For example, photoelectric sensors do better with smoldering fires that grow slowly and produce a lot of smoke while ionization alarms are better for detecting fast growing, flaming fires. UL is not alone in this recommendation; many other fire safety organizations make the same suggestion. If you want more information on smoke detectors, we recommend checking out the National Fire Protection Association's helpful guide, "Safety Messages About Smoke Alarms. "How We TestedEase of UseOur testing team built a custom apparatus designed specifically to analyze each smoke alarm’s detection capabilities. It was placed in the center of a room measuring 25. 33 x 18.