Message Board Thread - "Building Science - Stud Cavity R Value Determination"

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Building Science - Stud Cavity R Value Determination	MikeDuclos	3/13/2008
Hi, I use a BCAM-SD, and I'd like to know if it is possible to determine the effective R Value of the wall cavity between two studs. As an example, a house I am working on has a foam which may be old UFFI in the stud cavities. My home energy modeling software uses a stud cavity R Value as an input. Thanks !
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Re:Building Science - Stud Cavity R Value Determination	IRJay	3/13/2008
Dr. Bob Madding has built and is currently testing such a calculator. The tests and the tool will be presented at the 2008 Inframation conference in Reno.
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Re:Building Science - Stud Cavity R Value Determination	mlehman	3/13/2008
Doesnt your camera have an automatic way to shoot the outside and then the inside and it will calculate the R value.
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Re:Building Science - Stud Cavity R Value Determination	cflaws	4/2/2008
IRJay wrote: Madding has built and is currently testing such a calculator. The tests and the tool will be presented at the 2008 Inframation conference in Reno. Interested in what I have read here on determination of actual R-value, for use in assessing build quality within properties we have. Now proud owner of a new Flir B400, and quickly dragging myself up the learning curve. (Level 1 course in a few weeks time.) Currently trying to get my head around the science and variables, to come up with some way of estimating U value from field imagery as a building diagnosis tool. Don’t want to re-invent the wheel and any links to similar studies/research would be appreciated. Main areas of work are commercial/healthcare and educational facilities, with building pathology and energy management being the main influencing areas. Want to get to position to question/verify/dissemble U value of individual components of the building. (photo attached of external facade of a secondary school showing the radiated heat loss) Unfortunately a trip to Reno from sunny Scotland is out of the question. Can I therefore ask if anyone knows if the papers presented at the conference will be published to allow Global readership, and if so where? Any links to similar studies would also be appreciated. Many thanks in advance.
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Re:Building Science - Stud Cavity R Value Determination	Gary Orlove	4/15/2008
Dear CFlaws, "Can I therefore ask if anyone knows if the papers presented at the conference will be published to allow Global readership, and if so where?" All papers at the InfraMation conference are available for purchase at this web site. We offer the printed version (in color) or a fully searchable CD version, or both. See http://www.infraredtraining.com/store/ Gary Orlove Infrared Training Center
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Re:Building Science - Stud Cavity R Value Determination	cflaws	6/18/2008
Gary Orlove wrote: laws, "Can I therefore ask if anyone knows if the papers presented at the conference will be published to allow Global readership, and if so where?" All papers at the InfraMation conference are available for purchase at this web site. We offer the printed version (in color) or a fully searchable CD version, or both. See http://www.infraredtraining.com/store/ Gary Orlove Infrared Training Center Gary, Many thanks. Colin
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Re:Building Science - Stud Cavity R Value Determination	glassman	7/1/2008
cflaws wrote: Interested in what I have read here on determination of actual R-value, for use in assessing build quality within properties we have. Now proud owner of a new Flir B400, and quickly dragging myself up the learning curve. (Level 1 course in a few weeks time.) Currently trying to get my head around the science and variables, to come up with some way of estimating U value from field imagery as a building diagnosis tool. Don’t want to re-invent the wheel and any links to similar studies/research would be appreciated. Main areas of work are commercial/healthcare and educational facilities, with building pathology and energy management being the main influencing areas. Want to get to position to question/verify/dissemble U value of individual components of the building. (photo attached of external facade of a secondary school showing the radiated heat loss) Unfortunately a trip to Reno from sunny Scotland is out of the question. Can I therefore ask if anyone knows if the papers presented at the conference will be published to allow Global readership, and if so where? Any links to similar studies would also be appreciated. Many thanks in advance. Well arnt you the lucky one with the new Flir B400. you ask the question on 'R' value, there are calculations out there and they are usualy embraced within the SAP calcs as they take in all the variables of each building. This needs to be very precise on identification as differing materials perform differently and it is not a given that if you place two like rated materials together you get twice the value. If only life was that simple. To calc the 'U' value requires the whole structure to be listed with the given 'U' value of each component added together you then basicaly rob peter to pay paul if say the roof is poor and the glass is excellent. The short answer is add all together then devide by the number of components. Not realy that simple but gives you a broad idea of how it is done. Now can this be done with a camera the answer is yes provinance of products can be ratified but an overall that would be a long job and may not be very accurate. But then we have some very clever folks in the UK that are working on all sorts so do not be surprised if something does not pop out of the woodwork. Stay well The Verifier
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Re:Building Science - Stud Cavity R Value Determination	IRT Surveys	8/8/2008
glassman wrote: Well arnt you the lucky one with the new Flir B400. you ask the question on 'R' value, there are calculations out there and they are usualy embraced within the SAP calcs as they take in all the variables of each building. This needs to be very precise on identification as differing materials perform differently and it is not a given that if you place two like rated materials together you get twice the value. If only life was that simple. To calc the 'U' value requires the whole structure to be listed with the given 'U' value of each component added together you then basicaly rob peter to pay paul if say the roof is poor and the glass is excellent. The short answer is add all together then devide by the number of components. Not realy that simple but gives you a broad idea of how it is done. Now can this be done with a camera the answer is yes provinance of products can be ratified but an overall that would be a long job and may not be very accurate. But then we have some very clever folks in the UK that are working on all sorts so do not be surprised if something does not pop out of the woodwork. Stay well The Verifier You are welcome to visit our office in Dundee. We do exactly what you want to do. Visit the website at www.irtsurveys.co.uk If you want to come in you get call me directly on 07986 045 964. we have written unique software that quantifies energy loss from thermal images. You can upload your images to us and would be delighted to turn them into quantified reports for you. Stewart.
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Re:Building Science - Stud Cavity R Value Determination	Prunty	1/15/2009
glassman wrote: Well arnt you the lucky one with the new Flir B400. you ask the question on 'R' value, there are calculations out there and they are usualy embraced within the SAP calcs as they take in all the variables of each building. This needs to be very precise on identification as differing materials perform differently and it is not a given that if you place two like rated materials together you get twice the value. If only life was that simple. To calc the 'U' value requires the whole structure to be listed with the given 'U' value of each component added together you then basicaly rob peter to pay paul if say the roof is poor and the glass is excellent. The short answer is add all together then devide by the number of components. Not realy that simple but gives you a broad idea of how it is done. Now can this be done with a camera the answer is yes provinance of products can be ratified but an overall that would be a long job and may not be very accurate. But then we have some very clever folks in the UK that are working on all sorts so do not be surprised if something does not pop out of the woodwork. Stay well The Verifier R Value is the inverse of U value. There is currently nothing to verify R Values in the field. To get the R value of a wall requires Seperating the different components ie. percentage glazing, wood etc. and adding these together(remember R Values are additive, U values are not). You end up with a whole wall R value. This does not take into account the installation quality. However if you are doing Energy Star rating for new homes the software gives a value depending on installation quality.
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Re:Building Science - Stud Cavity R Value Determination	karoluxas	1/7/2010
Can anybody provide a function how to calculate R value, when outside T, inside T and surface average T are known. Thanks
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Re:Building Science - Stud Cavity R Value Determination	StecGuy	1/14/2010
karoluxas wrote: body provide a function how to calculate R value, when outside T, inside T and surface average T are known. Thanks It is not quite as simple as those three known factors. You have to take into consideration the changes in temperature affected by the mechanical heating cooling system, and the amount of air they are moving to keep the artificial temps what they are on the inside. The answer above stating averaging the individual r-value of each component is the more common way.
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Re:Building Science - Stud Cavity R Value Determination	BJenkins	1/29/2010
Prunty wrote: R Value is the inverse of U value. There is currently nothing to verify R Values in the field. To get the R value of a wall requires Seperating the different components ie. percentage glazing, wood etc. and adding these together(remember R Values are additive, U values are not). You end up with a whole wall R value. This does not take into account the installation quality. However if you are doing Energy Star rating for new homes the software gives a value depending on installation quality. Although this will not break down the wall for you, we use our FLIR camera and a Testo 435 http://www.aikencolon.com/Testo-435-HVAC-Test-Kits_c_1158.html to calculate R Value and U Value. It uses three sensors on the wall (structure) then uses a wireless probe on the opposite side of the wall for RH and temperature measurements. It then calculates the R/U value. I know of no other device that can do it. We back up our findings with the 435 like you would with any other meter (moisture, nuclear, thermocoupler, etc) Brian
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Re:Building Science - Stud Cavity R Value Determination	Tony C.	3/29/2010
There are no fast and easy ways to determine absolute R-values for specific areas on fame buildings. Dr. Bob's method and others who have explored this application have required the use of multiple readings along with time lapse thermography and/or heat flux readings to determine the true R-value for a specific spot on a wall. Time averaged results are required to get a better representation of the true R-value. The principle reason for employing these methodologies is to factor in the non steady state conditions that most of our frame wall constructions are subject to. There are multiple factors that affect heat flow through walls apart from ambient temperatures. These include variable air flow both on the inside and outside, radiant heat sources from both inside and out, convective patterns due to variable pressure differentials and variable capacitance due to moisture content. True R-value determination needs to account for these parameters. That's why the definitive test for R-value determination is the guarded hot box method. Now that you know the complexity of the issue, the question comes back to why you are interested in the absolute value when the relative value may suffice. In that regard, there is suitable temperature indexing (TI) software available that will provide you with relative performance levels for visible surface areas. These relative values still require knowledge of interior and exterior ambient temperatures and interior surface temperatures and a low air film coefficient around the interior surface being measured. The readings need to be done at night to negate solar heat gain effects and you need to know the calculated R-vlaue of the cross section you are looking at. The TI will always be a fraction of the calculated value. The only time you get higher than the calculated value is when you obtain interior surface temperatures less than 4 hours after sunset and solar heat gain has not stabilized within the wall assembly. Trying to do this from the exterior becomes hearder due to the increased and variable air film coefficients, solar heat gain variables and potential for convective patterns within cavity spaces between the cladding and the insulation layer.
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Re:Building Science - Stud Cavity R Value Determination	LarryMayer	4/23/2010
MikeDuclos wrote: I use a BCAM-SD, and I'd like to know if it is possible to determine the effective R Value of the wall cavity between two studs. As an example, a house I am working on has a foam which may be old UFFI in the stud cavities. My home energy modeling software uses a stud cavity R Value as an input. Thanks ! I understand an engineer at ITC has developed a simple R-value rating program based on ext. wall surface temp and interior wall surface temp. to arrive at a current effective R-value. If so can i download a copy or email a link to me. Larry Mayer lm321elite@aol.com
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Re:Building Science - Stud Cavity R Value Determination	waheed	5/27/2010
Please Email me a Copy or web link as well, waheed@kfupm.edu.sa I understand an engineer at ITC has developed a simple R-value rating program based on ext. wall surface temp and interior wall surface temp. to arrive at a current effective R-value. If so can i download a copy or email a link to me. Larry Mayer lm321elite@aol.com
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Re:Building Science - Stud Cavity R Value Determination	waheed	6/19/2010
IRJay wrote: Madding has built and is currently testing such a calculator. The tests and the tool will be presented at the 2008 Inframation conference in Reno. i read the paper of Dr. Bob Madding presented at the 2008 Inframation conference, in that he mentione that, he devoloped a R value Estimator. can i get a soft copy of that Excel Sheet??.
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