First the system goes into alarm, the fire indicator on the primary floor and in the cab illuminate. The elevator is now in stage one recall. The elevator will go down the the primary recall floor. If the fire was detected on the primary floor it will take the cab to the alternative floor. Once on the recall floor the doors open and the elevator is disabled. Then the shunt trip will engage shortly after. I remember Andrew saying about how it can cut power to the elevator before it reaches the recall floor. Kinda scary. :shock:
Oh I would also like to add that Primary Recall is when it goes to the Primary floor, if there is smoke on that floor it goes into secondary recall.
Uuhhh…isn’t it kind of redundant to have a sprinkler AND heat detector in the same space? I’m surprised nobody mentioned that.
Oh, and a nifty tid-bit. Here in Mass, we aren’t required to have sprinklers in shafts or machine rooms. 
Partial credit - you’re leaving a lot of information out but have the basics down!
How does the system go into alarm? What causes the elevator to go into primary recall? What causes the shunt trip to active? How is the system designed work to prevent someone from getting stuck in the elevator or from water being poured onto the controller before power is shut off? Explain it to me as if I was a layperson and knew nothing about fire protection.
I cannot answer that without giving away the answer to my original question!
For this area:
Having a sprinklered machine room is not uncommon - and the scenario I describe above is outlined in NFPA 72. As far as sprinklers in shafts and machine rooms, it does seem to be hit or miss. Even when you come across switchgear or electrical rooms. Working within 4 states and multiple jurisdictions, what’s code in Pennsylvania may not be code in Maryland. Seems like around the 80’s they shied away from placing sprinklers in these high voltage areas but lately everything has sprinkler protection. Occasionally, I will come across a building where the switchgear room is protected by a pre-action sprinkler system but that’s mostly “critical” building like hospitals and such.
Alright, let’s say Chris Enterprises has a 5 story building with a Lobby and a Basement. If one of the detectors on 2-5 or the basement goes into alarm, it triggers primary recall. If a heat detector is activated in the shaft or the machine room, the elevator goes into Primary Recall, if the fire was detected in the shaft down at the lobby it goes into Secondary recall. The worst case scenario is the shunt trip is activated and someone in still stuck inside. But usually the elevator gets down to the escape floor before the shunt trip is activated. I think there’s a relay that energizes a coil in the elevator’s circuit breaker, when that coil energizes it trips the breaker to prevent an electrical fire.
Here’s a few.
What are the four primary types of sprinkler systems, what are their applications?
What is a Class III FDC?
What agent is used in Class B extinguishers?
Great question Lambda. I promise not to give anything away on this.
Yes, this is correct. However, the original question is asking what would happen if a fire broke out inside the elevator machine room. Certain things will happen in a certain order. Think about how a fire acts, you’re going to have smoke first, then heat, and the heat will gradually rise. What is going to get activated first, the smoke detector, heat detector, or sprinkler head? This is one of these things where the fire alarm system is actually going to control the functions of other systems in the building, not just sound the horns and strobes! So something to think about. I’ll post the answer this evening if you can’t get it.
We have sprinklers in all our shafts around here. I’d prefer not too…
there’s nothing to detect fires in the shaft on each floor, there’s smokes in every lobby, if one is active on the primary floor the elevator goes to the secondary to prevent dumping people out onto a floor currently on fire.
and you’re still off on the heats… look at lamdba’s clues. and the shunt is there for a reason, it’s better to be stuck then electrocuted.
Doesn’t the smoke detector go off first that’s what activates the system and puts it into recall. Then the heat detector is what shunts the system, then the sprinkler activates and controls the fire.
That’s what I was looking for! You’re first response was a little vague, just wanted to make sure you understood what happens when and why.
Here are the specifics…
1.) Smoke in the machine room activates the smoke detector - FACP first alarm.
2.) Fire alarm panel activates primary recall - elevator car goes to primary floor, doors open, elevator stops operating.
3.) Fire alarm panel activates the “Hat Light” to flash (normally the hat light would only be steady on, the flashing indicates the elevator car may be unsafe to use for fire service because of a smoke condition in the shaft or machine room).
4.) Heat in the machine room rises due to fire - at 135 degrees, the heat detector activates - FACP second alarm.
5.) Fire alarm panel activates the elevator shunt trip breaker, disconnecting primary power to elevator. This action should be on a time delay to allow time for the elevator car to travel from the furthest stop to the primary recall floor.
6.) Heat in machine room continues to rise - at 165 degrees, sprinkler head activates to control fire in elevator machine room.
The purpose for this sequence of events is that you want the elevator to recall and let people out first - before the power gets disconnected and water starts pouring on the elevator equipment. The heat detector should be rated for less than the temperature rating of the sprinkler head (you wouldn’t want to put a 195 degree heat detector in an elevator machine room with a sprinkler head rated at 165 degrees). There should be a heat detector located within 24" of EACH sprinkler head in the machine room (or shaft). So if you have a large machine room with 4 sprinkler heads, the room should have 4 heat detectors. You can also use a waterflow switch to monitor the sprinklers in the machine room instead of using heat detectors but the waterflow must activate immediately with no delay and shut off power immediately.
I’ll add a few more details, at least from the jurisdiction I worked in.
Sprinklers in the machine room and shaft are dry pipe controlled by a solenoid valve. This is to protect equipment from possible leaks in the system and possible freezing. The heat detector, in addition to activating the shunt trip breaker, also activated the solenoid valve. This is to make water available should the temperature get high enough to trip the sprinkler head. Of course there is a shut off valve with a tamper switch and a drain valve. Heat detectors in each area operated only their associated solenoid valve. Machine room HD controlled machine room solenoid and shaft HD operates shaft solenoid valve.
In the case of a hydraulic elevator sprinkler head(s) and heat detector(s) are required in the bottom of the shaft (elevator pit). If the machine room for the hydraulic elevator is on the primary recall floor and shares a common wall with the shaft, the machine room smoke detector recalls to the alternate floor. The elevator pit smoke detector also recalls to the alternate floor (if the alternate floor is above the primary floor).
There are all sorts of variations that are evaluated on a case by case basis. One hospital I worked at has a office building with traction elevators (suspended on cables) but the machine room is in the basement instead of the roof (usual location for traction elevator machine rooms). That one recalls to the alternate floor (2nd) on a machine room SD.
Testing could be a real pain. The fire marshal from the city or county is interested in seeing the fire alarm devices work. However he didn’t give a rat’s backside about the elevator operation. The elevator inspector is interested in seeing the elevator controls work but doesn’t care about the rest of the system. Many times the elevator devices had to be tested twice. Sometimes we got lucky and got the fire marshal and elevator inspector to the site at the same time.
While there are standard code guidelines there are always special situations where the AHJ has to evaluate and might deviate from usual code requirements.
The sprinkler system you described in the first paragraph sounds more like a pre-action as opposed to dry.
In a way, but kept really simple. This does not involve the entire system, only a few heads. No control valve, no air compressor, or any other components associated with a preaction system. In a fully sprinkled building the elevator heads are a branch line of the system for that floor. They only have their own flow alarm switch in the case of an upgraded elevator in a non sprinkled building. Otherwise the elevator heads are annunciated by the flow alarm switch for the floor. Typically there is one head per elevator shaft. So a bank of three elevators has three heads controlled by the heat detectors and solenoid valve. Machine rooms may have one head or several depending on how many elevators there are.