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General Plumbing and Gasfitting Talk => Gas Station => Gas Fires Q & A => Topic started by: rubberducky on August 26, 2009, 12:45:31 PM

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Title: gas fire question from a consumer
Post by: rubberducky on August 26, 2009, 12:45:31 PM
Hi, I'm not a gasfitter, just a consumer - hope it's OK to ask questions here. Is it OK to install a flued (but not room-sealed) 25 Mj/h gas fire in a 48 cubic metre room, without having to install any permanent openings?
Title: Re: gas appliance question from a consumer
Post by: Plumber on August 26, 2009, 01:42:39 PM
Hi, No problem at all! This forum is designed for anyone with Plumbing and Gas Issues  ;)

here as per NZS 5261:2003 2.6.6

Where a gas appliance  is installed in a room or enclosure, that room or enclosure shall be ventilated. Where the total input of open flued gas appliances exceeds 3MJ/h for each cubic metre of the room or enclosure volume, the area shall be ventilated in accordance with clauses 2.6.6.1.

2.6.6.1 states: Two permanent openings shall be provided each with a minimum free ventilation area as calculated using the following formula:
A=F x T where

A= the minimum free ventilation area (mm-square)
F= the factor given in Table 3
T= the total gas consumption of all gas appliances (MJ/h)

Although a room sealed appliance draws required air from the outside, ventilation of the room may be required to prevent an excessive rise in ambient temperature.

Please refer to the manufacturers specification and consult a registered Gas fitter to ensure the appliance is suitable for its purpose and installed correctly.  

Hope this helps
Title: Re: gas appliance question from a consumer
Post by: rubberducky on August 26, 2009, 03:10:19 PM

Where the total input of open flued gas appliances exceeds 3MJ/h for each cubic metre of the room or enclosure volume, the area shall be ventilated in accordance with clauses 2.6.6.1.


Thanks for that! So if I understand correctly, do I need to divide the gas fire's maximum input of 25 MJ/h by the room volume of 48 cubic metres, which equals 0.52 MJ/h per cubic metre - and therefore the room size is fine? If the result was above 3 MJ/h per cubic metre then 2 permanent openings would need to be provided?
Title: Re: gas appliance question from a consumer
Post by: Plumber on August 26, 2009, 06:40:51 PM
that's pretty much it.. To establish wether the required air is to be provided by adventitious openings or additional ventilation openings, the total input of the gas appliances in the room/enclosure in MJ/h is divided by the room/enclosure volume in cubic m. well done..
Title: Re: gas appliance question from a consumer
Post by: jd24hrs on October 10, 2009, 10:28:48 AM
hi all
i agree to all above but also have to point out that you should allways refer to the manufacture instructions or call them on there tech phone line,then you should test the flue, turn on all fans extractors/cooker hoods that may have an effect upon that flue then do a smoke and spillage test as this will then prove the flue is working well on the day you tested it, then i advise leaving the pellet and match hidden within the case of the fire as proof that you did it.
I advise this because even if you fit the required ventilation other factors like fans extractors and sometimes the position of those vents can have an effect on the performance of the flue and in somecases you will have to add more ventilation.

also VERY IMPORTANT ADVISE 12 MONTHLY SERVICING AS THE MANUFACTER ADVISES THIS and it is also good for ongoing business
jd  kiwigas.engineers@yahoo.com