Fire detection · Johnson Controls · SIMPLEX
The sensitivity is not in the detector. It is in the panel.
A campus family: several networked panels, designed for large sites and for installations that cannot be stopped. What characterises it is where the decision is taken —the sensor measures, the panel decides— and that changes how it is maintained.
What it is, and where it turns up.
Johnson Controls · SIMPLEX — Enterprise, campus and critical infrastructure. Translated.
In a detection system there are two ways of splitting the work. Either the detector decides on its own that there is smoke and raises the alert, or the detector sends what it is measuring and the decision is taken by the panel. This family is built around the second: the sensor is an instrument and the judgement lives upstairs.
That has a very practical consequence. The panel keeps the history of every sensor, compensates for dirt little by little and can say which one has to be cleaned before it starts giving false alarms. And the sensitivity of a point is changed at the panel, without going up to the ceiling or changing the device: a store may ask for one criterion by day and another by night, when there are no forklifts inside.
You come across it on campuses: hospitals with ten buildings, universities, airports, industrial plants, data centres, public authorities. Places with several panels, a control room and one rule that is not negotiable — that the system does not stop to have an inspection done on it.
How it is built.
The cabinet is modular and grows by putting cards in: loops, output modules, audio amplifiers. The panels are linked in a network and any of them can show what is happening on the others, which is what allows the sensible arrangement on a campus: one panel per building, so that each building stays protected even if the cable between two is cut, and a single place from which everything is watched.
The loop carries elements with their own address, and with isolators spread along it so that a short circuit eats a section and not the storey. For detectors, the usual judgement: optical in offices, corridors and cabled voids; heat in kitchens, car parks and plant rooms; multi-criteria where you need sensitivity in a dirty atmosphere; flame outdoors and in tall industrial units; aspirating where the ceiling is very high or you have to find out very early, which is the case in a server room.
The part about alerting people has something of its own here: the sounders and the beacons can also have an address and say whether they are all right. It sounds like a detail and it is not, because proving that they all sound is one of the most expensive things to do by hand on a big campus, and the one that ends up being done «by sampling» most often. There is also voice evacuation with different messages by zone, which is what you need to empty a tall building in stages.
And what never appears in a bid: the power supply. Batteries sized against the consumption of what is fitted, to last a certain time with no mains. On a campus you also have to decide what hangs off the generator and what does not, and that is discussed with maintenance.
What makes it reliable, and what makes it go off.
In a hospital or a factory, an evacuation that was not needed costs real money. By the third one, somebody suggests disabling the zone.
What this system gives you is time to see it coming. Because the panel keeps the history of each sensor, a detector that is getting dirty appears in a report before it appears in an alarm. An inspection like that is not going round every point: it is going to the ones that are asking for it, and knowing which corner of the building dirties detectors — which is usually the symptom of something else.
What it does not fix is the wrong technology. An optical at a kitchen air outlet or on a loading bay where forklifts come in is going to give false alarms until somebody disables it, and turning its sensitivity down so that it copes is swapping a visible problem for an invisible one. There you have to change the detector, and that is design work.
And there is a trap that belongs to systems that let you tune this much: the adjustment becomes the answer to everything. The house rule is that a change of sensitivity is written down and justified —which point, why, who asked for it— and reviewed. A system where nobody knows why that detector is less sensitive than the others cannot be audited.
Who it suits, and who it does not.
It suits large sites with several panels, where you need a control room, phased evacuation and maintenance driven by data instead of by walking the round. It suits where the system cannot be stopped and where the periodic tests of everything that sounds are a real logistical problem.
It does not suit one building and one loop. It would work, and you would be paying for the ability to run a campus in order to use one corner of it, with a longer commissioning and maintenance to match. There are simpler panels that do that job well, and saying so is part of the job.
How far our work goes.
It is said in the first meeting, because it changes how many companies you have to ask for a price.
We are electronics people. Detection design, panel, loops, elements, alarm, voice evacuation, interlocks with the rest of the building, commissioning and maintenance: ours and all of it. Not the water: sprinklers, hose reels, dry risers, pressure sets and tanks are another trade, with another licence and other contractors. We would rather say so and lose half the works than appear on the certificate as though it were ours.
On a campus with technical rooms the question is almost always gas suppression, and there there is a clear line. The detection that decides there is a fire, the panel that counts the time before discharge, the do-not-enter warnings, the release button and the abort button and the interlock that stops the air conditioning and closes the dampers: electronics, and we do it. The bank of cylinders, its fixings and its pipework, no. A server room needs both halves and the same company almost never does both.
What we do with it.
The order matters more than the list.
- The project by zone and by building: what to detect and with what technology, how the site is divided, which panel takes which part and what is seen from the control room.
- The sensitivity criterion written down: which points carry a setting different from the normal one, why, and who can change it afterwards. It is the document that stops nobody knowing in three years' time why that detector is the odd one.
- The table of what happens with each zone, signed before any programming: what opens, what closes, what stops, who is alerted and what appears on screen.
- Commissioning point by point —every element checked where it really is, the full sequence, the power cut, the alert going out with the telephone in front of you— and the signed certificate with the result for every point.
- Maintenance with a schedule and a file, and the uncomfortable part said before signing: this costs money every year, not only the year of the installation.
Who operates it afterwards.
On a campus the answer has one more layer, because whoever is looking at the screen is not in the building where it goes off.
The operation is the client's: silencing, resetting after checking, reading the log to know what time and where it started, and understanding a fault alert. On a networked system you also have to teach what is seen from each screen and who alerts whom, because a building's alarm is going to be read by somebody three hundred metres away.
In the middle is the temporary disabling of a zone, which on a campus with permanent building work happens every week. It is taught, with a written rule and a record of who disables and who puts back. A zone disabled on a Friday is one of the most repeated holes there is, and the panel is saying so on a screen nobody looks at.
What is not the client's job: adding or moving elements, touching the programming, changing sensitivities and updating panels. It is not our preference: the installation has to be in the hands of a licensed maintenance company, with its schedule and its signed file. And what decides whether your people really can is not the panel — it is the drawings of what is there, the one-page procedures and training by role.
The other eight.
On a campus, what the project decides is how the site is divided and who looks at the screen. That is what the area talks about.
Get started
How many buildings and how many panels?
Tell us how the site is laid out, what is seen from the control room and when the installation was last tested as a whole. With that we will tell you what can be fixed by tuning, what has to be changed and which part of the work is not ours.