System Sensor Creates Whitepaper Addressing UL 1971 Revisions

ST. CHARLES, IL - System Sensor, a Honeywell company, has created a white paper informing manufacturers, fire marshals, AHJs and inspectors in the fire protection industry of Underwriters' Laboratories(R) (UL) 2004 revisions to UL 1971, Signaling Devices for the Hearing Impaired. The revisions standardize how operating currents are measured and how voltage ranges are listed and published.

System Sensor's white paper shows that with the revision to UL 1971, fire alarm system notification appliance circuits will be more reliable as designers learn to use maximum RMS current values for voltage drop and battery calculations instead of nominal values.

"Fire alarm system designers need to understand the risk involved in not using the new maximum RMS current draw specifications now dictated by UL 1971," Scott Lang, product manager with System Sensor's Audible/Visible business unit, stated. "By using nominal 24 volt current draw specifications, you run the risk of having inoperable devices near the end of the circuit. That could mean delays during the commissioning of the system or even liability later on if the system fails to function properly."

To download the white paper visit