ASHRAE Journal - March 2013 - 40

Implementation Phase
In this phase, the owner ﬁrst decides which recommendations to implement. Then, the selected recommendations are
implemented and are veriﬁed to conﬁrm that they were implemented correctly.
Verifying implementation of the recommendations usually involves repeating the functional performance testing or
trend data analysis that was performed during the investigation phase. In fact, using the same method for implementation
veriﬁcation that was used during the investigation is desirable
since it facilitates comparisons, clearly showing if the recommendation was implemented correctly and the system is now
operating as expected. Figure 4 shows how baseline performance can be compared to post-implementation performance
using trend data.
It’s good practice to document the ﬁnal performance of the
system since it is a record showing that the recommendation
was implemented correctly, and provides a benchmark for ongoing performance. This information can be included in the
ﬁnal EBCx report.

Hand-Off Phase
The hand-off phase is where the EBCx process transitions
from the EBCx team to the building operators and facility
management. It is an important step as it helps ensure persistence of the beneﬁts realized from the EBCx process. Lack of
routine maintenance is a common reason for economizer system failure, and this phase can create processes to keep those
issues from occurring again.

Update Building Documentation
It’s important to update any building documentation that the
building operators use on a regular basis with any changes
related to the airside economizer systems. An example of this
is the written sequence of operations, but can include other
documentation such as record drawings and documents in the
systems manual.

Plan for Maintaining Ongoing Performance
To help ensure that the issues identiﬁed during the investigation phase don’t pop up again in the future, the EBCx team,
which should include the building operators, should make a
plan for maintaining ongoing performance of the systems.
This plan does not have to be complicated. It may be as simple
40

ASHRAE Journal

5
0

MAT – RAT (°F)

• Re-enable economizer control;
• Calibrate temperature and/or enthalpy sensors;
• Replace failed damper actuators;
• Lubricate and adjust stuck dampers; and
• Adjust dampers for full closure.
This exercise may also include estimating the costs and beneﬁts related to implementing the recommendations. Once the
analysis is complete, the recommendations are presented to
the owner for them to review and select recommendations for
implementation.

–5

Ideal Operation

15% OA

Baseline Operation
Far From Ideal
100% OA

–10
Dampers
Modulating
–15 To Maintain
SAT
–20
–25
–50

Post-Implementation
Operation Closer to Ideal
–40

–30
Ideal

–20
–10
OAT – RAT (°F)
Baseline

Post-Implementation

Figure 4: After implementation of corrective actions, trend
data can be used to demonstrate proper performance. This
chart clearly shows that the system is now operating more optimally during economizer operation. For this example system,
it would also be good to confirm that the system is operating
properly during non-economizer mode (i.e., 15% OA).
as having the operators periodically observe the position of
the economizer dampers during various seasons and outdoor
conditions (e.g., hot, mild, cold), and compare to expected
performance. Periodic visits to the mixed air plenum can be
an effective method of observing economizer system performance. More complex methods include:
• Functional performance testing. Periodically repeat the
functional performance tests that were used when identifying
the original issues. The tests should include clear pass/fail criteria.
• Trend data analysis. Periodically gather trend data over
a range of conditions and compare to expected performance.
• Fault detection. Program rules into the BAS, and have the
BAS generate alarms when an economizer system is performing outside of the expected bounds.
Since sensor calibration is a key requirement for proper
economizer performance, sensor calibration activities should
be included in the ongoing maintenance plan.

Training
Building operators should be involved throughout the
EBCx process since they are responsible for operating and
maintaining the facility. For airside economizer systems, this
includes having the building operators participate in system
testing and implementation of the recommendations. During the hand-off phase, a more formal training session can
be conducted to conﬁrm that the operators understand the
changes that were made to the system, and to discuss the ongoing airside economizer maintenance plan that was developed. This may include a classroom-style training followed
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March 2013

ASHRAE Journal - March 2013

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