November 11, 8:30-9:30 AM
Architectural Sheet Metal: Lessons Learned by a Third-Generation Tradesman
Russell A. Raymond, RBEC, RRO, CDT, CEI
Morrison Hershfield Corporation | Houston, TX
Prior to becoming a building enclosure consultant, Raymond spent 17 years working as an architectural sheet metal worker in Louisville, KY. During this time, significant detailed information was derived from other industry professionals, time at the bench, as well as significant field experience with snips and soldering irons in hand. This experience—coupled with the last ten years as a building enclosure consultant—have given the presenter unique and well-rounded architectural sheet metal experience. While many in the industry proclaim elevated levels of sheet metal expertise, it is apparent during design peer review of these assemblies and numerous sheet metal installations that the skills needed for proper design and installation are lacking. The purpose of this presentation is to share the presenter’s experience and pass on both time-tested design nuances and installation techniques that will enlighten the intermediate and advanced consultant.
November 11, 9:30-10:30 AM
Mold In Office Buildings: It Won’t Go Away
Timothy Mills, PE, LEED AP, CIT II, Certified ABAA Auditor
TAM Consultants, Inc. | Williamsburg, VA
This presentation is a classic case study of an ongoing problem plaguing many office building facility managers across the country: mold. Although much has been written about this subject, many people in the building profession have little knowledge about why buildings keep filling up with mold, and less knowledge about what to do about it.
In this case study, the presenter will demonstrate the steps necessary to conduct a forensic investigation regarding cause of defective building systems, and review the approach, fact finding, conclusions, and recommendations. The presenter will demonstrate the implementation of antiquated design details in a 45,000-sq.-ft. office building with masonry cladding and standing-seam metal roofing. The building suffered from years of poor performance, poor indoor air quality, and unhappy occupants.
This case study offers insight into reviewing and diagnosing existing construction, including interviewing staff personnel, reviewing plans, as well as reviewing maintenance records. The presenter will discuss the performance of brick and concrete masonry unit (CMU) cladding, through-wall flashing, Kraft facing, and #15 felt as an air barrier and how mechanical systems come into play and interact with the building air barrier and enclosure systems.
November 11, 11:00-12:00 NOON
Re-Examining the Energy Efficiency of Built-Up Roofing and Modified-Bitumen Roof Systems
André Desjarlais, FASTM
Oak Ridge National Laboratory | Oak Ridge, TN
Built-up roofing (BUR) and modified bitumen (mod-bit) roofing systems represent some of the longest lasting roofing systems available for low-slope roofing. Over the past 20 years, the emergence of cool roofing and its enactment into multiple building codes in many cases has eliminated this roofing option from consideration because these systems typically do not have the required levels of solar reflectance.
Since BUR and mod-bit systems are typically ballasted with aggregate for ultraviolet (UV) protection of the asphalt, they are much heavier than their counterparts. With areal densities from 7-10 lb/ft2, the role of thermal inertia could provide a significant contribution to the energy savings of the building enclosure. Since the late 1980s, ASHRAE Standard 90.1 has given an energy credit to wall systems that have thermal mass. In the early 2000s, research demonstrated that ballasted roofing systems are more energy efficient than their lightweight counterparts, given equivalent applications. Aggregate is also available in a wide range of colors that can enhance BUR and mod-bit systems in reflecting solar load.
This presentation will report on a series of in-situ experiments that were designed to measure the energy performance of BUR and mod-bit roofing systems. These data were then used to calibrate a transient thermal model for roofs and to generalize the findings to the range of climates found in the U.S. Comparisons of their energy performance are then made to other traditional low-slope roofing systems.
November 11, 1:30 – 2:30 PM
Importance of Air Barrier Material Properties by Material Category: What You Need for Them to Work
Air Barrier Association of America, Inc. | Walpole, MA
Air barriers are critical to the performance of buildings. Originally siloed as an energy-saving material, they are now being recognized as impacting the total performance of buildings, including moisture management, sound control, HVAC, and other components.
Given a material that affects building assembly performance so directly, what is an air barrier material and what are the key requirements of each category of such materials? What are the different categories and types of air barrier materials currently on the market?
Requirements go beyond the maximum air flow rate, as other properties are critical. The material must perform as intended for its expected life.
Materials must be assembled to work together. Site audit reports from the last 17 years and industry research have prompted the development of material specifications for each category of air barrier material.
November 11, 2:30 – 3:30 PM
On the Weakening of Weathered Window Glass and Its Effect on Human Impact Resistance: Two Fatality Case Studies
Mark Meshulam LLC | Northbrook, IL
Older buildings face a heightened safety risk at windows because weathered glass is weakened against human impact. Magnifying this hazard is the additional factor that many buildings predate building codes that specify safety glass at floor level.
These risk factors came together tragically in two separate fatality matters studied by the author who served as an expert witness. The fatalities were a two-year-old boy and a 30-year-old woman. In each case, victims broke through weathered window glass and fell from heights to their deaths.
To understand the extent to which glass weathering was a factor in the deaths, the author adapted a safety glazing test method to find the impact force at which the glass was no longer a fall barrier. Weakening of the weathered glass was found to be significant.
Test results, building codes, safety glazing codes, historical approaches, and ASTM E1300 will be discussed.
November 11, 4:00 – 5:00 PM
Open for Business—Overcladding Strategies for Institutional Buildings
Simpson, Gumpertz & Heger, Inc. | Waltham, MA
Douglas Pac, PE
Simpson, Gumpertz & Heger, Inc. | Waltham, MA
Institutional buildings, such as research buildings, university classroom buildings, or courthouses, have stringent operational schedules that almost always prohibit disruptive activities and greatly complicate construction. At the same time, these buildings have rehabilitation needs like any other commercial structure—requiring, after decades in service—major renovation work to upgrade exterior masonry façades, fenestration, roofs, and mechanical and life safety systems. One leader of a prominent aviation museum likened this unwelcome but necessary work to “working on an airplane in flight.”
Drawing on their own experience working on the rehabilitation of major institutional buildings and focusing on early-to-mid 20th-century masonry construction, the presenters will discuss technical approaches to masonry whole-façade replacement while keeping a building fully operational. The presentation will cover structural engineering, building enclosure design, energy efficiency improvement, constructability, and logistical and economic aspects of overcladding projects.
November 12, 8:15 – 9:15 AM
ASHRAE 90.1 and Cold-Weather Condensation
Wiss, Janney, Elstner Associates, Inc. | Cleveland, OH
Wiss, Janney, Elstner Associates, Inc. | Northbrook, IL
To comply with the energy code, designers often utilize the Prescriptive Building Envelope Option described in ASHRAE 90.1 when determining the minimum amount of insulation required within a wall assembly. In cold climates, the minimum R-Value requirement for framed wall assemblies allows designers to utilize a split insulation arrangement to meet code requirements. However, these designs often carry an elevated risk of condensation that is not explained in the text of the standard and may lead a designer to unknowingly promote detrimental insulation combinations with regard to convective condensation.
A design tool has been developed based on psychometrics and ASHRAE 90.1 requirements that illustrates the ratio of continuous insulation to total insulation. The design tool currently assumes a high leakage rate; therefore, values along the pass-fail line may be overly conservative. In order to incorporate a more realistic air leakage rate and develop a more defined pass-fail criteria, our research uses software tools such as WUFI® to study the requirements offered by 90.1 to evaluate the hygrothermal performance of insulation combinations for framed wall assemblies based on the simplified exfiltration model. Hygrothermal engineering principles and the results will be presented with future publication of the design tool for the design industry.
November 12, 9:15 – 10:15 AM
Building Science and Physics vs. Architectural Sensitivity; Design of Enclosures in the Most Hostile of Environments
Structural Rehabilitation Group, LLC | Montgomery Village, MD
Kipp Gaynor, PE, LEED AP, CDT
Structural Rehabilitation Group, LLC | Montgomery Village, MD
Architectural design and sensitivity to skyline views and noise concerns for penthouse unit occupants impacted the original design of the cooling system on a high-rise, leading to placement of the cooling towers in the basements of the east and west wings. Eleven-story air shafts facilitated the cooling tower exhaust, as well as the parking garage ventilation. Organic growth and saturated drywall were observed, giving rise to an investigation.
A fire-rated shaft assembly was determined to be woefully inadequate in reconciling the vapor drive and water management issues associated with the extremely high humidity and the temperature differentials across the enclosure. Physical configuration and a lack of thought led to systemic water and air leakage through the enclosure wall. Full shaft wall replacement was required.
WUFI® analysis was used to validate the design concept using an exterior insulation approach, coupled with a redundant vapor barrier system. Further complicating the design were extreme vapor pressure differentials and flow reversals, as well as structural issues related to concrete deterioration and post-tensioned concrete pocket protection. Design provisions also included data logging, and a tattletale system to monitor for bulk water infiltration was designed into the enclosure system.
November 12, 10:45 – 11:45 AM
The Physics Behind Lessons Learned in a Full-Size Blindside Mock-up
Jerry Carter, Jr.
SmithGroup | Detroit, MI
David Leslie, RWC
Polyguard Products | Ennis, TX
Burying a pre-applied waterproofing system between an earth retention system and newly installed concrete—never to be seen again—creates a difficult scenario whereby designers, manufacturers, and contractors are left to wonder just how well their system will perform. For the new Chen Neuroscience Research Building at the California Institute of Technology, Hensel Phelps (design-builder) partnered with SmithGroup (architectural engineering firm). Based on previous success, Hensel Phelps proposed the use of a specific blindside system, which SmithGroup rejected based on their lack of experience with said system. For the proposed system to be approved for the project, both parties agreed to perform an evaluation. A significant part of the evaluation process included the assembly and forensic deconstruction of a full-size structural shotcrete mockup.
There are three areas of concern typically posed to all pre-applied waterproofing membranes:
- Does the system bond to the concrete?
- Will the system survive the installation of the structural shotcrete?
- Can the system resist lateral water migration?
From the lessons learned during the assembly and deconstruction of the mock-up, we will review the findings and use scientific methods with applied physics to evaluate the original assumptions and validate the findings.
November 12, 1:15 – 2:15 PM
Thermal Enhancements for Aluminum-Framed Curtainwalls: a Practical Perspective
Simpson Gumpertz & Heger, Inc. | Waltham, MA
Derek McCowan, PE
Simpson Gumpertz & Heger, Inc. | Waltham, MA
Aluminum-framed curtainwall systems have many positive traits, though they have historically been underachievers with respect to thermal performance. Developments in recent years have improved the options and performance available on the market. This presentation will discuss various modifications that may be made to aluminum-framed curtainwall systems to improve their thermal performance. We will discuss enhancement options for both the glazing and framing systems, such as the addition of non-metal pressure plates, gas-filled insulating glass units, warm edge spacers, and other available features. We will discuss how these thermal enhancements may affect the thermal performance of the system and will also touch on related design considerations, such as weatherproofing, durability, expected service life, and other factors.
November 12, 2:15 – 3:15 PM
Air Barriers: They Might Be Continuous, but Still in Danger of Allowing Building Component Damage
Ryan Krug, BECxP, CxA+BE
Pie Consulting & Engineering | Eden Prairie, MN
Uncontrolled airflow within a building enclosure can cause damage to building components. Due to our harsh winter conditions in Minnesota and the services our firm offers, we have had the unique opportunity through our forensics investigations, monitoring of existing buildings, and extensive design consultation to see areas of concern to designers, contractors, and building owners. Remediation and prevention of problems will be outlined.
November 12, 3:45 – 4:45 PM
Reroofing an Icon Is a Moving Target; A Case Study of the Reroofing of the Rogers Centre
Christopher DeRosa, PE, AIA
Walter P Moore & Associates, Inc. | Washington, DC
Walter P Moore & Associates, Inc. | Toronto, ON
Assessing, designing, and overseeing the roofing replacement of a retractable roof stadium is an uncommon project. The Rogers Centre, originally named the Skydome, is currently home to the Toronto Blue Jays Major League Baseball team.
The climate and location implications of this project were also unique. Rogers Centre is located on the north shore of Lake Ontario. The 1800-foot-tall CN Tower is immediately adjacent and hovers above the roof surface. Ice “missiles” breaking off from the tower have historically impacted the roof surface. These factors influenced the design of the new roofing system.
In this presentation, we will discuss the challenges and complexities encountered during this project, which began in the assessment phase. 3-D laser imaging, infrared thermography, cores, and exploratory openings were employed to determine the extents of membrane and substrate damage, the location of moisture infiltration through the original roofing membrane, and membrane attachment detailing at edge conditions.
Due to the geometry of the roof and its location, the roof sees harsh winter conditions for several months. Ice and snow collect and settle at the gutters, putting significant stress on the eaves. In addition to updating and strengthening the eave design from the original, a customized snow melt system was designed and installed.
In this presentation, these and other challenges encountered throughout assessment, design, and construction oversight will be discussed.