Dual Electrical Feeds Meet FA Secondary Power?

6/5/2025

Do dual electrical feeds from two separate sources (same service provider, two different substations) with a UPS storage battery system that will support full load for 4+ hours meet the requirements for fire alarm secondary power?

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6 Comments

Chad

6/5/2025 07:23:22 am

You need a generator if batteries are not calc'ed for 24 hours.

You can use an ESS or UPS for the 4 hours required to carry you between primary and secondary power.

2019 NFPA 72 10.6.7.3.1

The secondary power supply shall consist of one of the following:

(1)
A storage battery dedicated to the system arranged in accordance with 10.6.10

(2)
An automatic-starting, engine-driven generator serving the branch circuit specified in 10.6.5.1 and arranged in accordance with 10.6.11.3.1, and storage batteries dedicated to the system with 4 hours of capacity arranged in accordance with 10.6.10

Glenn Berger

6/5/2025 08:20:55 am

In the 2025 version of NFPA 72, Section 10.6 is applicable. This chapter has expanded greatly over the last few versions. I think that the answer to your question is -- maybe.

Todd E Wyatt

6/5/2025 08:40:03 am

The appropriate edition of NFPA 72 is determined by the scoping Code ... typically the IBC.

IBC-2024 ... NFPA 72-2022
IBC-2021 ... NFPA 72-2020
IBC-2018 ... NFPA 72-2016

From IBC-2024 :

Chapter 9 Fire Protection and Life Safety Systems
Section 907 Fire Alarm and Detection Systems
907.6 Installation and Monitoring
A fire alarm system shall be installed and monitored in accordance with Sections 907.6.1 through 907.6.6.3 and NFPA 72.
907.6.2 Power Supply
The primary and secondary power supply for the fire alarm system shall be provided in accordance with NFPA 72.
Exception: Back-up power for single-station and multiple-station smoke alarms as required in Section 907.2.11.6.

Ricardo Gonzales Jr

6/5/2025 09:07:16 am

My opinion. No.

We had this question at DEN with it's dual feed from the utility, different sub-stations, different power plants. This counts as a backup generator. However, the question comes along from NFPA 72 2019 Edition 10.6.6.1 states the secondary power shall be active within 10 seconds. So the utility can't act as a secondary power source.

However, the UPS/BESS may count if the power from the batteries is online in the 10 seconds and ALL the equipment powered from the UPS is accounted for in the calculations for duration of the 24-hours if no generator or the 4-hours plus alarm if there is a generator. The requirement goes back many revisions.

Jose Figueroa

6/5/2025 10:23:42 am

I wanted to say “no”, etc. All answers align.

Neil Chadwick

6/5/2025 10:28:37 am

Thank you for the replies! We tend to agree and are still requiring the 24-hr battery backup

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Dual Electrical Feeds Meet FA Secondary Power?

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