The intent of the 2010 revision to SAE J1319 was to create a new photometric table to allow an incandescent rear fog lamp designed to meet photometric values specified in United Nations (UN) Regulation 38 to also meet the photometric values contained in this standard. The photometric values shown in Figure 1 were lower than the UN. Regulation 38 values to account for differences between the UN. Test voltage of 13.5 volts versus the design voltage of 12.8 volts for incandescent light sources typically used in rear fog lamps at that time. With these changes, SAE J1319 and UN Regulation 38 were harmonized with respect to photometric values for rear fog lamps utilizing incandescent light sources.
However, L.E.D. light sources that may operate at constant current were were not fully considered in the 2010 update of SAE J1319. Rear fog lamps utilizing L.E.D. light sources may provide the same light output at any given test point throughout a range of voltages. An L.E.D. rear fog lamp designed to meet the minimum photometric values of UN Regulation 38 would be able to meet the lowered photometric values in Figure 1 of the 2010 version of this standard.
The issue needing to be addressed is that L.E.D. rear fog lamps fulfilling the UN Regulation 38 requirement that the maximum luminous intensity in which all directions in which the lamp can be observed designed is 300 cd per lamp can fail the 250 cd maximum luminous intensity value shown Note 1 of Figure 1 of the 2010 version of this standard. This is because the light output of rear fog lamps utilizing L.E.D. light sources may not be reduced in the same manner that occurs in rear fog lamps utilizing incandescent light sources. Accordingly, Note 1 of Figure 1 of this standard has been revised to read “The maximum luminous intensity in all direction in which the lamp(s) can be observed is 300 cd per lamp.” With this change, SAE J1319 and UN Regulation 38 are harmonized with respect to photometric values for rear fog lamps utilizing incandescent light sources and/or L.E.D. light sources.
Section 3.3 L.E.D. definition added. 6.1.7 Color section renumbered to 6.2 to coincide with 5.2 Color Test. Subsequent section numbers adjusted accordingly.