Sweating cold water pipe

[janya87]

I'm having an issue where I am getting a buildup of condensation on the cold water pipe in my home that is located in my kitchen.

I have insulated the pipe with plenty of foam but it's still doing it, It's then running down the pipe and down my stop tap and onto my wooden floor.

The cold water pipe feels absolutely freezing, much colder than it should be in my opinion and I can't understand why.

Any help would be greatly appreciated.

 

[SJB060685]

Have you checked for any leaks, dripping taps etc on the cold side?
When water is standing still in the network it will come accustomed to its surroundings temperatures, if there was a problem elsewhere you will constantly introduce cold water to the system will will cause condensation to form.

 

[PETE 123]

Could be high humidity in room get a cheap digital Temperature Humidity Meter Sensor ebay.

 

[Ric2013]

Quite typical for cold water to come into the house below 5°C and if the water comes in under the sink then any water used in the house will draw new cold water into that section of pipe. Worth checking, as others have suggested, that there isn't a tap or float valve (ballcock) dribbling somewhere.

If you have 20°C room air temperature at 70% relative humidity (RH) - this is quite a damp room - you'll get condensation on any surface below 12°C. If your relative humidity at that temperature is below 40°C - this is a reasonably dry room - then you won't start to get condensation until around 5°C. Either situation is possible in a typical British dwelling.

RH is a measure of how much water is in your air compared with how much water could be in that air at a given temperature. The temperature of condensation (i.e. 100% RH) could be reached at various temperatures depending on the amount of water dissolved in your air (i.e. ABSOLUTE humidity). You can look this up on a psychrometric chart if you know the temperature and RH. Or ask me 🙂.

Assuming the humidity of the room cannot be reduced, you either need to lag your pipe and apply a vapour barrier on the outside of the insulation (insulation tape or gaffer tape over the dry lagging would work) and your insulation needs to be thick enough to stay above the condensation temperature. The foam lagging probably doesn't need a vapour barrier, but if the joints aren't sealed then warm moist room air can get behind the lagging and condense on the cold pipe so you need to seal around the lagging somehow.

 

[janya87]

Have you checked for any leaks, dripping taps etc on the cold side?
When water is standing still in the network it will come accustomed to its surroundings temperatures, if there was a problem elsewhere you will constantly introduce cold water to the system will will cause condensation to form.

My hot water tap in my bathroom sink does not work (turns easily and nothing happens) and drips every couple of seconds, could this be the reason why I am having this issue?

 

[SJB060685]

My hot water tap in my bathroom sink does not work (turns easily and nothing happens) and drips every couple of seconds, could this be the reason why I am having this issue?

This could very well be the cause, if its constantly dripping then new cold water from your incomingmains has to make up for the loss. As Ric2013 said above, this is down to the science of relative humidity and dew point. His description above is very accurate.