12 replies to this topic

[Tom Sutton]

Check out http://www.nodj.co.u...e-machine.shtml Safety and usage information which says,

The smoke can activate smoke detectors and this is something that you should check with the venue first. Many venues have more advanced smoke detectors that allow this type of smoke, but some don't and the venue staff will be able to tell you if it's OK to use a smoke machine.

Which is pretty good advice, it all depends on which type of smoke detectors are being used, the type of smoke, the amount of smoke, the size of the room, and the potential temperature of the room. As I have said it all depends, even steam from a shower can activate a detector head if the conditions are right.

[Tom Sutton]

The sensors in a smoke alarm will degrade over time. This along with years of exposure to dust and contaminants will cause detector performance to falter. Thus smoke alarms should be replaced periodically in accordance with manufacturers’  recommendations. Whether isolating a zone will up speed this process up is debatable and I would suggest you contact the manufacturer for their recommendations.

As to isolating a zone this is not a good practice, you could be removing the protection of a concealed area. I would suggest you consider changing the affected detector heads with a more suitable head that is not sensitive to the smoke machines. Your fire alarm engineer should be able to assist you with this.

[Safelincs]

We are not aware that there are any detrimental effects from switching off smoke detector heads.

I would take particular care to ensure that the loops are re-activated after temporary switch-off. How about leaving your car keys near the fire alarm panel?

Harry

[Tom Sutton]

In my opinion answer is no if a smoke detector has been installed as required by the fire risk assessment then replacing it with a heat detector will reduce the response time, to a fire alarm, putting lives in danger.

Have you considered bringing in a fire alarm specialist to look at the problem and maybe s/he could provide a solution.

[green-foam]

Hi, I would agree with the fire officer.  Fixed temperature heat detectors activate at around 90 degrees c.  Some fire panels have a "fire delay" option perhaps yours has. The idea of it is that the panel indicates fire but the sounders are delayed for a short time so you can investigate the cause.

[Tom Sutton]

I am trying to find an answer but it may take some time assuming one exists. I have come across a detector called Advanced Multi-Criteria Fire Detector and you could check it out and see if it solves the problem.

Check out http://www.esmagazin...s-system-sensor and www.systemsensor.com/pdf/COPTIR-performance-report.pdf another make by Honeywell http://www.notifier....adv-sensing.htm

[Tom Sutton]

Welcome green-foam its nice to have more support on the answers side.

[Tom Sutton]

The Fire Alarm System has to be an addressable type system and,

I think the best solution would be replacing the offending heads with advanced multi-criteria fire detector heads (4 sensors) if the control panel is compatible and you are prepared to accept the higher cost/availability. (Like System Sensor or Honeywell Notifier IntelliQuad)

Another solution would be to program all the offending detector heads and program them to reduce their sensitivity, or build-in a simple key switch to the system that automatically isolates the required affected detection heads.  At the same time, provide various visual and/or audible warning that the system is in a 'partially disabled' state.

The problem with smoke machine fog is that it is hard to control it at a level that will definitely not affect your 'adjusted less-sensitive' detectors. You end up still getting some, if as not as many, unwanted alarms. It is far more practical to temporarily totally isolate automatic detection in the smoke machine affected areas during those times those areas have people present.

A further safety requirement would be to conduct a fire risk assessment for when the smoke machine is in use and also produce a Permit to Work system covering the use of smoke machines, part of the sign off procedure is to reinstate the fire alarm system.

Any fire, in the area that involves the fog from the machine, would soon be discovery by the persons present or the staff dedicated to fire watching in this area.