See all forum discussions about NC-2009 EAp2
 Subscribe to new posts about NC-2009 EAp2 Post a new question aboutNC-2009 EAp2
See LEEDuser’s guidance on NC-2009 EAp2»
FAQs about EAp2 :

Can the Passive House Planning Package (PHPP) be used to energy model for LEED?

Is it acceptable to model a split-type AC with inverter technology compressor as a heat pump, like modeling VRF?

Can the Trace 700 'LEED Energy Performance Summary Report' by uploaded to LEED Online in lieu of the Section 1.4 tables spreadsheet?

A portion of our building envelope is historic. Can we exclude it from our model?

Which baseline HVAC system do I use if my building has no heating or air conditioning?

For an existing building, do I need to rotate the model?

Our project has a diesel backup generator. Should we include it in our energy model?

Our project has a large process load—75%. Despite our efforts to make an efficient HVAC design, the cost savings are minimal. What can we do to earn this prerequisite and be eligible for LEED certification? Is there any flexibility in how we model the p

Can SHGC be higher in the proposed than in the baseline model?

Our process load is higher than 25%. Do we have to justify that?

Do I need to justify the electrical and fuel rates I am using in my model?

Our local code references ASHRAE 90.1-2010. Should I use that for my documentation, or 90.1-2007?

Can I claim exterior lighting savings for canopy lighting even though a baseline model cannot include shading elements?

The project is built on a site with existing exterior lighting installed. How should this be accounted for?

Can mezzanines open to floors below be excluded from the energy model?

How do I provide a zip code for an international location?

For a project outside the U.S., how do I determine the climate zone?

For a project outside the U.S., how do I determine the Target Finder score?

Do hotel rooms need automatic light shut-off control?

How commonly are the 90.1 mandatory compliance forms submitted as part of EAp2/EAc1?

View answers »

Forum discussion

NC-2009 EAp2:Minimum Energy Performance

ASHRAE 90.1-2007 definitions

I am trying to determine the R-values required for a project - a major renovation to a 1940's existing building. The building structure is steel beams and columns, encased in concrete. The exterior load-bearing walls are limestone veneer and brick. There is no cavity in the exterior walls. In the ASHRAE Table for Building Envelope Requirements under walls, above grade , there are several types of elements - mass, metal building, steel-framed and wood-framed. Would this building be considered steel framed or mass? If it's a steel-framed wall, there are two R-values - R-13.0 + R-7.5 c.i. Which value is to be followed? I assume that if the insulation is continuous and not interrupted by metal studs, the the R-7.5 value is applicable.

4
Post a reply

You rely on LEEDuser. Can we rely on you?

LEEDuser is supported by our premium members, not by advertisers.

Go premium for $15.95  »

Default Avatar
Aaron Wascher
Mechanical Engineer
Alvine & Associates
LEEDuser Basic Member
13 thumbs up

Tue, 06/28/2011 - 18:07

It would be considered a mass wall. Steel-framed is for metal stud based exterior walls. When you have a steel or wood-framed wall, the two R-values are both required. You need to provide both R-7.5 of continuous insulation as well as R-13 between the studs.

Wed, 07/06/2011 - 21:14

Just be aware that R-13 insulation is "derated" in metal studs according to the tables in Appendix A. The lower installed R-value takes the metal into consideration. The insulation maintains the full insulation value when installed between wood studs.

Add new comment

To post a comment, you need to register for a LEEDuser Basic membership (free) or login to your existing profile.