Subscribe to glassBYTEs!

CARB Holds Workshop, Addresses New Proposed California Auto Glazing Requirements
March 13, 2009

The California Air Resources Board (CARB) held a public workshop yesterday to provide information about its proposed Cool Cars Standards and Test Procedures, including the changes to automotive glass requirements in the state.

The regulations would require that, beginning mid-year in 2012, all new vehicle windshields reflect at least 30 percent of the total solar spectrum, while still maintaining 70 percent visible light transmittance requirements.

In addition, under the terms of the regulations, starting mid-year in 2013, sidelites and backlights will not transmit more than 55 percent total solar transmittance, while still maintaining 70 percent visible light transmittance requirements when applicable.

The regulations would require that sunroofs and other glass roofs transmit no more than 20 percent of the total solar spectrum.

On the replacement side, the new CARB regulations would require that all auto glass replacements adhere to these standards as well, and records of all replacements—and their adherence to the regulations—would be required.

CARB anticipates that this will cost an extra $25 per windshield; and $6 to $25 per vehicle for sidelites and backlites.

During the workshop, CARB explained that the organization is working under the idea that 50 percent of solar heat gain via glass passes through the windshield, 20 percent passes through the backlite and 30 percent passes through the sidelites. CARB estimates that rooflites increase solar heat gain by 50 percent or more.

However, they predict that a windshield with a direct solar reflectance (RDS) of 30 percent will reduce "heat soak" temperatures by 4 degrees Celsius, and solar management glazing for the glance of the vehicle will reduce soak temperatures by 3 degrees Celsius.

CARB also discussed concerns about the regulations, such as that perhaps the RDS requirement for windshields should be higher; that solar-reflective front sidelites and backlites should be required to reduce the need for paint requirements; and that the requirements should be phased in with model changes, rather than with specific model years.

The group also said there still is more research to be done on the rooflite portion of the regulations. CARB is trying to answer the following questions:

  • What is the average/best performance currently available for rooflites?
  • How much more does better solar performance cost for rooflites?
  • What is the typical surface area of a rooflite per vehicle?
  • What percent of vehicles sold in California currently contain rooflites?

The group plans to investigate the aforementioned issues and questions and release a final draft of the regulations on May 11, at which point a 45-day public comment period will begin. On June 25, CARB will hold another hearing, during which the CARB staff will review the draft and decide whether to adopt it.

The proposed CARB regulations have come about as a result of AB 32, California's Global Warming Solutions Act of 2006, which requires the state to reduce greenhouse gas emissions to 1990 levels by 2020-a reduction of 25 percent. The glazing requirements are accompanied by several automotive painting requirements that CARB believes will work toward this goal.

CLICK HERE for full text of presentation.

Need more info and analysis about the issues?
CLICK HERE to subscribe to AGRR magazine.