[Greenbuilding] infrared thermometer

[John Straube]

Most cheap IR units have emissivity fixed at 0.9 or 0.95. 
To measure glass or shiny metal temp during non sunny hours just put some painters tape on the area you wish to measure and then use the IR to measure its temperature (which will be the same as the glass within a minute or two of application). 

Sent wirelessly from my BlackBerry device on the Bell network.

-----Original Message-----
From: Corwyn <corwyn at midcoast.com>
Sender: greenbuilding-bounces at lists.bioenergylists.org
Date: Wed, 02 Mar 2011 07:44:16 
To: Green Building<greenbuilding at lists.bioenergylists.org>
Reply-To: Green Building <greenbuilding at lists.bioenergylists.org>
Subject: Re: [Greenbuilding] infrared thermometer

On 3/1/2011 11:42 PM, Reuben Deumling wrote:
> I like my Fluke 63. Got it (fairly) cheap on ebay. Supposedly on glass their
> accuracy drops off a bunch, but I still felt it was useful doing what you're
> proposing to do.


It isn't that their accuracy is reduced, but rather that you are outside 
their design compromises.  The only thing they can do is measure the 
radiant energy from a given direction.  In order to figure out the 
temperature of an object, they need to make an assumption about the 
emissivity of that object.  For most common household objects, 
emissivity is roughly the same; not so for glass and metals.  For those, 
you can take a reading, and calculate a conversion based on 
emissivities, and get as accurate a reading as on any other object.

Thank You Kindly,

Corwyn

-- 
Topher Belknap
Green Fret Consulting
Kermit didn't know the half of it...
http://www.greenfret.com/
topher at greenfret.com
(207) 882-7652

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