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New Fire Extinguishers Use Water on Electrical Fires
the latest generation of fire extinguishers employ a mist of distilled water. To what voltage would this be safe as we have a lot of 600VAC equipment?
By Gerald Beaudoin on 27 June, 2012 - 8:29 am

Seems that the latest generation of fire extinguishers employ a mist of distilled water. It is said to be non conductive and safe for electrical fires. My question is: To what voltage would this be safe as we have a lot of 600VAC equipment? I would be interested in hearing about some practical experiences using this type of extinguisher on control cabinets, etc. After 60 years of "don't mix electricity and water", I am having a bit of difficulty with this one !!!

Cheers
Gerald Beaudoin

By bob peterson on 27 June, 2012 - 11:27 am

At one point computer rooms mostly had Halon extinguishers in lieu of water sprinklers.

Over time, people realized that the halon was almost as bad as water on the equipment and even a fire that water sput out was pretty disruptive.

I don't see how distilled water is any safer to human beings to use on electrical fires than tap water.

--
Bob

2 out of 2 members thought this post was helpful...

Gerald... for years distilled water has been used for washing high-voltage, live-line insulators.

It is non-conductive, but must be applied as a mist when used to extinguish "electrical" fires!

Regards, Phil Corso

1 out of 2 members thought this post was helpful...

I'm seeing these water mist fire extinguishing systems used for turbine equipment enclosures, but haven't seen them used for control rooms with lots of electronics.

The idea is that by using fine nozzles to turn the water into a mist the heat of a fire will cause the water to vaporize (turn to steam) and the ensuing expansion due to vaporization will displace the air (and oxygen) from the fire.

It's not meant to be sprayed directly on the equipment, but rather in the enclosure where the heat can vaporize the mist. Some literature I've seen says it's better for hot components (turbine shells, etc.) than discharging cold CO2.

I do know that this method of fire-fighting has been used on ships for decades with a great deal of success.

As for using it, though, in control rooms, well, I guess if one could guarantee that only mist was going to come out of the nozzles and that even the mist would not drip or condense on electronics, well, maybe. But, in the event of a fire, do we really care about trying to save the electronics? Isn't it people we're most concerned about (or should be anyway)?

I guess in thinking about this a little more, when the fire was extinguished and there was no more heat, the steam and water mist would begin to condense and rain down on the electronics if left uncontrolled for some period of time anyway.

I don't know; I still think it's human life that's the most important consideration in fire-fighting, especially in a control room where people are likely to be congregated in an operating plant. Electronics can be replaced. My colleagues can't.

I would have to believe the vendors of this equipment have some kind of rating, or the NFPA in the USofA, or some other responsible bodies in other parts of the world, have something to say about what kinds of extinguishing agents are used on what kinds of fires, and what is "permissible" in a control room. If not a regulatory agency, then surely an insurance company has some guidelines or limitations.

Given a choice between CO2 or Halon or water mist (distilled or otherwise) in a control room, I, personally would rather see water mist used as an extinguishing agent. The vaporization of water is going to displace air/oxygen, but I'd rather get a little water/steam in my lungs than either CO2 or Halon. That's just my personal opinion at this point in time.

The new water extinguishers utilize distilled water because, water does not conduct electricity. Yes, you heard that right. Water does not conduct electricity. The "minerals" in the water conduct electricity. Therefore, if you take the minerals out, as in distilled water, you can use on electrical fires. And, the distilled water is far less disruptive to sensitive electronic equipment for the same reason. The minerals in standard tap water would lead to corrosion and all other kinds of nasty things happening to those electronic components. No minerals, no corrosion. That's why the new extinguishers are particularly effective for small electronic or computer fires.

2 out of 2 members thought this post was helpful...

This is correct and remember salt is a mineral.

I was a Volunteer Fireman and taught State Certified Firefighting for many years. Once I set up a demonstration using regular hydrant water to prove that water plus electricity was not as dangerous to firefighters as legend would have them believe.

I had the city set up a 3 phase 480 VAC motor with a manual disconnect in our outdoor training area. I took a 1-1/2" fire hose and sprayed it on the open door of the disconnect while the motor ran. I started about 10 feet from the box with a spray and gradually adjusted the spray to full stream while advancing toward the live three phase power. I turned the water off at about 2 feet from the box and a jet stream of about 65 GPM flowing into the powered box at about 70 PSI. The only thing noticeable was that everything and everyone in the area got wet.

Water and electricity are not good partners but the danger and damage is done when there is a container or body of water that covers the electrical contacts. Spraying water on electrical equipment does very little damage as the resistance is too high when it is mixed with a lot of air as it is coming from any nozzle.

This is partly why the "5 second rule" applies when you drop your phone in the toilet. :-)

By telly reyes on 18 May, 2018 - 6:07 pm

So my question is: if I have a metal fire extinguisher on an electrical fire and if I tried to use the extinguisher while in contact with the ground, could it be dangerous? it is only capable of discharging in burst would advice be wrap electrical tape around the handle?

thoughts please thank you!!!

By M.Narendranath Bharathi on 11 June, 2015 - 4:46 am

>The new water extinguishers utilize distilled water
>because, water does not conduct electricity. Yes, you heard
>that right. Water does not conduct electricity. The
>"minerals" in the water conduct electricity. Therefore, if
>you take the minerals out, as in distilled water, you can
>use on electrical fires. And, the distilled water is far
>less disruptive to sensitive electronic equipment for the
>same reason. The minerals in standard tap water would lead
>to corrosion and all other kinds of nasty things happening
>to those electronic components. No minerals, no corrosion.
>That's why the new extinguishers are particularly effective
>for small electronic or computer fires.

I agree with you

By Curt Wuollet on 17 June, 2015 - 8:11 pm

Distilled water has been used for many decades to cool metal envelope tubes dissipating thousands of watts with thousands of volts on the plate. This requires high purity water and careful material selection to prevent dissolving anything in the cooling water. It's easy to know when the water has been contaminated, the leakage increases greatly for very small amounts of contaminates. Using the wrong screw can cause major downtime.

Regards

cww