Gas question- Can a novice UNinstall gas fires?

darkcyde

Sorry, forgot to subscribe to the thread to know when people reply slating my post! ;-)

thescouselander

darkcyde wrote: »

I think this DIY question is a no brainer to be honest - no, unless you are certified as competent then you should not attempt anything with gas.

With regards to the comments surrounding gas piping, it's not just a matter of making a sound/tight joint. Certain appliances require certain gas rates in order to operate correctly, such as Combi boilers. If you run a gas line in 15mm to a Combi boiler your water from the hot tap won;t get hot enough because the boiler cannot burn enough gas to achieve the required temperature. Training will tell you how to calculate the correctly pipe sizing. Also, there are regulations regarding how deep you can cut into joists to stop people from weakening the overall strength of the house. There are regulations on the distances between surface run pipe clipping to ensure the pipe is adequately supported, etc, etc.

Regarding the general DIY at home, what about this...a home owner decides to put in a new boiler themselves prior to selling the house. The house is sold, new people move in and an incident occurs whereby someone is killed due to a poor installation. You can't tell me that that is acceptable because it is within the law. If a certified competent persons was to do a poor installation which resulted in death they would find themselves in court for manslaughter. Should this also apply to the home DIYer?

There are reasons for registration, and there are reasons for regulations. I'm not saying that they are entirely fair, and Corgi can be a bunch of facists more often than not, but they do save lives.

Couple of examples for you...

Recently a non-competent person installed a new gas line in a customers house and decided to use Hep - the Hep leaked and blew the house up at a cost of £180,000 - luckily no-one was killed.

Again, recently a non-competent person installed a room sealed boiler at a customers house and decided that the flue wasn't required, effectly turning it into a flueless appliance. Killed the entire family, which included two little toddler twin girls.

And not to mention the Corfu incident where Carbon Monoxide killed all those kids!

Regarding these new B&Q flueless decorative effect gas fires, these are borderline dangerous. Regulations state that you can place a flueless appliance of no more than 11/12kw (I forget the exact figure) in a room provided that the room is more than 10m squared and it has an openable door or window to the outside. These decorative fires usually exceed this, but get around the regulation by using some kind of catalytic device. However, the resulting gases from combustion are still vented into the room, and this can include Carbon Monoxide. That sweetish smell you can associate with gas? That's formaldehyde which is a signal that gas is not being burnt properly and will result in Carbon Monoxide being released into the room.

Sorry to rant on for so long, but people should be made more aware of the reasons behind the compentency schemes, and why DIY gas work should not be attempted in any way whatsoever.

(and yes, I am a Corgi registered gas engineer for those of you that were wondering!) :-)

DC

Yes but the original post was about removing a gas fire, not doing a new installation. So provided the gas pipe is sealed properly after removal (an easy thing to check) there will be no problem.

Also, what sort of domestic gas fire exceeds 11/12 Kw? Gas fires are usually more like 2/3 kw. In any case, flueles gas fires should only emmit CO2 if they are working properly so as long as there is adiquate ventilation in the room I dont see how they are "semi dangerous" - using the same logic a gas hob would be semi dangerous too.

TornadoTom

thescouselander wrote: »

Yes but the original post was about removing a gas fire, not doing a new installation. So provided the gas pipe is sealed properly after removal (an easy thing to check) there will be no problem.
Also, what sort of domestic gas fire exceeds 11/12 Kw? Gas fires are usually more like 2/3 kw. In any case, flueles gas fires should only emmit CO2 if they are working properly so as long as there is adiquate ventilation in the room I dont see how they are "semi dangerous" - using the same logic a gas hob would be semi dangerous too.

I spoke to my neighbour who's corgi.
He agreed with the principle of someone competent carrying out basic gas works.
He said it's not the capping off part thats the dangerous part. Competent DIY'ers usually dont carry out a tightness test, neither do they purge the pipes of air. The chambers in the gas meter need purging of air, else an explosive ratio of gas to air could be achieved......booooooommmm !

On your second point, a hob usually burns in a kitchen where there is usually ventilation from windows or back door. Not many prople fall asleep in the kitchen.
A lounge will invariably have some dust which is drawn in by the fire, this potentially will cause the fire not to burn correctly....lots of people fall asleep on the sofa......especially me
If the fire isnt burning correctly and there is no flue, where do the c/monoxide gases go ?
I think you have to have large ventilation bricks with these fires......hmmmmmm that'll look great in the lounge wall :think:
Tom

thescouselander

TornadoTom wrote: »

I spoke to my neighbour who's corgi.
He agreed with the principle of someone competent carrying out basic gas works.
He said it's not the capping off part thats the dangerous part. Competent DIY'ers usually dont carry out a tightness test, neither do they purge the pipes of air. The chambers in the gas meter need purging of air, else an explosive ratio of gas to air could be achieved......booooooommmm !

On your second point, a hob usually burns in a kitchen where there is usually ventilation from windows or back door. Not many prople fall asleep in the kitchen.
A lounge will invariably have some dust which is drawn in by the fire, this potentially will cause the fire not to burn correctly....lots of people fall asleep on the sofa......especially me
If the fire isnt burning correctly and there is no flue, where do the c/monoxide gases go ?
I think you have to have large ventilation bricks with these fires......hmmmmmm that'll look great in the lounge wall :think:
Tom

I totally disagree. If a competent DIYer has just capped off a gas supply they will at least check the cap for leakage using some sort of leak detection fluid. Although this isn't quite a full gas soundness check it does check the joint that has the most risk of leaking after the work.

Also, even if the DIYer does fail to purge the air out of the pipes it will quickly purge itself as other gas appliences are used. It would take a large amount of air to enter the pipes before an explosive mixture is achived - the ratio of gas and air is quite critical to achive an explosion. Even then it is unlikely there would be a source of ignition inside the pipe.

Lastly, DIYers have been removing gas fires for years without incident. Although instences of people blowing themselves up are high profile it doesn't happen often.

PROFESSIONAL_LANDLORD

The LAW is If your COMPETENT you are are allowed to do YOUR OWN DIY gas work. OF COURSE if your not COMPETENT leave it to those who are !

The facts are most gas incidents are caused by CORGI installers and not by DIYers. Simply because most DIYers, won't touch gas .

TornadoTom

I'm not arguing for the side of corgi here In fact I think the whole organisation is a money making racket.

I just think that if you are gonna do these types of jobs yourself, you should at least read up and follow the proper procedures for carrying out these simple safety tests.
Tom

darkcyde

thescouselander wrote: »

Also, even if the DIYer does fail to purge the air out of the pipes it will quickly purge itself as other gas appliences are used. It would take a large amount of air to enter the pipes before an explosive mixture is achived - the ratio of gas and air is quite critical to achive an explosion. Even then it is unlikely there would be a source of ignition inside the pipe.

The ratio of gas to air is 5% on the lower end and 15% on the upper end. The reason for a purge procedure is to ensure that the ratio in the pipe is greater than 15%. If you were to just simply light the appliance without purging, then as the gas flows through and replaces the air, the ratio gradually increases from 0% upwards. When the ratio reaches 5% in the majority of the pipe, you can experience what is known as flash back - this is where you have an explosive ratio in the pipe and the flame rushes back down the pipe until it reaches the meter. The resulting explosion will be enough to rip a hole in the wall and propel the meter shrapnel through the air.

This is quite rare, BUT it can happen which is why there are procedures.

darkcyde

PROFESSIONAL_LANDLORD wrote: »

The LAW is If your COMPETENT you are are allowed to do YOUR OWN DIY gas work. OF COURSE if your not COMPETENT leave it to those who are !

I don't disagree with this, but please define competent. Is this someone who simply knows/thinks what they are doing, but then how do you measure this competency, or is it someone who has been trained to a level deemed competent, as in a trained professional?

PROFESSIONAL_LANDLORD wrote: »

The facts are most gas incidents are caused by CORGI installers and not by DIYers. Simply because most DIYers, won't touch gas .

This statistic really doesn't say anything - the majority of incidents are caused by Corgi installers because they are the people doing the work, and accidents do happen as we are only human. That is like saying the majority of road accidents are caused by drivers.

PROFESSIONAL_LANDLORD

darkcyde wrote: »

I don't disagree with this, but please define competent. Is this someone who simply knows/thinks what they are doing, but then how do you measure this competency, or is it someone who has been trained to a level deemed competent, as in a trained professional?

Competent = having the skill or knowledge to do something well. {collins english dictionary}

This statistic really doesn't say anything - the majority of incidents are caused by Corgi installers because they are the people doing the work, and accidents do happen as we are only human. That is like saying the majority of road accidents are caused by drivers.

Ummm! ......................................that's what I said.


Originally Posted by PROFESSIONAL LANDLORD
The facts are most gas incidents are caused by CORGI installers and not by DIYers. Simply because most DIYers, won't touch gas

thescouselander

darkcyde wrote: »

The ratio of gas to air is 5% on the lower end and 15% on the upper end. The reason for a purge procedure is to ensure that the ratio in the pipe is greater than 15%. If you were to just simply light the appliance without purging, then as the gas flows through and replaces the air, the ratio gradually increases from 0% upwards. When the ratio reaches 5% in the majority of the pipe, you can experience what is known as flash back - this is where you have an explosive ratio in the pipe and the flame rushes back down the pipe until it reaches the meter. The resulting explosion will be enough to rip a hole in the wall and propel the meter shrapnel through the air.

This is quite rare, BUT it can happen which is why there are procedures.

I think you are overstating the consequenses of such an incident here. Even if the scenario you stated happened the amount of gas and air in the pipes is relitivly small so the explosion will be nowhere near big enough to cause the scale of destruction you are talking about. Most likely the pressure from the explosion will escape through the open burner on the applience being used or maybe through some weak part of the piping such as a joint. I seriously doubt such a spectacular explosion would be caused in the gas meter. If fact a quick search of the internet brings up no incidents of exploding gas meters.