The Darien Police Department underwent a gut renovation and new addition in 2012, after which they began to experience a multitude of issues. Not long after construction was completed, the existing portion of the facility began to experience poor indoor air conditions, ranging from high levels of humidity in the summer to cold complaints during the winter months.

After years of finger pointing and contractor callbacks, the Darien team decided to pursue a retro-commissioning investigation to determine the root cause of the problems they were experiencing. SES began the project by first developing a retro-commissioning plan and presenting it to the team. During the presentation, the building staff and facility teams were interviewed to better understand the issues they experienced and what steps have been taken, in attempts to address them.

Using the original design documentation and information gathered from the facility interviews, clarity on the current facility requirements was established.  Custom functional performance test procedures were developed and executed on the various HVAC systems. Methodically, each system was fully tested to identify current systems operation and identify the deficiencies contributing to the poor indoor conditions. Following the functional testing, a comprehensive list of deficiencies was developed with recommendations for corrective actions.

As the space comfort issues became prevalent soon after the original construction project in 2012, various companies were brought in with attempts to remediate the problem. However, each company was only specialized in their field. None took a holistic systems approach to solving the facility’s problem. As a result, many of the “fixes” would result in additional problems in other systems of the building. After the retro-commissioning investigation, the space comfort issue was tied back to a variety of problems ranging from design and construction issues, HVAC controls, air balancing, building pressurization, and building envelope deficiencies. Examples were found to include uncalibrated airflow stations, disconnected outside air dampers, improper control signals for factory packaged controllers, and negative building pressure.

As typical with most retro-commissioning, there was not one root cause that led to the comfort issues the staff experience, but rather a variety of deficiencies that resulted in a compounded problem. Systematically the issues were broken down and individually identified; and a recommended corrective action was provided for each. The facility department was then able to use the 3rd party retro-commissioning report to receive Town funding to implement the recommendations.

By utilizing a retro-commissioning process, SES was able to provide detailed answers to the ongoing issues that plagued the facility since turnover of the 2012 project. Not only was the initial occupant comfort problem solved, but the police station also benefitted from increased energy efficiency and improved facility training.

Corrective Measures:

• Control sensor recalibration
• Sequence of operation modifications
• Controller upgrades
• Factory controller repairs
• System re-balancing
• Building envelope repairs
• O&M repairs