3/4" pipe lagging

Mar 15, 2007 14 Replies

I have some hot water pipes that I want to lag. I tried a bit of split sided lagging and 15mm was too tight - it wouldn't close over the pipe, while 22m was very loose. I haven't got a set of calipers on me, but I suspect it may be 3/4" pipe. Nobody this side of the pond seems to stock imperial sizes any more. Any suggestions?



Cheers,



Ben



just use the 22mm lagging and apply tape every 18 inches to keep it in place

I guess though that if the lagging is loose then looses will be increased due to air movements within the insulation...

No, because the pipe will heat the little bit of air within the insulation and that cannot escape, provided you tape each joint too.

Ah yes - therein lies the problem. The pipes are very inaccessible, so the only way to fit the lagging is to push it on from one end, which leaves no way of sealing the split. I may use 15mm lagging which is better than nothing, although it only covers about 75% of the surface...

Ben

I'm puzzled to know what type of pipe you've got! The old 1/2" copper pipe was virtually the same size outside as currently used 15mm pipe. [Imperial copper is sized by the nominal bore, and metric by the external diameter]. Likewise, 3/4" copper was virtually the same size as 22mm.

Even 1/2" (bore) iron pipe had an external diameter very similar to 22mm. So I'm surprised that the lagging doesn't fit.

So what *have* you got - lead maybe?

=============================== Use a very sharp utility knife (plus straight edge if necessary) to cut a thin slice off one edge of the slit / opening. Experiment with the cut to find out the correct amount to remove to produce a snug fit. Tape as much as you can reach at the suggested distances.

Cic.

seems

3/4" pipe is still in use in the air conditioning HVAC arena - you may get some there, but in practical terms 22mm and the odd tywrap to hold it in place is probably a better real world solution.

AWEM

Certainly not lead. Some are 22m, because that fits perfectly. Th rest are smaler, and the 22mmlagging is very loose, but the 15mm aggingis too small. I'll check the rest and let you know...

Cheers,

Ben

Ok - that's odd. It seems that as I had initially thought my pipes were 22mm and 28mm. However, he 28mm lagging is loose on the 22mm pipes, and the 22mm lagging is loose on the 22mm pipes. But the 22mm fits the 28 perfectly :-)

Oh well....

Have you been sniffing stuff you shouldn't have?

On 15 Mar 2007 15:44:49 -0700, "Ben" mused:

You haven't been buying the cheap crap from some DIY hovel have you? I've found some of these to be very 'random'.

|!Ben wrote: |!> I have some hot water pipes that I want to lag. I tried a bit of split |!> sided lagging and 15mm was too tight - it wouldn't close over the |!> pipe, while 22m was very loose. I haven't got a set of calipers on me, |!> but I suspect it may be 3/4" pipe. Nobody this side of the pond seems |!> to stock imperial sizes any more. Any suggestions? |!>

|!> Cheers, |!>

|!> Ben |! |!just use the 22mm lagging and apply tape every 18 inches to keep it in place.

Cable ties do the same job and last longer.

They do, but the thinner ones can cut into the lagging if tightened up too much

(snip)

I had something similar with tap washers not so long ago and came to the same conclusion - ie : Sod it.

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