Automotive exterior testing has been using back spray for years. It’s required in order to run SAE J2527, the performance-based replacement for SAE J1960. This is the only standard that we know about which requires this odd function. Although we do offer back spray as an option on our Q SUN Xe-3 and Xe-2 testers to meet this standard, one may still wonder: does the back spray function accomplish anything? Is it useful?

The answer to both questions is an unequivocal NO. Furthermore, back spray is counterproductive, since it wastes a lot of water and can at times even wash off specimen labels.

The back spray requirement in SAE J2527 provides a great example of the perils of hardware-based weathering standards. The original tester used in developing this standard was improperly set up for this back spray “feature” over 25 years ago, and its implementation via a hardware-based standard forced everyone to propagate this error. As a result, today we’re stuck with a standard that uses more than twice the water it should, can only be run in certain testers, and does not produce better results than front spray or condensation test procedures.

To read more about Q-Lab and to find more articles like this, please visit Q-Lab Blog.