Brick Veneer Wall Sink Locations

[hkpdx]

Hello,
I am modeling in WUFI Pro an existing brick veneer wall with concrete backup wall.
I have read conflicting locations where to place the moisture source for driving rain and air exchange source.

Typically I have placed 1% driving rain at the exterior edge of the vapor/weather barrier, following ASHRAE 160. In this project's case, placing at a start depth of 0 the 5perm vapor barrier on exterior side of the concrete. As the wall only has weep holes, I have not considered it vented, and added no air exchange.

However, some forum questions lead me to reference the WUFI Example Project (Example_USA_Leakage_Vent.w4p) which puts the moisture source interior of the building paper and air exchange source in the air gap.

Which is the correct method?
Thank you for the advice.

See 2 the approaches below:

Source in VB

WUFI Brick Cavity1.JPG (108.31 KiB) Viewed 5786 times

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Modeled after Example project

WUFI Brick Cavity.JPG (122.04 KiB) Viewed 5786 times

[Manfred Kehrer]

Sorry, it is not easy.
I am a member the SSPC 160 subcommittee and we just met last week.
The standard says to put the 1% source on the "exterior surfae of the WRB" which I do know does not help a lot for practical purposes.
The 1% rain source originally comes from measurements (ASTM 1715), which is for brick veneer only.
Though it makes sense as this source takes account for imperfection in the enclosure, which happens all the time.

So at the end I think is is the best to understand the physics and do judgement based on this.