North Thurston School District, Washington

Timberline High School Phase II&III

Systems Commissioned: Project included Cx of 4-Pipe AHU’s, WH’s, 2-Speed exhaust fans, Dx Split system AC’s, Variable Air Volume Units(VAV’s), Hydronic pumps, Packaged Outdoor 155 Ton and 250 Ton Chillers with Heat Tracing,   BAS controlled Exterior lighting, Generator backup power, Kitchen Hood Exhaust fans and Vehicle Exhaust fans. BAS control system included BACnet Tridium Automated Control System.  

Our commissioning services mainly focused on the mechanical and electrical systems throughout the path of the projects’ design and construction phases. In addition to the electrical and mechanical verification we also included the fire alarm system and emergency lighting burn down testing within our scope of work. Through commissioning we were able to break whatever is prone to failure and to discover whatever design and installation errors existed. We used our strong working relationship with McGranahan as leverage to create a highly effective approach to facilitating the Cx process and ensure the equipment performs in accordance with the design intent and the finished facility operates as intended.   Key issues included:
 
·         The OSA damper in several air handler units were not quite shut all the way when commanded to do so from the BAS. These dampers were still about 5% open when the BAS showed them fully closed.  
·         In other cases it was observed that several units were not driving the return damper to the correct position when the unit entered morning warm-up mode. 
·         The return ductwork for AHU-C207 was feeding the wrong room. 
·         According to the contract submittals when an air handler looses a belt due to breakage, or slippage, the computer should show an alarm. MENG Analysis noticed the programming had not yet been implemented for this feature or it had been overlooked. 
·         Due to the entering and leaving temperatures of AHU-C104 this air handler may have had a plugged or possibly shut off heat valve.  
·         The return damper for AHU-D232 failed shut when power is disconnected to it rather than failing open as specified in the sequence of operations. 
·         MENG Analysis noticed a lot of air seemed to be in the water piping system. Specifically it could be heard rushing through AHU-D234 heating valve. Based on field experience this excessive air in the hydronic piping decreases the efficiency of the heat coil and can potentially damage the control valve if it is not evacuated.  
·         Several pipe clamps were missing on various heating and cooling pipes throughout the mechanical spaces.   Code requires these to be installed.
 
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