Much of the benefit to contractors from commissioning arises from improved planning, scheduling and coordinating of work. These benefits will only be achieved, however, if the commissioning agent makes commissioning a top priority, right through to acceptance of the completed installation. Therefore, it is important that the commissioning agent be assigned to the commissioning function and not be taken away from that function to do other tasks.
PreparationsThe commissioning agent's first task is to pull together:
- Statement of design intent
- Schedule information
- List of equipment and systems needing to be commissioned
- List of subtrades, suppliers and other contractors (most commonly the electrical contractor) who will be involved in the commissioning process)
- All submittal data and controls-sequence descriptions needed to prepare commissioning checklists.
The commissioning agent prepares a commissioning schedule that identifies commissioning tasks and the estimated time each will require. This is coordinated with the overall project schedule. Any conflicts need to be resolved, or at least identified, so they can be watched carefully.
This schedule is usually a simple bar chart. Typical events and tasks on it include:
- Dates for completion of installation, ready for pre-start checks, often on a system-by-system basis
- Elapsed time allowance for pre-start checks and start-up, possibly on a system-by-system basis
- Time allowance for correcting any pre-start problem and rechecking
The schedule is a critical planning and communications tool. It lets each supplier, subtrade and other contractors know when their work must be completed on a system-by-system basis in order not to delay commissioning and final acceptance.
Equipment and system pre-start and start-up checklistsThe commissioning agent prepares equipment and system pre-start and start-up checklists. These checklists focus on critical item that suppliers, subtrades and other contractors must complete before start-up can occur safely and operation under control can take place. These checklists should identify installation responsibilities and will generally cover:
- Equipment mounting and hook up
- Electrical services
- Controls installation, including safety controls
- Any other applicable pre-start requirement, for example, pressure testing, pipe cleaning and water treatment or boiler/gas/electrical inspections.
For efficiency, these checklists should be produced from master lists, with modifications to suit the project-specific equipment or system. The use of computers to store masters and retrieve, edit, file and print these lists greatly speeds their production and improves their content, consistency and legibility.
These lists identify who must do what in sufficient detail to define responsibility. When combined with the schedule, they also pinpoint when work must be done to stay on schedule.
Commissioning planThe schedule, the pre-start/start-up checklists and the functional-performance checklists together will form the commissioning plan. The timing of its preparation and the extent of its distribution is up to the contractor; however, preparation as soon as the necessary information is available is recommended,
Early preparation, including elapsed-time requirements and the optimum sequence of tasks, can help to identify any scheduling conflicts early, making resolution more likely. Subsequent schedule revisions are almost certain to be needed, but making revisions from a coherent schedule is much better than scrambling with no plan.
Distribution to all parties with responsibilities related to the successful completion and operation of the HVAC installation is recommended.
If everyone is not informed, there is reduced coordination. If they are informed and make commitments accordingly, then the contractor has a better basis for demanding and getting timely performance and results from subtrades and suppliers.
Operations instruction and demonstrationCommissioning is of little lasting benefit if the operating personnel do not understand the systems and how to operate them properly. The contractor who carries out Level One commissioning services should therefore include a well-organized series of instruction and demonstration sessions. However, it is important that the owner is informed of the operating and maintenance requirements of the HVAC systems and (the owner) is encouraged to participate and to implement a proper operations and maintenance program.
If appropriate, contractors may wish to make a service contract proposal to the owner, using their commissioning expertise and performance as partial evidence of his capabilities.
(To order SMCANA's HVAC Systems Commissioning Manual, write 4201 Lafayette Center Drive, Chantilly, VA 22021 or call (703) 803-2980; fax (703) 803-3732.