Effect of Moisture Absorption in Plastic on Automotive Lamp Venting

The effect of water vapor transfer from plastic materials commonly used in automotive lighting assemblies can be experimentally measured. This is accomplished by isolating this phenomenon from other mechanisms effecting water vapor concentration in the lamp. Quantifying this effect helps to address design considerations for liquid water and water vapor egress in the lighting assembly. The relevance of the current moisture clearing type test required in the industry is discussed in light of the empirical results for this effect.