Commissioning Your Building
Published on Wednesday, 19 March 2014 04:53:27 Written by Marc
In order to optimize your operational costs and to limit the carbon footprint, many companies are introducing new HVAC technologies and equipment into the market. They are making them so sophisticated and complex that the building owners and operators might easily get lost when trying to select a system for its efficiency or simply try to understand how some of the systems operate.
The process begins by identifying the needs and requirements of the building. The first question one can ask is, "Did the building owner define properly his or her needs and establish a proper budget for the installation of the HVAC systems in the new building?" Next, one must identify how much energy and effort each group really spends. Professionals know that they are often retained based on how competitive their fees are and will thus delegate to a design firm, which has the proper competence level, to make sound recommendations and translate into drawings the particular needs of the building owner. The question becomes, "Will the contractors, which are often the lowest bidders in the process want to take sufficient time to properly coordinate the tasks and understand properly how HVAC system operate, or will they simply read the drawings and install what is specified in them without asking any questions?" Will the work of measuring and balancing be carefully executed? The questions above come back at each construction project, and will always remain in doubt in the mind of those designing the building (architects, engineers, and system designers). In this context, it becomes important to consider integrating the "commissioning" process in the projects. It is a "continuous quality insurance process" that verifies and ensures that the systems installed correspond to the required specifications, and that they properly operate according to the building specifications. The commissioning can intervene at different steps of a project: New Construction
- Pre-design: The pre-design phase is very crucial because it allows the clients to define their needs. This includes the required space for the short and long-term; define the overall expected quality of the work (building standards, green certifications, sustainability, etc.), the cost of general operation during the life of the building, as well as the cost of energy, maintenance, and repairs. All of these items are defined at this stage. The pre-design phase also allows clients to establish the overall construction budgets, with the help of the various professionals involved, in order to make sure that the set targets are realistic and in-line with the overall requirements and expectations of the clients. Finally, it is at this stage that various concepts and visions on the overall project can be discussed amongst the stakeholders.
- Design: In the phase of "design," the concepts and detailed systems prepared by the professionals will be examined to ensure that they meet the building requirements. For example, the electromechanical systems that will require commissioning will be identified and elements of validation that will be required will be added to the drawings. Finally, the drawings will be verified in order to plan the layout of the equipment, and to allow maintenance specialists sufficient space in order to conduct maintenance. Drawings will also be reviewed to make sure the operation sequences to be implemented are explained with sufficient clarity, and for the level of performance required from the systems. It is important to note that in no case does the commissioning process substitute itself for the professional responsibility of the people conceiving the design.
- Construction: In addition to the standard construction activities, the contractor in charge of measuring and balancing (as well as the contractor in automation) will have an important role. They have to submit for approval, their drawings, as well as the procedures for measuring and automation (including the elements of calibration or regulation required and the coordination of the schedules of visits during the work). Close collaboration between the contractors is crucial. The automation contractors will play a more important role. They must submit for acceptance their drawings as well as their procedures of measurement or control, including the elements of calibration or of regulation that are required as well as the schedule of visits for the coordination during the construction work. The close collaboration between them is crucial in order to calibrate the systems and confirm their capacities and good working order. IN order to preserve their autonomy, it is recommended to hire them as direct subcontractors of the general contractor or hire them at the same level as the ventilation or plumbing contractors.
- Acceptance: The reports for start-up, balancing, and the "as-built" drawings will be received and examined at this stage. In addition, the process of adjustment starts if the results are not satisfying. The suppliers and installers of the systems will perform the work acceptance following the training provided to the owners' representatives.
- Post-Acceptation: In some cases, the mandate of commissioning could be prolonged past the construction period. This can be the case, for example, for a building in a northern region that was completed during the summer and which will require a differed commissioning period for the validation of the heating systems once the weather will be more favorable to allow for this work.
- Re-commissioning/Retro-commissioning: These two terms apply to commissioning work in an existing and occupied building. The difference being that re-commissioning implies the existence of a past building commissioning during the construction work, and retro commissioning is reserved for a building that did not previously undergo a commissioning process.
The re-commissioning/retro-commissioning becomes a necessity after a few years of operation (often when the operational energy and labor costs to maintain the systems increases significantly either compared to the first years of occupation or compared to other similar buildings.
The Re-commissioning/Retro-commissioning will highlight the elements answering the following questions:
- Is the equipment still performing as well as originally, in terms of flow, pressure, and electric power demand?
- Is the degradation caused by normal wear, or by a deficiency of the maintenance program?
- Was the distribution network modified for new architectural configuration? Do the changes meet the standards? Were they subject to testing, adjusting and balancing each time?
- Are there abnormal leaks in the air distribution network?
- Are the elements of control, such as the terminal boxes, the dampers, and valves still in good working order?
- Are the initial hourly schedules as well as the sequences of operation respected? Are the implemented modifications justified?
- Are there particular needs among the building occupants (that require the systems to operate in unusual conditions)? What are the consequences of these requirements?
- Did the climatic needs of the building change in general? Are the existing systems easily adapting to the changes in question?
- What are the foreseen modifications required to remedy to the problems? Do we need to redo the testing, adjusting and balancing of the systems? Do we need to modify the design or even redo parts of the systems?
- The Owner
- The architect, the engineers, or the technicians
- The general contractor and his sub-contractors
- Those responsible for the systems maintenance
- Communicator: They must be able to demonstrate the importance of their plan and to get all the required information from the different stakeholders (namely the client);
- Diplomacy: Since they must remind the system designers that to attain the objectives and to ensure that the elements of commissioning are included in the plans, it is important that the professionals do not feel invaded in their respective fields of practice;
- Technical Competency: They must have good multidisciplinary experience, especially in electro-mechanical competencies, to be able to appreciate the subtleties of the proposed systems;
- Independence: They must report directly to the owner and not be part of one of the conception teams;
- Perseverance: The role of the commissioning responsible might span a period of more than one year. They must remain interested and motivated throughout the entire process.
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