Читать книгу Maintaining Mission Critical Systems in a 24/7 Environment - Peter M. Curtis - Страница 21

The definition of commissioning (Cx) has developed over the past twelve years from being nothing more than vendor start‐up to the comprehensive quality control process it is today. Some still cling to the idea that commissioning is something that starts at the end of construction or after the design is complete. Indeed, for most of the 20^th Century, when building systems were much less complex, and tradesmen did not need additional expertise to activate them, this approach was sufficient. Today, many commissioning professionals have found it helpful for themselves and their clients to organize the effort into “levels” of commissioning, and level one starts after the design is complete at Factory Acceptance Testing (FAT). The advent of the Leadership in Energy Efficient Design (LEED) program and its various certifications forced the industry once again to rethink the commissioning process. For several good reasons, LEED requires design reviews and other requirements that start earlier in the project than commissioning professionals were accustomed to. A widely accepted definition of commissioning can be found in ASHRAE’s Guideline 0. ASHRAE’s Commissioning Guideline 0‐2005 is a recognized model and good resource that explains commissioning as a quality control process in detail. Although its intent is to apply to all kinds of buildings, it can be applied to critical facilities with some embellishment to address the unique needs of verifying critical system performance. The quality control process given by ASHRAE is in phases starting with the Pre‐Design Phase and continues throughout the Occupancy and Operations phase.

A summary of the phases given in ASHRAE appears below, with some additions for mission critical facilities. These additions, along with all phases, should be included in all mission critical facility projects.

 Pre‐Design phaseDocument Owner’s project requirements and basis of design

 Design phaseCommission focused Design reviewWriting Cx specifications

 Construction phaseFactory Acceptance Testing ‐ FATConstruction check listingStart‐up (Pre‐functional) testing

 Acceptance phaseSite acceptance (Functional)Acceptance testing to verify the performance of critical equipmentIntegrated testingO & M document reviewStaff training oversightDevelop and prove out EOPs. SOPs and MOPs

 Occupancy and Operations phaseContinual review and updating of materialsContinual training of O&M staffReliability Assurance Testing (continual commissioning)

A quality control process would never be overlooked in any valuable production project such as a new model automobile or TV. Why would we neglect quality control for critical facility projects? In the case of critical facility projects, quality control or commissioning starts in the pre‐design phase so we can make sure the Owner’s Project Requirements (OPR) are fully developed and track all relevant documents such as the Basis of Design (BOD). We do this so that during value engineering, we can evaluate any impact to the BOD and OPR, and if the proposed change does not meet the documented requirements, then the team must sign off on it. It should be clear that these documents are the foundation of your project and part of the quality control process required for the commissioning of a critical facility. Without them, the commissioning team is left without a clear set of criteria upon which to base their findings and actions.

In the design phase, we have a commissioning‐focused design review that should not be confused with a peer review. In a commissioning‐focused design review, the commissioning engineers should provide input on making the building and systems easier to commission and easier to maintain. They should also examine equipment layout, labeling schemes, and other ergonomic factors, which can result in a facility that operations team members find intuitively easy to work with. This, in turn, reduces the likelihood of operator error in emergency response situations. The CxA should also verify that bid documents adequately specify building commissioning as this will help reduce vendor change orders. It many cases it is better to have the CxA provide commissioning specifications and have them included in the pre‐purchase and other bid sets. The focused review also needs to verify that there are adequate monitoring and control points specified to facilitate commissioning and O&M (trending capabilities, test ports, control points, gages, and thermometers). A review needs to include a review of design as it pertains to the reliability and redundancy standards of the owner and industry standards and verifies that building O&M plan and documentation requirements specified are adequate.

During the construction phase, much of the rudimentary testing is accomplished. During this time, the factory acceptance testing is being conducted, and it is important to have the CxA involved to verify that the controls and interlocks will work with the complete system. During this time, equipment is being delivered and installed. During this installation, the vendors and GC should be verifying the installation using construction checklists provided by the CxA. These checklists basically track the construction process and verify that the vendor delivered what was paid for in good condition, installed properly, and has the proper clearance. The vendor startup will follow, and if performed in accordance with the agreed procedures, all the functions, including all the alarms, will be verified. It is important to track all these documents and have them signed off by the vendors as proof of proper startup. In some cases, the vendors will sign off the documents and not perform all the requirements, and that will slow down the acceptance and integrated testing. In this case of improper start‐up, the delays can be back charged to the responsible vendor.

In the Acceptance Phase, the CxA will first operate all the equipment in all configurations and verify the proper start‐up by the vendors. Once this is completed, the CxA should verify the performance of certain equipment without using vendor‐provided test gear. This is done to keep the quality control process in the hands of the CxA and make sure that only calibrated equipment is used, and the calculations are performed without bias. The equipment list below is recommended to be subjected to this extra acceptance test phase.

1 Emergency power systems and controls.

2 Uninterruptible power supply (UPS) systems and batteries.

3 Flywheel energy storage systems.

4 Static Transfer Switches (STS) and all associated controls.

If the acceptance testing is done properly, it should, at a minimum, verify the equipment is worthy of critical load. In some cases, deficiencies found during this process have forced the vendors to meet their own specifications and improve product quality.

We are now ready for integrated testing, and the intent of this test is to verify that the building and all the systems work together to meet the client’s design requirements. Some hints for having a successful integrated test that proves proper operation and no unwanted system interaction are:

1 Perform a full data center heat load test, including any enclosed cooling systems.

2 Perform integrated testing at 25%, 50%, 75%, and 100% of the design load.

3 Use data loggers on the data center floor to verify measured data and BMS controls.

4 Check all operating modes, including maintenance configurations.

Staff training and operations documents need to be provided before we can start operations. Proper training must be given to the staff for systems and integrated operations. I would suggest that the vendors provide system training, and the CxA provides overall operations documents. The operations documents should include Maintenance Operation Procedures (MOP), Emergency Operation Procedures (EOP), Standard Operation Procedures (SOP), and Alarm Response Procedures (ARP). With properly trained staff and proper operations documents, the human error faults can be minimized.

As we stated earlier, the commissioning process continues into the occupancy phase to maintain operational continuity. A yearly review and update of training as required due to system upgrade or operational requirements maintains staff and procedural quality. For mission critical facilities, a yearly verification of performance for critical electrical system prevents loss of productivity due to system degradation referred to as Reliability Assurance Testing. These tests should be similar to those performed in the system acceptance test procedures used during the acceptance phase and use the original data for trending any changes in the system. The Reliability Assurance Testing should be performed after the vendor has provided Preventive Maintenance (PM). The reason we perform these tests after the vendor preventive maintenance routine is that the vendor just interacted with a commissioned system and disassembled some portions. In some cases, they are providing updated software or control boards. The system now needs to be certified through Reliability Assurance Testing to be worthy of critical load. Remember that the vendor provided PM does not measure performance or track system degradation, so without a Reliability Assurance Testing program, the quality control process had been compromised.

Before the facility goes on‐line, it is crucial to resolve all potential equipment problems (Technology, Operations, etc.). This is the construction team’s sole opportunity to integrate and commission all the systems, due to the facility’s 24/7 mission critical status. At this point in the project, all systems installed were tested at the factory and witnessed by a competent Commissioning Authority (CxA) familiar with the equipment processes and procedures.

Once the equipment is delivered, set in place, and wired, it is time for the second phase of certified testing and integration. The importance of this phase is to verify and certify that all components work together and to fine‐tune, calibrate, and integrate the systems. There is a tremendous amount of preparation in this phase. The facilities engineer must work with the factory, field engineers, and independent test consultants to coordinate testing and calibration. Critical circuit breakers must be tested and calibrated prior to placing any critical electrical load on them. When all the tests are completed, the facilities engineer must compile the certified test reports, which will establish a benchmark for all future testing. The last phase is to train the staff on each major piece of equipment and prepare for the transition to operations.

Many decisions regarding how and when to service a facility’s mission critical electrical/mechanical equipment are going to be subjective. The objective is easy: a high level of safety and reliability from the equipment, components, and systems. But discovering the most cost‐effective and practical methods required to accomplish this can be challenging. Network with colleagues, consult knowledgeable sources and review industry and professional standards and best practices before choosing the approach best suited to your maintenance goals. Also, keep in mind that the individuals performing the testing and service should have the best training and experience available. You depend on their conscientiousness and decision‐making ability to avoid potential problems with perhaps the most crucial equipment in your building. Most importantly, learn from your experiences and those of others. Maintenance programs should be continuously improving. If a scheduled procedure has not previously identified a problem, consider adjusting the schedule respectively. Examine your maintenance programs on a regular basis and make appropriate adjustments to improve constantly.

Acceptance and maintenance testing are pointless unless the test results are evaluated and compared to standards, and to previous test reports that have established benchmarks. It is imperative to recognize failing equipment and to take appropriate action as soon as possible. Common practice in this industry is for technicians to perform maintenance without reviewing prior work tickets and records. This approach defeats the value of benchmarking and trending and must be improved. The mission critical facility engineers can then keep objectives in perspective and depend upon his/her options when faced with a real emergency.

The importance of taking every opportunity to perform preventive maintenance thoroughly and completely ‐ especially in mission critical facilities‐cannot be stressed enough. If not, the next opportunity will come at a much higher price: downtime, lost business, lost potential clients, and not to mention the safety issues that arise when technicians rush to fix a maintenance problem. So, do it correctly ahead of time and avoid shortcuts because it will be very difficult to do it again.