Guidelines for Design
|Any building project is complex, from the first design concept through
to the final stages of construction and occupancy. Some buildings, such
as those with unusual electrical or air-conditioning systems, or those
with special “green features”, may require extra attention to be sure
that they operate as designed. Ensuring that all features and systems
are built and function as intended is called building commissioning.
Commissioning buildings usually covers air conditioning, electrical, communications, security and fire management systems and their controls. It may also include other systems and components, particularly if they are unusual or complex. Commissioning begins by documenting design intent for future reference. This is followed by testing components when they arrive on the jobsite, and again after they are fully installed. Adjusting (balancing) of air and water distribution systems to deliver services as designed, and checking and adjusting controls systems to ensure energy savings and environmental conditions is the next phase. Providing maintenance training and manuals for building staff is usually the last step of commissioning.
Along with drawings and equipment manuals, a final commissioning report is also submitted to the owners. A complete commissioning report contains all records of the commissioning procedures, testing results, deficiency notices and records of satisfactory corrections of deficiencies. In rare cases, commissioning may also extend to testing the building and systems several months or a year after occupancy.
System commissioning is primarily done by a mechanical consultant with special experience and training, ideally hired by and responsible directly to the project owner and often independent of the mechanical design firm and contractor. A special commissioning coordinator may be responsible for whole building commissioning for very complex projects such as health care facilities. The architect typically oversees the completion of commissioning.
Commissioning is a relatively new procedure that includes what was formerly referred to as “testing, adjusting and balancing” but it goes several steps further. Commissioning has been found to be very valuable, particularly with complex mechanical and electrical systems, to ensure that they operate as intended, and to realize energy savings and a quality building environment - which are often the reasons more complex systems are installed. When special building features are installed to generate renewable energy generation, recycle waste or reduce other environmental impacts, commissioning is often necessary to ensure optimum performance.
Two of the Santa Monica Sustainable City Program goals are to increase the use of conservation techniques and practices, and to reduce non-renewable energy use. Many of today’s buildings contain highly sophisticated conservation and environmental control technologies which, in order to function correctly, require careful supervision of installations, testing and calibration, and instruction of building operators.
The purposes of commissioning are to ensure:
performance of contractual obligations;
quality of construction and correct operation of all functions;
environmental quality and energy-efficient operation as designed; and
that complete as-built information and operating and maintenance information are passed on to owners and operating staff.
The degree of commissioning should be appropriate to the complexity of the project and its systems, the owners’ needs for assurances, and the budget and time available. HVAC commissioning costs from 1% to 4% of the value of the mechanical contract. In 1996 whole building commissioning for an office building cost $0.20 to $0.40 / sq.ft.depending on the degree of the process and complexity of the systems.
Which Buildings Need Commissioning?
Formal commissioning is recommended for buildings with complex and digitally-controlled HVAC systems, or those with renewable energy, on-site water treatment systems, daylighting or occupancy sensor lighting controls, natural ventilation systems integrated with HVAC systems, or other unusual technologies. Commissioning is usually not used for projects with very little mechanical or electrical complexity, such as typical residential projects.
Commissioning also serves an important construction quality-control function for all building types, and helps consultants track the progress of contracts. Commissioning should be done for:
- both new construction and major retrofits;
- medium or large energy management control systems (systems with more than 50 control points);
- unusually complex mechanical or electrical systems;
- on-site renewable energy generation systems, such as solar hot water heaters or photovoltaic arrays; and
- innovative water-conservation strategies, such as graywater irrigation systems or composting toilets.
Last updated: Monday, 02/08/2010