Lagging / casing external pipe

[mikeyw]

Hi,

I've recently had to have an high strength external grey pvc pipe routed from my pumping station in a basement flat to a nearby drain which is 2m higher than the pump.

The pipe will always have a head of water in it so i need to lag and case it before ther really cold weather arirves.

What do people advise as the best materials to use for this ? Is something like rockwool insulation packed around it sufficient ? What about casing?

It's in a town centre location and protected from wind so realistically only going to drop to -5c max on a really cold night.

Many thanks in advance,
Mike.

 

[KenGMac]

mikeyw good evening.

There are several differing types of Pre-Formed insulation types, as a general thing, you get the correct diameter of this types of Insulating material, the principle is that there is a correctly sized hole in the middle of the insulating material, there is also a cut into the central hole to the outside of the Insulating material, this allows the insulation to be slipped on to an existing pipe, and because [if you choose the correct internal diameter for this type of Pre-Formed insulation] The installation of this type of Insulation is fast and easy.

Angled bends and the like, can be protected by this type of insulation, using a very sharp knife [other products rather than Stanley knives are available???] and because this material is relatively cheap good old trial and error simply works fine.

OK, you live in an urban Setting? do not be fooled, at times the thermometer can drop way, way below -5

As an aside how much of the pipe is actually externally exposed? One possibility is to wrap the pipe, as above, then encase any external pipe with a waterproof cover or a box of some sort?

Ken.

 

[Nige F]

Armaflex external lagging - should be sufficient on it's own.

 

[bernardgreen]

If the ambient temperature remains belong freezing point for a prolonged period then thermal insulation only delays freezing. As long as the temperature of the liquid is higher than the ambient there will be some heat loss through the insulation albeit a very slow loss until the temperature of the liquid is the same the ambient.

Pumping out a small quantity of warm water from time to time can "recharge" the heat in the liquid in the pipe,

 

[KenGMac]

As last post by Bernard, I fully agree.

A few years ago there was a major freeze, temperatures even in cities dropped to below -10 and remained there for several days.

The result was I got inundated with work, two main culprits were

1/. Exposed, Un-insulated External Condensate drains from Central Heating boilers, the boilers simply blew off the condensate drains that caused mayhem inside the property.

2/. External cast iron waste pipes even froze, resulting in a first floor flat [for example] being flooded by a back flow of the water in the external cast Iron discharging into the flat, the water containing goodness knows what running down into the ground floor in a typical Tenement, this occurred on dozens of occasions.

mikeyw, Suggest that whatever you decide to do, keep an eye on the external lagging over time, I have lost count of the number of Central heating plastic pipes that have been lagged but the lagging has been damaged and rendered worse than useless.

Ken.