Fas zoning issue ???

[Benzerari]

Hi Guys;

Have you ever seen FAS's zoning in one of the customer’s sites stating all MCPs in one zone and All detection in another zone, even both zones are quite the same area I do not see the point why zoning a FAS like that?

What do you think?

Could that be against BS5839?

Thank you

[John Webb]

I followed this method for an installation for my local church and (physically linked) hall for the following reasons (system is an L5 with detection in storage areas and kitchen and MCPs at the usual locations; building floor area is well below the maximum allowed for a single zone in BS5839.)
(a) If the MCP zone goes off we can assume that someone has spotted a fire, or if a false alarm, we only have to look at the MCPs to see which has been operated. We don't have to check the storage areas as well = quick response and determination of the cause.
(b) If the detector zone goes off we can immediately silence the alarm to minimise interruption while the cause is sorted out by looking in just three places - again = quick location, knowing that if we have a genuine fire event we can restart the alarm by hitting the nearest MCP and thereby initiating evacuation etc. without having to return to the control panel.

Seems to me this is quite in tune with the BS5839's requirements for speedy location of the initiating event.

[Benzerari]

I followed this method for an installation for my local church and (physically linked) hall for the following reasons (system is an L5 with detection in storage areas and kitchen and MCPs at the usual locations; building floor area is well below the maximum allowed for a single zone in BS5839.)
(a) If the MCP zone goes off we can assume that someone has spotted a fire, or if a false alarm, we only have to look at the MCPs to see which has been operated. We don't have to check the storage areas as well = quick response and determination of the cause.
(b) If the detector zone goes off we can immediately silence the alarm to minimise interruption while the cause is sorted out by looking in just three places - again = quick location, knowing that if we have a genuine fire event we can restart the alarm by hitting the nearest MCP and thereby initiating evacuation etc. without having to return to the control panel.

Seems to me this is quite in tune with the BS5839's requirements for speedy location of the initiating event.

Thanks for this info John, also I have been told by a colleague that such systems can have MCPs for evacuation pattern, and detections for just alert with intermittent alarm and that's quite similar to what you have said.

Do you mean by speedy area where are less than 300 square meter, which can be considered in BS5839 as one zone?



or even in large area

[John Webb]

Yes, the actual size is around 260sq m. One of the storage areas is a large roof space only acessible by pull-down loft-ladder, which was a major contribution to the decision  to put MCPs and detectors on seperate zones to speed up searching the building.
A lesser factor was that we could not afford the detectors when the hall building was first put up, so by putting them on another zone we could keep the system running until the detectors and associated wiring was complete and needed to find less than an hour to connect and commission when the building was not in use.

[Benzerari]

Yes, the actual size is around 260sq m. One of the storage areas is a large roof space only acessible by pull-down loft-ladder, which was a major contribution to the decision  to put MCPs and detectors on seperate zones to speed up searching the building.
A lesser factor was that we could not afford the detectors when the hall building was first put up, so by putting them on another zone we could keep the system running until the detectors and associated wiring was complete and needed to find less than an hour to connect and commission when the building was not in use.

Thanks for this example John, this is new to me to be honest, as long as it is OK with the requirement of BS5839, I will take in consideration when getting in a similar situation.

[Galeon]

This method was quite common , and the only real way around the head removal scenario , before most panels were able to do this function. It was belt and braces as usually you had to make sure the call points were either wired first then and detectors to the eol , therefore any head removed would keep mcp's active or separate zones as you describe..

[Benzerari]

This method was quite common , and the only real way around the head removal scenerio , before most panels were able to do this function. It was belt and braces as usually you had to make sure the call points were either wired last  on one zone or above how you have descibed above.

Yes I have got your point and thanks for that, but it is not common to me to be honest because of the simple reason, that I wasn't in fire industry that days... also the old philosophy saying that the call points have to be wired first and detectors last, I could not really see the point why?

So many people said because of the head removed was considered as open circuit it prevents the normal working operation of any MCP fitted afterward in the circuit, but in fact it prevents the normal working operation of any smoke detector fitted afterward in the circuit too!..... Kind of problems that goes into closed circuit and it will never end…

Sounds like ‘who born first the chicken or the egg'

Luckily, the head removed has been sorted out for good, and we do not need to worry any more about who born first!

Thank you

[Graeme]

A lesser factor was that we could not afford the detectors when the hall building was first put up

you need to adopt a more aggressive means of collection at the front door John.

[John Webb]

you need to adopt a more aggressive means of collection at the front door John.

We were building the Parish Centre very much hand-to-mouth - 18 months after opening we still owed £20,000 plus to the bank - 3 years after opening we had a surplus for ongoing maintenance - and have run in profit most years since so were able to add the detectors without any trouble. Mind you, that was 20 years after opening in 1985 and not long after we replaced the original FA panel after it broke down.