Pipe Insulation Blog

22 Mar.,2023


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is a new easy to install pipe insulation, ideal for frost protection on external pipework. Most pipe lagging sold in the UK is not suitable for long term use outdoors as it is either not UV stable and degrades in sunlight or not waterproof and becomes ineffective when wet (in actual fact wet insulation is worse than no insulation as the water acts as a conductor and will accelerate the freezing speed of a pipe).

is a new easy to install pipe insulation, ideal for frost protection on external pipework. Most pipe lagging sold in the UK is not suitable for long term use outdoors as it is either not UV stable and degrades in sunlight or not waterproof and becomes ineffective when wet (in actual fact wet insulation isas the water acts as a conductor and will accelerate the freezing speed of a pipe).

What can I use to insulate a pipe outdoors? Will foam insulation keep pipes from freezing?

So, first things first. Anybody who tells you that you can stop a pipe freezing using insulation alone is just wrong. It is physically impossible. BUT - you can significantly prolong the time it takes for a pipe to freeze by using a suitable pipe insulation (such as the Isopipe material). A good rules of thumb is that the smaller your pipe the quicker it will freeze as it means there is smaller volume of water. If possible it is worth trying to allow for a bigger pipe at the planning stage if you can. Another option is to install a Thermal Heat Trace underneath the insulation, these two products together form a very secure means of protecting your pipes from freezing.

How much insulation do I need on an external pipe?

Ideally as much as possible. Conventional wisdom regarding frost protection is to use 25mm thickness on a 15mm pipe and 19mm thickness on 22mm and 28mm pipe. 13mm thickness is recommended as the minimum for a 35mm pipe and beyond that the risk of freezing is lower and 9mm thickness should suffice. If you want to read into this in a little more detail you can read about it in our blog entitled Frost Protection for Domestic Pipes . It is worth noting though that even if you were to use 25mm on a 15mm pipe (ie the thickest generally commercially available as a single layer) then this is still not enough to give you overnight frost protection as set out in the criteria of British Standard 6700 which is designed to give 12 hours protection against freezing at a continuous -6C. In theory you would need 62mm of insulation to achieve this but the reality is that using as much insulation as you can practically fit on to your pipe gives you your best chance.

How do I install pipe insulation outdoors?

The most important part of installing a pipe insulation, be it indoors or outdoors, is to leave no exposed pipe by closing up all seams and butt joints. The best way to do this for a conventional material is to glue and tape all joins for maximum protection. Using a product like Isopipe TC Solar Slit & Seal makes this a doddle as it is pre split with tapes along the seam of the insulation and along an overlap on the protective outer layer so that you can seal everything up with the minimum of fuss (although you will still need tape & glue for your butt joints). If you didn't want to go for the pre split, self-adhesive option there is also Isopipe Solar TC Tube which is available in Black, White & Silver coatings. This material is one you will need to split yourself if you are unable to feed it on from the end of the pipe as you might do if installing the lagging at the same time as the pipe itself.

How do I insulate a tank or large pipe outdoors?

If you are looking to insulate something larger than a typical domestic pipe outdoors (we can offer products up to and including 114mm outside pipe diameter for external use) then you may wish to use a sheet material which is also a good way of insulating water tanks or storage vessels that are kept outside. The material is supplied 1m wide and comes in 6mm - 32mm thicknesses as well as in either White, Silver or Black coatings that are all give the insulation itself extra protection against mechanical damage as well as being totally waterproof and totally UV stable when installed correctly.

What pipe insulation is required by the water authorities if I am burying my pipe?

This is a tricky one as all of the water authorities have different rules; the short answer is you are best getting them to confirm what types of product will comply and using that to make your choice. In most cases they will require that you use a closed cell insulation, it is best if this is a flexible foam (ie a polyethylene such as Climaflex or a nitrile rubber such as Eurobatex or K Flex). If you are burying your pipe deeper than 750mm it may well be the case you do not have to insulate, but it is still a good idea if space and budget allow. Some will require that you used what is referred to as "Class 0 pipe lagging" or rubber pipe insulation - in both cases this means that you must use something like the Eurobatex or K Flex although Polyethylene is better in many ways as it has lower water absorption characteristics and is a foamed plastic so cannot rot. A product like the Isopipe is best though as it is a flexible nitrile rubber pipe insulation with a special polyolefin (plastic) skin that makes it totally waterproof and very resistant to mechanical damage.

What type of pipe insulation is best?

This is very much a "horses for courses" situation; there is no such thing as an insulation that is best for every application. As mentioned above, flexible foams tend to suit outdoor applications. Polyethylene will last a number of years before it needs to be replaced and is very water resistant due to it's high μ factor - you want this number to be as high as possible for water resistance and Climaflex has a μ factor of 16,000 meaning it would take it around 90 days to absorb 1.5% by volume of water if saturated in it. However, if you are putting insulation on a solar thermal collector's pipework then you would need to use an EPDM rubber based product, sometimes referred to as "High Temperature Rubber", as this type of pipework gets so hot that it would melt or bake conventional insulation. If you need advice you can always call us on 01942 295926 -we are always happy to help.

Does pipe insulation really work?

Yes - but only when installed correctly. The main factors to consider are whether or not you have got the correct pipe lagging, whether the thickness is what you need for your application and whether it has been correctly installed. If the answer to all of these is yes then you ought to be fine. Proper preparation prevents poor performance. As stated above, you cannot guarantee a pipe will not freeze with insulation alone but when used correctly it is an incredibly effective tool. 

What kind of foam is used for pipe insulation?

That depends on the insulation; the most common, grey pipe insulation in polyethylene - a type of foamed plastic. This insulation is a good insulator, cheap and does not degrade easily - it also usually contains recycled material. Foamed rubbers are most commonly PVC Expanded Nitrile Rubber - this material tends to be used for its flexibility and the fact it is Class 0 to the old BS476 Parts 6 & 7 which are reaction to flame spread and smoke release tests. This standard is now technically defunct as it was superseded by the EN 13501 Euroclass standard to which nitrile rubber should achieve Euroclass B (if it is of a good quality). You can also get High Temperature pipe insulation which is an EPDM foam rubber, or ethylene propylene diene monomer rubber to give it it's full name, which looks very similar to nitrile rubber but the trade off for it's high upper service temperature limit is that it loses some of the insulation value. These 3 products (polyethylene, nitrile rubber & EPDM rubber) are collectively known a flexible elastomeric foams.

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