Consulting-Specifying Engineer - September 2008 - (Page 32)

\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\ agent with the opportunity to confirm that the manufacturers are providing the equipment as specified and that the systems meet the design intent. Factory testing provides the design team and commissioning agent with an opportunity to inspect and test the functional operation of the equipment before it arrives on-site. Once on-site, Load banks for testing static transfer switches and power any equipment defects or distribution units on the data center floor also can be used problems can cause delays as a heat source to test the HVAC systems. in the construction schedPhoto: KlingStubbins ule. The standard manufacconstruction documents to verify that the turer’s factory testing procedures typically goals and requirements set forth in the predo not fully test the function of the equipdesign are being met. ment, especially interfaces with building In this phase, the commissioning proce- controls, mechanical, and fire/life safety dures and acceptance criteria are outlined, systems. It is the responsibility of the comand the contractor and manufacturer’s missioning agent to confirm that the factory expectations are identified. Determining testing procedures are adequate or develop how a system will be constructed and com- additional testing procedures to ensure that missioned/tested is important during this the equipment operates as required to meet phase because it may have an impact on the design intent. how the distribution system is designed. The commissioning agent also may be For example, phased construction may responsible for overseeing the factory testrequire additional load bank connections ing, confirming that the results meet the and/or isolation breakers to allow for testing acceptance criteria, and documenting any without affecting those portions of the facildeficiencies. ity already online. Systems with automated In this phase, the on-site commissioning (often programmable logic) controls and plan is finalized. All of the on-site commisinterlocks should be given special attention sioning test procedures and checklists are to ensure that the design documents include developed, and the commissioning schedsufficient operational details, such as timer ule is coordinated with the construction presets/ranges and operational sequences schedule. for all operational modes. The coordination study and arc flash analysis should be reviewed, implemented, Construction phase and verified during this phase. For safety, The construction phase is when the sys- it is recommended that those performing tems are manufactured, inspected, tested, the commissioning follow the industry stanand installed in accordance with the con- dards regarding use of the proper personal struction documents. This phase can be protective equipment in accordance with broken down into three steps for commis- the hazard risk category determined by the sioning: arc flash analysis. • Shop drawings submittal review • Factory testing Operation phase • Finalizing the on-site commissioning In the operation phase, installed equipplan. ment and systems are tested to verify and A review of shop drawings submittals ensure that they perform in accordance with for all major electrical equipment provides the design intent and owner’s operational the design team and the commissioning requirements. This phase also can be broken down into three steps for commissioning: • Individual equipment test • Discrete system test • Integrated system test. The first step tests each piece of equipment separately to ensure that it functions correctly before testing the equipment as an electrical system. This stage generally starts with a visual and mechanical inspection of the equipment to make sure that it was installed properly and that no damage occurred during shipping or installation. During a visual inspection of a piece of equipment, the commissioning agent should: • Compare nameplate data with design drawings • Inspect the physical condition • Inspect anchorage, alignment, and grounding • Verify that the unit is clean • Inspect connections • Verify breaker and timer settings. After successful completion of the visual inspection, electrical and functionality tests are performed on the individual piece of equipment to verify operation. Once the operation of each individual piece of equipment in the electrical system is confirmed, the equipment will be examined as a discrete system. For example, in the first step the power distribution unit, UPS, and switchgear are tested as individual components. In the second step they would be tested as a system to verify their compatibility under load and various operating conditions, such as on generator power, where harmonics can sometimes be an issue. Smaller facilities may not have any discrete systems. The integrated system test is the final step in the verification process. This is where the entire facility as a whole is tested. During this integrated system test, the mechanical, control, and life safety systems should be incorporated to evaluate the true operation of the facility’s combined systems. The most common electrical integrated system test is a simulated site-wide power outage, also known as the “black start” test. During this test, various partial systems failures can be initiated to stress the system and validate backup system performance. It is vital that the O&M personnel be involved in all testing so that they can 32 Consulting-Specifying Engineer • SEPTEMBER 2008

Table of Contents Feed for the Digital Edition of Consulting-Specifying Engineer - September 2008

Consulting-Specifying Engineer - September 2008 Contents Viewpoint Letters News M/E�Roundtable Selecting Appropriate Egress Strategies Commissioning On-Site Electrical Systems Mentoring Control Engineers and Technicians Casting Call for Cx Case Study New Products Equipment Lifecycles Advertiser Index Green Space

Consulting-Specifying Engineer - September 2008

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