Conventional Manual Call Points

[Galeon]

I may have took up one of my suppliers wrong , but I will ask him to clarify the point is there any requirement incoming or existing that conventional call points now need to have a led indication once they have been activated.

[Ricardo]

BS 5839 -method of operation of MCP's in a system should be that of type A as specified in BS EN 54-11, where the change to alarm condition is automatic when the frangible element is broken or displaced.

BS EN 54-11, states that “if” an additional visual indicator is provided it shall be positioned within the operating face or within the front face of the MCP which released an alarm, be red in colour and visible from a distance of 2m directly in front of the MCP in an ambient light intensity up to 500 lx.

[Allen Higginson]

No.

[Wiz]

What they said

[Galeon]

Thank you boys , whether you are in the banter squad or not.

[Benzerari]

I may have took up one of my suppliers wrong , but I will ask him to clarify the point is there any requirement incoming or existing that conventional call points now need to have a led indication once they have been activated.

All conventional manual call points I have seen up till now are just simple switches and have no electronics circuitry incorporated, particularly the pre1988 manual call points.

As for post1988 manual call point it may incorporate a simple internal resistor, some people call it the ‘fire resistor’, some call it the ‘trigger resistor’, once the call point is triggered it shorts out the ‘fire resistor’ to make it in parallel with the EOL, and as a result, the equivalent resistor value would be quite similar to the fire resistor itself, because the fire resistor is usually 10 times smaller then the EOL...etc

Sorry all of that is not the main answer to the original post but just to say, apart form that internal resistor, there is no electronics circuitry to make an LED to light up in simple conventional manual call point.

As for what is required by BS5839 in this issue, I prefer to leave it to the relevant expert as unfortunately, I am not  

[Wiz]

Further to Benzerari's answer the operation of a manaul call point in a non-addressable system ibasically just ncreases the current flowing through the zone wiring circuit to a level recognised by the control panel as a fire condition.

If this amount of current is fully or partly provided by the operation of a LED indicator or not, has no bearing to how the concept works.

There is no recommendation in BS for MCPs to have LED indication of operation.

There is no recommendationt in BS for MCPs to not have LED indication of operation.

In my opinion, the small extra cost of having MCPs with integral LED indication of operation is far outweighed by the benefit of being able to quickly identify which MCP has been operated in a zone of a non-addressable system.

[AnthonyB]

I assume you mean it would be of use for fault finding as surely you would know which call point was used by the fact it's glass has been broken/resettable element in used position.

How often do MCPs cause false alarms without having their element broken/used? I've once had one not reset after using a test key and needing replacing before the fire alarm could be reset, but that's about it.

[Wiz]

I assume you mean it would be of use for fault finding as surely you would know which call point was used by the fact it's glass has been broken/resettable element in used position.....

Sorry Anthony B, I thought my post was clearer than it obviously was.

My opinion was based on the assumption that it is sometimes difficult to see an operated element on a MCP from a few feet away (sometimes a few inches!) but an illuminated LED may be seen from probably up to 10 metres or more.

The LED on a MCP for use in non-addressable systems wouldn't illuminate to what I would call system faults, but it would obviously illuminate to a 'fault' on a call point affecting the operating element that in turns affects the operating switch which in turn allows the 'alarm' current to flow.

MCPs with LEDs cost less than £1 more than those without. It seems a small price to pay for the time that could be saved searching a zone and being able to look for LEDs on detectors from a distance but having to get very close to each MCPs if they don't have LEDs.

[Wiz]

....How often do MCPs cause false alarms without having their element broken/used? I've once had one not reset after using a test key and needing replacing before the fire alarm could be reset, but that's about it.

Anthony B, I've found that most test key functions on MCPs use quite a fiddly arrangement (mainly to try and ensure a some other 'simple' tool can't be used to operate the test facility) and it is easy to 'jam' that arrangement in use, leaving the glass/element no longer pressing against the operating switch. This means the MCP still in an operated condition. Normally, in these cases, you can see that the element/glass hasn't repositioned itself into it's normal/standby position and can often be repaired. If not, as you say, the MCP has to be replaced.

[Graeme]

With Wiz

i installed resetable mcp's with led's in an HMO stairwell mainly due to the forsight of them being hit by people who don't stay in the block.
The resetable element is not always easy to see when it has been pushed in,so the led helped greatly for the confused customer in the middle of the night.

[Galeon]

So if BS gets updated and recommended that conventional call points had leds , it could effectively cut down the search distance within a zone .

[Allen Higginson]

So if BS gets updated and recommended that conventional call points had leds , it could effectively cut down the search distance within a zone .

No because the search distance relates only to the distance required to locate a fire,not to actually inspect the device that has ativated.
Under 13.2.3 of 5839:part 1 the avtual search distance of 60m relates to the entrance to a zone proptected by non-addessable AFD.

[Benzerari]

So if BS gets updated and recommended that conventional call points had leds , it could effectively cut down the search distance within a zone .

Also, if incorporating a simple electronics circuit into a conventional manual call point, the major impact I think is not the cost of a simple LED in serial with its protecting resistor and a small relay to switch the feed to light up an LED in fire condition...

It is rather the manufacturing process of this additional (as it looks) simple electronics circuit, just to do a simple function, this might not make conventional MCP cost effective in this emerging competition, probably some manufacturers might cope with, but not every manufacturer would support that additional cost… etc

This remind me, about two years ago when proposed to Apollo company, a ‘seven segment display’ to be incorporated in any addressable head to display the right programmed address so (what you see is what is really set), their answer as a marketing specialist of the product was as I stated above.

But we never know, the BS may trigger on day that competition, with just a simple decision.

[Wiz]

Benzerari,
MCPs with integral LEDs for non-addressable exist now. Most MCP manufacturers offer them as an option. They are nothing special. They just cost a bit extra.
No relay is required. Just the LED and the appropriate current limiting resistor.

I can understand Apollo showing no interest in having a visual display of the set address on an addressable device. This would be costly for the benefits achieved especially as it would need three digits. If such a display was only to be used during addressing then why provide something so costly for use for just a few seconds. If this is dispaly was to be illuminated at all times, it would add to the current consumption (it's important to keep this down in addressable systems) and so any benefit for it could equally be achieved by a simple label.