The 2015 issue of AS 1670.1 changes the rules about occupant warning systems. That’s because AS 1670.1:2015 section 2.6 c says that a single fault on the audio distribution circuit must not affect more than one “area of occupant warning covering not more than one level and not more than 2000 m².”

A single supervised 100 Volt audio circuit can no longer be used to cover multiple warning areas, because a single short-circuit will affect the entire circuit.

Two Solutions

One option is to provide a separate amplifier for each area. Each amplifier drives a supervised 100 Volt line with speakers throughout the occupant warning area. Here at Pertronic Industries we build many systems like this. Typically the fire indicator panel will have multiple 50 Watt evacuation amplifiers.

Another approach is based on the Pertronic audio distribution modules (ADM-2, ADM-4). These modules split the output from one amplifier into multiple independently-supervised 100 Volt audio circuits. One amplifier can drive multiple parallel distribution modules. With a single 50 Watt or 120 Watt amplifier, we can cover multiple evacuation areas with AS 1670.1:2015-compliant monitored audio circuits.

Which is Best?

Sometimes one option is more economic than the other, so it’s worth costing both options.

Physical space can be important. Because of the ADM-4’s compact dimensions, a single-amplifier system with multiple ADM-4s will often fit into a smaller space than a multi-amplifier system.

Another important factor is whether the warning system will be used for non-fire messages. Our audio distribution modules can detect line faults even when the system is broadcasting audio. If the warning system is being used for non-fire audio, we recommend the use of Pertronic audio distribution modules.

Click here to find out more about Pertronic Audio Distribution Modules