Multi fuel Stove - Distance from combustibles.

[waddmiester]

Gents,

I hope this is the correct forum.

The situation I have is that, as an afterthought, a customer would like to place a multi fuel stove in a corner of a room, within a single storey barn conversion.

One wall is an external wall of brick and block construction. It will be cement rendered. Therefore non combustible.

The other a stud wall infilled with insulation. As yet it is not boarded.

If this was boarded and plastered it would clearly be combustible and therefore require the full distances within the MI for the stove which is a Hunter Herald 6.

My initial thought was to put some block work in to the required height and width to bring the distances down.

However......

What, if any, would the difference be, if instead of normal boarding, 12 mm spacers were attached to the studding and then it was over boarded with non combustible board such as Hardiebacker ? The rest of the wall could then be double boarded to even it out.

I appreciate that this is a similar solution to shielding combustible materials from flues (i.e reducing the distance from 3 x D to 1.5 x D), but cant see any other reference to this in the building regulations.

In the case of the wall, could this then be considered non combustible?

Any thoughts / advice appreciated.

 

[gmartine]

Would it be worth splicing in some metal studwork (C-stud) instead?

 

[waddmiester]

Hmmm, good idea.

 

[Geyser]

Fire resistant board and plaster from Vitcas is good stuff.

 

[joni os]

When we tell clients what they want to hear we are experts. Tell them that MIs are not optional and our expertise is called into question. In this instance many factors should influence decisions:-
1. Few people wanting to heat a room would position a pair of K2 rads adjacent to each other in a corner. The same principle applies to a hearth.
2. The best exit point for the flue is near the ridge. Flues exiting from low part of roof need extending and increased support, which is dependant on spacing and section of rafters, if unsightly stays are to be avoided.
3. 12mm air gap, dependant on free flow of air and relates to circular thin walled flue, not 100 kg. plus lump of cast iron.
The easiest option is to locate the stove away from the corner, and combustibles optimising both heating of room and exit of flue closer to ridge.

 

[waddmiester]

joini os - Yes, I hear what you are saying and all your points are valid.
I was only canvasing for ideas and views.
Fortunately, due to the height if the ceiling I would be able to get 4.5m (and I anticipate good pull) without the need for stays or guys. The build is thoroughly insulated and has u/f heating all the way through - the stove being move for a life style feature than as a sole means of heating the house which is why I have even considered the option.
Totally agree about MI etc!

 

[gmartine]

As I suspected the OP's clients would like it as a form of secondary heating so I don't see any problems with it being sited in the corner, in fact you can buy MF stoves built for that specific purpose.

As for flue termination you can run twin wall virtually anywhere with the right bracketry including following the roof line internally if you want to exit nearer the ridge line.

There should be no problems situating the stove in the corner... use C-stud, rockwool and combustion proof boarding (Hardie or Vitcas) for behind the stove and it will easily meet regulation.

 

[edd789]

When we build false chimneys for the stoves we fit. We build them out of metal stud work and fireboard.

Regarding the twin wall flue mentioned above, this can run anywhere and only have to be 60mm away from combustibles BUT it can only be run horizontally for 20% of the entire flue run. So if the flue is 5m long, you can only have it horizontally for 1m.

 

[joni os]

MIs for the stove require 650mm clear of combustibles at the rear. The suggestions given may well suffice, but unless you can refer to authoritive research studies to confirm, then the risk and liability remains with you. The client will say he was guided by an experienced installer. Normal liability insurance will not cover you for design.

 

[edd789]

The best thing to do would be to just get a HETAS engineer out to actually look at it.

You need to be HETAS to install them anyway, so might be best to get him involved at this stage so he/you don't have to redo things at a later date.

 

[gmartine]

Build the stove and flue surround to code using the materials mentioned, I see no potential issues as long as they perform to specification. You could even run insulated twin-wall along the outside wall BUT depending on roofline the height of the termination may look unsightly.

 

[waddmiester]

Thanks for the comments guys.
Interestingly, the reason I've posted this is a combination of all of the points above.
I see nothing wrong with installing a stove in the corner of a room as long as it conforms to the regs and above all it is SAFE!
All over the country firms are using the techniques detailed by gmartine and edd789 to put stoves into interesting places ....
Your right joni os, normal liability insurance will not cover you for design, the HETAS cover will, but its twice the price of my insurance which still covers me for stove installation.

 

[waddmiester]

gmartine, lol, I know what your saying but I'm a solid fuel stove convert. I've two installed in my house, ones been riunning virtually 24/7 since before Christmas. I dont mind the look of twin wall running externally, but thats just me.

 

[gmartine]

Eh? Sorry Wadd maybe my last post didn't make a whole lot of sense, just saying an external flu arrangement might be another option for your client.

 

[waddmiester]

Thanks gmartine, reckon I've got it sussed now, cheers.

 

[joni os]

The reason I urge caution is that the times in my working life when I've had most problems is the times I've tried to solve problems for other people. This is a typical case.
A Scan 45 would sit in corner, needs only 150mm from combustibles and at 5 Kw a dedicated air supply is not required. Your client has purchased a stove without consideration of clearance, and now expects others to make it work.

 

[waddmiester]

Valid point mate