Jeremy Harris

I'd be inclined to consider fitting silencers on both the room supply and room extract sides, close to the MVHR unit, as we found that we had significant noise coming into our utility room and downstairs WC from the fairly short duct runs between those rooms and the plenum chamber. I know that one well-known supplier only chooses to supply a single silencer for the room supply side, but I'm not convinced that's the best option. Some MVHR units are significantly noisier than others, too, so it's well worth looking at the specs and considering where you'll fit the thing. Longer duct runs tend to attenuate duct noise, but you can then get flow noise if the ducts aren't sized correctly (if opting to use a radial duct system then you might possibly need double duct runs to some terminals). Definitely a good idea to look at where to fit silencers during the initial installation. I didn't, and ended up making silencers out of OSB and acoustic foam, that were a custom shape to fit in the restricted spaces I had left. With hindsight, I could have made room for ready made silencers just by positioning some of the ducts differently, but this was near-impossible to do after second fix.

Thanks, @Onoff, that's the one I was looking for. The photos of all the tangled cables that have dropped, especially those on the staircase, were the ones I remember seeing back when this happened.

I remember that, and had been looking around for a photo that was doing the rounds then showing the way wires dropped down to form what looked like something Spider Man might have used to restrain people to illustrate the point here, but couldn't quickly find it. Not sure why it too so long to get included in the regs, TBH. It was in the 17th to a limited extent, all the 18th has done is make it apply to all wires and cables, I think.

It seems to be a bit of a judgement call. The intention is to support wires after ceilings etc have burned through or collapsed, so they can't drop down and entangle firefighters, so I'd say that all horizontal cable runs need fire resistant supports, that are able to prevent the cables drooping down low enough to cause a problem for a firefighter wearing BA.

You're welcome to pass it on to him for free. I think I still have your address somewhere, I'll stick it in the post either tomorrow or the day after.

@Onoff, I have a USB CNC driver here somewhere, a Mk1 Smoothstepper: https://warp9td.com/ It's yours if you want it. I bought it but never got around to using it, as I opted to use a stand-alone system.

That's the clipped direct mechanical support requirement. All the 18th has to say about the fire cable droop prevention requirement is this:

Doesn't need a sign off - it's data cables I believe, so no Part P, but still needs to comply with the regs. It's a bit of a loophole, really, as data cables can present as much risk to firefighters as power cables (the last job I looked after before retiring had many thousands of metres of data cable in), so they need to comply with the regs as far as cable supports, fire provision, perhaps even the need to use LSF cable, yet no one has to sign the work off as being compliant, AFAIK.

There's been some discussion here on CDM before, worth a read:

I'd only use trunking (or cable tray for that matter) where there are long runs and lots of cables to support, just because it makes life a bit easier when laying the cables. It's easy enough to just route short runs of cable out of the trunking to devices, sensors etc, just clipping the wires directly.

The regs just say this, so not much help! : The intention is to prevent cables being able to droop down and cause a snagging hazard for firefighters, so I'd guess that fitting clips every 300 to 500mm or so in trunking is probably OK.

The metal fire clips stop the cables from falling. Before the changes to the regs, PVC trunking on it's own was fine for most applications, after the changes you just need to add the metal fire clips when fixing the trunking in place, so these can hold the cables up when the trunking melts.

We're really pleased with ours. New Forest did a very good job of fitting it, and it looks as good as new, despite me having used part of it as a plumbing workbench during the build! Silestone doesn't seem to stain at all, the only thing that leaves any sort of mark is anything greasy, but a wipe over with kitchen cleaner removes any marks. We are careful not to put hot pans directly on it, not sure how well it deals with very hot stuff, but it seems very scratch resistant. All our cookware is pretty heavy, cast iron stuff, and we've knocked it against the sink cut out a few times, but it's never left a mark. We have the dark grey Silestone, with a polished finish.

As long as the metal fire clips are used PVC trunking is fine. The advantage of the trunking is that it's a easy to just lay cables inside the stuff with the lid off. Means you can go back and forth with additional cables, then secure the lot when you're finished by bending the metal clips over and clipping on the lid to make things tidy and provide additional protection to the cables.

It's normal with conduit to fit junctions that allow access, both in long straight runs and at corners: https://www.tlc-direct.co.uk/Main_Index/Conduit_Pvc_Index/20mm_Conduit_and_Fittings_Black/index.html With trunking you don't need these, as the lid comes off, so everything is just laid in the U section of the trunking, then when all the cables are in, the fire clips are bent over and the lid clipped on. Trunking still needs corner fittings, tees etc, but like the trunking itself the top comes off for access.

Our experience was that our kitchen supplier contracted out the templating and fitting of the Silestone. Talking to the stone fitters, I got the feeling they worked for several different kitchen companies. We went back directly to the stone company to get some matching Silestone internal window cills and they seemed a fair bit cheaper, so I suspect there is a significant markup applied. The company that supplied, cut and fitted our Silestone was New Forest Stone: https://newforeststone.co.uk/ and I'd definitely recommend them, they did a really good job.

Remember to factor in metal brackets/supports for the cable trays, though. PVC trunking can just be screwed to timber or walls directly, using metal clips to give the fire resistant support needed for the cables.

If it were me, then I'd run the data cable in trunking, with the trunking secured with fire resistant clips.. Take a look at something like the D Line trunking system, as they include fire rated clips. Makes the installation a fair bit easier if you're just feeding cables into trunking. Trunking: https://www.tlc-direct.co.uk/Main_Index/Trunking_Pvc_Index/index.html D Line fire rated clips: https://www.tlc-direct.co.uk/Main_Index/Trunking_Pvc_Index/Dline_SD_CLIPS/index.html More details from D Line: https://www.d-line-it.com/safed-clips/

The drooping wiring bit in the regs is because firefighters have been trapped in burning buildings by the maze of wire that has dropped down, rather like a net. Doesn't matter if the house is "foobared", as the purpose of the regulation is to save the lives of firefighters, who may well have to enter a building in order to try and rescue someone that's trapped.

You should keep data and power cables well separated, but that's really the only restriction, other than the previously mentioned one of fire resistance of cable clips and supports. Personally I like to make sure cables are clipped to a batten or board, in a location where they aren't likely to get damaged and also where they can be seen easily for inspection, etc. Doing this in neat lines also makes it easier to identify circuits later if there's a need to change anything. There's also a max spacing between cable fixings in the regs, plus I'd not use potentially sharp edged banding as cable clips.

On the topic of linear LED lights, I bought some diffused LED lights that look a bit like fluorescent tubes that I'm really impressed with. I fitted them in my workshop, to replace LED strip, and they are far brighter than I expected and have a really even spread of light. The can be daisy chained together, too, so the power lead can be plugged in at one end and additional lights just connected by clipping them together. They fix to the ceiling with clear plastic snap-in clips, so are dead easy to install.

Welcome. Any chance of a close up of one of those? Given there's an air brick ventilating the underfloor void, it's hard to know from that photo quite what those other things are doing.

Is there a requirement for everyone posting in a thread to formally acknowledge contributions from others when replying? If so, then it doesn't seem to be in the terms and conditions of using this forum, neither does it seem to be common or accepted practice. Actually, it's a direct interpretation of defamation law, as it currently stands. The Defamation Act 2013 is quite clear about this:

You can just get two runs of 2.5mm² T&E in 20mm conduit. If you want to get a lighting run in as well, then move up to 25mm conduit. Alternatively, forget about using T&E altogether, as it's fine to run single core wires in conduit (it's what conduit is really designed to take). It's a heck of a lot easier to feed singles through conduit than it is T&E. Do not use the conduit as the primary PE conductor, but do make sure it is connected to PE. If wiring with single wires, then you can just size a single PE wire in each conduit run to deal with the worst case fault current.

As long as it's fire resistant. Since the 18th, cables need to be secured so they cannot droop down in the event of a fire, as a consequence of the cable supports melting.