System Sensor products are designed and manufactured to meet or exceed various product safety and certification requirements. To view our listings, please visit one of the following sites.
FM Approval Guide
The FM Approval Guide contains information about tens of thousands of products and services tested and FM Approved, as well as engineering data and technical information on the application and use of listed products. Registration is free and is required.
Underwriter’s Laboratories (UL)
Explanation of Published Voltage, Current, and SPL Specifications
In May 2004 Underwriters Laboratories changed standards UL 1971 & 464 to require that operating current measurements are made using RMS (root mean square) instead of peak or average values. RMS measurements more accurately predict the power consumption of a device since they take into account the entire current draw profile including surge, repetitive surge, and peak values. The published RMS current is the maximum operating current of that device within its operating voltage range. This current maximum may or may not occur at the endpoints of the voltage range.
Similarly, UL tests the audibility of devices by measuring them across the operating voltage range to determine the minimum sound pressure level produced at any particular setting.
During May 2004, UL also changed the way they list the voltage range of a device. All 12V products will be listed between 8 - 17.5V and all 24V products will be listed between 16 - 33V. Those devices are considered “regulated.” Any product that does not operate within these ranges will be listed as a “special application” with its operating voltage specified on the device.