boiler firevalves

[Stephen]

Hello,

For oil fired boilers, please can someone clarify what firevalves are required? I've done a google and apparently they are specified in BS xxx. It seems British standards are not available online and I am expected to pay £148 to find out what this particular one says! What's the point having standards if they are kept secret?

My old boiler had a firevalve that looked very much like an isolating valve inside the casing. I see these are still for sale in the catalogues. Are they still used? I thought practice now was for the sensor to be inside but the valve to be outside the property. I see these valves have two temperatures: sixty-something C and 90C. Am I right to thing the 90 degree one is for Agas and that a boiler requires the sixty-odd degree one?

Thanks, Stephen.

[cynic]

The currently OFTEC reccommended type is the Teddington capillary type KBB (or competitor versions but I prefer the Teddington) with the valve outside the dwelling and the heat sensor inside the boiler casing. Most decent boilers have a suitable clip positioned for the sensor bulb to locate into. Capillary lengths are available as 1.5m,

3.0m, 6m, and 10m, possibly others may have been added to the range.

Correct.

[Stephen]

Thanks. I have seen those. The tank is obviously outside but the pipe runs underground (under the drive presumably) and into the kitchen, coming up through the concrete floor. So would I have to put the valve near the tank (the only section where the pipe is above ground) and run a long capillary back to the boiler? I don't really want to dig up the drive looking for the pipe if I can help it!

I suppose these "split" valves are useful. I always thought it was silly having the valve inside because what if the other side of the valve caught fire?

The valve we have at present is like Toolstation part #22278. Is it worth still fitting something like this inside to use as an isolation valve for when servicing etc?

I see they also sell 66C and 90C valves, are their prices reasonable? So to double check 90C valves are only for Agas and 66C are for everything else?

Thanks again, Stephen.

[cynic]

There is an exception for retrofitted firestop valves where a metal pipe is under a solid, noncombustible floor. In this case it is allowed to fit the firevalve immediately after the point of emergence. Note only mechanical i.e. non heat susceptible joints should be used. Once you have the firestop protection in place and functional it is up to you if you want to fit a servicing valve at the burner or at a convenient place.

[Stephen]

How close to the point of emergence is this considered to be? Are you allowed a couple of centimetres after it comes through the floor? I presume you are not supposed to have the nut touching the concrete!

In other words, no solder?

In this scenario, what valve would you fit? The same as I had before, or would you use a Teddington with the sensor in the boiler and the valve at the point of entry?

Is it worth running a teddington from the tank? If so, what do I need to do to protect the capillary? Do I need to run it in conduit for example?

Thanks. Stephen.

[Stephen]

To add to my own post, the oil is in 10mm copper pipe which rises through the concrete floor close to the wall. Bizarrely it then runs about 60cm into the room (the adjacent unit is 60cm and it runs about the length of that), it then doubles back on itself and goes back 60cm to the wall before turning one last time and coming a further 60cm forwards and into the boiler. What is the point of all this zig-zagging?

I also note that outside the pipe from the tank drops into the concrete below the tank and the pipe seems a bit green. Do I need to worry that the pipe is corroding?

Thanks.

[cynic]

Apply engineering judgement - a solid pipe with a compression joint is "relatively fireproof" any fire with enough heat to melt a couple of inches of copper pipe at ground level with heat absorbing mass next to it is going to have destroyed the building by then.

Correct. Solder should not be used on an oil pipe anyway but its amazing what you find out there.

A Teddington with capillary at the boiler as previously described.

Not really worth doing this and I once had a lengthy debate with one OFTEC inspector who criticised mounting the valve which had a 10 metre capillary at the extremity of the length from the boiler. He considered there would be a lot of oil in the pipe after the valve. Exactly how it was supposed to flow out of a small bore closed end tube running horizontal for 9 metres outdoors he didn't say. In the end he gave up as the situation was better than say an approved installation with a long run under a wooden floor to a boiler with the valve outside as recommended. I think he was just trying to find a fault where there wasn't one to put down on his advice to installer form. You also have the problem of protecting the capillary from damage or corrosion over that length and then crossing over the concrete floor area to reach the boiler. I would use a shorter capillary version mounted close to the emergence of the pipe from the floor and run the capillary into the boiler along the oil pipe route.

[cynic]

Pretty pointless really - has the boiler been relocated or replaced by one in a diferent position at some time and the pipe been concertinad or alternatively did the installer for some reason place it temporarily with a view to relocation which never happened?

Probably not but keep an eye on it. 10mm oil pipe is quite thick walled and a surface discolourisation will not normally be serious. There are sometimes problems when an unprotected copper pipe has been buried in ashes but many older installations are buried direct in soil and have no problems. Nowadays I would use plastic coated pipe and/or pass it through a suitable duct. The point of change of environment is always where signs of corosion start so if you do eventually have problems it may be adequate to chop out the concrete to expose good pipe and join on with a compression or flare joint.

The environmental brigade have succeeded in putting all sorts of requirements in place and put fear of disaster into the publics mind regarding fuel leaks. Its funny that in the past we occasionally had a kerosine spill or loss into the ground and all it did was kill the grass for a few weeks until it had evaporated and nature then rapidly recovered. One traditional "cure" for wireworm in grass was to dose it with kerosine :-)

[Stephen]

Thank you for all your help.

I hadn't thought it out as thoroughly as you. You are quite right that if a fire is hot enough to melt the copper, the oil is the least of my problems! I shall put the fire valve near where it enters the room (with capillary to the boiler) but I shan't worry if there's a few inches of copper first. Before I wasn't sure if even an inch or two of non-isolated pipe was a no-no but you have reassured me that that will be ok.

As it happens the zig-zag of copper is soldered! A plumber that came too quote told me that that is no longer allowed. I thought it was in case a fire melted the solder. Is there another reason? Does the oil cause it to dissolve or something?

I have used 15, 22, and 28mm copper before but not the smaller stuff. Is there anything I need to be aware of when using 10mm copper? Do I need to use inserts or anything?

The notes in the back of the Worcs-Bosch brochure mention fitting two oil filters: one at the tank and one at the boiler. I have one at the tank and my old boiler had one built in. Will my new boiler likely have a filter built in or should I fit one after the fire valve? I'm thinking of buying a Grant rather than a WB because (i) grant is higher up the sedbuk table and (ii) WB condensing boilers seemed to be criticised in a post I read here.

Thanks again, Stephen.