Water Mist vs. Water Spray

[Guest Michael Bodstrup]

Hi, I recently received my order for 4 fire extinguishers, 1 x 1L Water Mist and 3 Water Spray (1 x 6L + 2x 3L), replacing Dry Powder units in my house. Delivery was fast and quality appear to be excellent, so thanks for that.

Now a few questions.

I have set aside one of the 3L units as a test and training unit for my family, especially the kids. The spray pattern appear to be very close to water mist, certainly very different from the old 'jet' style nozzles you see on traditional units like an Amerex 240.

How big is the difference in drop size between a Water Mist unit and a Water Spray unit ? From watching videos of Water Mist units they appear close, perhaps with a somewhat larger drop size for the water spray unit ?

Which unit would you recommend for Class A fires ? - Will the assumed larger drop size of the Water Spray give it a bit more range against really hot fires - like a polypropylene sofa ? - after all, the water has to reach the burning material, not evaporate on the way.

Finally, I have noticed a very small amount of corrosion on the collar thread - right above where the gray painting stops. I could get rid of it by scrubbing with a soft cloth, and has lubricated the thread with plumbers paste. Is this an accepted way to preserve the unit ?

B.t.w., I pressurize the unit to about 12.5 Bar with a good quality bike pump (the type with foot rest), saves me a trip to the gym :-)

Regards

Michael

[Safelincs]

Hi Michael

The 'dry' water mist extinguishers (E-Series) were designed to achieve a microscopic droplet size at a lower pressure (12 bar) than sprinklers use. The dry water mist extinguishers produce a 25 micron droplet size. Water spray, whilst also creating droplets rather than a continuous jet, have a much larger droplet size.

For a pure A class fire if you compare the 3l dry water mist (8A) and the 3l water with additive (13A), the latter one is of course more powerful. If, however, you are looking at a typical household with its spread of fire risks (paper, wood, electrical, fats, gas, clothing, Christmas trees), the dry water mist extinguisher is capable to deal with all of them, while the water with additive extinguisher would struggle with one or two of the categories (fat, possibly electrical, possibly Christmas tree). Dry water mist extinguishers are also safer to use, as they form a barrier between the fire and the user.

Dry water mist extinguishers also cause less damage. We had a customer recently, who installed the E-Series dry water mists in their hotels and a fire broke out a few days later when a customer crammed a croissant in a toaster which promptly started to burn. The customer extinguished the fire successfully (of course), but surprisingly, the toaster was still found usable when PAT tested after the fire!

The area between coated cylinder and thread, with most traditional extinguishers. appears slightly rusty. The area is covered in grease and looks brownish. You can just wipe it off with a cloth.

I am impressed by your resourcefulness!

Harry

[Guest Michael]

Harry, one question more. When inspecting all my units after mounting them on the wall yesterday, I noticed that the nozzle on the 6L unit was different than on the 3L units.

While the 3L units had 3 rotary plugs inside the nozzle head, there were only on installed in the 6L unit - it could be seen as larger holes in the nozzle when viewed from the front, and unscrewing the nozzle confirmed the situation:

I asked your support dept, if I was missing 2 plugs in the nozzle, and got a slightly vague answer, saying that "the nozzle on the 6L is slightly different than on the 3L". Could you please verify if I the nozzle is missing parts ?

Regards

Michael

[Safelincs]

Hi Michael

we are referring here to the 3 and 6 water with additive (Ultrafire). Both the 3 and 6 l version, although having different hoses and nozzles, have 3 rotors each. I checked some extinguishers this morning in the warehouse and they are all correct. There is, of course, the chance that the rotors fell out when you were opening them. When I opened the 6 l version, I had rotors flying all over the carpet!

Nevertheless, I appreciate inquisitiveness and I wish more people would take an interest in the subject of fire fighting and the equipment used.

I spoke with Shawn, the engineer who yesterday answered your earlier email. He had concentrated mainly on your questions and missed the fact that one photo only showed one rotor.

If you are still short of two rotors, I will see if I can find a spare hose and send it to you. In actual fact, Shawn is rifling through his stock of spares right now!

Harry

[Guest Michael]

One rotor fell out when I opened it, no more.

I did check the floor and there are no more rotors there.

There are also some toolmarks on the nozzle tip, looking like someone had used a wrench to open/tighten the nozzle, so something might have happened during production.

One step in a fire extinguisher inspection is checking the hose for blockage, so you may see people accidentally loosing rotors, but I am confident that the unit only arrived with one rotor in this case.

If you find the parts, it will be a lot cheaper to send just the rotors.

One of the reasons for my interest and active training of my family is a tragical incident recently, where two small kids died during a fire that broke out in their home while their grandmother was taking care of them. I do have a 5 and a 7 year child, and both know the placement of our extinguishers and how to use them. Only problem for them is breaking some of the tougher tamper seals, I use a 'strip' like unit on our training extinguisher after refilling.

Regards

Michael

[Guest Michael]

CANCEL the search.

I found the rotors... INSIDE the hose :unsure:

They came out after a bit of a shake...

Regards

Michael

[Safelincs]

Hi Michael

I am glad all is sorted.

I have four daughters and a tragedy as you described it is really unbearable to even think about when you have children yourself.

I guess you have already carried out escape route planning with the children? Do they know how to get out of the window if the landing is filled with smoke?

Harry

[Guest Michael]

Yes, at least when they are not stressed. My son's bedroom window has direct access to a roof over a 'shed' from there there is about 2.5 meters down to the lawn, but they can also move across to the next door shed roof - so they can definately get away from smoke unless the whole block gets involved.

I do have some anti burglary locks on the side of the window, and opening the window is a two step process, you have to lift a small lever in the side frame to open fully. This requires some practice now and then. Now that you brought it up, I think I will disable the lever on the escape window. It is there to prevent children from acidentally falling out.

We also have radio linked smoke alarms in all rooms, a total of 7, so we should be covered OK on that. I just don't get the general acceptance that ONE alarm mounted high on the top floor is enough. A fire started behind a closed door could get quite involved before the top floor alarm goes off.

We live in an area, where a certain group of young people likes to lit up garbage containers almost every night, occasionally a car, so finally we do have a 3/4" 25 meter hose reel with a fire nozzle giving about 40 liters/min, so perhaps we have a bit more than we will ever need :)

My son loves it though:

Thanks for your support

Regards

Michael

[Tom Sutton]

Is that a picture of your garage is it Micheal? :D

[green-foam]

One step in a fire extinguisher inspection is checking the hose for blockage, so you may see people accidentally loosing rotors

I doubt it. 99% of engineers do NOT take the hose off to inspect it, they merely look at it and look to see if the nozzle is free from obstruction.

[green-foam]

Tip for breaking an extinguishers tamper seal. Most demonstrations you will see the tamper seal being pulled, this does work if you have the "OK seal" But if it has the "normal" seal, these do not break easily if pulled, but do break easily if twisted, which is easier for most folk.

[Guest Michael]

That is what I found too, I pull it very tight with the 'tab' against the ring, turning the ring breaks the seal easily.

Regards

Michael

[green-foam]

Michael, I would like to personally say "well done" for teaching your family what to do in the event of a fire, its not something most folk do. An even bigger "well done" for buying safelincs fire extinguishers and showing your family how to use them, I only hope they never have to use them for real.

I would also like to make a small suggestion. Since fires break out at any time, I suggest you activate a smoke detector and everyone evacuates the home at an hour they would normally be asleep.

[Guest Michael]

I think awaking my wife that way would be a greater threat that fire, but the idea is very good :-)

[Guest charlypres]

I wonder if Michael also discharged and refilled the water mist extinguisher and if he just used water or de-mineralised water?

You are supposed to use de-ionised water. Not sure why, though

Charly

[Safelincs]

Hi Charly

yes, you are supposed to use de-ionised water. Whilst this makes no difference with regards to the ability to fight a fire, bacteria could theoretically breed in un-treated or normal water. As the 'dry' water mist extinguishers produce such a fine, microscopic water mist, the user could inhale some of the fine mist when fighting the fire and after a few years and refills, the water can get a bit smelly. Our engineers therefore carry de-ionised water for refills.

Harry

[Tom Sutton]

De-ionized or distilled water is purified water which has a low conductivity which is necessary because of the claim it can be used on a fire involving electricity. But as the method to tackling a fire involving electricity is to isolate the electricity supple first then maybe it is not necessary, other than if you are tackling a fire close to an electricity supply and you accident direct the nozzle on the live contacts.

Incidentally when tackling an electricity fire you should isolate the electricity supply this is why there is no class for electricity, isolating the gas supply is also how to tackle gas fires.

http://en.wikipedia.org/wiki/Purified_water

[Safelincs]

Hi Tom

The E-series water mist extinguisher is tested to 35000V and can be sold as safe on live electrical fires up to 1000V, as long as a safety distance of 1m is adhered to. Interestingly, the conductivity of normal water, if used in a 'dry' water mist extinguisher, was not seen as a particular issue by the manufacturer. I guess this is due to the droplets not touching each other to conduct electricity?

What makes the E-series water mist safe on electrical fires is also the fact that it does not form puddles that could conduct electricity.

Harry

[Tom Sutton]

Hi Harry

I thought the low conductivity of de-ionized water would be to do with the electric safety of the extinguisher but I do agree the small droplets are the main reason the current doesn't backtrack.

However what I was was trying to convey was in the UK, they do not have a class for electricity because the way to tackle a fire involving electricity is to isolate the supply, which if modern standards apply in the home with RCD and miniature circuit breakers this will be automatic, and use the appropriate extinguisher usually class A. Also in most cases you should never extinguish a gas fires, again isolate the gas supple then use the appropriate extinguisher this is to avoid explosions.

Tom

[Guest Michael]

I use plain water with additive for the water spray extinguishers.

I do have a 5L bottle of distilled water in case we decide to test the 1L water mist unit.

Since the nozzle from the WM unit fits the WS extinguishers, you might get away with a test of water mist that way...

The 6L, 3L and 1L units appear to have the same valve assembly.

b.t.w. - is the 'valve' in line with the manometer a safety valve ?

Regards

Michael

[Safelincs]

Hi Michael

Just be careful when changing things around. The Water mist maintenance manual is here

Please follow it carefully.

You do invalidate any warranties of the extinguisher if you are starting to swap things around or start taking things apart without being a certified engineer.

Harry

[Guest Michael]

No worry, I only fool around with one unit, the others are as delivered from the factory.

Regarding the smoke alarm tests we talked about previously; I had my own 'Toaster incident' a few days ago:

Decided to toast some old bread after a workaout late at night, apparently cut one piece like a wedge with a very thin edge. That was enough to really burn the thin edge. No visible smoke, but some smell, and all the alarms going off while family was sleeping.

Kids, 5 & 7 just slept on, my wife did wake up but went back to sleep when I told her it was toast..

It would probably take som serious training to enable young kids to wake up and react to a smoke alarm..

Regards

Michael