hollow tubing close to the
point of use, and requires virtually no labor (automated take-off
equipment, automated saws and stacking, and then straight onto the
flatbed).
Joerg
The vent pipes sticking out the roof on our house are like that.
Deterioration over >35 years: None.
Jasen Betts
Yeah that's what I meant,
ingvald44
Jasen Betts
Over here it's a byproduct of converting titanomagentite sand to pig
iron, or was when I did chemistry in highschool. As has been show my
recollection of the details is less than perfect.
wikipedia: "rutile"
|Rutile derives its name from the Latin rutilus, red, in reference to
|the deep red color observed in some specimens when viewed by
|transmitted light.
This may explain RFI-EMI-GUYs words.
bye.
rex
Yes, I was wondering about this browning of pipe in the sun. I have
about an 8 foot length of 2" PVC in my back yard that I put out there
standing vertically to support the low end of a wire antenna. It has
been there for at least 15 years and is still white. I think it came
from some stuff I bought in the early 80's so I can only guess new PVC
must be crap compared to old PVC.
No idea about what's different in composition or chemistry.
Joerg
UV stabilizers, probably. The previous owner had also placed such
vertical posts but mostly to support sprinklers and stuff. He painted
them and that greatly helps. But as usual there are always bare spots.
No blackening in about 20 years of truly pelting sunshine. Then I saw a
utility repair where thy used PVC just a few years ago. Already looks
like chocolate ... I think this PCV stuff _was_ better 20 years ago.