Fire or Smoke detection


Thread Starter

Bryan Weir

Hi all,

I have responsibility for a semi-automatic assembly machine which is crucial to our manufacturing operation. It was developed in-house a few years ago and there is no other in existence. We are obviously vulnerable to
catastrophic failure of this machine and I now want to look at any methods I could use to reduce risk. One thing I have been thinking about is trying to minimise the potential for damage caused by a fire in the main electrical panel. Has anyone been involved in a similar situation? For example, what sensors can be used in the panel to ensure that all power is isolated before
any fire gets out of hand?

Bryan Weir
Equipment Development Engineering
Polaroid UK. Ltd.

R A Peterson

Its pretty common with air handling equipment and equipment in hazardous areas to have a shunt trip circuit breaker feeding the equipment. The CB is
tripped by the fire alarm system.

Should be fairly easy to have your fire alarm company add some sensors inside your cabinets and give you a contact to trip the main cb.

You could also add an automatic halon extinguishing system for a relatively modest cost. I have seen this done to protect machinery, and I see no reason it could not be done to protect the controls.

Personally, I think the chance of a fire developing inside a properly designed and overcurrent protected control panel is pretty remote. The only fires I can remember in control panels were both caused by improper design.
I did not design either one BTW. In one case a fan sucked lint into the control cabinet and a spark ignited the lint (the spark probably came from a large DC contactor.

In the other case due to a design flaw a 14 gauge wire was inadvertantly being protected by a 400 A fuse. A ground fault occured. The 400 amp fuse
was large enough that the 14 gauge wire melted then caught fire rather then blow the fuse.

Phill O'Meley

Try Trollex, they have a lot of products for monitoring various NOX gas levels. I have used their CO and CH4 detectors. They are widely used in the underground coal industry. They are a UK company
Phill O'Meley
[email protected]

Bilbey, Russell

Hi Bryan,

the key point here is not just the detection (there are a huge array available for various types of fire/smoke), it iswhat you do when it is
detected. This kindof isolation is common in the Petrochem industries where localised fire detection is tied directly to specific isolations. It may be possible to add detectors into your existing system, or to manufacture a
simple isolation system using a dedicate fire detection system tied into some isolation relays.

Try Thorn or Cerberus or similar for detectors.

Russ Bilbey
Smoke and/or flame detectors can be employed, with feedback to a breaker external to the panel. The breaker would open upon detection of flame and/or smoke in the enclosure, thus isolating
power. Additionally, a Halon fire extinguishing system could be employed to smother any fire in the cabinet upon detection.

Once a fire occurs, however, damage has already occurred in the enclosure. An extinguisher, etc. will stop the spread of damage, but some damage will have inevitably happened already. Why not
have a backup control panel, equipped with Harting-style connectors, so that your manufacturing can continue while repairs are made to the first unit?

John F. Vales
Director of Technology
Wes-Tech Automation, Inc.
[email protected]

Derek Hughes

[email protected] has a fine response, however you should know that in North
America, Halon should be considered a 'banned' substance, and some other EPA
approved (non-greenhouse, non-ozone depleting) supression gas may be considered...

In the UK, I have no idea what guidelines prevail...

McGinnis, Patrick W


I suggest you investigate using an aspirating incipient smoke detection system which will pull samples from multiple points from inside the machine into the detector and provide annunciation of a pending fire (or of a fire,
if it is instantanious). I'm familiar with Vesda and found some info at

If your machine uses cutting oil or normally produces its own "smoke" this system may be too sensitive or be fouled. Of course, the actual isolating of power in the panel is a separate task from detecting smoke/fire...


Patrick W. McGinnis
DCS / Instrumentation Superintendent
SAPMT, BI-3141 ShGP Debottlenecking Project
Tel: (966) 3 - 577-4388, ext 164
Fax: (966) 3 - 577-4379
Internet E-Mail: [email protected]
If your electrical panel is properly designed the chance of an electrical fire hazard is remote. Proper conductor sizing along with correct fuse/circuit breaker selection should deenergize and isolate the electrical energy source. Further steps such as using UL flame tested wire/cable, UL 94V-1 rated circuit boards, heat sinks, etc. will add an additional level of protection. Extra fire protection is usually only required if manufacturing process uses combustible and/or
smoke generating materials.

Anand Sharma

Try Wormald Control Systems who are specilized in installing plant-wide Fire and Gas Detection systems. Almost all the Smoke detectors used by them are of Thorm Security make and UV and IR smoke detectors are also provided by them.
Seiger is a company that manufactures Combustible gas detectors ( from o/p xylenes, toluenes to benzene to methane to propane to butane, etc) and Hydrogen gas detectors. We are using Wormald's Fire and Gas Detection systems.

Johnson Lukose

VESDA (Very Early Smoke Detection Apparatus) has come a long way. I believe the pioneer of this technology is a company that has become IEI-VESDA.
There are many more manufacturers today. The suction pipes suck the air in the compartments to the air sampling unit. The early air sampling units were made of red light for detection. Today's systems use laser light and you can set the sensitivity level. You would be hard pressed to find another technology to answer your needs.

Can anyone give me a rough idea as to the cost/price of a typical VESDA installation? Or, possibly a range of prices for a 10,000 sqft data center environment.

Use the low cost VEFSA (Very Early Fire and Safety Alarm) which also comes in a duct mount kit for return air duct installation. In computer and data-rooms in case of overheating host of mixed gases are generated (before non-visible smoke, or visible smoke or fire). The VEFSA senses these and the 4-20 mA signal can be used for alarms or shut-down the mains. Ideal for early fire prevention in telecom, computer or power station sub-stations

Alak Jha
Gas Alarm Systems
[email protected]