Central heating pipes lagging

[deema]

Just a quick question, pipes running through the floor between floors, do they need insulating according to building standards?

 

[clogs]

I'd insulate where poss any hot water pipe that can loose heat.....
plus point, the insulation is cheap.....get the thickertype.......
well worth the effort if already exposed.....
but I wouldn't take the floor up to do it..........

 

[deema]

@clogs, thanks, to put it into context, I’m having UFH installed throughout and wondering if the plumber should be insulating pipes to comply with regs, and if so what thickness / type should be applied.

 

[TFrench]

I'm a lagger but we are purely industrial - dealing with clients is bad enough, let alone the general public! I've never seen any plumber lag central heating pipework on domestic systems so I'm fairly confident its not in building regs. Certainly worth doing though, if its easy enough to get to. Thickness depends how much clearance the plumber gives you!

 

[Phil Pascoe]

As the whole system is designed to lose heat why would you insulate any part of it?

 

[TFrench]

As the whole system is designed to lose heat why would you insulate any part of it?

To make it lose heat where you want it to lose it. The flow to the UFH should be as hot as possible so the energy is transfered to the slab, not the air. Same with radiators - they're a more efficient heat exchanger than a piece of copper pipe.

 

[Spectric]

The only pipes I would definitely insulate are those at risk from freezing, then it depends on the length of the pipe run. For larger homes and long pipe runs then insulating the feed / supply to the rads has some benefit as it gets the heat to where it is needed but in a lot of cases leaving the feed / supply uninsulated can give some underfloor heat to landings etc. As for the return there are benefits in not insulating it, with a condensing boiler it will help lower the return temperature and deliver some heat into the property.

 

[Spectric]

The flow to the UFH should be as hot as possible

UFH requires less heat than a radiator, you would not want 60° in the UFH hence the mixing valve.

 

[Phil Pascoe]

To make it lose heat where you want it to lose it. The flow to the UFH should be as hot as possible so the energy is transfered to the slab, not the air. Same with radiators - they're a more efficient heat exchanger than a piece of copper pipe.

But the pipework is underfloor anyway. I wouldn't think the little lost to another room would be worth worrying about.

 

[Fitzroy]

A 15mm pipe loose running at 60°C in a 15°C environment looses approx 30-40 w/m of length, so 300-400w over 10m. If you have a 1kw radiator demanding full heat to a room, you could be 'loosing' 30-40% over a 10m run if the heat is going somewhere it is not required. Alternatively the radiator may not warm up at all if the system is poorly balanced and can't supply sufficient flow to offset the heat loss.

 

[deema]

Thanks guys, anyone know what the regs require? In old money I have some pipes running 50 feet under the floor, I’m setting everything up for air source heat pump heating, so I’m vary concerned about losing heat. The plumbing is being done by good trades guy, but I’m getting the impression he doesn’t believe insulating the pipes would be standard practice. Just want to know so I can understand his perspective and come to an agreement of what we do.

 

[Bingy man]

As far as I can recall the only requirements for lagging was to protect against freezing or when replacing a conventional hot water cylinder. The old gravity systems had to have a tap stat fitted as a minimum hot water control and all visible hot water pipe work lagged . If your plumber won’t do it then consider doing it yourself ( if possible) tape , cable ties to secure it and the ability to crawl into tight places and back out again is all there is to it . As above I’d not be ripping up floors to achieve this but if it’s reasonably accessible then it certainly won’t hurt ( apart from your back lol)

 

[Mwalker56]

Morning.
Part L (Conservation of fuel and power) of the building regulations requires you to make ‘reasonable provision to conserve fuel and power… from pipes ducts and vessels’.
The Approved Document requires that in a new heating system both primary and secondary circulation pipe work is insulated (p 31). There is also a useful section specifically targeted at underfloor heating (p.48) that states any distribution pipe work that does not supply useful heat to the room should be insulated.
Insulation thickness should meet the min set out in 4.26 but be careful if thin screed is proposed!
Note that as per the new regulations the system should be sized for a maximum water temp of 55c - if you’re using an ASHP, the lower you can get this, the more efficient your system and lower your bills!
Part L can be found here:
https://assets.publishing.service.g...021_edition_incorporating_2023_amendments.pdf

 

[Dave Moore]

Hi,
I suggest you look on YouTube at some of the plumbing vids. Most on their lag pipes and it seems in all cupboards now. Ask PlumblikeTom or one of the others. They will put you on the right path. You definitely need insulation where you have floorboards on the ground floor due to risk of freezing or massive heat loss so in old houses.
Regards,
Dave

 

[RogerS]

Thanks guys, anyone know what the regs require? In old money I have some pipes running 50 feet under the floor, I’m setting everything up for air source heat pump heating, so I’m vary concerned about losing heat. The plumbing is being done by good trades guy, but I’m getting the impression he doesn’t believe insulating the pipes would be standard practice. Just want to know so I can understand his perspective and come to an agreement of what we do.

You're the customer. 'Agreement' doesn't come into it. You tell him/her what you want. I'm in the 'why bother' camp a la Phil Pascoe. Bit like all that worry about incandescent lamps wasting energy in heat ...means I warm the room up a bit quicker ergo not wasted heat.

 

[Doug71]

Mine were all insulated as I remember the plumber telling his apprentice to fit the insulation with the slit uppermost so if there were any leaks it wouldn't drip down onto the ceiling, not sure if that was a good or bad thing

I'm sure he mentioned something along the lines of any pipework within a metre of the boiler didn't need insulating but all the rest should be?

 

[ChaiLatte]

The Approved Document requires that in a new heating system...

For the sake of clarity, it is important to keep in mind how much work 'new' is doing here.

As the customer you can ask whatever you want but it would valid to say that alterations to an existing system do not make it 'new' so the regulations detailed above do not apply. It depends on how you want to use the regulations - as an example of best practice that you wish to emulate or as a stick with which to beat someone.

There are practical considerations: if the pipes are under floorboards, in a shallow notch in a joist, the top of the pipe might be too close to the underside of the floorboard for a useful thickness of insulation. I have never seen insulation in 3/4 of a circle but that might be a marketing opportunity for someone.

 

[deema]

I have had the entire heating system ripped out and it’s all brand new.

 

[John Brown]

You're the customer. 'Agreement' doesn't come into it. You tell him/her what you want. I'm in the 'why bother' camp a la Phil Pascoe. Bit like all that worry about incandescent lamps wasting energy in heat ...means I warm the room up a bit quicker ergo not wasted heat.

Of course. Incandescent lamps warm the house in summer and in winter, and by my reckoning, at approximately 3 times the cost of gas heating.

 

[Sideways]

That's the underfloor heating in your landing sorted then . The dogs will love that just like the cats love sitting above the similarly placed pipes that form the 'spine' of our CH system.

Coincidentally, I have the upstairs floor of ours open at present changing some microbore drops to 15mm and I notice a modest draught into the floor space from where the ends of the joists go into the end wall of the house.

Draught proofing may be more important in practice than pipe lagging.