Definition of standard office environments for evaluating the impact of office furniture emissions on indoor VOC concentrations

ASHRAE Transactions, July, 2007 by Randal D Carter, Jianshun S Zhang

INTRODUCTION

An evolving variety of sometimes conflicting test methods, model office environments, and requirements for modeling volatile organic compound (VOC) emissions from office furniture have been specified by various US organizations from 1989 to the present (Washington 1989; US EPA 1996; US EPA 1999; California 2000; Greenguard 2001; California 2004; USGBC 2004; BIFMA 2005a, 2005b; SCS 2005; California 2006). In these varied programs, environmental chamber testing of office furniture workstations or components is used to determine the emission rates, which are in turn used to estimate the impact of the workstation system on the VOC concentration levels in actual buildings by using a prescribed office environment model (i.e., occupant exposure scenario). Some of these programs define office environment models that are intended to be representative of specific buildings (Washington 1989; US EPA 1996; California 2000), while others do not contain any office environment model (US EPA 1999). The proliferation of office furniture emission programs with varied and potentially outdated office environment models raises questions as to how well the models represent actual building environments and makes it extremely difficult to compare VOC emissions performance across the broad variety of office furniture types available today.

The objective of this study is to define a standard, representative "worst-case" office environment model for new office furniture used in North American office buildings. This office environment model is intended to be used to provide a common basis of comparison for a broad variety of office furniture to relevant emissions requirements. These comparisons to requirements generally occur when estimating the impact of office furniture emissions on indoor VOC concentrations using the results of environmental chamber emissions testing. This study was conducted jointly with a working group of the Business and Institutional Furniture Manufacturers Association (BIFMA) (1) International, Furniture Emissions Standard (FES) Subcommittee, in support of the development of the BIFMA M7.1-2005 standard test method.

In 1994 the United States General Services Administration (GSA) requested that BIFMA develop a harmonized, voluntary, open consensus standard for office furniture emissions testing. Work began and in 1998 BIFMA filed public notice through the ANSI Project Initiation Notification System (PINS) announcing the ongoing development of a draft ANSI standard for office furniture emissions. In parallel with this work, BIFMA, along with the US Environmental Protection Agency (EPA), the Research Triangle Institute, and other relevant stakeholders, helped to develop the US EPA 1999 test protocol for large chamber emissions testing of office furniture. BIFMA FES work continued, reaffirming the ANSI PINS for office furniture emission standards in 2004 and leading to a test method development project, including this study, which was conducted in 2005. The results of this study have been incorporated into the BIFMA M7.1-2005 test method, which was issued by BIFMA following industry consensus in September 2005 and adopted as an alternative compliance path within the United States Green Building Council (USGBC) Leadership in Energy and Environmental Design for Commercial Interiors (LEED-CI) Environmental Quality (EQ) credit 4.5 for low-emitting furnishings on July 12, 2006. The state governments of California and Minnesota have incorporated the BIFMA M7.1 test method into their respective procurement specifications for office furniture. Scientific Certification Systems (www.scscertified.com) has also adopted the BIFMA M7.1 test method as part of their Indoor Advantage[TM] certification program. (2)

An office environment model defines the size and volume of the office space, the amount and type of office furniture surface area, and the outdoor, clean airflow rate. In this study, 31 randomly selected floor plans from North American office buildings were analyzed in detail. The floor plans were from current projects (late 2004 and early 2005) and were provided by an industry cross section of seven major office furniture manufacturers (see "Acknowledgments"). The analysis included documenting the potential emitting surface area for each workstation and determining how much common office space (aisles, etc.) was present as shared between workstations and other adjoining spaces. The 90th percentile conditions for total furniture surface area within the 50th percentile workstation footprint sizes were identified from the more than 5000 workstations analyzed, to provide a representative "worst-case" office environment model for estimating the impact of office furniture emissions on VOC concentrations.

This study is based on analysis of office floor plan drawings and related furniture dimensions. These drawings did not include measurements or specifications of ceiling heights or the airflow levels present in each building. Therefore, the requirements of ANSI/ASHRAE Standard 62-2001 and ANSI/ASHRAE Standard 62.1-2004 were used to determine the minimum amount of outdoor, clean airflow required in order to determine a representative "worst-case" office environment model. The two ASHRAE 62.1 standards were used because most US jurisdictions specify ASHRAE 62 as a minimum legal ventilation requirement within building codes and the USGBC has specified ANSI/ASHRAE Standard 62.1- 2004 as a prerequisite requirement for LEED projects. For determinations of office volume, a 2.74 m (9 ft) ceiling height has been assumed as a representative "worst-case" condition. The authors note the Standard 62.1 criteria and the emissions concentration calculations are based on steady-state environments, which are dependent on airflow rates (cfm or L/s) and not room volumes.