Question About My School's Fire Alarm System

I have a question about my school’s fire alarm system. I little information first. The bell for the beginning of classes is a beeping noise on the intercom, like most schools. When there is a fire drill, the intercom speakers make a Hi-lo style noise and all the notification appliances go off. If an announcement is made on the intercom and the bell rings while the announcement is being made, the bell overrides the intercom announcement, so you cannot hear the announcement while the bell rings, only the bell. The notification appliances do code 3 in a fire drill.

Anyway, one day at school it was almost the end of 7ᵗʰ period, and that’s when they decided to a fire drill, and literally 1 second after the fire drill was started, the bell rang for the passing period to 8ᵗʰ period. (In other words, the end of 7ᵗʰ period) Immediately when the bell rang, the notification appliances SHUT OFF! Not even the strobes were going! The hi-lo noise on the intercom even shut off. I can understand why the bell would override announcements but the FIRE ALARM is another thing. Isn’t this a violation of NFPA code? I thought about this for the rest of the day. They started another fire drill afterwards but please, DOES ANYONE KNOW HOW AND WHY THIS HAPPENED? I’m just curious.

The hi-lo on the PA system is similar to what my elementary school did. I think, according to NFPA 72 (and I may be wrong), “mass notification” signals take priority over “fire” signals. I’m not sure what PA system your school has that’s tied to the fire alarm system.

Could have been in walk test? Or false alarm?

It’s a hacked together system if it ties to the PA system at all in the first place for notification. Nothing on a PA system meets fire code, particularly the requirement that all notification appliances be supervised. PA speakers aren’t. This has been in the code ever since voice systems were introduced in the 70s or 80s.

Mass notification was only introduced into the code in 2007 or 2010, and even though they take priority over fire alarm, the 7th period bell doesn’t meet the requirements of mass notification. It’s meant for weather alerts, lock downs, etc. not random school announcements.

Can you imagine: Bwwwwwwwwwa-bwaa a- bwaa. Then BOOOOOOOOOOOOOOOP. No fire then? Better go to 7th period!

Then why would a school’s PA system do a hi-lo tone for fire? My elementary school PA system did that too.

The high school I attended (going back to 1993 here) had an old Executone intercom system - the thing was huge by today’s standards, about the size of three washing machines, but probably “state of the art” in 1969 when it was installed. But anyway, I remember there was three switches near the top for “emergency overide”, one of the switches was labeled “air-raid”. Never knew what they actually did but assumed they broadcast some sort of tone over the speakers for whatever event was going on. Your fire alarm system must be tied in to some auxiliary function of the intercom system. Question is when was this done? Could be possible is was an approved method back in the day, even though it would not meet today’s standards. It is quite possible too the time clock system is an independent component from the intercom, and is simply connected to an auxiliary function of the intercom system, just like the fire alarm. I would imagine there is a priority to the system and the time clock got in front of the fire alarm on the priority and was never actually checked.

The school’s construction was finished in 1979. My father went there for middle school. He says the hi-lo sound went off during a fire drill back then. The band director has been working there since around 1984. (Yes, he has been teaching there for over 26 years) He says says it was the same back then. I do not know the FACP. It is in one of the many locked service rooms in the school. I could probably ask the head custodian, but then he would likely think I’m weird because not the average person would want to know the FACP model number.

I just emailed the school administrator. He might not answer because of chance of the use of the information for sabotage. Policies might prevent him from telling me.

Nah, its public record. You could get it from one source or another, plans were submitted to the city, there’s probably bids out there for any additions/remodels citing what the current fire alarm system is, etc.

As NFPA 72 2007 annex “E” systems are not to interfere with one another. I guess, maybe this has changed or the school does not comply with NFPA?

Allowing this old topic bump since it is by the OP.

I’ll ask about this one tomorrow at work if our “code guru” is working tomorrow – a lot of people aren’t because of the holidays.

This is an odd problem and does not make much sense… how can a PA system stop a fire system?

My best guess is someone accidentally shut off the alarms when they were not supposed to right at the same time as the bell ringing.

I guess thats about it. At my school, even if it’s a lockdown warning, the bell will ring in the middle…

Most PA systems are programmed so that the bell tone is a high priority event, which to me doesn’t make sense why that’s the high priority in the system.