[Equest-users] F-Factor of ASHRAE 90.1

[Nick Caton]

Omar,

 

U-factors describe heat transfer over an area (ft2).  F-factors are very
similar except they describe heat transfer over a lineal foot (that may
be where the 'F' comes from... not sure) of perimeter.

 

There is not a straight conversion between U and F factors.  F-factors
are accounting for heat transfer through multiple planes (the
wall/footing and the floor), and insulation present along one and/or the
other has slightly different effects.

 

While you could dig up the science/math behind it all, I find
representative F-factors are most easily found and used from 90.1
Appendix A - specifically read section A6 and the referenced table A6.3.
I believe ASHRAE Fundamentals may have a similar table if you want to
dig up other possibilities - I think theirs varies based on degree
days... but it's been awhile...

 

~Nick

 

 

 

 

NICK CATON, E.I.T.

PROJECT ENGINEER

Smith & Boucher Engineers

25501 west valley parkway

olathe ks 66061

direct 913 344.0036

fax 913 345.0617

www.smithboucher.com 

 

From: equest-users-bounces at lists.onebuilding.org
[mailto:equest-users-bounces at lists.onebuilding.org] On Behalf Of Omar
Katanani
Sent: Monday, January 24, 2011 6:38 AM
To: equest-users at lists.onebuilding.org
Subject: Re: [Equest-users] F-Factor of ASHRAE 90.1

 

James,

 

I did not understand the appendix exactly! Isn't there 1 value for
converting between F-value and U-value that anyone can help me with?

 

Thanks!

Omar

___________________________

Omar Katanani
Sustainable Design Engineer

Email: omar at ecoconsulting.net

 

EcoConsulting (Lebanon)

Nahas Building, 4th floor

4 St-Maron Street / Georges Haddad Avenue

Postal Code: 2028 5806 SAIFI

Beirut, Lebanon

Tel:          +961 (0) 1 971 266
Mobile:    +961 (0) 3 045 045

 

EcoConsulting (UK) Ltd
28 Marshalsea Road
London, SE1 1HF
Tel:  +44 (0) 207 939 0989
Fax:  +44 (0) 207 939 0981

Website: www.ecoconsulting.net <http://www.ecoconsulting.net/> 

 

  

________________________________

From: James Newman [mailto:James.Newman at me-engineers.com] 
Sent: 19 January 2011 18:38
To: Omar Katanani; equest-users at lists.onebuilding.org
Subject: RE: F-Factor of ASHRAE 90.1

 

Omar,

 

Look in Appendix A in ASHRAE 90.1 to figure out what construction you
need to meet the appropriate F-Value.

 

James M. Newman, EIT, LEED AP

project engineer / energy analyst

 

M-E Engineers, Inc. <http://www.me-engineers.com/> 

10055 west 43rd avenue

wheat ridge, co 80033

 

office:  303.421.6655

direct:  720.898.3148

james.newman at me-engineers.com <mailto:james.newman at me-engineers.com>  

 

From: equest-users-bounces at lists.onebuilding.org
[mailto:equest-users-bounces at lists.onebuilding.org] On Behalf Of Omar
Katanani
Sent: Wednesday, January 19, 2011 9:08 AM
To: equest-users at lists.onebuilding.org
Subject: [Equest-users] F-Factor of ASHRAE 90.1

 

Dear all,

 

I read numerous forum discussions and articles about the F-factor. My
question is much simpler!

 

For LEED purposes, ASHRAE 90.1 requires the F-factor for the unheated
slab-on grade floor in climate zone 3 to be F-1.264

 

I do not have insulation in my project.

 

I go to my floor construction makeup in eQUEST, and I have to enter the
U-value.

 

The question is: How can I transform the F-1.264 to a U-value that I can
enter into eQUEST?

 

Many thanks,

Omar

___________________________

Omar Katanani
Sustainable Design Engineer

Email: omar at ecoconsulting.net

 

EcoConsulting (Lebanon)

Nahas Building, 4th floor

4 St-Maron Street / Georges Haddad Avenue

Postal Code: 2028 5806 SAIFI

Beirut, Lebanon

Tel:          +961 (0) 1 971 266
Mobile:    +961 (0) 3 045 045

 

EcoConsulting (UK) Ltd
28 Marshalsea Road
London, SE1 1HF
Tel:  +44 (0) 207 939 0989
Fax:  +44 (0) 207 939 0981

Website: www.ecoconsulting.net <http://www.ecoconsulting.net/> 

 

 

 

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