ASHRAE Guideline 0 “The Commissioning Process” is widely recognized as the best guide for the commissioning of new construction projects. The latest edition, Guideline 0-2013, provides a comprehensive description and step-by-step guide for how formal commissioning should be performed. This guideline is generic in that it does not differentiate between the types of facilities being constructed, and is equally applicable to data centers as to commercial office buildings and other types of facilities. Basically, commissioning is a quality assurance process based on formal, third-party verification and validation.
This is not to say that data centers do not have their nuances and challenges that require different strategies and processes than other facilities. Even so, the overall commissioning process as described by Guideline 0 is applicable and this guide is an excellent tutorial for anyone seeking to gain a thorough grasp of what formal commissioning is, and what to expect from a quality commissioning agent and firm.
Interestingly, and surprising to many who are not familiar with formal commissioning, the guideline recommends that commissioning begin as soon as an owner or developer decides to initiate a new construction project. The commissioning agent should manage and oversee the programming and requirements definition process and record the results in a document called the owner’s project requirements (OPR) document. The commissioning agent should set up a requirements definition workshop and act as the facilitator of in depth discussions including all major stakeholders to capture the overall goals, objectives, purpose, and mission that the facility is to perform. Also important is to capture the overall budget and resource constraints, absolute must-haves, and establish the priorities of the nice-to-have requirements so that as competing, and in some cases, conflicting requirements arise, the project stakeholders have an objective basis for making decisions on which to include, and which to compromise on.
A good commissioning agent will ensure the programming phase also addresses and incorporates the needs and requirements for the facilities operations and maintenance (O&M) functions so that the built facility is provisioned appropriately. This includes office and storage space for the O&M staff’s use, a facility command center (FCC) where the “front-end” of facilities related monitoring and control systems will reside, and adequate maintenance access and transportation routes are provided to ensure long-term and major repair and replacement activities can be performed safely.
The programming phase should also ensure decisions are made regarding how the O&M functions will be performed such as using in-house staff to do routine maintenance, or to outsource these activities to outside vendors and contractors. These decisions will directly influence how much storage space is required as well as what parts, tools, and materials should be procured and kept on site. The programming phase should also address what training and as-built documentation should be captured and provided as part of the construction effort, who will provide these services and deliverables, and what content and format they should be delivered in.
The commissioning agent should perform design reviews as the development of both drawings and specifications proceed to ensure they reflect the requirements and decisions agreed to during the programming phase and as documented in the OPR. The development of the construction documents (CDs) should include phased deliverables including a conceptual design package, several sets of design development drawings and specifications (aka 50%, 75%, and 90% CDs), and a final (100%) set suitable for issuance for permitting and bidding. An important deliverable by the engineer-of-record (EOR) and the architectural firms is the basis-of-design (BOD) document. An important aspect of the commissioning agent’s design review is to ensure the BOD reflects decisions and incorporates the requirements as captured in the OPR.
The commissioning agent should deliver an initial commissioning plan by the end of the design phase that establishes the overall scope of commissioning, the roles and responsibilities of the project team members with regard to commissioning, and the required commissioning activities and deliverables. This document is considered a “living document” in that it is updated and embellished as the project evolves and as deliverables are developed and received. By the end of the project, it becomes the basis for the final commissioning report and includes submittals, issue and discrepancy tracking logs, completed test scripts, training records, etc.
As the project transitions from design to construction, the commissioning process continues to verify and validate by reviewing submittals to ensure products and materials are consistent with and meet the requirements established by the drawings and specifications. The commissioning agent should also lead progress inspections attended by the owner (or owner’s representative), the EOR and architect, as well as the general contractor (GC) and associated subcontractor representatives. The commissioning agent should record these inspections and any issues and discrepancies identified in a formal tracking log.
Most data center projects include factory witness testing (FWT) of some of the more critical and/or complex equipment such as emergency generators, UPS modules, paralleling switchgear, and chillers. The commissioning agent should ensure the vendor’s proposed test procedures reflect project-specific performance requirements and if not, that these scripts get revised and embellished appropriately to ensure the equipment is proved to perform as required prior to shipment to the site.
As the construction progresses to where equipment and systems are ready for startup, the commissioning agent will deliver formal acceptance test procedures that verify that systems and equipment will perform as required. In some cases, the commissioning scope only requires the commissioning agent to review and approve the contractor’s startup and checklists prior to proceeding with actual functional testing. A recognized best practice is to have the commissioning agent actually develop site specific startup scripts (aka “pre-functional test” scripts) and to witness the equipment startup.
In general, it is best to structure testing to start with the small and simple and progress to the large and complex. The commissioning agent should manage the acceptance testing process and associated schedule to ensure that components and equipment are tested prior to testing systems, and that systems are tested and proven prior to proceeding to integrated testing where a myriad of systems are required to operate in concert. In other words, all pre-functional testing must be completed (including resolution of identified discrepancies) before proceeding to functional testing, and that all functional testing (including resolution of identified discrepancies) is completed for the equipment that makes up a system prior to proceeding to integrated systems testing (IST). Again, all systems must complete functional testing prior to proceeding to ISTs which are typically the last acceptance testing activities to occur. The commissioning agent should again maintain an issues tracking log to capture identified discrepancies and track them to resolution.
Acceptance testing of data centers differs somewhat from commercial office buildings and other non-critical facilities in that data centers have a much higher requirement for reliability and availability due to the requirement for continuous operations. Continuous operations require designs and installations that are fault tolerant and allow for concurrent maintainability. This equates to a much higher degree of redundancy, fail-over and backup systems, and more complex automation and associated sequences-of-operations. Whereas the acceptance testing of a typical non-critical facility focuses on ensuring everything works correctly, the acceptance testing of critical facilities must also ensure that equipment and systems fail correctly. This means that when utility powers fail, emergency power systems start and assume the load, when chillers fail, redundant equipment and/or systems start and assume the load, and that the data center and associated mission critical operations continue without interruption. This obviously means the commissioning agent must have a different mindset than one who is not experienced with commissioning critical facilities.
The commissioning process is not only focused on delivering the physical facility, but also on ensuring the entire process of design, construction, and testing is documented and recorded. This not only includes ensuring that accurate as-built drawings (aka “record drawings”) and O&M binders are delivered, but that the entire process is documented. Final project closeout documents should include the OPR, BOD, record drawings, final specifications, approved submittals, pre-functional tests (including air and water testing, adjusting, and balancing (TAB) reports), completed functional and IST test scripts, written sequences of operations, standard operating procedures (SOPs), and other site specific documentation that provides the owner and O&M staff a comprehensive description of the facility and how it is intended to perform for posterity.
Last, but in no way least important, is for the commissioning process to ensure that the facility O&M staff receive formal, site specific training on how to operate and maintain the site. Again, since data centers are more complex and have more demanding operational requirements, the respective training needs of the O&M staff are higher than for commercial building staff. It is therefore important that the training provided not be generic, but that it is tailored to address the site specific conditions, topologies, and emergency response procedures required to maintain critical operations during planned system and equipment maintenance as well as unplanned outages. Ideally the training is performed in a structured manner that includes academic sessions in a classroom environment during construction, hand-ons, and/or observation sessions during the startup and acceptance testing phase, and includes formal staff testing and certification prior to the site transitioning to critical operations. All training materials and sessions should be recorded and in editable formats so it can be repeated as refresher and remedial training for existing staff as well as for new hires as part of their onboarding process, and can be updated as the site evolves over time.
So in short, the commissioning process starts at the very onset of a new construction initiative and ends when the site transitions into operational status. The commissioning agent should be the first one in, and the last one out. n