Building Commissioning is a quality-oriented process for achieving, verifying, and documenting that the performance of facilities, systems, and assemblies meet defined objectives and criteria. It begins at project inception and continues through the life of the facility. The process of commissioning, as defined by ASHRAE Guideline 0-2005 The Commissioning Process, can be applied to any system, new or existing.
In order to understand how commissioning can be applied to the building envelope, you must first understand the overall Commissioning Process. There are four commissioning phases to a project: Pre-Design, Design, Construction, and Occupancy and Operations, with each phase having specific commissioning tasks that should be completed. The commissioning authority should be on board at project pre-design in order for the owner’s project requirements to be developed and used to guide the remaining scope of work.
The major components of the commissioning process include: developing the owner’s project requirements(OPR), developing the commissioning plan(CP), creating the basis of design(BOD), reviewing plans, specifications and submittal documents, conducting pre-installation meetings and site inspections, conducting testing of systems, developing systems manuals, conducting training for staff, and finally verifying that all systems are working properly and meeting the owner’s project requirements. It should be noted that the OPR and CP should be developed in the pre-design phase and updated throughout the course of the project.
Commissioning of the building envelope is often overlooked when it comes to this process. After all, most LEED-New Construction(NC) only requires that the HVAC, lighting, domestic water and renewable energy be commissioned in order for a project to be certified. However, according to LEED-NC 2012 drafts, building envelope commissioning is now being taken into consideration. The systems listed above will still be a prerequisite, but the building enclosure must be included and reviewed in the OPR and BOD. In addition, points will be awarded as an option under the enhanced commissioning credit if full envelope commissioning is addressed in accordance with ASHRAE Guideline 0-2005, and NIBS Guideline 3-2006, Exterior Enclosure Technical Requirements for the Commissioning Process.
Although LEED Existing Buildings(EB) does not require building commissioning for a project to be certified, points are awarded if the lighting, process loads, HVAC & R, domestic water heating and renewable energy are commissioned. There is no specific mention of building envelope commissioning, however the process can still be applied.
Evaluate the current performance of the building envelope by reviewing
prior design and submittal documents, and conducting investigative
site visits. Perform testing on the building envelope which may
include scanning the envelope with a thermal imager and performing
water and air infiltration testing. Then, evaluate the results and
determine if the envelope is performing up to the standards and owners
requirements. If it is not, implement solutions by developing
improvement plans. Finally, verify that improvement goals have been
achieved by using the methods previously mentioned.
NIBS Guideline 3-2006 should be used in conjunction with ASHRAE Guideline 0-2005. The NIBS guideline focuses on applying the commissioning processes described above to the building envelope. It addresses performance objectives for the exterior enclosure including the control of heat flow, air flow, noise, fire, light, infrared, ultraviolet, rain penetration, moisture, structural performance, durability, security, reliability, aesthetics, value, constructability, maintainability, and sustainability, however commissioning objective requirements will vary tremendously by type of owner, type and size of building and project objectives.
In summary, the commissioning process is an excellent tool in ensuring that a project is meeting the owner’s requirements and buildings are performing up to energy standards and codes. Although envelope commissioning may be new to some, it is important to include in your commissioning plan. “The building envelope plays a crucial role in the performance of any building. A failed building envelope will not only create persistent operational problems from leaks and drafts, other building systems cannot perform as intended. ” (Commissioning the Windows: Design Phase Strategies for High Performance Buildings)
Top 10 reasons you should include the building envelope in your commissioning plan
- Financial Savings – Energy costs will be reduced by ensuring that the envelope is sealed properly and commissioned systems are coordinated. “Operating costs of commissioned buildings are reported at 8-20% lower than those of a comparable non-commissioned building.” (General Service Administration, Building Commissioning)
- Achieve LEED Points and Certification – Meet LEED certification needs by adding envelope commissioning prerequisites and recommendations.
- Assure the Owner’s Project Requirements are met – Checklists are developed at project inception to track and coordinate progress, making the commissioning process as seamless as possible. This ensures all of the owners requirements are accounted for and followed throughout the life of the project.
- Assure there are proper design documents – There can be design errors related to weather barriers, air barriers, vapor barriers, glazing assemblies, and roofs. Design and specification documents should be reviewed throughout the project.
- Prevent water and air intrusion, mold, mildew, and poor indoor air quality – If there is a moisture problem, it will be from the building envelope. Envelope assemblies should be field tested and verified to ensure proper installation.
- Installation quality control – All components of the envelope systems should be properly documented and regular site visits should be conducted to ensure proper installation.
- Integrate facility systems and coordination among disciplines – In order for the HVAC system to work properly, the envelope must also be performing up to its requirements. Coordination among building systems is crucial in order for the Commissioning Plan Objectives to be achieved.
- Proper training of building staff – Verifying that building operators are familiar with the building envelope is important to long-term performance. They should be trained as to the maintenance requirements of the envelope systems and have the ability to identify components that may not be performing to requirements.
- Enhanced Environmental Credentials – Building envelope commissioning is a valuable selling point and will be above the rest in a competitive marketplace.
- Occupant/Tenant Comfort – A building with properly functioning envelope and HVAC systems provides occupants with a comfortable and healthy work environment in all weather conditions. This is the building owner’s ultimate goal – a building full of satisfied tenants.
Shauna Sproul has a Bachelor’s Degree in Civil Engineering with 3 years of building envelope experience with Glazing Consultants. Shauna has provided forensic investigations, analysis and report compilation as it relates to hurricane damage. Ms. Sproul also holds a Certified Building Commissioning Professional title from the Association of Energy Engineers as well as a LEED Green Associate certificate from the United States Green Building Council. Shauna can be reached at email@example.com