Ventilation for dfe fires.

[kirkgas]

Most of DFE's are under 7Kw and MI would say - purpose built ventilation is not normally required for this appliance.

We could have more appliances in the same room but this is another question.

if we do a vote of whether we have seen more that require a 100cm2 than dont, i think most people will say they have seen a lot of fires that do require it

 

[Puddle]

On the subject of dfe fires,would just add that it is important to gas rate them,manufacturers stating no extra ventilation required as say only 6.9 k/w,they base this on the 7k/w rule and but you will find many of these fires are over the 6.9 k/w stated on the badge pushing it over the seemingly magical old 7 k/w figure

 

[Blackcatgas]

[QUOTE=aggis;262808]If the DGF's MI states it doesn't need ventilation, thats the case as long as the client has the instructions.
Where as if it states it needs ventilation, the minimum is 100cm2 unless MI states it needs more.
100cm2 free air thro' floor & 100cm2 min thro' the vents into the under drawing in your case.[/QUOTE]



The MI states that it needs extra ventilation, 14.6cm2 to be precise, the vents/fire were installed 8 years ago. Do I need to upgrade to 100cm2 or will the existing vents (50cm2) suffice?.

 

[Billy Bob Bob]

[QUOTE=aggis;262808]If the DGF's MI states it doesn't need ventilation, thats the case as long as the client has the instructions.
Where as if it states it needs ventilation, the minimum is 100cm2 unless MI states it needs more.
100cm2 free air thro' floor & 100cm2 min thro' the vents into the under drawing in your case.

The MI states that it needs extra ventilation, 14.6cm2 to be precise, the vents/fire were installed 8 years ago. Do I need to upgrade to 100cm2 or will the existing vents (50cm2) suffice?.[/QUOTE]

upgrade to 100cm2

 

[Blackcatgas]

apologies in advance if im wrong, but are you sure you read the MI properly? any dfe i've seen by definition of design needs a minimum of 100cm2
and at 10.2 requiring a vent it would be 10.2-7x5 is more than 15cm2 haha

Hi Kirk ,defo 14.somthing, il scan them in tomorrow

 

[kirkgas]

Hi Kirk ,defo 14.somthing, il scan them in tomorrow

cheers, wasnt sure, only ever seen nil or 100cm2

 

[Simon F]

taken from "Corgi Fires and Space heaters" third ed page 56,

"unless the manufacturer's installation instructions specifically state that purpose provided ventilation is not required, a minimum 100cm2 free area of ventilation needs to be provided. the purpose of the ventilation is not only to provide combustion air for the appliance but also to satisfy the requirements of the unrestricted chimney".

 

[GrahamM]

apologies in advance if im wrong, but are you sure you read the MI properly? any dfe i've seen by definition of design needs a minimum of 100cm2
and at 10.2 requiring a vent it would be 10.2-7x5 is more than 15cm2 haha

I have viewed similar MI's that state the same small vent size for a DFE fire. The customer produced the old MI's for some ancient fire that BG had been servicing and passed year after year. They argued that the removed window vent more than gives the 15cm² required. IIRC it was around 9kw.
I argued the old MI's are out of date and AR'd fire. Customer was not interested in forking out to upgrade ventilation to 100cm².

 

[Rob Sale]

Mi's trump regs.

 

[Puddle]

Mi's trump regs.

not as regards to updates in ventilation requirements

 

[Reg Man]

Just because a DFE is under 7 kw does not mean it does not need added ventilation,all DFE's need ventilation unless otherwise stated by manufacturer and that ventilation shall be no smaller than 100cm2

Agree with you. British Standard 5871 part 3. All DFE fire installations require in a minimum 100cm2 free air ventilation unless the manufacturer for the appliance specifies otherwise. DFE fires less than 7kW may not require additional ventilation if the flue flow is greater than 70m3/h, manufacturer would have to be consulted before accepting this as acceptable.

 

[arran197]

DFE's require a MINIMUM of 100cm2. End. If the M.I.'s recommend more then it must be provided. If less then 100cm2 is needed. The adventitious ventilation does not suffice for DFE's. Are you sure it's a DFE and not and LFE?

 

[sparra1100]

all dfe,s have to have 100cm" regardless and as above if mi,s say bigger you go bigger but carnt be less than 100cm2 full stop

 

[AlexGas]

No, no, no...
OK, BS can be confusing...
Here's same thing in our good old TB from Gas Safe:

Technical Bulletin 041

Note 2: DFE appliances with a rated heat input less than 7kW (Net) will normally require a minimum of 100cm[SUP]2[/SUP] free-area ventilation, however, reference should be made to the manufacturer’s installation instructions, as some models may not require additional ventilation.

Note 3: DFE appliances with a rated heat input greater than 7kW (Net) and up to 20kW (Net) will normally require a minimum of 100cm[SUP]2[/SUP] free-area ventilation, (or as by manufacturer’s installation instructions).

It's in black and white. So, it can be less than 100 cm[SUP]2[/SUP] or none.

 

[GrahamM]

Mi's trump regs.

In the majority of cases yes, but with important issue such as ventilation requirements the Regs/Standards overrule.

Another example is, how many sets of MI's does it state the flue must be fully inspectable along it's run?

Sometimes we have to take a balanced view/approach between the MI's and regs!

Nothing is straightforward in this game. Even more so in recent years. We now have more and more MI's contradicting regs/standard and vise versa. Keeps us on our toes.:smile:

 

[ADM360]

I could be wrong but I though that you couldn't just cut a hole in the floor to give a vent to a fire, I was under the belive that if it was under the floor it had to be purpose provided ventalation and ducted directly from out side to the vent!!

 

[kirkgas]

I could be wrong but I though that you couldn't just cut a hole in the floor to give a vent to a fire, I was under the belive that if it was under the floor it had to be purpose provided ventalation and ducted directly from out side to the vent!!

floor vent only needs to be ducted if under floor communicates with more than one property or there is a potential for radon gas

 

[ADM360]

Thanks Kirk, I though someone would put me right!!

 

[sparra1100]

to be honest i couldnt care less what anyone says as on my acs its said 100cm2 and says the same in the corgi book and viper book so as long as i cover my own rear and no one dies al stick to what ive been taught granted the mi,s overule everything but its been 100cm2 for as long as ave been doing it and this is the first time anyone has questioned it so all i would say is if someone wants to take the risk so be it on there head but i no what i would do

 

[AlexGas]

to be honest i couldnt care less what anyone says as on my acs its said 100cm2 and says the same in the corgi book and viper book

Sorry mate, you have to read the books again.

CORGI book (page 72) For DFEs - check the MIs as some models may not require any additional ventilation - or as per MIs.

VIPER (page F-4) Decorative fires may not need purpose provided ventilation where the MIs clearly identify this.