The Pathway to High-Performance Buildings
Originally published by: Building Enclosure — May 24, 2019
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Editor’s Note: Building envelope issues impact multiple performance issues in a building including HVAC performance, building pressures and increase the risk of moisture intrusion. If a properly design building envelop system is correctly aligned with thermal, air and moisture control layers problems from moisture intrusion, poor indoor air quality and comfort complaints are reduced. Missing details, incorrectly placed barriers, disconnects in the continuous systems are all common design considerations that will impact the building performance for years to come. Sealants or transition materials may not be specified correctly at intersections of components or there might be missing sealant requirements for penetrations by fasteners when installing cladding or bracing for exterior shading. Wall sections may promote thermal bridging, which is the unrestricted movement of heat through the wall section. This leads to excessive energy leakage and lost cost. The Continuous Insulation website was built to help provide the science behind details, like energy performance, transition detailing, WRBs, thermal bridging and so forth.
Photo Courtesy of Kingspan Insulated Panels
The term commissioning, referred to as Cx by the pros, is a process for new and existing buildings that ensures the systems and components in a building are designed, installed, tested, operated and maintained according to the operation requirements of the owner or final client. The commissioning process can improve the efficiency of the equipment and systems to prevent issues from construction, installation and maintenance negatively impacting the performance and energy usage over the lifespan of a building. Through a systematic evaluation of the buildings designed and implemented systems, the commissioning process formalizes review and integration of all project expectations during planning, design, construction and occupancy phases by inspection, functional and performance testing, and oversight of operator training and record documentation.
When assessing the benefits, barriers, opportunities and savings that encompass the commissioning process, who better to ask than a working industry professional with over 15 years’ experience in the field? In this Q&A session with NCBPA Board Chair and building scientist, Meghan McDermott of High-Performance Building Solutions, we will discuss the benefits, goals, setbacks and industry trends of all things Commissioning.
The Benefits of Pursuing Building Commissioning
Commissioning is an all-inclusive, quality assurance-based process working with project and operation teams which document the planning, delivery, verification, and managing risks to functions performed in, or by, buildings. Commissioning also helps to maximize energy efficiency, extended performance, and ensure environmental health and occupant safety. The process also improves indoor air quality by making sure the building components are working correctly and that the plans are implemented efficiently and effectively. Commissioning reduces operating costs while delivering preventive and predictive maintenance plans, tailored operating manuals and training procedures for all users to follow.
Meghan McDermott: "The main benefit of pursuing whole building commissioning is that there is an independent third party reviewing the design, construction and O&M of a building to ensure the overall performance meets the owner’s requirements. The process ensures the owner is getting what they need and want within their budget, hopefully without costly change orders once construction starts. Catching missing items or deficiencies in the design phases reduces the likely hood of costly changes during construction or worse when the building is completed and occupied."
Goals to Accomplish in Each Project
There are various goals associated to differing projects and building types, but generally, once setting a Commissioning scope, budget, plan and schedule, the overall goal is to deliver buildings and construction projects that exceed or meet the owner's project requirements (OPR). Once a project undergoes commissioning, there are opportunities to prevent or eliminate problems inexpensively through proactive quality techniques, verify systems that are installed and working correctly and benchmark those correct operations.
When reviewing the final commissioning report, a major goal, which is almost always accomplished, is to lower overall first costs and life-cycle costs for the owner. Providing documentation and records on the design, construction, and functional and performance testing can facilitate ongoing operation and maintenance of the facility—this can be done by implementing trend logs and various automated Cx tools to enable the Operations and Maintenance (O&M) process. With these Cx goals and others, the important deliverable is to maintain performance for the entire life cycle of the building.
Common Barriers Found in the Commissioning Process
Every new and existing construction project is unique, but many of the same design and construction issues arise from time and time again. Commissioning and the efforts involved are focused on avoiding these reoccurring issues, and in many cases the fee building owners pay for commissioning is paid back by the costs avoided detecting and resolving issues early, for a new construction project, for example. Many of the issues below are fairly easy to correct or plan for and, as many experts know, without commissioning involvement, new building projects are delivered without these types of issues ever being corrected.
- Mechanical equipment sequences of operation: Frequently, sequences of operation in mechanical design documents create conflict between systems or could be unclear to installers and controls contractors. At times, they are missing entirely from the design documents and do usually not integrate energy savings operations.
- Missing mechanical equipment in design documents: Missing mechanical system equipment in the design documents, such as mini-split systems serving IT closets, exhaust fans, dampers, access panels, and valves, is common upon walkthroughs.
- Electrical circuits not sized appropriately for loads: It is important for Cx agent to inspect circuit capacity and comment when the design includes loads larger than circuit components can accommodate, or when circuit components are oversized significantly, and financial savings are available by reducing components to a more appropriate size.
- Building enclosure infiltration: Enclosure issues can impact multiple performance issues in a building including HVAC performance, building pressures and increase the risk of moisture intrusion issues. If a properly design building enclosure system with correctly aligned thermal, air and moisture control layers are not problems included from moisture intrusion, poor indoor air quality and comfort complaints are common. Missing details, incorrectly placed barriers, disconnects in the continuous systems are all common design issues that will impact the building performance for years to come. Sealants or transition materials may not be specified correctly at intersections of components or there might be missing sealant requirements for penetrations by fasteners when installing cladding or bracing for exterior shading. Wall sections may promote thermal bridging, which is the unrestricted movement of heat through the wall section. This leads to excessive energy leakage and lost cost.
Meghan McDermott: "The main barrier to building enclosure commission (BECx) is lack of understanding of the process and fears that the cost is too expensive. Several building owners I have talked to have asked their team about including building enclosure commissioning and it has been scrapped because of cost. When I investigated the cost estimates, they were including all of the performance testing in the NIBS guide instead of just the performance testing that was beneficial to the owner. As with any commissioning project the main objective is to follow the Owner’s Project Requirements (OPR), if the owner wants to do just a few performance tests related to the enclosure that is fine; there is no need or budget to cover all the performance tests listed in NIBS."
Gather installed technology manuals, drawings, specs, and other documents before starting commissioning process – it is difficult to locate documents at manufacturers resources or websites. Ensuring that the building is prepped and there are set times for operating is critically important, keeping to a schedule and keeping track of daily changes will add up to significant positives that will likely not delay the project. Understanding the most frequent commissioning issues documented in both the design and construction phases of new or existing building commissioning projects can give building owners and managers a leg-up on ensuring these issues are resolved quickly and efficiently.
Meghan McDermott (A): "For the BECx discuss with the Owner at the beginning the reason they want to include BECx in their project. Many times, during the discussion you will find they have had specific issues in their existing building inventory. The Owner will be able to provide insight into what performance testing is critical to their needs; include performance testing that will address the issues from previous projects and where common failures occur, not everything in the NIBS guide."
Trends in the Cx Industry
Meghan McDermott (A): "LEED Version 4 including Building Enclosure Commissioning credit instead of just getting an Innovation in Design credit will likely increase the number of projects we see pursuing building enclosure commissioning."
The Commissioning process has been practiced for years but has been required and marketed in various ways. Historically, voluntary green building certification standards have been the primary driver for Cx standards, specifically for LEED and ENERGY STAR building certifications. Green building certifications have their own set checklist of requirements that the Cx agent must complete to obtain the credit or compliance for that specific project. Although, with a wider and advancing market growing for green building across the U.S., sustainability goals, building codes, and utility incentives have been implementing required Cx standards into state-wide building codes and utility incentives.
For example, a successful market-based policy measure known as commercial building benchmarking has been making its way across the U.S. for several years and is becoming more and more popular. Several states such as California, Washington and Maryland have adopted commercial building benchmarking laws which vary from state-to-state. With the energy code being implemented across various states and mandates such as benchmarking laws are becoming more and more popular, the push for Cx will not only become good practice, but will be required for testing and maintaining optimal building performance.