Ventilation for dfe fires.

[Blackcatgas]

Further to my other post about floor vents..... I went to a job today, the dfe fires been capped, the paper work says 100cm2 vent required, its a 10.2 kw fire, Ive calculated that it needs a 15cm2 vent, the installation instructions concur with this. Is there some new reg that I dont know about that says all dfe fires must now have a 100cm2 vent as a matter of course now?.

 

[Puddle]

No,100 cm2 is the smallest vent that can be fitted

imho

 

[Blackcatgas]

No,100 cm2 is the smallest vent that can be fitted

imho

I dont understand Puddle?

 

[southcoastboile]

mis overide everything but i thought the smallest vent is 100cm2 for any fire

 

[Billy Bob Bob]

I dont understand Puddle?

WHAT PUDDLES SAYING IS ALL DFE,S REQUIRE A 100CM2 VENT BCG(sorry for the caps my keybords stuck)

 

[Blackcatgas]

mis overide everything but i thought the smallest vent is 100cm2 for any fire over 7kw

Ahh, ok, this is the crack, the fire was fitted 8yrs ago,the manuufactures instructions say a 14cm2 vent is required, there is a 50cm2 vent into the floor void, Ive been outside and there is only the old victorian brick vents from outside into the floor void. what I was going to do was core a new black hole ventilator from outside into the floor void, this is 35cm2 because of the internal baffels.
Is this ok to do?. Cheers for your replies.

 

[Puddle]

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

 

[Puddle]

If mi says 140 cm2,fit a vent to suit through floor,you can increase ventilation under floor to outside if you wish but you should find underfloor vents already at front and rear of building,which should be adequate if meeting building regs

imho

 

[Blackcatgas]

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

Cheers Puddle, the dfe is 10.2 kw, the MI state a 14.6 cm2 vent is required, my calculations agree with this, I know the MI always overide anything, but...... will my above plan of work suffice or do I have to now put in a 100cm2 vent even though the old MI says I dont have to put one in that big?

 

[Blackcatgas]

If mi says 140cm2,fit a vent to suit through floor,you can increase ventilation under floor to outside if you wish but you should find underfloor vents already at front and rear of building,which should be adequate if meeting building regs

imho

14 (Fourteen) cm2 vent required in the MI.

 

[AlexGas]

Here we go, from the current BS:

BS5871-3:2005
Specification for Installation and maintenance of gas fires, convector heaters, fire/back boilers and decorative fuel effect gas appliances —
Part 3: Decorative fuel effect gas appliances of heat input not exceeding 20 kW (2nd and 3rd family gases)

8 Ventilation

8.2 Sizing
Unless the manufacturer’s instructions specifically state that purpose provided ventilation is not required, such ventilation shall be provided in the room or internal space containing the appliance. Where purpose provided ventilation is required, the air vent free area shall be a minimum of 100 cm2, or, where greater, as stated in the manufacturer’s instructions.

COMMENTARY AND RECOMMENDATIONS ON 8.2
Normally, appliances covered by this standard will require a minimum of 100 cm2 of purpose provided ventilation. However, in the case of an appliance of not greater than 7 kW input which generates a clearance flue flow not greater than 70 m3/h when tested in accordance with Annex A, an air vent may not be necessary.
The manufacturer’s instructions will provide details in such circumstances. It should be noted that Annex A describes a laboratory test which is not for use by gas installers seeking conformity with this standard.

Hope it helps.

 

[Puddle]

14 (Fourteen) cm2 vent required in the MI.

got that and edited to suit before this post,finding it hard to keep up this evening :dozey:

defo no need to increase underfloor ventilation to outside would of thought ,should be alot more than 14 cm2

 

[Blackcatgas]

8.2 Sizing
Unless the manufacturer’s instructions specifically state that purpose provided ventilation is not required, such ventilation shall be provided in the room or internal space containing the appliance. Where purpose provided ventilation is required, the air vent free area shall be a minimum of 100 cm2, or, where greater, as stated in the manufacturer’s instructions.


Cheers Alex, Iam sorry to be thick its been a long day, the manufacturers instructions say that extra ventilation is required, it states 14.6cm2. I was always taught that the manufactures instructions trump any regulation, so will the existing 50cm2 vent suffice or do I need to put in a 100cm2 vent becuse the MIs are old and not to current standards.

 

[Blackcatgas]

got that and edited to suit before this post,finding it hard to keep up this evening :dozey:

defo no need to increase underfloor ventilation to outside would of thought ,should be alot more than 14 cm2

Thanks everyone!

 

[AlexGas]

You got it! Stick to the MI.

 

[Blackcatgas]

I was still writing some of my replys when people had already replied, looks like I was being ignorant/thick. sorry.

 

[Puddle]

If it is an old fire and fitted before reg change,I would increase ventilation to 100cm2, as ventilation requirements must meet todays standards and sounds like mi's in this case are based on old standards

imho

 

[aggis]

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.

 

[kirkgas]

Further to my other post about floor vents..... I went to a job today, the dfe fires been capped, the paper work says 100cm2 vent required, its a 10.2 kw fire, Ive calculated that it needs a 15cm2 vent, the installation instructions concur with this. Is there some new reg that I dont know about that says all dfe fires must now have a 100cm2 vent as a matter of course now?.

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

 

[AlexGas]

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.