pipe insulation

[Fred]

Hi,

I was wondering what the group thought about the economy pipe lagging versus byelaw version?

I notice that Tool station say the economy lagging cuts up to 70% of heat loss, whilst the byelaw description says it cuts over 75%.

first I wondered whether it is worth the extra expense to save 5% heat loss?

But now I read the descriptions again, I notice it says up to 70%, implying that under ideal conditions the economy version will reduce heat loss by 70% but in other conditions it might be less; in other words, 70% is the maximum performance of the product. Whereas the byelaw description says over 75%, implying the 75% is a minimum figure and in ideal conditions the savings could be greater. If this interpretation is correct, it could be that the difference between the two products is more than 5% and worth paying more for.

What does the group think?

TIA

[Onetap]

The 'economy' and 'byelaw' descriptions are something Toolstation has made up, no-one else uses them SFAIK.

The information you need is the thermal conductivity, thickness, material and finish (flammability, surface spread of flame and such stuff).

If you're looking for savings, you should bear in mind that it should be in place for a long time (30+ years, quite plausible) and that a major part of the cost is in the time invested in installing it.

There not much point in making economies on the thickness if it will be costing you energy for the rest of your natural. I get the thick stuff for my DIY jobs. I like to do a decent job. No-one installs this plastic foamy stuff properly (with contact adhesive opr manufacturer's purpose-made tape), it's too time consuming. Too much time (& therefore money) is required to do a proper job.

It's almost invariably bodged, bulging open at bends and fittings and stuck on with dodgy tape. It (Armaflex, Insultube closed-cell type stuff) is usually only used commercially on refrigeration pipes where there could be condensation forming on the pipe. There are detailed instructions on the Armaflex website.

Commercial specifications usually require mineral fibre with aluminium foil outer, which is quickly fixed into position with self adhesive ali foil tape.

[meow2222]

no-one else uses them SFAIK.

Wickes does too.

place for a long time

invested in installing it.

costing you energy for the rest of

You can improve (or if totally brassic even replace) by adding wrapped rag over the insulation.

NT

[fred]

In article , Fred writes

The figures they quote are nonsense, the more expensive stuff is twice as thick and so twice as effective, it's the stuff I have used here and is what I would recommend.

Good fitting is important, I tape all the joints (including the longitudinal slit) with good quality duct tape (the adhesive on crap stuff will harden and it will fall off).

[GMM]

There is a practical issue of course, which is pipe spacing. If you're installing new pipework, it would make sense to allow for the thick stuff but on most existing installations it's difficult enough to get the thin stuff on where, for example, you have flow and return radiator pipes close together, so pragmatism often has to rule. I also failed to get any sensible performance data on the various types, but it's pretty clear that the thin stuff is better than nothing (or in my case, old yellow foam that had gone brittle over the years). Somewhere (maybe here), I saw it quoted that a CH run could lose 400 watts per metre. Sounds like an awful lot to me but even at a fraction of that, insulating pipe work in the garage etc etc even with the thin stuff has to be a good thing. I'll probably get shot down in flames for saying this but the tiny percentage of the pipe that's allowed to lose some heat in (for example) an untaped joint seems like very little to worry about in my understanding of physics.

[RJH]

>>>>>>>>

installing new pipework, it would

it's difficult enough to get the

close together, so

it's pretty clear that the thin

brittle over the years).

metre. Sounds like an

garage etc etc even with the

of the pipe that's allowed

worry about in my

I'd be interested to know what the loss is. I've just lagged about 20m of cellar pipe using the thin version (Climaflex Pipe Insulation 15mm x

13mm x 1m).

CH water about 70C, cellar usually about 10C, pipe 15mm. I can't see any of the lost heat getting inside house - the cellar's pretty well ventilated.

Rob

[Perry525]

While you only mention insulation, its important to consider the possibility of your pipes freezing. Keeping this in mind, it makes sense to use the best insulation. My central heating and hot and cold system pipes all run in the loft (concrete floors) I have the best insulation available plus I have 4 inches of fiberglass laid over the top. When you slip your hand under the fiberglass its amazing just how much heat is escaping through the pipe insulation.

[Fred]

no-one else uses them SFAIK.

Thanks. I think other sellers have a thin and thick version but may call them other names. I'm sure Wickes and Screwfix do.

[Fred]

Certainly for the 15mm there is a big difference in thickness. For the

22mm version, there seems to be little difference in thickness. I wonder whether there is much performance difference between the two thicknesses for 22mm pipe, considering the difference in thickness is smaller?

Is the heat loss proportional to ratio of surface area to volume? That would explain why the 15mm stuff has to be thicker.

Does one that is twice as thick really halve the heat loss or is it more exponential? Is it a case of diminishing returns? I don't know.

Like other posters have said, there seems to be very little data about these easily available.

I have tried to do this, even mitering for shoulders.

Thanks.

[Fred]

installing new pipework, it would

difficult enough to get the

together, so

Yes, I have used the thinner stuff to insulate my CH pipes and had to use the thinner version for precisely this reason. Like you, I figure it is better than nothing.

of the pipe that's allowed

worry about in my

I would agree but I am not an expert in physics, so I am happy to be proved wrong. I suppose the point is that whilst it might not be the end of the world, if you are DIYing, you may as well DIY it properly and minimise as much heat loss as possible and I suppose the losses all add up so that several small losses equal one big one over the whole system.

Thanks.

[GMM]

installing new pipework, it would

it's difficult enough to get the

close together, so

of the pipe that's allowed

worry about in my

Indeed: When doing anything it's best to do it as well as possible and when I fitted a lot of pipe insulation recently, I mitred tight joins and put a birds mouth into tee junctions etc. There are, however, some locations where it's just extremely difficult to get everything to fit as well as you'd ideally want it to. In those cases, my approach would be to do it as well as possible then not lose any sleep over it if it's not perfect. After all, a 1mm gap between two metre lengths of insulation will only will reduce efficiency by 0.1%, whereas not doing it at all because it's too difficult/complex to do it perfectly will reduce its efficiency by 100% ! (regardless of the specific performance characteristics of the insulation)

[Grimly Curmudgeon]

of the pipe that's allowed

worry about in my

It's not so much the slight loss of heat from an elbow or joint, it's the freezing of the elbow or joint when the whole attic is at sub-zero. The ice will attack - it knows where to go. Dashed clever stuff, ice.

[Grimly Curmudgeon]

Ding! I did the same last year, just out of principle. Lagged pipes under 8" of sheepswool (which is amazing stuff to work with, btw).

[Perry525]

I would agree but I am not an expert in physics, so I am happy to be

proved wrong. I suppose the point is that whilst it might not be the end of the world, if you are DIYing, you may as well DIY it properly and minimise as much heat loss as possible and I suppose the losses all add up so that several small losses equal one big one over the whole system.

Thanks. Pipe insulation isn't very good, as you increase the surface area by using thicker insulation you loose more heat because of the much larger surface area.

That is why the surface area of 15 and 22mm pipe for the same result by the same manufacturer is the same diameter.

The amount of water in the 22mm pipe is about 7 times as much as the 15mm pipe and it takes a lot longer to cool.

The 15mm pipe cools more quickly as it holds a lot less heat, so it needs more insulation.

If you take a room at 22C and a pipe full of hot water at 70C , a uninsulated 15mm pipe in still air looses 55 watts per metre, a 22mm pipe losses 60 watts, as the speed of the surrounding air rises so the heat loss increases, this is an horrendous amount of heat loss.

That insulated GLC standard 15mm pipe looses 20 watts per metre. Check the length of your pipe runs and that amounts to a great deal of wasted heat over a year.

Insulation really saves and is noticed, when hot water is sitting in a pipe to the kitchen sink, the slower heat loss due to thicker insulation means that there is less hot water wasted when you turn the tap on. You avoid the situation where the previously hot water is now cold and you have to run off half a bowl of cold water, before the hot water arrives from the tap.

[Andrew Gabriel]

I try to avoid splitting them open at all. When I installed my heating, I threaded them onto the pipework as it was assembled. Since you can't solder right next to the stuff, you do end up having to slit some small lengths to put in place afterwards, but I ensured the slit lengths were on straight sections, and bends always used unslit pieces. I also made them slightly over long so they were under slight pressure, having seen in other installations big gaps between the lengths. I also mitred the elbows, drilled holes through for Tee's (which you can do with a freshly cut pipe end which still has the burr on it), and curved the cut ends where they butt up against another piece, e.g. at a Tee.

No tape used anywhere, and whenever I see installations which have relied on tape, it's all fallen off.

11 years later, mine is still all in place. Only thing is that it seems to have shrunk a little, and instead of the lengths being forced against each other, there are a few gaps now, which would probably have been worse if I hadn't installed them slightly over-long.

[fred]

In article , Andrew Gabriel writes

Likewise, I used plastic pipe for my install and used climaflex semi slit 15-25 pre-threaded on the pipe before installation.

When was the last time you installed though, I haven't seen semi slit on sale in years, it all seems to be fully slit now (much to my annoyance), hence the recommendation for taping new installs.

Where I have used tape it was good stuff (as I have seen what cheap stuff turns to) and is still in place 8 odd years later. Odd bits near the boiler & cylinder have cable ties lightly applied to make sure the slit stays closed.

[The Other Mike]

Eh?

Eh?

No, just over 2 times