What happens when the building fire alarm is pulled at a television station while they are broadcasting a live news program? Would TV viewers observe a screeching fire alarm, followed by the news anchorman getting up from his desk to leave the building? Or would the fire alarm be hooked up to the control room so that as soon as the alarm is pulled, the picture feed instantly switches to one of those “We are experiencing technical difficulties. Please stand by. Do not adjust your set.” screens?
If there really is an emergency and the building needs to remain evacuated for some time, possibly without power, what happens to the broadcast signal? I suppose for a big news company like CNN, they can simply switch to another news center elsewhere in the world. But what about local stations? Would most local stations have some backup control room, located in a different building, whence they could feed to the antenna/cable some prebroadcasted filler programming until the emergency in the main building clears up?
At the bottom of this wikipedia article are the details of the BBC’s major unplanned breaks in transmission (IRA bombing, powercut and fire). In all cases an onscreen caption is shown whilst they switch from BBC Television Centre to alternate studio locations (they have a fair number around the country to choose from).
At least one of our local stations has onsite generators and such that it can still broadcast with no power for a couple days. Much of what a news crew does can also be done with mobile battery powered gear that can be powered and or charged off of vehicle electrical systems or from inverters driven by the same.
The ambulance company I used to work for had a setup where we could power our dispatch center with an ambulance. Flip a switch, plug an extension cord from plugs in ambulance to plug in wall. We used it twice while I was employed during power outages.
The broadcast signal does NOT come from the studio. They just produce a master signal, which they transmit to a small building at the bottom of the antenna (often called a ‘head end’ shack). That is where the high-powered transmitter is located, which broadcasts the signal over the airwaves.
Generally, broadcasters have backup paths to get their signal from the studio to the transmitter. And they generally have some contingency plan to allow them to create a signal right at the antenna tower, if they lose all connection to the studio building. It might be nothing more than a VCR and some tapes in the antenna shack. But that will fill the air time for a while. They can even record the signal onto tapes and have drivers frantically rush them from the studio to the antenna shack. So they will be able to provide some signal to broadcast until they can get things fixed.
I recall a time when a local radio station here in Minnesota had this problem, and lost connection from the studio to the antenna shack. But they had planned for this, and had a record player & some records in the shack, so the engineer could play those, and a microphone, so he could imitate a disk jockey. However, they hadn’t had to use this for years, and there were only a couple of records there, and they were decades old, far from the kind of music the station currently played. But rather than have ‘dead air’, the antenna engineer played those records (over and over) until the problem was fixed.
Then listeners started calling in, requesting those songs again. They’d decided they liked those old songs, and wanted to hear them more. Then the studio had to send someone out to the antenna shack to get those records and bring them back, since that was the only copy the station had. And they had to dub them, since the modern studio equipment wasn’t set up to handle those old LP records! This went on for quite a while; it became a bit of a joke locally. Every few days, someone would call in and request one of those old songs.
Not aware of any exemptions in NFPA 72 for television studios, unless the Authority Having Jurisdiction grants a waiver or exception, the viewer would hear (not observe) a temporal 3 tone, observe strobe flashes in the background, followed by Ned McNews getting up from his seat, announcing that he was leaving as part of an orderly evacuation procedure, and urge those watching to do the same when presented with a fire alarm activation.
