Commissioning LEED™ Buildings: Different Levels of Sophistication Require Different Levels of Commissioning

A typical US Green Building Council LEED certified building is anything but typical. For example, small office buildings are installing complex mechanical systems such as central plants with thermal energy storage and underfloor air distributions systems in an effort to increase energy efficiency. The rigors of the LEED rating system require advanced energy performance and excellent indoor environmental quality coupled with top-notch construction practices. The commissioning authority is charged with verifying that these advanced concepts are translated into reality. This paper presents three case studies that examine the ways that building type, system complexity, and owner commitment impact the scope of the commissioning process for a LEED green building.

Introduction

What is LEED?

The Leadership in Energy and Environmental Design (LEED) Green Building rating system is a self-assessing system designed for rating new and existing commercial, institutional, and highrise residential buildings. It evaluates environmental performance from a "whole building" perspective over a building's life cycle, providing a definitive standard for what constitutes a green building. LEED combines seemingly disparate measurements of “greenness” within a single point-based rating system. LEED was developed by the United States Green Building Council (USGBC). The system represents the USGBC’s efforts to develop a standard that improves environmental and economic performance of commercial building using leading-edge industry principles, practices, materials and standards.

In order to achieve LEED certification, a project must meet numerous prerequisite criteria and also earn a minimum number of “points” from a list of performance criteria covering everything from site selection to indoor air quality. The number of points earned by a project determines the level of certification awarded, ranging from “Certified” to “Platinum”. Commissioning the “fundamental building systems” is one of the prerequisites of a LEED green building. In addition to this prerequisite, one point can be earned by completing an enhanced commissioning process. The tasks completed as part of this enhanced process are referred to as “additional commissioning”.

Commissioning as a buzzword

While commissioning processes and procedures have been developed and applied to a variety of buildings for almost 20 years (and have been performed for Naval ships for much longer than that), the nearly instant popularity of the LEED rating system has created new interest in commissioning. Since the release of LEED version 1.0, commissioning has been re-introduced to the building community. Because it is a requirement for LEED version 2.0 certification, many commissioning authorities throughout the country have seen an increase in project volume. In addition to more work, commissioning authorities are also working on a greater variety of projects such as 20,000 square foot libraries, tilt-up office buildings and ski lodges as well as “traditional” commissioning projects like medical and manufacturing facilities. The impact of LEED is also being felt in the sophistication of mechanical, electrical, plumbing, and envelope systems for all types of buildings, affording commissioning authorities the opportunity to work on more complex building systems. Of course, the most important advantage of commissioning’s sudden popularity is that more buildings are commissioned and, as a result, are working better. Not including LEED buildings, it is estimated that less than 1% of new...

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