What are the correct procedures and provisions for emergency extinguishing of a RMH?

What are the correct procedures and provisions for emergency extinguishing of a RMH?


For _reasons_, I'm working with a very restricted space budget on a design.   Being in restricted / small spaces increases the risk that something will get bumped into something else, or dropped into the wrong place.  Possibly combustible things.  Possibly on 500+ degree stove parts.


A knee jerk reaction might be dumping a few gallons of water down the side of the barrel... This might end up with a large amount of very hot steam confined in a very small space with a now par broiled everything I care about.... like lungs.


Closing off the feed tube with bricks is a way to restrict the airflow and will get a RMH to stop combustion in a little bit.   Presuming that "that's not fast enough".   What other options are there and what are the results?  e.g.   Will the standard RMH be damaged by the procedure?   Will the RMH be temporarily out of commision until maintinance can be carried out? ( e.g. sand dumped into the feed tube would need to get cleaned out of the entire burn path ).   Will there be boom squish?


The internet told me to a) close dampers, b) fire off a fire extinguisher (ABC?) into the wood stove.   Is that a reasonable thing? and where does that land on the result metrics?


I have my own ideas about things, and some of them are certainly silly and wrong, so what's the most expedient way to get a RMH down to less than burning temperatures without endangering people, pets, etc. ?    Ideally three options, one for just getting it turned down quickly,  one for turned down quickly with maintenance to turn it back up, and one for getting it stopped ASAP with the RMH being possibly sacrificed along the way?


What's the right way, and what should be avoided?  And for the literature edification... why?  

Thank you in advance for your time.

They make, or at least used to make, a sort of flare looking thing that could be tossed into a woodstove or fireplace to put out chimney fires.  Something like this should work in a RMH.  If you use a fire extinguisher make sure you use it in very short bursts so as to not blow embers out into the room.

Walt Chase wrote:They make, or at least used to make, a sort of flare looking thing that could be tossed into a woodstove or fireplace to put out chimney fires.  Something like this should work in a RMH.  If you use a fire extinguisher make sure you use it in very short bursts so as to not blow embers out into the room.

These are still around. Here is an article which contains information on a couple different versions.

https://www.firerescue1.com/fire-products/suppression-equipment/articles/taking-the-fight-out-of-a-chimney-fire-Y0MbR0611X5ToR0X/


I think it might be necessary to block the intake pretty effectively, as these work by consuming available oxygen. A roaring rocket might just pull so much air in that it can burn on..

Big bucket of sand into the feed?

Hi Tom;
If I understand your concerns correctly. You are wondering how to stop a RMH in mid burn in an emergency situation? I'll assume we are discussing a J tube RMH and not a batch box.
To start)  Water is a big no.  flash steam  / cracked firebricks . Everything will still be super hot.
A fire extinguisher won't work well either. It will go out but... The firebricks are so hot your wood will reignite as soon as oxygen is available.
A thick steel plate to completely cover your feed tube and deny oxygen to the burn. This is a fool proof way to stop the fire.
Filling the feed tube with sand would also work. This is, if you happen to have a bucket of sand sitting nearby.

You will not be able to cool any of the core burn unit or the mass quickly.  If you try... it will crack and the parts will still be super hot.
When your fire is burning at 1800 F in the riser, things get really hot. Nothing but time will cool the brick.
If you try to force it sooner it will crack and require a rebuild before it can be used again.

If you can afford it , building a core with ceramic fiber boards and a riser with ceramic blanket would cool sooner...  
But the mass is the mass and nothing but time will cool it.  Its job after all is to get and stay hot...

Remove oxygen.

There is gasket material used in boilers and other hot places which would help seal a steel plug fully. The steel plug can be made to double as a table surface and keep the feed tube closed off (and  not ventilating the space) when not in use. It would be nice if it were _really_ easy to throw it on and have it end up sealed tight. Interesting design problem.

Removing oxygen by displacing it with another gas is the tried/true way to stop HOT fires. The chimney fire extinguisher sticks probably work this way.  In the past, various gasses have been used to displace oxygen. None is particularly cheap and the delivery mechanism is critical. I believe carbon dioxide will work - there used to be CO2 fire extinguishers for sale at hardware stores. May still be. There needs to be thought viz the people in the area breathing whatever is used.

Also, search ["engine room fires" extinguishers] and [restaurant stove fire extinguishers]. I don't' know what current tech is - it probably involves more than gas displacement because of the concern for people breathing the stuff.

A sand bucket (or two?) sounds like the best emergency measure. That and emergency egress from the space that does not pass close to the RMH. Small spaces and fire make a deadly combination leaving almost no time to react and/or escape.

_Experienced_ (ie. "old")  firefighters might have very useful input, if you can connect with them. Both chimney fires and wood stove fires would be germane to your question.


Regards,
Rufus

Tom

I will add that your question is THE smartest one I have seen about RMH builds, here or anywhere. Things fail and when they are part of something that's 800-1200F (and maybe rising) with people close by... That risk needs to faced squarely and not left unthoughout, unattended.

Thank you for raising this issue.


Rufus

Ceramic blanket could be glued to the steel plate to make a seal.  
Buckets of sand sound nice, but if space is that limited then where do you store dry unfrozen sand?

I'm really not understanding, exactly what emergency would require rapid shut down.
Do you have any scenarios your thinking of?
The flame is the least hot part of the whole system, the rest simply will not cool down rapidly.  

thomas rubino wrote:Ceramic blanket could be glued to the steel plate to make a seal.  
Buckets of sand sound nice, but if space is that limited then where do you store dry unfrozen sand?

I'm really not understanding, exactly what emergency would require rapid shut down.
Do you have any scenarios your thinking of?
The flame is the least hot part of the whole system, the rest simply will not cool down rapidly.  

Buckets of sand are just another sort of thermal mass.. must be ways to work them into a bench design!

I don't know what scenarios OP had in mind, but the one that would be on my mind is structural failure, causing very hot flue gasses and/or actual flames to go Bad Places.

Unlikely? That's no reason not to take cheap and simple precautions. There WILL be a massive earthquake in my area, sometime. And there are plenty of trees around that could smack a house in a suboptimal spot.

I don't tend to insure things. And I doubt I would be able to get insurance for a building with a RMH in Canada... so I try to spend a bit of that saved money on precautions.


I have yet to require my seatbelt, in 19 years of driving..

Sand is really not a good thermal mass.  Too many tiny air pockets.
If you had enough dry sand quickly available (10 gal.) you could smother the feed tube and stop the flame. This will do nothing for hot gasses venting into the room.
Now in a limited space, who? is going to store 10 gal of dry sand within easy reach.  A steel plate possibly gasketed can sit next to the rmh all the time. In the event of catastrophic event, you take two seconds to place it on the feed tube and leave... taking your family with you (don't forget the dog /cat )  call the fire department.
Any wood burner, of any type is subject to earth quakes (any disaster) ... for that matter a propane heater that gets crushed could also burn the house down. A simple electric heater could do the same.

In the event of a complete catastrophic incident.  (tree falling on rmh,  severe earth quake, truck crashing into house... )   You will not care if your rmh makes it or not.  Your life and loved ones are in danger ...you leave the house, If only your rmh is compromised then you deal with it as best you can.  (sand, dirt ,water , fire extinguisher)   If the rmh is broken, it can be fixed. If you or the loved ones are broken its not worth it. Leave the house!

There's an old recipe which was used in former days in the Netherlands. Somewhere beside the cole stove a two pounds paper bag of salt was placed on the floor. It could stay there for years until a chimney fire occured. The recipe was to rip open the paper bag and throw it in the fire, bag and all. Immediatly after that all the air inlets should be closed and the chimney fire went out just like that. Presumably the salt getting hot, was producing a gas that's supplanting the oxygen in the stove and the chimney. The stove shouldn't be opened immediatly after the fire was out, the fire could start again in a flash.

Maybe it would work in a J-tube rocket as well?

Peter van den Berg wrote:There's an old recipe which was used in former days in the Netherlands. Somewhere beside the cole stove a two pounds paper bag of salt was placed on the floor. It could stay there for years until a chimney fire occured. The recipe was to rip open the paper bag and throw it in the fire, bag and all. Immediatly after that all the air inlets should be closed and the chimney fire went out just like that. Presumably the salt getting hot, was producing a gas that's supplanting the oxygen in the stove and the chimney. The stove shouldn't be opened immediatly after the fire was out, the fire could start again in a flash.

Maybe it would work in a J-tube rocket as well?

I do like the good old ways, thank you.

https://www.nist.gov/system/files/documents/el/fire_research/R9302952.pdf

Baking soda seems to be one of the options.    A smaller than feed tube sized bag of baking soda might be the thing, followed rapidly by sand /  a cover plate.

Some answers :

More specifically the questions arose from me working on phase changing materials (PCM) for use as part of the thermal mass in one heading solutions.    The easy PCM materials are water, waxes and fats.    Water ; Boom squish  and if it's left to freeze it'll destroy it's container.  ( though hyper saturated salt water might be an option for the freezing part ).  Waxes and fats... they tend to be flammable.   Which brought up the idea of, WTF does one do if one breaks PCM containment over a hot part.


In other fields the answer would be something like Emergency Power Off (EPO) the equipment and get out.    


I completely failed to consider the earthquake / major structural issue angle.  

Maybe a fiberglass fire blanket?    

Possibly a wad of fire safe cloth like stuff on a stick to plug up a ruptured chimney?


Thank you all for the helpful comments.