Folks:

I am a bit confused when modeling unrated vertical fenestration for the proposed
model. 90.1 states that we need to use the values determined in accordance with
NFRC 100 or we can use the data in Table A8.2 for vertical fenestration per
Exception b, Section 5.8.2.4.

If so, the values in Table A8.2 exceed the maximum allowed fenestration u-values
listed in Table 5.5-5 (my zone), so will this not disqualify the proposed
building model?

I have often found it impossible to get the architect to supply the NFRC
assembly ratings of the glazing and field erected curtain-wall systems.

I have used the LBNL Window 6.3 program to calculate the vertical fenestration
ratings, but 90.1 Section 5.8.8.2 states that the fenestration product shall
have a permanently installed nameplate or the manufacturer shall provide a
signed and dated certification for the installed fenestration.

I don't see any wiggle-room where 90.1 allows the modeler to calculate the NFRC
rating of vertical fenestration.

Saying that, I have submitted projects where I calculated the fenestration
assembly u-values without any kick-back from the GBCI.

I am concerned that the reviewers will push this issue since it is now clearly
defined on the new Section 1.4 Table and if I submit my own ratings I will end
up remodeling the project and/or the proposed building envelope will be rejected
since it doesn't meet the mandatory requirements of Section 5.4.

Any thoughts?

Thank you,

Paul Diglio, CEM, CBCP