An Orkney Build (in ICF)

Out of interest: how much of a bend can you put on the insulated flexible ducting before it loses its shape?

Ive read somewhere (although I can't remember where!) that you shouldn't put a bend radius on it as it reduces the flow but equally I've seen a few pictures online that seem to show it turning 90 degrees out of the top of the MHRV without issue. Or is it perhaps that there is metal/plastic pipe inside it?

I think for sharp turns, you really need to use a rigid bend as the flexi stuff ends up deforming if you try bending it too much. I've just posted an new blog entry about the silencer, where to make final connections to the MVHR unit and supply manifold, I used a combination of rigid bends and flexi. I think large radius curves are preferable to sharp bends, but sometimes that's just not possible.

Hi Stones, 

 

Sorry for the bit of a delay, my back ground is I am a chartered building services engineer, so design heating, vent, cooling etc in homes and commercial buildings. 

 

What i am not 100% sure is what are you trying to do. are you trying to reduce room noise? building a box around the MVHR tends to deal with the break out noise but what deals with room site is inline duct attenuators. 

 

Ryan

 

8 hours ago, Ryan4Healthy Home Movement said:

Hi Stones, 

 

Sorry for the bit of a delay, my back ground is I am chartered building services engineer, so design heating, vent, cooling etc in homes and commercial buildings. 

 

What i am not 100% sure is what are you trying to do. are you trying to reduce room noise? building a box around the MVHR tends to deal with the break out noise but what deals with room site is inline duct attenuators. 

 

Ryan

 

 

Ryan, there is a lot of history here on this forum about duct silencers that is relevant.  I take the blame for starting it a couple of years ago, when installing our Genvex active MVHR unit, and making an error in not fitting the recommended silencers, because a late change to the services room layout in our build, and a change of MVHR unit, left insufficient room to fit off-the-shelf absorption silencers.

 

As a consequence, I made units very like the ones that @Stones has made, and found they were very effective.  Others have done much the same.  I made ours because I needed a custom shape to fit in the available space, originally.

 

There is a requirement to build an insulation box around an MVHR fitted outside the heated envelope, both in the MIs and Part F (or the Scottish equivalent in this case).  The access requirement in Part F (or it's equivalent) still has to be complied with, but generally everyone on here that's fitted MVHR (that's a lot of us now) seem to have found that building control are fairly relaxed about demonstrating compliance.

@Ryan4Healthy Home Movement it's fan noise that is being emitted via room supply valves.  Blog entry Part 21 details the inline 'silencer' that I've now fitted.