Hi Fog anti fire systems

I have zero experience in these systems, but they are becoming more common in a wide range of installs, especially in ships.

Active agent is water. Works well on engine fires, and fuel fires, Works on electrical fires. No messy agent clean up. Yes!

I'm supposing, due to the complexities in the pumping component, nobody reading this thread likely owns such a system, and they likely target > 100 ft vessels, due to cost and size.

But; I predict these systems will shrink significantly in the coming years.

I will also suppose trawler owners on these threads have something like CO2 or Halotron, which is perfectly effective in small ER.
Any comments on Hi Fog?

These are solid systems. I have not worked with them personally but have followed their development the past few years. They are also being used on shore to protect equipment spaces such as GT enclosures where they don't want a high flow traditional sprinkler head in an area where water damage can cause as much damage as the fire in some cases. Agree, they will always likely be geared toward larger vessels due to the components needed which take up space and are $.

Thanks for posting that, it's very interesting!

Ted

Being someone with frequent exposure to high pressure air (scuba compressors); I envision a couple of 3000psi air tanks in the ER, a fixed pressure regulator, a solenoid valve, a tank of fresh water, a piping system with two to 4 fogging jets, and a hi-temp sensor. What could be easier. OH, and, then the year long, $75k qualification cycle with Marine UL.

Perhaps my early vision of a small system is too simplistic and optimistic.

The other advantage of Hi-fog is the ability to be in the ER during discharge, accidental or otherwise, without the hazard of asphyxiation; currently a hazard with the systems we use now.

After watching the video and being impressed with that pressure delivery system, I'm wondering about a couple of things:


-could it be plumbed into the boat's fresh water system?
-how much pressure would it take to deliver those tiny droplets?
-could you plumb in a high pressure water pump into your freshwater system?
-is this even feasible to think about in a smaller boat like the ones we use?

https://www.orrprotection.com/suppression/water-mist

There seems to be a couple of options. We are talking either storing compressed air, or making compressed air, on quick demand to the tune of roughly 1000 psi.


I don't favor the "making compressed air" with an already compromised ER on fire. This will only work on very large vessels with a secure compartment for the mechanicals. SO, we need a bottle of HP air on board. How much? dunno. But, i'll bet 100cf of compressed air would be enough (WAG #1) Next step is a water supply. You won't need much; maybe less than 20 gallons to do a 75' boat class ER (WAG #2). I would have a dedicated plastic drum of stabilized (ice and bugs) water, not rely on the drinking water supply, the level of which is unknown.
The piping. Is smaller than the typical sprinker head arrangement you see in buildings. A flood of water is not wanted. A flood of mist/fog is wanted.
I don't see anything yet that pushes this out of the 40 to 90 foot class vessels.

we had fog nozzles in the USCG just plumbed into the high pressure fire fighting system....

maybe something like a small electric pressure washer would be enough.

I am not positive, but my recollection says small water droplets are converted to steam within the fire and it suffocates and cools the flames.

I think halon derivatives or CO2 will still be preferred as they hopefully snuff the fire before it gets to the point of fog being of use... but a great backup to prevent an all out blaze.

Water mist has been around for a long time. Its the same principle as a traditional sprinkler head, except instead of using water pressures in the 50 to 150 psi range to create water droplets to penetrate a fire plume, it uses a high pressure pump and a nozzle to create the mist with a relatively small volume of water (comparably). The application is therefore geared to enclosed spaces. It has its limitations when it comes to flammable liquids fires depending on which standard or research project you are looking at.

High end water mist systems for ships, yachts, and shore side machinery spaces like gas turbine enclosures are not cheap but they are using sophisticated componentry, detectors, etc.

The clean agents on the market (Kidde Fireboy for example) are still the best choice for us IMO. A relatively small volume, self contained, with a simple detection system (fusible link for example). Not very $, compact, and proven for our small engine rooms if you have enough gas and calculated the protected volume properly which is not always done.

There are many other clean agent gases that came on the market after Halon was classified as an OD years ago. These can be used with humans which will allow them to breath as they egress the space. Most of the big computer rooms use these along with a dry, pre-action sprinkler system as the back up in case the gas (which is often single shot) fails to control the fire.

C02 is generally not used in normally occupied spaces because it is can kill people if they get stuck in the space.

Shoreside C02 use in non occupied machinery spaces, and to protect flammable liquids are still used; however, the fire protection community has learned that C02 is not as effective as originally thought for FL fires...long story.

walked into a couple of large fires under a fog nozzle with WWII fire gear...pretty effective for large scale petroleum fires in an open area...but I can see the nuances of small spaces and why I thought the halon derivatives would still be a small trawler choice.

6% CO2 will take out a human. So, the issue there is not just asphyxiation but toxicity. The body wants to expel CO2, but can't due to diffusion.

Halotron, per the MSDS, requires 2% to have issues with cardiac arrhythmia.

Both these gases are heavier than O2, so that can be an issue with enclosed space, as the O2 goes away.

http://amerex-fire.com/upl/downloads/safety-data-sheets/english/halotron-i-f1d41aa3.pdf

Thus, the rule to ventilate well before entering the ER, if no breathing gear.
Of course, fire makes its own cocktail of toxic gases in a space.
Fires are just generally bad.

I also walked in to an oil fire with full gear on my back with a fog nozzle overhead from the guys behind me at Treasure Island for Naval fire fighter training. That was over 30 years ago.

Water mist/fog application in complex, modern, automatic fire protection systems for flammable liquids, engine spaces, and other projects are a different animal than a controlled burn at a training center.

And yes, they did send us back in without SCBA's so we could fully appreciate what our situation would be like if things didn't go well and the fire got the better of us in real life.

my main point was that most people dont think water can be used in liquid fuel fires...obviously they can and for several reasons....and NOT like sprinkler systems from my training as they would not be effective.

I also posted that in small trawler engine rooms, their desireability.... not so much....

Water can not be used on all HC liquid fires, depending on the situation.

Sprinkler systems can be used for HC liquid fires, but not always, it depends.

Water mist is being used, but there are various view points as to what it can, and can not protect in regards to HC liquid fires, depending on which code or study you reference.

What about CO2, are you still ok with that previous statement?

Look, not busting your ba#’s, but it’s ok not to comment on every single subject that pops up on a web forum just because you have limited past exposure and or training on a subject. Asking questions and being curious is a good thing.

Not sure which statement am I OK with you are referring to?