When it comes to commissioning data centers, no stone can be left unturned. A thorough commissioning process is essential to system uptime and maintaining business continuity. Verifying resilience and performance of MEP systems has its challenges, requiring systematic planning and testing. The game of "What if..." has potential to start important discussions throughout the project, and if asked at the right time, provide huge value. Here are five (5) ways to enhance the data center commissioning process on your next project:
1. Document Owner Requirements
Start with the end in mind. Every client has specific needs, sometimes provided in documents with various names; Owners Project Requirements (OPR), Design Guidelines or Standards, User Requirement Specification (URS). But more often than not, none are provided at all. "What if..." everyone on the team was informed of what the owner wanted from the start? It's important that documented direction is provided by the Owner to the Design, Construction, and Commissioning teams as to how the facility should be designed, built, operated, and maintained to ensure the final product meets the Owner’s intent. These requirements become the benchmark for the commissioning process and are essential to a successful project.
2. Perform Focused Design Reviews
It is important for the Commissioning team to understand their role when it comes to reviewing design documents. Let the architect and engineers of record do their job, which is to design a code compliant facility that meets the Owner’s needs. Commissioning is a quality assurance/quality control (QA/QC) process, and reviews should be conducted as such. Here are four (4) areas of focus when it comes to commissioning design reviews.
Compliance with Owners Requirements: Verify all specific prescriptive and performance metrics provided by the Owner. Does the Owner have a specific power requirement per rack? Check to ensure that MEP systems are sized appropriately to handle these needs plus future growth. Are redundancy requirements specified (N+1, 2N)? Check that systems and equipment are designed based on these needs. Is an Uptime Tier Rating specified? Ensure the requisites are met.
Point of Failure Analysis: Identifying points of failure is essential. "What if..." a chilled water pump motor fails? "What if..." the condenser water valve loses power? "What if..." an EPO system wire is disconnected? "What if..." I need to hook up a temporary chiller? "What if..." the CRAC unit controller fails? "What if..." the building loses power? "What if..." the building loses power for 3 days? As a rule of thumb, the detail of the analysis should increase as the design progresses. This ensures large areas of risk, like utility power infrastructure, are reviewed early. A well-executed analysis will explore all failure scenarios and open discussions to redundancy at system, equipment, and component levels, maintenance considerations, temporary MEP system considerations, and methods of procedure.
MEPF Coordination: Coordination of mechanical, electrical, plumbing, and fire & life safety systems requires strong communication between all team members. With so many details, having a third party with the big picture in mind is very valuable. "What if..." the commissioning agent lead the charge of filling these gaps? In some cases, the design intent of one system is impacted by the design intent of another, and the puzzle pieces don’t fit. An example being fire alarm zoning and coordination with mechanical systems. Fire zones may be designed for rated walls and smoke dampers with the intent of isolating areas while allowing others to operate normally, but if the HVAC system isn’t zoned accordingly and has a single supply fan for the building, everything is going to shut down during fire alarm.
Controls and Monitoring: Thorough reviews should be conducted of the control details and diagrams, MEP points lists, third party equipment integrations, and Sequence of Operations. Simple requirements like monitoring data center Power Usage Effectiveness (PUE) involves numerous meters and calculations which need to be clearly detailed and identified to achieve successful results. Integration to third party equipment like UPS systems requires coordination between disciplines to ensure the equipment is properly specified and procured. Controls systems are often the Achilles heel of mechanical systems; however, they can be designed to limit risk. Go back to the "What if..." game. What if the VFD loses our control signal: Is it specified to fail OFF or fail to RUN? "What if..." the AHU chilled water control valve loses power: Should it fail open, closed, or in place? "What if..." we lower the risk of the Building Management System (BMS) through coordinated design and commissioning? Our team has successfully assisted with designing control systems for mission critical facilities which will continue to operate even after pulling the DDC controller off the wall.
3. Strategic Factory Acceptance Testing (FAT)
Factory testing can provide great value if expectations are well defined. For certain systems, e.g. cooling towers, a controlled environment may be the only feasible way to test operation under full load/design conditions. "What if..." it is the middle of winter during execution of testing? Identify systems where variables outside of your control will not allow for proper onsite system verification, and ensure these systems are factory testing under these conditions. Factory acceptance testing does not imply that onsite testing is not required. Many things can change from the factory to the project site, so re-testing is recommended if feasible.
4. Conduct Comprehensive Failure Testing
Failure testing is a critical part of Level 4 and 5 testing (Functional Performance Testing and Integrated Systems Testing). "What if..." I shutoff power to the UPS? "What if..." the condensate overflow triggers? "What if..." I disconnect power to the BAS controller? Develop a list of the equipment and systems on your project. Based on design and submittal information, identify areas of risk or failure and test every point during commissioning to see how things react. Start your failure testing at the component level (example: AHU supply duct static pressure sensor), then move to the equipment level (example: Entire AHU), finishing at the system level (example: complete air distribution system). This sequence provides value by identifying which component or equipment level item(s) will trigger shutdowns at a higher level. On a recent project, we identified that when a leak detection sensor in the MDF space tripped, the amperage overloaded the 120V control circuit feeding the chilled water system controller, causing a total cooling failure for the entire facility.
5. Develop a Load Bank Plan – Performance Testing
It's not possible to properly commission a data center without electrical demand and heat load on the supporting utilities, systems, and equipment. A well-constructed load bank plan will establish a temporary onsite power demand system to verify performance of MEP systems throughout their full range of capacity. Load banks come in many types, but most often for data center commissioning are packaged as Server Simulators or Suitcase-type units which are resistive heaters that consume power with a byproduct of heat. They benefit the commissioning process by providing adjustable amounts of power consumption and heat output. They allow for capacity and performance testing of the supporting electrical, mechanical and metering systems. A thorough plan is essential and should include the following specifics:
Roles and responsibilities for Cx team members
Owner rack/server layout
Cut sheets of load banks being provided including power output and voltage specifications
Quantity of load banks
Installation locations
Power locations including specific circuit/breakers names
Quantities and lengths for supporting power cables
Requirements for rack blank plates or temporary containment systems
Load bank operating instructions
Safety procedures and protocols
A good question has the potential to save money, save time, decrease risk, and increase quality. "What if..." someone on the team knew the right questions to ask, at the right time, and had the technical expertise to provide solutions. "What if..." .