2026 Convention Session: Effects of Interior Air Management Systems on Exterior Enclosure Performance (Hughes, J.)

Effects of Interior Air Management Systems on Exterior Enclosure Performance
(Hughes J.)

Course Overview
This session was originally presented at the 2026 IIBEC Convention & Trade Show in Sacramento, CA. 

This course includes the following required components.

• recording of the live session
• summative assessment consisting of 10 multiple-choice questions
• course evaluation survey

Description

A midrise judicial building developed to replace federal and local court systems was completed in 2021; however, difficulties with closing out the project resulted in shortcuts taken by a bond company that took control over the work, culminating with an improper phased test and balance of the building air management system that was performed floor by floor and not as a total building.  By not considering the building as a whole, this phased approach to the HVAC commissioning and test and balance did not identify a potential for high negative interior air pressure resulting from unbalanced supply and return to the air handler units for each floor.  Although the building enclosure was commissioned with satisfactory completion of all air/moisture barrier systems, two years following occupancy the building experienced water intrusion on every floor during multiple rainstorm events.  Storm water migrated to the building’s interior critical occupancy spaces during each event.  Initially, it was assumed to be a cladding and glazing installation failure, even though the construction phase enclosure commissioning integrity tests were successful.  After a year of diagnostic evaluations performed on the enclosure systems, a full diagnostic/forensic mode-of-failure analysis that included the buildings heating and cooling design finally identified the primary cause of water intrusion.  The results of that mode of failure or root cause investigation identified significant negative interior pressure throughout the building.  This interior negative pressure combined with exterior positive wind pressure during certain rain storm events that resulted with a large pressure differential exceeding the design tested pressure of the robust curtainwall glazing system under normal use.  This presentation focuses on the physical effect of air pressure differential on a building enclosure resulting in moisture intrusion despite proper installation of exterior cladding. The interior air management of a building affects performance of the enclosure roofing and cladding systems and must be considered as part of a leak/failure analysis protocol. 

Speaker/Author

Joseph Hughes, AIA, RA  

Course Access
Courses are accessible in LearnUpon for one year from the date of purchase.

Course Recommended Prerequisite(s) 

Attendees should have an understanding of basic air barrier design and specifications, including code requirements for the air barrier assembly.  They should also have a basic understanding of requirements such as standardized testing for air pressure minimum performance of fenestration and glazing systems, both in situ and manufacturer design lab performance tests.  Attendees should have a basic understanding of the general function and performance of air management Heating Ventilation and Air Conditioning (HVAC) systems. They should also have a basic understanding of the physical nature of air pressure differential on a building enclosure that causes high positive and high negative pressure zones based on building exposure and based on building design parameters such as wall/roof height, roof slope, parapet, surrounding terrain, etc.


IIBEC Core Competencies: Building Enclosure Commissioning, Exterior Walls

Knowledge Level: Advanced

Disclaimer
The views and opinions expressed in the session content at the 2026 IIBEC Convention & Trade Show are those of the content author(s)/speaker(s) and do not necessarily reflect the policies or positions of the International Institute of Building Enclosure Consultants (IIBEC). IIBEC makes no warranty, whether express or implied, as to the completeness, accuracy or validity of the information provided.

Credit Start Date 1/23/26    
Credit Expiration Date 1/23/29

Continuing Education Credit Statement
This course is approved for 1 IIBEC CEH
This course is approved for 1 AIA LU/HSW
AIA Course Number: CONV26_22_OD
AIA Provider Number: G024

Continuing Education Credit Claim Information

To claim IIBEC CEHs and download a Certificate of Completion, learners are required to complete all components of the course, including a passing score of 70% or higher on the summative assessment.  Participants are provided unlimited attempts to complete the summative assessment with a passing score of 70% or higher.

• After completing the course requirements download a Certificate of Completion. 
• Participants are responsible for self-reporting IIBEC CEH credit by uploading their Certificate of Completion to their IIBEC Portal. For assistance in self-reporting CEHs, please reach out to: cehs@iibec.org
• If you are a member of AIA and would like IIBEC to report your participation in the course to AIA, there is a place in the course evaluation survey to input your AIA member number.

AIA CES Provider statement

IIBEC is a registered provider of AIA-approved continuing education under Provider G024. All registered AIA CES Providers must comply with the AIA Standards for Continuing Education Programs.  Any questions or concerns about this provider or this learning program may be sent to AIA CES (cessupport@aia.org or (800) AIA 3837, Option 3).

This learning program is registered with AIA CES for continuing professional education. As such, it does not include content that may be deemed or construed to be an approval or endorsement by the AIA of any material of construction or any method or manner of handling, using, distributing, or dealing in any material or product. AIA continuing education credit has been reviewed and approved by AIA CES. Learners must complete the entire learning program to receive continuing education credit. AIA continuing education Learning Units earned upon completion of this course will be reported to AIA CES for AIA members. Certificates of Completion for both AIA members and non-AIA members are available upon request.