Dreadnaught

On the subject of silencers, I notice the Ubbink Air Excellence 800-series manifold box has the option of putting sound attenuation foam within the manifold itself. It is shown in this video. And it seems you can buy extra attenuation foam pieces too to bump it up yet further, although I am not sure about this. Could such a manifold also act as a silencer too I wonder? Two birds with one stone.

Ask away. My frame is in the very final stages of specification and is due to go in to production very soon and will be erected on site hopefully the other side of Easter. Having chosen my frame company more than a year ago, I remain very pleased with my choice. They are a friendly relatively local company and it has thus far been a joy to work with them. They also introduced me to a splendid frame designer and it has also been a pleasure to work with him, albeit lockdown slowed him down as it has for many people with families.

I read your reply with care. Really interesting and highly relevant. Thank you very much. Regarding doubling ducts, what about pressure as well as noise from turbulence from within the pipes. For all longer runs, wouldn't doubling ducts also reduce pressure, which in turn would reduce how hard the fans need to work, which I turn could would reduce noise from the appliance itself. Any merit in such reasoning too? And given that ducting is not a big cost in the overall costs, suggest doubling long runs as a matter of course? Oh yes, I forgot about that document. Thanks for the reminder.

Thanks @Iceverge. When you say 90mm is that the external dimension? And internal would be 75mm? Is that right? 2.5 m/s noted, thanks. I am thinking of using Ubbink Air Excellent System, which 90/75 duct and even higher capacity one that is semi-rectangular in various sizes. Ubbink has good data on their website for each component showing volumes, flow rates and pressures, which are very hopeful. I have calculated my room sizes on-the-back-of-an-envelope, which has been helpful in deciding on duct numbers and sizes. For example, I have quite a large living room and was thinking of putting two supply outlets, each with two 90mm ducts attached. Four ducts in total. Running the numbers showed that a single 90mm duct to each of the two outlets would be fine but, conversely, one single outlet with two ducts attached would have been border-line noisy.

Do I actually need someone like BPC to design my MVHR ducting system? For my new-build bungalow, it seems really simple. I have designed the ducting plan myself following the basic rules: equal number of supply and extracts across the house (5x of each) double pipes to every terminal so it is quiet supply to bedrooms and living room (x3 & x2) extract from bathrooms, kitchen, utility room and plant room (x2, x1, x1, x1) room terminals as far from the door as possible Seems simple! What am I missing? Is a pro-design for the air-change data, which is needed for building control? The reason I am thinking about this now is that I am just about to put the timber-frame in to production. The frame has one single structural steel. And that steel would benefit from some pre-cut holes (x6) to allow the 75mm MVHR ducting to pass through it. I can cut the holes based on my design. Or should I get a professional involved?

Welcome @Phaedrus! There's a few us around East Anglia self-building. I'm in Cambridge and @Nick Laslett is in Suffolk as two examples.

Resurrecting this old thread. The MVHR extract vents in my kitchen either need to go though a steel beam or can be a linear diffuser in a wall without needing cut a hole in the beam. But I am still not sure whether linear diffusers are good as extract terminals. I wonder, has anybody used a linear diffuser in their MCHR system? @MikeSharp01, did you use one in the end?

I'm doing this now. We will be boxing out the foul risers under the showers for the concrete pour. The pour will hopefully be next week or the week after once it warms up. I'm having wet-room shower formers too in my passive slab, which made things extra complicated. Probably wouldn't do that next time.

Yes, I'm going for the extra fat, super-insulated version in this design. 1.5m wide so a bit wider than in the image. Black escutcheon (yes I didn't know either: keyhole) unlike in the image. That's a bespoke groove pattern by the way.

Unfortunately not. The entrance door is close to 1.5m wide however, which could help. Do have a 2.5m x 0.8m roof window over the kitchen. Sofa delivery by helicopter could work if all else failed.

? Thanks guys. Now I have to work out how to convince RK Doors to lock-in the price for a year. Anyone tried that?

I am resurrecting this old thread as I am watching the cold weather now for my concrete pour for my insulated raft foundation. Anyone else doing the same? At the time of writing (February 2021) it looks like overnight temperatures will not consistently rise above 4ºC for another month (!?!) in Cambridge if long term weather forecasts are any guide. And then my concrete team will probably have a backlog of pours to do. Patience is a virtue – I need to be more virtuous!

I am just about to order my front door, an expensive RK-model. I am worried about this pricey door getting bashed and scratched during the build. Unusually, I only have a single external door into my whole dwelling – no back door. Would it be better to pay a chippy to put in a temporary entrance door now and delay the installation of the expensive one for a year, until the end of second-fix? Did everyone else do this? I have seen entrance doors covered with protective sheeting. Does that really work? How is it attached? (My current progress: just about to pour my concrete raft foundation – when the weather warms-up. Am currently ordering the doors & windows, etc., so they all arrive soon after the timber frame goes-up.)

Thanks @Timedout & @Russell griffiths! Helpful insight! I've think I have found a local air-con merchant that stocks it. I will pop over on Monday and see if they will sell me some. My concrete contractors are on site so I don't really want to wait for mail order if I can avoid it.

Does 10mm pipe-insulation exist? Neither toolstation nor any of my local plumbers merchants have it. They all only seem to stock 15mm. Is it that 15mm pipe insulation fits snuggly on a 10mm Hep2O pipe? (I will be using it to lag my Hep2O pipes as they emerge from my insulated raft-foundation.)

Thanks @Russell griffiths. As @DevilDamo says, in my experience the arboriculturalists have a way around every objection that a council tree-officer can raise. Ingenious fellows! But you are likely to get a long list of planning conditions related to trees to sign-off as you build.

On @dpmiller's ingenious idea of using a Urinal-PIR sensor to empty the dead-leg of water, how about a cobbled-together Smart-home solution like this: - a 15mm Solenoid Valve Nylon (normally closed), 230v version, like this, £21 - A smartplug (Homekit, Alexa or Google Assistant, etc.) - A PIR sensor (Homekit, Alexa or Google Assistant, etc.) ← I would have this anyway for the lights. The PIR sensor triggers the smart plug, which opens the valve for a set period. Could even program it not to trigger again for a set period. Why might that not work? I suspect there are some reasons. The solenoid:

Ah, I actually calculated it for 10m not 15m. Sorry. In reality the length is about 13m or so. Note that 15mm is the outside diameter. I think the internal diameter of 15mm Hep2O is 11.3mm (wall thickness being 1.85mm). (11.3/2)^2*3.15*13 ≈ 1.3 litres

I wonder if that would be audible.

Thanks. I like this solution a lot. Now, I wonder if I can convince my M&E advisor of its merits. By my calculations, a 10mm hot pipe would hold 352 ml of cold water. Or if I chose to use a 15mm pipe, and included the shower in the arrangement too, then that would hold 1-litre of cold water. Thus when you entered the bathroom a litre of cold water would go down the drain. I notice that the urinal-PIR-thingy has a settable timer so that if you walk in-and-out of the room 5x times, 5x litres of water does not head down the drain.

With such an Ali-Express-type PIR-flush-valve, where would the water discharge? I imagine it would go down its own drain connection, not visible (and audibly) out-of-the-tap and down the sink. Its an ingenious solution.

Battery powered – is it not allowed to have a mains version in a bathroom I wonder?

This discussion also makes me think of sensor taps too. Anybody installed those?

This looks good as a possible solution (and doesn't look hideous): https://www.washroomhub.co.uk/dvs-ac02-023-wall-mounted-brushed-stainless-steel-urinal-sensor-c-w-2m-extension-cable, £125. But seems to need an expensive handheld controller to program it (£250).

How does that work? Microprocessor controlled?