CARB Holds Workshop to Discuss "Performance-Based Options" for Solar Glazing Regulations; Final Draft to be Released by End of October
September 17, 2009

The California Air Resources Board is holding a workshop today in El Monte, Calif., to discuss the Performance-Based option for the recently adopted "Cool Cars" regulations, which call for enhanced auto glass to reduce the use of air conditioners in vehicles in the state. CARB calls for total solar energy that enters a vehicle through the glass to be reduced by 2014 using both solar-absorbing and infrared-reflective glass.

The regulations call for an even further reduction of solar energy by 2016-using either solar-absorbing or infrared-reflective glass or "a combination of technologies that result in equivalent reduction in solar heat gain." The aim of today's workshop is to discuss a test by which the "equivalent reduction in solar heat gain" can be measured.

The group is proposing two tests for the temperature based metric-one for stationary parked cars, and one for moving vehicles. In addition, CARB is proposing a possible CO2-based test, which would measure the vehicle's internal temperature and differences in CO2 emissions to reach a "comfortable temperature," according to today's presentation.

There are still many questions to be answered, though, if the CO2 test were adopted-such as what a comfortable temperature is, what test cycle would be used, and how the test correlates to actual driving conditions, according to a presentation from CARB.

The group also notes that a CO2 test could be somewhat complex and costly, and would need to be in place by the middle of 2016.

The final text of the regulation is scheduled to be released by the end of October, at which point a 15-day comment period will begin. The final regulation must be approved by May 2010, according to information from CARB, so it can be submitted to the full Board for review in summer 2010.

In the current draft of the regulation, the first tier of the current regulation draft calls for the following: 50 percent TTS through the windshield, 60 percent TTS through the sidelites and backlites and 30 percent TTS through sunroofs. The second tier calls for a further reduction of TTS-to 40 percent in 2016, for all except the sunroof, for which CARB calls for 30 percent TTS in 2016, or a combination of technologies to achieve the equivalent result.

The regulations initially focused on the use of reflective paints, but during their development, the paints effort was dropped and glazing requirements were added. The regulations came about as a result of California AB 32, a bill passed in 2006 aimed at reducing the state's greenhouse emissions. The goal of the glass regulations is to reduce the load on a vehicle's air conditioner by cooling the vehicle through the glass.

The regulations were then extended to include a possible equivalent for the 2016 phase, during the June hearing during which the board voted to adopt the regulations, at the suggestion of several in attendance, including CARB member John Balmes.

"I feel much more comfortable with performance-based standards were there are alternatives available, because I just think we get into trouble when we try to be too prescriptive about any one specific technology," he said.

Another board member noted at that time that by extending the regulations beyond the glass, it opens it up for something the entire nation might take on.

"But if our true goal is to reduce greenhouse gases, I think the most important thing we can do is to write a regulation that … is not just used in California but is used throughout the United States," said CARB member John Telles. "And if we have something that is too prescriptive or whatever, that is not being-that cannot be incporated in the rest of the United States-then we-then we haven't really accomplished our goal. We've just kind of put a little bit of water in the bucket, but didn't fill the bucket."

CLICK HERE for full text of today's presentation.

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