Objective - To develop test methods, reference materials, and control strategies to ensure low contaminant levels in low-energy buildings, and to enable their integration into product development, building design and retrofit guidance, standards, codes, and building material emissions labeling programs.
What is the new technical idea? NIST is developing the measurement science required to support strategies that maintain or improve indoor air quality (IAQ) in high-performance buildings. Changes that are being made in the design, operation and furnishing of buildings to save energy and promote sustainability (e.g., envelope insulation and tightening, alternative ventilation approaches, and installation of “green” building materials) have the potential to alter the indoor environment and to adversely affect the health and productivity of building occupants.
Formaldehyde reference material. The use of building materials with low volatile organic compound (VOC) emissions may allow energy savings by lowering outdoor air ventilation requirements. Many sustainable building programs require or otherwise promote low emitting materials and furnishings.. To support improved labeling of low VOC products, NIST is developing a formaldehyde reference material with known contaminant emissions profiles to ensure accurate determination of product emission rates. The reference materials will provide more confidence in materials and furnishings emission ratings systems that are used in specifications of low-energy and high-performance buildings.
SVOCs. Currently, some industry groups are proposing that building products be evaluated via a risk-based emission approach rather than a content-based approach. Content based evaluations list the chemical contents of a product. Risk based approaches would measure the emission of a chemical from a product, determine the transport to an occupant and the relative risk to that occupant. Although there are existing standards to measure VOC emissions from building materials, there currently is a lack of consensus standards that allow accurate quantification of SVOC emissions from building materials that are needed for SVOC exposure modeling. SVOCs may have comparable health risk as VOCs, but the fundamental processes controlling emission can differ significantly from that of VOCs. VOC emission rates from building materials are primarily dependent upon the VOC and material properties. In contrast, SVOCs emissions rates are dependent upon not only the material, but also the air flow over that material. There are several new analytical approaches that have been developed to measure SVOC emission parameters. NIST is leading an effort to validate these SVOC emission methods and develop consensus standards based on these new analytical approaches.
Emerging Indoor Concerns. Our knowledge of exposure to VOCs and SVOCs in the indoor environment is limited by what we can measure. New methods and instruments have expanded our ability to investigate previously ignored chemicals and exposures routes in the indoor environment. The oxidation of indoor chemicals typically is associated with elevated ozone concentrations, with many indoor irritant contaminants being ozone oxidation byproducts. However, the nitrate radical could also be a key oxidation agent indoors. NIST is coordinating an effort to measure indoor nitrate radical concentrations for the first time using a new instrument developed by the National Institute for Occupational Safety and Health (NIOSH). In addition, exposure modeling to SVOCs indoors has traditionally been concerned primarily with oral inhalation. However, SVOCs exposure can also occur through skin contact with surfaces, clothing, and bedding that has become saturated with SVOCs. Since SVOCs readily partition to these materials from the air phase, partitioning from these materials to the skin could represent a significant exposure route for some SVOCs. NIST is beginning an effort to investigate and design new methods for determining SVOC uptake through skin when exposed to air, clothes, and bedding.
What is the research plan?
Formaldehyde reference material. For VOCs and formaldehyde, the most effective and energy efficient control strategy is to reduce emissions from building products and materials. NIST has been developing a formaldehyde reference material to improve the reliability and reduce the uncertainty of emissions testing. These reference materials will allow manufacturers and designers to more accurately estimate indoor contaminant levels associated with different product choices and support existing and future product labeling programs. A formaldehyde reference material is being tested in an interlaboratory study to determine the variability of the use of the material. NIST will then produce the formaldehyde reference material for commercial use.
SVOCs and Standards. Control strategies for SVOCs in the indoor environment are largely non-existent. A risk based approach for SVOC exposure modeling requires consensus standards for determining SVOC emission parameters. There are several new analytical approaches that have been developed to measure SVOC emission parameters. NIST is organizing an ASTM workshop to promote better understanding of these new methods. In addition, NIST is leading an effort to support the development of consensus ASTM standards based on these new analytical approaches. Finally, NIST actively supports efforts by ASTM D22.05 (sub-committee on indoor air quality) to finalize a spray polyurethane (SPF) micro-chamber emission standard.
Emerging Indoor Concerns. NIST is coordinating an effort to field test NIOSH’s new nitrate radical instrument in a fully instrumented test house (air change, temperature, formaldehyde, nano-particles) to determine if the nitrate radical plays an important role in indoor chemistry. NIST is also developing a research plan to determine the feasibility of investigating new methods for determining SVOC uptake through skin when exposed to air, clothes, and bedding.