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This is one of the reasons why I'm not a huge fan of the mandatory use of voice evac systems. A lot of these newer installations seem WAY too quiet, and it seems from your shot of the hallway that the signals may be spaced too widely in addition to not being loud enough. Voice evac is also expensive, and it seems your school paid a lot of money for something that ended up being a net negative. It's like treating a roach problem with a grenade launcher except with firecrackers as the projectile.
That said, effective voice evac systems do exist. The newer wing of my former college uses Simplex TrueAlert speaker/strobes operating off a voice-capable 4100U panel. They’re decently loud compared to the ambient noise level, and it’s highly unlikely that there’d be a problem hearing them. However, the signals are also a lot more closely spaced than in your example, and more speakers usually means more $$$.
My old middle school was another one. The main system used horns, but the larger rooms all had voice evac. The speakers were Simplex 2902’s (actually made by Atlas Sound), on strobe plates. In the gym, there was also a Simplex 2901-9806, which is an EXTREMELY loud horn. It should’ve been removed with the introduction of the voice system, but they kept it anyway. When the system went off, you could easily hear the slow whoop, but the voice sounded muffled. Great speakers.
Source: Just a fire alarm geek.
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It got me thinking - how is current draw calculated for fire alarm speakers? Or at least, what is the equivalent, since I’d imagine it varies based on the content of the audio feed.
In my personal opinion, we need more “blended” voice-evac/horn systems that actually take into account ambient noise levels. For example, in a school a history classroom wouldn’t have nearly the same ambient noise level as a woodshop; just the same with an auditorium and a gymnasium. Voice-evacuation is perfect for areas where there may be a large concentration of people in a relatively small space (like a history classroom or an auditorium), and can reduce levels of panic or anxiety that come with hearing a startling horn. In areas like a woodshop, however, a fairly quiet speaker could go unnoticed for a long period of time. In those scenarios, horns or bells provide the most effective sound output. Of course, you could install audio boosters or use alternative speakers as opposed to horns, but why spend the extra money when you could just install a horn? Then there’s the whole issue of language and instruction. No matter where you’re from, a loud screech or buzz means get out, whereas a nice man telling you calmly to leave the building might be harder to decipher if you don’t know English. Code requirements should be adjusted to give schools (and other buildings, for that matter) more leeway with regards to installing horns. Just because a building has voice-evac doesn’t make it safer; and I’d argue that a building that knows where to use both where appropriate probably does it the best of all.
In my personal opinion, we need more “blended” voice-evac/horn systems that actually take into account ambient noise levels. For example, in a school a history classroom wouldn’t have nearly the same ambient noise level as a woodshop; just the same with an auditorium and a gymnasium. Voice-evacuation is perfect for areas where there may be a large concentration of people in a relatively small space (like a history classroom or an auditorium), and can reduce levels of panic or anxiety that come with hearing a startling horn. In areas like a woodshop, however, a fairly quiet speaker could go unnoticed for a long period of time. In those scenarios, horns or bells provide the most effective sound output. Of course, you could install audio boosters or use alternative speakers as opposed to horns, but why spend the extra money when you could just install a horn? Then there’s the whole issue of language and instruction. No matter where you’re from, a loud screech or buzz means get out, whereas a nice man telling you calmly to leave the building might be harder to decipher if you don’t know English. Code requirements should be adjusted to give schools (and other buildings, for that matter) more leeway with regards to installing horns. Just because a building has voice-evac doesn’t make it safer; and I’d argue that a building that knows where to use both where appropriate probably does it the best of all.
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I have seen videos of voice-evac systems that had horns in a few mechanical rooms…
…No matter where you’re from, a loud screech or buzz means get out, whereas a nice man telling you calmly to leave the building might be harder to decipher if you don’t know English. …
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This is not entirely true. Loud screeches and buzzes can come from almost anything that could indicate something is wrong. I almost always associate loud buzzing sounds with an automatic door closing or something coming at me (i.e. store lifts) because of my past experiences. I’m familiar with piezos because I’ve been in a school that uses them for over two years.
One of the dominant signals in Japan to signify an [color=transparent]earthquake (I’ll let you guess after listening) via a television broadcast is a https://www.youtube.com/watch?v=Dla60rWUwcw fancy little sequence of chimes. We have no such thing in the US, and without any context or past experience we would have no such idea what the heck those creepy chimes are supposed to indicate.
Fire alarms are only as good as their familiarity, which is why voice evacuation systems have a much higher advantage for those without any knowledge of a building’s fire alarm system. Those who do speak English may be able to assist others by providing context clues or assistance as needed.
To answer the OP’s question, current draw involves some simple maths (except it can get a bit complicated when you’re dealing with multiple models and volume settings). This is measured in watts, which is the rate of energy transfer between two systems.
Suppose I am working with a Potter EVAX 200 for a school, which is capable of providing up to 200 watts of power to a NAC, a set of Wheelock E50s, which outputs 88 dBs when set to 2 watts power, and a set of STH-15S, which outputs 90 dBs when set to 0.94 watts of power. Note that each of the NAs have adjustable outputs, so it’s important to make sure to change the numbers to reflect their settings.
The total number of watts required must NOT exceed a panel’s capable output. We can find if the number of each devices does not exceed the limit by an inequality: 2a + 0.94b ≤ 200 watts
My opinion in voice evac is that they are good if they are in the area that I am in so if the fire alarm goes off it doesn’t make me jump out of my skin but when I watch fire alarm videos on YouTube, I want there to be systems that have all horns instead.
To tell you the truth, I prefer horns only because I grew up with them. I didn’t attend a school with voice evac until college.
My opinion in voice evac is that they are good if they are in the area that I am in so if the fire alarm goes off it doesn’t make me jump out of my skin but when I watch fire alarm videos on YouTube, I want there to be systems that have all horns instead.
To tell you the truth, I prefer horns only because I grew up with them. I didn’t attend a school with voice evac until college.
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Same here, I rarely heard about of voice EVAC systems, let alone heard one in person.
In my country, VE (Voice EVAC) systems are fairly rare and seldom used outside of malls or high-rise buildings.
I don’t see a ton of voice evac. systems, as it’s only required in Canada if your building is 14 stories or higher. I have seen a few mixed systems, where they have horns/bells throughout, and a paging system as well.
