In order to optimize your operational costs and to limit the carbon footprint, many companies introduce new HVAC technologies and equipment into the market. They are making them so sophisticated and complex that the building owners and operators can easily get lost when trying to select a system for its efficiency. Simply trying to understand how some of the systems operate can become a challenge.
The process begins by identifying the needs and requirements of the building.
Asking the proper questions
The first question one can ask is, “Did the building owner define properly the 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. They delegate to a design firm, which has the proper competence level, to make sound recommendations. The firm then translates 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. They 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:
- 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. It defines 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. This is achieved with the help of the various professionals involved. They do this 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. This is done to ensure that they meet the building requirements. For example, the electromechanical systems that require commissioning are identified and elements of validation that are required are added to the drawings. Finally, the drawings are verified in order to plan the layout of the equipment, and to allow maintenance specialists sufficient space in order to conduct maintenance. Drawings are reviewed to make sure the operation sequences to be implemented are explained with sufficient clarity. 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) has 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. This includes 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. Another option is to hire them at the same level as the ventilation or plumbing contractors.
- Acceptance: The reports for start-up, balancing, and the “as-built” drawings is 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 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. Retro commissioning is reserved for a building that did not previously undergo a commissioning process. This process 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?
- Does the air distribution network have abnormal leaks?
- Looking at the elements of control, such as the terminal boxes, are 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?
- Is there any particular need among the building occupants (that requires the systems to operate in unusual conditions)? What are the consequences of this requirement?
- 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?
Who must participate?
During the Commissioning process, varying degrees of participation of all of the stakeholders is required. In order for a Commissioning to obtain the anticipated results, it must rely on:
The architect, the engineers, or the technicians
The general contractor and his sub-contractors
Those responsible for the systems maintenance
The Person(s) Responsible for Commissioning (Commissioning Responsible)
Since the main role of the commissioning responsible is to coordinate and to validate, many qualities are attributable to them:
- 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.
How Much Does It Cost To Do a Commissioning?
The costs are generally correlated to the process of commissioning. Costs are between two and five percent of the total HVAC costs, and between 0.5 to 1.5% of the total cost for new construction. This includes roughly 20% of that amount for the consultant responsible for the process.
On some occasions, the commissioner responsible can use his/her experience to participate in identifying efficient solutions. The direct benefits from the commissioning process are often hard to quantify. One thing is certain; a project that does not go through a validation process, such as a commissioning, will run the risk of higher unforeseen costs during the construction. It will also most probably have higher energy costs during the building operations because of buildings systems that are improperly adjusted.
Commissioning does come at a cost. And it is difficult to quantify in terms of direct benefits. However, it is more in the reduction of risks, such as higher costs during and after construction, that commissioning brings benefits to the project.