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Contaminant Control in High-Performance Buildings Project

Summary:

To develop test methods, reference materials, and control strategies to ensure low contaminant levels in low-energy buildings, and to enable their integration into building design and retrofit guidance, standards, codes, and building material emissions labeling programs.

Description:

Net-zero energy strategies have the potential to significantly impact the indoor air quality of buildings. This project is designed to better understand how strategies to achieve net-zero energy and sustainable buildings will impact the concentrations of high-priority indoor air contaminants and to support the development of effective low-energy solutions that also improve the health of indoor environments. Specific project outcomes include improved test methods for measuring the emission of aldehydes and amines from spray polyurethane foam insulation (SPF), development of formaldehyde reference materials for product emissions testing, and performance measures for low-energy indoor air quality controls.

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, with the potential to adversely affect the health and productivity of building occupants. [1,2]

For example, SPF insulation can reduce both conductive and convective heat losses in both new and retrofit construction. Because of energy saving programs the foam insulation industry expects to see significant growth in the use of their products over the coming years. [3,4] At the same time, federal agencies have received a number of complaints regarding health effects resulting from the installation of SPF in homes, which tend to occur several days to months following the SPF installation. Emissions from SPF can include isocyanates, amines, flame retardants, and aldehydes and may be due to product formulation issues or misapplication. Both EPA and CPSC (Consumer Products Safety Commission) are concerned about emissions from SPF and have efforts underway to address these issues. At present there are no standardized test methods that adequately address the measurement of chemical emissions of SPF insulation products. This project will investigate methods to quantify amine and aldehyde emissions from SPF in support of ASTM standards currently under development.

The use of building materials with low 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. Currently, EPA is promulgating a rule limiting formaldehyde emission from wood products. To support improved labeling of low VOC products, NIST is developing reference materials with known contaminant emissions profiles to ensure accurate determination of product emission rates. Improved data on the emission rates from materials and furnishings will be useful in low-energy and high-performance building design and in estimating occupant exposures. 

What is the research plan?

The research plan addresses the performance of IAQ controls for reducing contaminants and building energy requirements. The first objective of the plan addresses the emissions of SPF. Methods were developed to use micro chambers for measuring the emissions of aldehydes and amines from SPF products in collaboration with ASTM and CPSC. NIST participated actively within ASTM subcommittee D22.05 in the development of standard methods for measuring SPF emissions using micro chambers and an ASTM symposium on SPF standards development. In FY16, efforts will be made to experimentally validate the proposed standards.  Parameters for the proposed micro-chamber standard such as temperature, flow, humidity, carrier gas and reporting requirements have been recently agreed to by the ASTM workgroup. However, issues remain before the proposed standard can proceed to ballot.

Research will be conducted to determine possible causes of reported varying emissions based upon the SPF substrate. In addition, once a range of appropriate chemicals have been agreed upon by the workgroup the precision and bias for those chemicals must still be determined. In FY16 involvement with ASTM D22.05 will include efforts to finalize the SPF micro-chamber emission standards in preparation for ballot. 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 reference materials 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. In FY16, a formaldehyde reference material will be redesigned to minimize user variability. Testing of the new reference material will commence in collaboration with EPA. Coordination activities with other NIST groups (gas metrology, statistics, and flow) will be continued to ensure effective experimental designs and traceability of the final product.

 


[1] Fisk, W.J. and Rosenfeld, A.H. (1997). Estimates of Improved Productivity and Health from Better Indoor Environments, Indoor Air, Vol 7:3.

[2] Committee on the Effect of Climate Change on Indoor Air Quality and Public Health (2011). Climate Change, The Indoor Environment, and Health, National Academies Press, Washington, D.C.

[3] Logue, J.M., McKone, T.E., Sherman, M.H., Singer, B.C. (2011) Hazard Assessment of Chemical Air Contaminants Measured in Residences, LBNL Report Number 3650-E.

[4] National Science and Technology Council (2008), National Nanotechnology Initiative: Strategy for Nanotechnology-Related Environmental, Health, and Safety Research, Executive Office of the President: Washington, D.C.

Major Accomplishments:

Outcomes:

  • The further development of the toluene reference film. Packaging challenges were addressed to move the material closer to production phase.
  • Exposure scenarios were developed in conjunction with ASTM and the California Department of Public Health (CDPH) to assist in evaluating acceptable VOC emission rates in building products.
  • In-duct electrostatic precipitator (ESP) experiments showed that these devices are ineffective at removing nanoparticles (3-10 nm) and revealed the propensity of these devices to emit significant levels of ozone.

Impact of Standards and Tools:

  • Reference VOC source developed which is to serve as a NIST Standard Reference Material.