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Building Enclosure Commissioning

May 15, 2012

S Y M P O S I U M O N B U I L D I N G E N V E L O P E T E C H N O L O G Y • OC T O B E R 2 0 1 2 WA T E R S T O N • 8 7
311 Summer Street, Suite 300, Boston, MA 02210
Phone: 617-946-3400 • Fax: 617-946-0740 • E-mail: and
Over the past decade, commissioning of the building enclosure has steadily evolved and
gained acceptance in the building design and construction industries. This includes development
of building enclosure commissioning (BECx) standards such as the National
Institute of Building Science (NIBS) Guideline 03, and, most recently, ASTM E2813-12,
Standard Practice for Building Enclosure Commissioning. WJE will share its experience
gained through involvement in development of both of these standards and provide insight
on the future of BECx. The distinction between a formal BECx process and traditional quality
assurance peer review and quality control construction observation services will be discussed.
Through a presentation of case studies, WJE will review fundamental and advanced
aspects of the BECx process, important lessons learned, and recommendations for engaging
and working with a Building Enclosure Commissioning Authority (BECxA).
WILLIAM WATERSTON is an associate principal at Wiss, Janney, Elstner Associates,
Inc. (WJE) in Boston, MA. His work includes the investigation, evaluation, and design of
roofing and waterproofing systems. He is also experienced in construction document preparation
and specification writing. He is both a registered architect and a Registered Roof
Consultant. Mr. Waterston served as chairman of the RCI Building Envelope Symposium
and is the author of several articles on roofing material choices and roofing practices. He
has presented at Build Boston, RCI, and Construction Specifications Institute meetings and
WEI LAM, PE, is an associate principal at Wiss, Janney, Elstner Associates. For more
than 15 years, his career has focused on performance and design related to heat, air, and
moisture control related to building enclosure systems. Mr. Lam is regularly involved in
building enclosure commissioning for academic and healthcare projects. He is a registered
professional engineer and a contributing member of ASCE, ASHRAE, and BEC-Boston. He
is an investigator in ASHRAE project 1478 RP, measuring the airtightness of mid- to-highrise
buildings built after the year 2000.
JOE STANDLEY, EIT, is an associate at WJE. Mr. Standley has experience in both architectural
and structural investigations, with specific experience on projects ranging from
waterproofing, roofing, and façade inspections, to structural-load tests and material testing
for both new and existing construction. Mr. Standley regularly preforms design peer review,
façade testing observation, and construction observations.
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Over the past decade, the practice of
building enclosure commissioning has been
increasingly adopted by building owners to
achieve successful building projects. As a
result, commissioning has been defined
more rigorously, refined, and gained acceptance
in the building design and construction
industries. This is especially true in
complex building types such as hospitals or
museums, where building enclosure performance
is critical. Building enclosure (envelope)
commissioning (BECx) encourages a
focus on quality assurance during the
design phases, and quality control and validation
during the construction and occupancy
phases of a facility.
Some may argue that BECx is simply a
fancy new term for the same services building
enclosure consultants have been providing
for years. These traditional activities include
peer review of construction documents,
periodic construction observation,
and performance testing. As this paper will
demonstrate, a comprehensive definition of
BECx includes these elements but also a
host of other activities that are intended to
improve the quality of construction projects
and increase value to the owners, occupants,
and users of a building (ASHRAE,
The idea of commissioning buildings
and building systems was first formalized
by the American Society of Heating,
Refrigerating, and Air-Conditioning Engineers
(ASHRAE), who formed a committee
in 1982 to document best practices to realize
facilities that performed according to criteria
set forth by building owners. Based on
the work of this committee, ASHRAE published
its original technical commissioning
Guideline 1 for HVAC&R in 1989. Following
this work, ASHRAE developed Guideline 0,
which outlines the general requirements of
a commissioning process not focused on
any particular discipline. Guideline 0 has
become the basis of the National Institute of
Building Sciences’ (NIBS) technical commissioning
guideline series, which includes
NIBS Guideline 3, “Building Enclosure
Commissioning Process.”
In recent years and with growing
demand for these services, the industry has
sought to further define and clarify the
process and requirements related to building
enclosure commissioning or BECx. This
has resulted in publications and standards,
including ASTM E2813, Standard Practice
for Building Enclosure Commissioning, and
the General Service Administration’s
“Building Commissioning Guide.”
The Executive Summary from NIBS
Guideline 3 (GL03) states
The process of commissioning the
enclosure follows a similar process
as other building systems. However,
commissioning the enclosure differs
from commissioning other building
systems in the focus on materials
and assemblies. The enclosure is
designed and field-assembled from
numerous materials with varying
properties. These materials are manufactured
by different companies for
a specific function, assembled mostly
on-site one piece at a time by
many different trades people [sic] working for several different contractors
with often minimal coordination.
The work is performed in all
possible weather conditions with the
intention of meeting very welldefined
performance criteria. The
performance of the enclosure cannot
be verified until the entire building
is completely enclosed. At this time,
it is not possible to tune or dial-in
the performance. To access a nonperforming
subsystem or assembly
might be very expensive. Thus, the
most reliable means to achieve performance
targets during construction
is to assure that an expert with
technical knowledge of the design
and installation of the systems being
proposed for the building is integrated
into the design process and to
visually observe the installation of a
statistical sampling of the work.
Verification testing should be performed
throughout the installation
of the enclosure subsystems and
GL03 describes a process that provides
the flexibility for an owner to
incorporate building enclosure commissioning
into their [sic] project.
The Building Enclosure Commissioning
(BECx) process is utilized to
validate that the performance of
materials, components, assemblies,
systems, and design achieve the
objectives and requirements of the
owner as outlined in the contract
documents. The most effective commissioning
process ideally begins at
project inception (during the predesign
phase) and continues for the
life of the facility (through the occupancy
and operations phases).
Commissioning relies on a well-developed
set of owner project requirements (OPR) and
is a critical component of BECx as the
building moves from concept to reality. The
direction for the commissioning team is provided
by the OPR, which is defined early
and refined through predesign, design, construction,
occupancy, and operations phases
of the project. The OPR includes design
criteria and quality standards for the building
as well as long-term durability and performance
guidelines, sustainability, acoustical,
safety, and security objectives. The
OPR provides guidance to the designers and
others on the construction team as the project
advances. The designer then develops a
basis of design (BOD) for the various components
of the enclosure that draws upon
the requirements listed in the OPR.
There is a significant distinction between
true commissioning and a traditional
peer review and construction observation
services provided by the architect or engineer
of record. With commissioning, there is
involvement in the entire building design
and construction process by an experienced
commissioning professional, the building
enclosure commissioning agent (BECxA),
acting on behalf of the owner. This agent
focuses on the quality and performance
aspects of the building, providing input on
product selection, compatibility of materials,
durability of detail assemblies, quality
of construction, building operations, etc.
Conversely, peer reviews tend to focus on
review of construction details or the design
as it develops, in an effort to improve the
quality of the construction documents,
which is only one component of BECx process.
The commissioning process is applied in
various levels within all phases of the
design and construction process to improve
the quality of the completed building or system
and assure that the building or system
conforms to the OPR. The earlier commissioning
can be integrated into the design
and construction process, the higher the
quality of the delivered building or system.
Beginning the commissioning process at
project inception will maximize benefits and
minimize the cost (NIBS, 2012)
The BECxA employs several tools
through the project life. These tools include
specifications, mock-ups of systems, construction
checklists, periodic site observations,
field testing and monitoring of issues
and deficiencies, and remediation of deficient
conditions. All of these are used for the
verification of the performance of the built
components within the building enclosure.
As the project moves into construction
documents, it is important to establish a
commissioning specification and systemspecific
performance testing requirements
within the technical specifications. The project
specifications should include specification
sections related to building enclosure
commissioning that define and describe the
commissioning process for the project.
There are three locations for this information.
The first includes general commissioning
requirements. MasterSpec includes
Section 019113 – General Commissioning
Requirements, which covers the “general
requirements that apply to implementation
of the commissioning process without
regard to the system or equipment being
The second will be specific commissioning
aspects for only the building enclosure,
such as Section 019119 – Exterior Enclosure
work included
in this section
includes req
u i r e m e n t s
common to all
exterior enclos
u r e – r e l a t e d
• Validation of installation of exterior
enclosure components
• Component performance verification
• Documentation of test procedures
and installation
• Coordination and requirements for
testing events and preparation
• Coordination of the Building Enclosure
Commissioning Report
The third location for commissioningrelated
specifications will be within the
technical specifications themselves, where
validation testing and mock-up construction
and other system installation items are
specified. This includes specific tests to be
performed on the materials and systems,
the frequency and quantity of testing,
pass/fail values for each test, and retesting
of failed tests. Quality control and monitoring
that detail the commissioning aspects of
the material or system are also included in
the technical sections.
Mock-ups are used for critical assemblies
such as windows and walls and at
interfaces between complex systems. Mockups
of building components such as curtain
walls are constructed at laboratories for a
variety of testing situations. Testing is performed
to confirm that the system meets
specified performance criteria. Site mockups
are built for visual approval at the site,
with example corners and materials that
will be used on the building. The site mockup
is typically used to establish expected
quality of work. They can also be used to
verify that the systems meet specified
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Figure 1 – Example of a simplified lab mock-up
containing a punched window opening and rainscreen
stone panels.
Figure 2 – Example of complex lab mock-up
containing curtain wall, louvers, metal panels, and
multiple inside- and outside-corner conditions.
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requirements, such as air and water infiltration resistance.
Laboratory settings allow for testing and analysis in a controlled
environment. Structural testing, water and air infiltration,
and even impact testing can be performed in the laboratory
setting. The BECxA helps the design team determine the
validation and quality testing required for each system. The
laboratory mock-up may range in size and complexity, depending
on the level of validation required by the owner and BECxA,
as well as the project budget. Mock-ups may be as simple as a
stand-alone curtain wall section or as complex as a wall containing
multiple cladding systems. It is suggested that the laboratory
mock-up contain typical conditions, complex details
such as inside or outside corners, and transitions from one
cladding type to another. The key is to build the lab mock-up
as similar to the actual construction as possible while incorporating
as many of the “difficult” details as possible. This provides
two major benefits for the project: First, the installing
contractor is afforded an opportunity to make a “trial run” and
truly learn how to build the assemblies; and second, the design
and construction becomes validated through a series of rigorous
tests. Lab mock-up testing should be witnessed by the contractor,
BECxA, architect, engineer, and owner. See Figures 1
through 6.
Site mock-ups represent a portion of the building enclosure
and include typical construction of walls and windows but
Figure 3 – Spray rack installed in front of large curtain
wall system during laboratory mock-up testing.
Figure 4 – Deflection gauges installed on
framing system during laboratory
structural testing of mock-up frame.
Figure 5 – Airplane engine used during dynamic water
penetration testing of laboratory mock-up.
Figure 6 – Laboratory setup for impact
testing of a window assembly.
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should also include corners and intersections.
The site mock-up, like the lab mockup,
affords the contractor and design team
a trial run and helps develop and understand
sequencing, material-to-material
joints, flashing details, and support details.
Often the site mock-up remains on site for
the duration of the project to serve as a
benchmark of the accepted details and
quality standards for the included systems
and assemblies. In some cases, such as
projects that do not have the budget for lab
mock-ups, the site mock-up may also be
used to perform tests. Involve the manufacturers
of the materials used for key components
of the building enclosure, such as the
air barrier, flashings, sealants, curtain wall,
or wall panels to review and comment on
the assembly. Figure 7 is an example of a
site curtain wall mock-up.
Checklists are developed by the BECxA
for use by field personnel observing the
installation of the components and systems.
They can be used by the general contractor,
the subcontractor, the architect, or
the BECxA. They are developed after the
submittals are approved by the architect,
since they utilize details from the product
installation guidelines specific to the products
and systems being installed. Product
names and designations are used directly
from the submittals so that observers can
easily identify the specific components that
have been approved and are expected to be
installed. Figure 8 is an example checklist
developed for under-slab vapor retarder
Consider adding information about the
compatibility or
the integration
with adjacent
materials that
may be installed
by another trade.
Ask for letters
from manufacturers
to confirm
c omp a t i b i l i t y .
Materials may be
compatible with
each other, but
they may not
adhere. This can
be important in
the sequencing of
applications of
sealants and air
barriers or other materials, since silicone
sealants adhere to many substrates, but
few materials adhere to cured silicone.
Conduct meetings with each trade and
with the general contractor to review the
requirements of BECx. These can occur as
a part of the preconstruction meetings. The
construction checklists should be reviewed
in detail along with the review of testing and
quality control measures. Shop drawings
and submittals should also be reviewed
during this meeting.
Periodic site observations by the BECxA
are important. Utilizing checklists when
observing the installation of a component is
a great method to record what was completed
or installed. The observer must be specific
about where any deficiency is located,
using column line, elevation number, or
some other specific locator to assist in finding
and repairing the work. The BECxA is
typically on site only periodically and must
rely on the quality control methods of the
Figure 7 – Site visual and assembly mock-up with various
materials used in the building wall.
Figure 8 – Example checklist for under-slab vapor retarder installation.
contractors to follow through between visits.
The BECxA should plan for longer site
visits when construction activity increases
and the number of components and systems
installed is greater. Consider participating
in a review of the deficiencies with
the GC and building enclosure subcontractors
at the end of the site visit, or develop
methods to create and issue reports immediately
to reduce the risk of deficient conditions
being covered.
Field testing should be performed by an
independent third party and, when possible,
observed by the BECxA. ASTM E2813
contains in Annex 2, Table A2.1 (ASTM
International, 2012)—a listing of test methods
and practices that may be utilized in
building enclosure commissioning.
In the project specification, include not
only the number and type of tests to be performed
but also the consequences of failed
tests. Also specify when during the construction
the testing is to occur, such as
during the first 10% of the installed system.
Require that
failed tests be
repeated on the
remediated unit
or area and a
new unit or
area be selected
for an additional
test. As an
example, if the
call for four
ASTM E1105
tests to be performed on the installed window
system when construction is 10% complete,
the four tests should be performed. If
all four pass, no additional tests are
required. If one or more fail, those failed
units are remediated and retested, and that
same number of untested windows are
found and tested. This process continues
until four tests are passed on previously
untested windows.
Figures 9 through 14 show testing of
building envelope components in progress.
Each issue or deficiency observed and
recorded by the BECxA should be reported
to the construction team in a timely manner.
A tracking system of each issue or deficiency
should be utilized. Such a system
should describe the issues and allow for
contractor comment, along with confirmation
of resolution and approval or acceptance
of remediation by the BECxA. Some
BECxA use a log or spreadsheet of issues
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Figure 10 – Air leakage testing
of insulation fastener. ASTM E1186.
Figure 9 – Cavity wall drainage testing on newly
constructed cavity wall. ASTM C1715.
Figure 11 – Air leakage and water
penetration testing of newly installed curtain
wall unit. ASTM E1105 and ASTM E783.
and resolutions. These can be quite numerous
on large projects, so managing all the
data becomes a burden. Several projects
have utilized a computer data management
system called VELA, which allows for different
members of the design and construction
team to author an issue, post the item, and
direct it to one or more of the parties
involved in the project. This system also
allows for posting of photos and comments.
It is also web-based, making for timely
input of issues.
It has proven to
be an effective
way to communicate
and record
along with
when and how
they were resolved,
when all
the team members
utilize the
Based on our experience with several
commissioning projects, we have made the
following positive observations on the BECx
• A BECxA has full involvement during
design team meetings to provide
comments on architectural drawings
as they are developed. We discovered
that meetings in person over a twoor
three-day session to review all
details prior to each design phase
completion are very effective. The
design team is most familiar with the
development of design elements and
the reasoning for various decisions
as the project has developed.
Challenging aspects of the design,
such as breaches in the thermal
envelope, integrity of the air and
vapor barriers, or potential construction
sequencing problems, are great
discussion points. The implementation
of hygrothermal modeling or
other advanced analytical techniques
is useful in comparing alternatives.
There is also opportunity to
provide input on the methods of testing
and quality assurance methods
to be included in the specifications.
• A BECxA has full involvement in
major shop drawing reviews. This
can be most useful if this is done
alongside the design team in a faceto-
face meeting for the major systems
or components, such as the curtain
Figure 12 – Water penetration testing of
curtain wall system. AAMA 501.2.
Figure 13 – Pull testing of EIFS
mock-up. ASTM D4541.
Figure 14 – Air leakage testing of window.
ASTM E783.
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wall assembly. Including the curtain
wall fabricator in these face-to-face
meetings can also be effective.
• A BECxA is a full participant in all
mock-up testing and observes construction
of the mock-up. This provides
an opportunity to learn the ins
and outs of the systems, how the
components are installed, what
trouble the construction team may
have, and any remediation that
would be required as the system is
installed in the building.
• Regular site walk-throughs and
meetings with the contractors responsible
for the construction of the
building enclosure are important
while the project is in the early
stages of construction. Involvement
of the various tradesmen in discussions
with the air and vapor barrier
installing contractor is beneficial,
because all parties will develop an
understanding of the impact of their
components to the overall quality
and performance of the wall assembly.
Similarly, the roofing contractor,
curtain wall installer, or metal panel
erector can provide input to improve
the overall completed project.
• Observation of field-testing, with the
knowledge of mock-up testing, can
assist in diagnosing test failures.
• The BECxA should insist on using
online systems for tracking site
observations and deficiencies or corrective
items. These have proven
very effective in organizing and communicating
to the team. This makes
reporting of new issues a more
streamlined and organized process.
It is important that issues are
recorded promptly so that the team
members can correct them quickly.
We found a verbal review of issues
encountered during our visit is valuable
when made after every site visit
with the building enclosure subcontractors.
The following have been found to be
negative or difficult aspects of the BECx
• The design team can become reliant
on the BECxA to solve or design difficult
design conditions or detailing
between systems or refuse to resolve
design issues identified by the
• The design or construction team can
become overly reliant on the BECxA
site walk-through and may not
devote enough of its own time and
effort toward QA/QC. Monitoring of
construction quality by each subcontractor
is important and requires
pressure from the construction
manager, general contractor, or
• Checklists are developed and issued
by the BECxA, but may not be fully
implemented in the field by the contractor
and its subcontractors. The
BECxA should insist on receiving
copies of completed checklists for
systems installed between BECxA
visits. If this is done early, good
habits can be developed. Asking for
them later can be disappointing.
• As the project moves through construction,
it may be difficult to stay
on top of all the design changes that
happen after the bid documents are
issued. It can also be difficult to follow
RFIs. This is due to the much
smaller time involvement of the
BECxA in comparison to the other
members of the design/construction
team; the BECxA is typically
involved on an intermittent basis,
whereas the design/construction
team is involved on a day-to-day
basis. Being part of discussions and
reading documents from the design
team are difficult but necessary to
track changes that may affect the
building enclosure.
• Closing of issues discovered during
site walk-throughs can be a difficult
communication process. The contractor
is to provide photos, comments,
and other documents to indicate
what was done to remedy a deficiency
to assure that the quality
standards are met. Often, the contractor
documentation is provided
well after the condition is covered, or
there is no documentation provided
at all. Working with the contractors
early can improve this, but recording
what has been done or doing
paperwork is generally not a priority
for contractors. Once they have to
remove completed work to prove
that something was done, they then
remember to record it before it is
covered up.
• Depending on construction sequence,
there may be a lot of “workin-
progress” issues identified by the
BECxA during site visits. These
types of deficiencies are often
ignored by the contractor. With multiple
observers, it is possible that the
same issue may be recorded by the
designer of record or other observers,
making for duplicate work
by the construction team.
The following should be avoided:
• The BECxA should only review
approved submittals. The ideal
workflow would have the architect
review and approve the submittal,
then forward the submittal on to the
BECxA. If the BECxA has no further
comments, the submittal is forwarded
to the GC. If the BECxA has additional
comments, the submittal is
returned to the architect for additional
review and the process starts
again. Otherwise, the BECxA and
architect are simultaneously reviewing
submittals and providing redundant
or sometimes contradictory
comments. The submittal process is
especially difficult for the BECxA,
because his or her time commitment
to the project is much smaller than
the rest of the design/construction
team. No one likes the added time
this may create. When concurrent
reviews are completed, it is often the
architect who has to resolve the
• BECx is often rolled into the electrical/
mechanical commissioning contract.
While these are both commissioning,
the timing of involvement
during the project is quite different.
These two disciplines are not related
and should be completely separate.
• The GC or the construction manager
should avoid reassigning personnel
assigned to focus on the building
enclosure construction issues and
coordination. When personnel
change, project history is lost, quality
control processes may not be
understood, and additional time is
dedicated to training. Dedicate one
person for the duration of the project.
• The BECxA is often asked to attend
meetings, provide comments, or
complete other tasks within a tight
schedule, often with limited or no
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advanced scheduling. This is challenging
to accommodate, because
the BECxA may be typically involved
in several concurrent projects that
have similar time-sensitive needs.
As stated in the NIBS Guideline 3, “The
Building Enclosure Commissioning (BECx)
process is utilized to validate that the performance
of materials, components, assemblies,
systems, and design achieve the
objectives and requirements of the owner as
outlined in the contract documents. The
most effective commissioning process ideally
begins at project inception (during the
predesign phase) and continues for the life
of the facility (through the occupancy and
operations phase).”
BECx is a defined process that includes
a host of activities that are intended to
improve the quality of construction projects
and increase value to the owners, occupants,
and users of a building. These activities
and processes of the BECxA begin with
assisting in defining the owner’s project
requirements; performing design reviews of
the building enclosure, specification, and
documentation of the validation measures;
observing mock-ups; periodic observation;
and observing testing and remediation of
deficiencies. These are all focused on delivering
a building that performs to the established
OPR. BECx is not the same for every
project, but it is an effective process. It is
particularly well suited for complex or highperformance
building projects.
ASHRAE Guideline 0-2005. Atlanta, GA:
American Society of Heating, Refrigerating
and Air Conditioning
Engineers, Inc., 2005.
ASTM E2813, Standard Practice for
Building Enclosure Commissioning,
Conshohocken, PA, ASTM International,
NIBS Guildeline 3-2012, Building
Enclosure Commissioning Process
BECx. National Institute of Building
Sciences, 2012.
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