Frozen pipe in extension

grumbler

Section62 said:

Thames Water (who ought to know what they are talking about)

Absolutely groundless assumption. I remember reading some E-on's guide (on energy) written by some absolutely clueless idiot(s).

Section62

grumbler said:

Section62 said:

Thames Water (who ought to know what they are talking about)

Absolutely groundless assumption. I remember reading some E-on's guide (on energy) written by some absolutely clueless idiot(s).

I get the feeling you just want to have an argument here grumbler, rather than actually offering helpful advice to people who have frozen water pipes.

grumbler

Section62 said:

grumbler said:

Section62 said:

Thames Water (who ought to know what they are talking about)

Absolutely groundless assumption. I remember reading some E-on's guide (on energy) written by some absolutely clueless idiot(s).

I get the feeling you just want to have an argument here grumbler, rather than actually offering helpful advice to people who have frozen water pipes.

No, I am a well educated person and it's just my nature to find real sense in everything and to try to understand instead of just believing in everything said.

Anything wrong with this?

There are far too many urban myths around to believe in everything you hear.

Section62

grumbler said:

Section62 said:

grumbler said:

Section62 said:

Thames Water (who ought to know what they are talking about)

Absolutely groundless assumption. I remember reading some E-on's guide (on energy) written by some absolutely clueless idiot(s).

I get the feeling you just want to have an argument here grumbler, rather than actually offering helpful advice to people who have frozen water pipes.

No, it's just my nature to find real sense in everything, and to understand instead of just believing in everything said.

Anything wrong with this?

There are far too many urban myths around to believe in everything you hear.

Water expanding in volume as it is heated, once it is warmer than 4C, is not an "urban myth" though. It is a scientific fact.

But you don't have to believe it if you don't want to.

chris_n

Section62 said:

grumbler said:

Section62 said:

grumbler said:

Section62 said:

Thames Water (who ought to know what they are talking about)

Absolutely groundless assumption. I remember reading some E-on's guide (on energy) written by some absolutely clueless idiot(s).

I get the feeling you just want to have an argument here grumbler, rather than actually offering helpful advice to people who have frozen water pipes.

No, it's just my nature to find real sense in everything, and to understand instead of just believing in everything said.

Anything wrong with this?

There are far too many urban myths around to believe in everything you hear.

Water expanding in volume as it is heated, once it is warmer than 4C, is not an "urban myth" though. It is a scientific fact.

But you don't have to believe it if you don't want to.

It may well be, but the volume increases by close to 10% when it freezes, no amount of heating water is going to cause a 10% expansion while it is in liquid for. If you heat it enough to boil it then it's an entirely different matter.

diystarter7

Hi OP

To take the thread back on topic and in order to ensure you get the best help.

As I said in this thread between the irrelevant arguments.

Before the pipe/s unfreeze please locate if not already aware where the stopcock is and ensure
it is not jammed, easily accessible etc.

Have a plan ready just in case it leaks.

For future needs, ensure pipes have lagging, adequate lagging as it is pretty exposed ie in an extension, next to the outside wall.

Good luck

PS - if you have a garden tap, get a cover for that as well

Section62

chris_n said:

Section62 said:

grumbler said:

Section62 said:

grumbler said:

Section62 said:

Thames Water (who ought to know what they are talking about)

Absolutely groundless assumption. I remember reading some E-on's guide (on energy) written by some absolutely clueless idiot(s).

I get the feeling you just want to have an argument here grumbler, rather than actually offering helpful advice to people who have frozen water pipes.

No, it's just my nature to find real sense in everything, and to understand instead of just believing in everything said.

Anything wrong with this?

There are far too many urban myths around to believe in everything you hear.

Water expanding in volume as it is heated, once it is warmer than 4C, is not an "urban myth" though. It is a scientific fact.

But you don't have to believe it if you don't want to.

It may well be, but the volume increases by close to 10% when it freezes, no amount of heating water is going to cause a 10% expansion while it is in liquid for. If you heat it enough to boil it then it's an entirely different matter.

So if we were talking about a pipe where 100% of the water was frozen then that would be the most important factor.

The practical reality though is that the freezing typically happens in only one section of the pipe run, leaving a volume of liquid water which hasn't undergone that amount of expansion on freezing - it may be in the 0C to 4C zone, or may be warmer.

When the pipe starts warming up, the water which is above 4C will be expanding.  Heating the pipe directly with a hairdryer or fan heater will cause not insignificant increases in temperature and volume.  Whilst the ice 'plug' remains solid, the increase in temperature and volume will cause a "build up of pressure" inside the section of pipe containing liquid water - unless care is taken to ensure that one end of the pipe is 'open'.

It is a golden rule of plumbing and heating engineering not to heat water/pipes in a 'closed' system unless there is capacity for expansion.  That applies to temperatures well below boiling point.  We do that because water being a non-compressible substance will burst or rupture pipes and joints if provision is not made for expansion.

When 'pipes freeze' what often happens is a system which was open or semi-open temporarily becomes partially 'closed' due to the formation of one or more ice plugs. That is when the risk of pipes bursting on thawing is a real risk, not an "urban myth".

grumbler was not wrong in his theory, but it applies in the special case where all the water in the pipe run has frozen.  Which most of the time doesn't reflect the practical realities.

Because of that, and it being impossible to know how much of the water has frozen or exactly where any ice plugs may be, it is essential to deal with frozen pipes by gradually warming them, and ensuring that at least one end of the pipe run is open so the water can expand freely (i.e. by running to drain) as it warms up.

grumbler

Section62 said:

grumbler said:

Section62 said:

grumbler said:

Section62 said:

Thames Water (who ought to know what they are talking about)

Absolutely groundless assumption. I remember reading some E-on's guide (on energy) written by some absolutely clueless idiot(s).

I get the feeling you just want to have an argument here grumbler, rather than actually offering helpful advice to people who have frozen water pipes.

No, it's just my nature to find real sense in everything, and to understand instead of just believing in everything said.

Anything wrong with this?

There are far too many urban myths around to believe in everything you hear.

Water expanding in volume as it is heated, once it is warmer than 4C, is not an "urban myth" though. It is a scientific fact.

But you don't have to believe it if you don't want to.

Yes, it's a fact - absolutely isolated, not explaining anything. 

Before the water started expanding, it was frozen. When melted, it contracted significantly first.

Section62

diystarter7 said:

Hi OP

To take the thread back on topic and in order to ensure you get the best help.

As I said in this thread between the irrelevant arguments.

A discussion on the correct method of dealing with frozen pipes and the scientific principles underlying that is not off topic, nor "irrelevant".

It is important that people use the right techniques to deal with domestic emergencies, and if there is any doubt about the correct method that there is an understanding why it should be done a particular way, or using the safest possible technique.

diystarter7 said:

Before the pipe/s unfreeze please locate if not already aware where the stopcock is and ensure
it is not jammed, easily accessible etc.

Have a plan ready just in case it leaks.

If you'd been following closely you'd be aware that the OP was given that advice right at the beginning of the thread, and also that the pipe was sucessfully unfrozen yesterday.

ThisIsWeird

I completely accept the physics described by Section62, and Google searches appear to confirm this as a potential added cause of pipe bursts. What I am not convinced by is that it is a significant cause of pipe bursts, or that the rate of warming needs that fine a control. Even Thames Water recommends placing a hot water bottle on the pipe. This will be, what?, 45oC plus, over a 350mm section of pipe? I would suggest that this is a more intense and focussed application of heat than directing a fan heater (which I fortunately - phew - suggested should (initially, at least) be on a medium setting - am I glad I said that...) under the plinth of the base unit. Doing this will not make that area 'hot'. The pipe will absorb heat at a slow, steady and more even rate. You can test this by sitting a few feet in front of a fan heater whilst clutching a hot water bottle.

I cannot see that a pipe that is at sub-zero in places (ie, where it is frozen), and near-zero surrounding this, is not going to increase in temp at anything other than a very slow rate unless a more intense form of heat is applied more directly to it. And a hair dryer aimed in through a potential hole in the adjacent w/m recess will also not do this.

Yes, if one were to 'blast' a frozen pipe with, say, a blow torch or similar, then there's a chance they'll cause the issues described, such as tipping an already-expanded & tipping-on-the-edge-of-fracture pipe wall to destruction.

Even for this, other variables would also need to be involved, such as the water expansion having to occur in a completely sealed side of the frozen plug. Most often, surely, at least one side will be available to accommodate such tiny expansions, either by pushing the water back down the 'mains' system, or up to a storage tank, or even just being swallowed by an elastic expansion of the rest of the pipework as occurs in normal use?

I do not think that what Section62 has brought to our attention is a myth, but I just wonder if it has been over-claimed in the cyber-ether, perhaps from a misinterpretation of what happens in reality - the pipes thaw out, and the leak is then revealed?

I am certainly not 'arguing' - I would honestly love to know the full facts.