Radiator pipe insulation outside of warm house area

[trigger01]

Hi, hope someone can give some advice on insulation for radiator pipes that are outside the insulated space in the house.
We are having an extension and the first fix has just put radiator pipes in the loft space and the 'cold' vented part of the roof (the wrong side of the 170mm of pir we have to have) so pretty much classed as outside. I can see why it was done to avoid pipe routing on show but now I don't know how this is supposed to be insulated to meet current standards. Our plumber doesn't seem to think there is an issue but I can't see how it is doing anything but throwing heat away and maybe at slight risk of freezing. Any suggestions on what is normally done please?

 

[StephenStephen]

I've been amazed by intelligent heating engineers designing a system taking efficiency into account...
...and then heating a cold loft in this way.

I took out their poorly installed lagging, redid it thicker then put loft insulation over it.

 

[trigger01]

Yeah it does seem a bit strange. Lof of pipework by vents in uninsulated space. Loft space is not too bad because I can at least get to it and lag in Phenolic Pipe insulation and tuck a few inches of rockwool around it. The 50mm cold roof vented space is a bit different thought. Maybe lagging the pipes is enough to meet building regs.

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[Madrab]

If CH pipework is run within an unheated space then yes it should be insulated. It's not rocket science, simple economics.

Just tell them you want it done properly and can you have the pipe insulated please .... simples.