Building Envelope Commissioning - Energy Exchange · George Bourassa, P.E., CCP, LEED AP Jacobs August 16, 2017 . 2 Energy Exchange: Connect • Collaborate • Conserve ... 7 Energy

Tampa Convention Center • Tampa, Florida

Building Envelope Commissioning New & Existing Buildings

Commissioning for Performance

George Bourassa, P.E., CCP, LEED AP Jacobs

August 16, 2017

Energy Exchange: Connect • Collaborate • Conserve 2

Presentation Highlights

Team experience • Building envelope commissioning

services for existing & new facilities

Commissioning of building envelopes

• Recent development driven by failures of new construction & deterioration of existing facades

Important consideration • Influence on energy consumption

driven by building envelope performance

Case study examples


Presentation Highlights

Commissioning industry has evolved • Whole Building Commissioning (WBCx)

Building Envelope • Important influence on energy

performance • Ability of infrastructure to maintain

interior environmental conditions • Multiple envelope failures in United

States have prompted high level scrutiny over design & construction of envelope configurations

• Building Envelope Commissioning (BECx) integrates with all systems to be commissioned to deliver performance of the entire facility


Introduction

Context: According to industry experts, building envelope related moisture & moisture vapor problems: Account for approximately 90% of construction litigation according to some industry experts

ASTM estimates water-related defects cost us more than $9 billion each year

Where is the source of these issues?

- Quality of design detailing? - Problems during fabrication or

manufacturing? - Improper construction in the

field? - Combination of the above?


Introduction

Deficiencies witnessed • Fabrication & manufacturing process (factory) • Assembly of products (factory/shop) • Interface between factory made product/assembly

and field-installed construction (field) • Interface between two different field-installed

products/assemblies (field)

Deficiencies occurred with surprising frequency • 100% of windows tested by a manufacturer failed

air & water infiltration testing • Due to a large number of test failures, 25% of all

windows on one project were eventually tested for air & water leakage


Introduction

Better understanding of when and where issues are developing: Include and specify the proper quality control procedures to mitigate risks

Obtain understanding of their causes, and prevent them from happening in the future. • Learning Objectives….

- Discuss the causes of many problems with the building envelope observed in the field

- Better understanding of the benefits of field testing - By expanding our knowledge of best practices

we can avoid these problems in the future - Recognize other available tools used for field testing


Building Envelope Impact On Energy Performance


Building Envelope Impact On Energy Performance


Zero Energy Target Projects

Building envelope performance key to achieving target

• Recent completion of Fort Carson Hangar design/construction

• Comprehensive planning by project team from concept to completion of construction

• Enhanced insulation value for roof R-50 and walls R-47; above code

• Air barrier 62% more stringent that required; 0.15 CFM/SF vs. 0.4 CFM/SF requirement

• Reduced air leakage/heat loss from hangar doors by double seals at perimeter

Energy Exchange: Connect • Collaborate • Conserve

• American Society for Testing & Materials (ASTM)

• National Institute of Building Sciences (NIBS)

• American Society of Heating, Refrigeration & Air Conditioning Engineers (ASHRAE)

• Envelope Design Guideline for Federal Buildings Thermal Integrity & Air Tightness (NISTIR)

• ANSI/ASHRAE/USHBS/IES Standard 189.1-2011 Building Envelope Thermal, Moisture & Pressurization IGCC 2012 903.1

• American Architectural Manufacturers Association

• Differences in State codes

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Building Envelope Performance Code References


• Elements to be replaced vs. what remains?

• Junctions between existing & new elements always critical - Importance of appropriate air & water

testing

• Existing materials/assemblies in window/wall systems to be tested? How does this impact performance criteria of chosen test method?

• Test criteria adjusted for existing assemblies?

• Recent experience of 70 year old masonry wall junction with new curtain wall

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Challenges Presented By Existing Envelopes


Commissioning Activities

Project Timeline


Sample Responsibilities Matrix


Sample Responsibilities Matrix


• Important to establish specific test matrix

• Responsibility: Who & when? Who witnesses?

• Laboratory mock-up tests

- Our experience

• Lessons learned from failed mock-up testing

• Distributed responsibilities associated with envelope construction leads to inherent quality control issues

• Goal of holistic Cx

- Identify performance problems early & drive resolution

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Testing Protocols


Sample Test Criteria


Infrared Thermography: Water Infiltration


Infra-Red Photographs Of Envelope Heat Loss

Heat Loss From Typical Hangar Door Assembly


• Transit station in a cool, humid climate

• Custom curtain wall system

• Insulated glazed panels captured on two sides

• Insulated glass panels approximately 1.6” thick

• Intermediate joint consists of silicone sealant and a gasket

• Concealed joinery

• More than 50 different materials and products

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Case Study: Assembly Facility


• Insulated glazed panels span between continuous extruded aluminum clips

• Each clip has two cutouts – 4 cutouts at each panel

• Each panel then sits upon four steel anchors fastened back to structural frame of the building

• Structural columns reduced to ½” steel plate to provide space for concealed joinery

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Typical Curtain Wall Bay • Two-part air & water barrier system

Inner: • Each insulated glass panel, silicone

sheet flashing membrane & frame stop assembled in shop

• Termination bar fastened in the field with liquid membrane & silicone sheet

Outer: • Outer seal: weatherproof silicone

sealant installed in field



JAMB: Weatherproofing Barriers • Outer seal: 1-part weatherproof silicone sealant • Inner seal: .08” thick continuous silicone sheet

flashing membrane (embedded in silicone sealant at column)

• Seal at glazing: 2-part structural silicone • Exterior & interior steel jamb panels



Silicone sheet membrane flashing embedded in weatherproof silicone with termination bar



SILL: General • A drainable cavity allows for escape of

moisture & condensation • Sill cavity drains into gutters • Gutters collect water from….

- water that penetrates outer sealant - sill cavities



SILL: Weatherproofing Barriers • Outer seal: 1 part weatherseal silicone • Inner seal: 1 part weatherseal silicone • Thin gauge stainless steel sill flashing • Fastened to steel curb






Test Methodology: Assembly Facility

TEST #1 AAMA 503 • Field Test of Newly Installed Storefronts, Curtain

Walls, & Sloped Glazing Systems - pressurized

Test Pressures • Air infiltration: test pressure = 6.24 psf

- allowable air leakage = .06 cfm/sf • Water infiltration: test pressure = 10 psf

- allowable water leakage = none


Test Methodology: Assembly Facility

TEST #2 AAMA 501.2 • Diagnostic Water Leakage Field Test

- non-pressurized

Test Pressures • Water infiltration:

Test pressure of water = 30-35 psf • Observing the joints during testing

required use of an inspection camera with a 5/8” camera head



Sill Cavities • Confusion in the contract drawings:

- Weep holes were shown on only one of the details in the contract drawings, & not in several others

- This contradiction was missed during shop drawing review – proper drainage of cavities not shown

- This deficiency was identified during the course of field testing & corrected

- Without detection, water damage would have occurred.

Best practices… • Review of shop drawings is an important process – staff

appropriately - Include field testing of both a mock-up as well as

installed work for air & water infiltration



Robust Detailing • The silicone sheet membrane flashing

provided a strong & flexible secondary barrier to the outer silicone sealant joint (no water infiltration observed at jamb conditions)

Best practice… • Use a two-part barrier strategy when flashing

curtain wall, storefront or windows to adjacent walls

• One of those barriers should be membrane flashing



Construction Tolerances/Building Movement • Interface between insulated glass panels & exterior/

interior jamb panels (width of panels was constant) - As a result, there is frequent variability in the

installation of the outer sealant joint & inner gasket joint

- Interior jamb panels & gaskets did not touch glass surface

- Gaskets were crushed between glass & steel panel - Outer sealant had no backer rod & little surface for

purchase

Best practice… • Be sure to provide for movement between the

structural frame & the air, water & weather barriers


• Seventy-year-old facility; curtain wall vertical addition

• Laboratory mock-up tests of curtain wall failed; modifications to sealant installation resulted in tests pass

• Field installation required modifications to accommodate beam penetrations & uneven slab edges; curtain wall tests passed, but Cx discovered significant air & moisture migration at junction of existing & new

• If aggressive Cx had not highlighted test failures, building would have failed all internal environmental criteria performance

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Case Study: Existing Masonry Structure



• Forty-year-old high rise office building

• Glazed curtain wall with aluminum spandrel panels

• Extensive deterioration: Potential risk of materials falling on plaza below

• Extensive energy modeling & CFD analysis influenced final façade replacement decision

• Double wall assembly with sealed cavity

• Extensive commissioning of laboratory mock-up & field installation

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Case Study: Existing Curtain Wall


• New high rise judicial facility in northerly climate

• Comprehensive BECx program developed early in the design phase

• Multiple failures in laboratory mock-up tests despite conventional curtain wall design

• Modifications to installation resulted in pass result for mock-up tests

• On site installation progressed favorably & all BECx tests had pass result

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Case Study: New High Rise Facility


• New healthcare facility in southern climate

• Failure of laboratory mock-up tests at joint between windows & metal or precast panels

• Sealant determined to be cause of failure

• On site installation produced similar failures

• Implementation of high intensity Quality Control program resulted in pass result for BECx testing

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Case Study: New Healthcare Facility


• Verified performance of building envelope systems

• Measurement and verification of air leakage within specified tolerance

• No water infiltration into the building

• Control of air and water vapor from inside the building to outside

• Interior environmental metrics established and maintained in accordance with Owner Project Requirements

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Building Envelope Commissioning Benefits


• Building envelope commissioning provides significant value

• Mock-up testing provides early identification of design or installation failures, resulting in resolution of problems before corrections are required on site

• Owner is ultimate benefactor because we do not sign off as approved any envelope elements or systems that have not passed all of the functional testing identified in early design phase

• Value driven proposition: Building Envelope services repeatedly result in savings to owners multiple times the cost of our professional fees

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Building Envelope Commissioning Conclusions


Thank You

Questions?

George Bourassa

[email protected]

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Documents

Building Envelope Commissioning - Energy Exchange · George Bourassa, P.E., CCP, LEED AP Jacobs August 16, 2017 . 2 Energy Exchange: Connect • Collaborate • Conserve ... 7 Energy