Author Topic: Trying to Quieten the 110KVA Generator (Read 49093 times)

awemawson · « **Reply #75 on:** October 15, 2020, 04:05:10 PM »

Yes I'm hoping so Tom!

I've now got sixteen slabs fixed to that long partition wall, so it is pretty well covered - just four to go at the far end.

I've just done a very quick 'start it and turn it off' test (before anyone notices

) and the noise in the generator enclosure has dropped from 107 dBA to 103 dba

Tomorrow I hope to complete that wall and the end wall near the PVC strip curtain.

I've just ordered a bolt of heavy duty waxed cotton canvas to make the air duct from the radiator to the outside world - this will be about 2 metres long and a metre by 1.5 metres square. Hopefully this will absorb some of the sound of the emerging fan driven air which can then be prevented from re-circulating back round the radiator as it does at the moment.

Downside is I need to open negotiations to use the sewing machine as the canvas is 60" (1.5 metres) and I need 2.8 metres to wrap round the radiator cowl

nrml · « **Reply #76 on:** October 15, 2020, 04:37:24 PM »

I'm surprised you don't have an industrial sewing machine tucked away in one of your workshops waiting for it's moment to emerge and shine. The insulation job is looking good.

awemawson · « **Reply #77 on:** October 15, 2020, 04:49:56 PM »

Well I did years ago! I do have a light duty one sold to me as industrial but it isn’t, they lied !

(Back in my youth I had a holiday job in a haberdashers on the Fulham Road in Chelsea. (Tulleys) They had a side line making rather rectangular sofas and I was involved at all stages from making the wooden frames, upholstering them and making their covers. So when I left home at the tender age of 17 and went to live in Southampton and needed a sofa for my flat, I made one. From that it grew into me making one or two a month, and I got registered as a manufacturing upholsterer ! Even had an exhibition at the Southampton Show one year ! Still got my magnetic tack hammer and staple gun from those days)

awemawson · « **Reply #78 on:** October 16, 2020, 09:56:20 AM »

Cracking on today I got the north wall covered in acoustic insulation apart from where it abuts the west wall, and I got the south wall insulated over the wooden cladding, again leaving a gap next to the west wall. The east wall is finished so I am left with the lower (masonry) half of the south wall and the west wall to complete.

The west wall is where the radiator air leaves the enclosure, and I need to bend up the cowl arrangement and insert it through the wall before fitting the sound insulation.

I also want to sound insulate the ceiling - probably using wire mesh of some form with the Rockwool resting on it - I have two unevenly spaced rafters to fix it to so it needs to be stiff enough to carry it's weight and that of the Rockwool over a cantilever of 600 mm and a 'both ends supported' span of a metre. 50 mm mesh with 2.5 mm wire is looking like the best candidate at the moment but £12 a sheet and 6 sheets takes the shine off it. If I could get over the cantilever somehow I'd use 1/2" mesh chicken wire but by the time I've messed around with batten etc I think probably I'll go for the simpler solution of stout mesh!

russ57 · « **Reply #79 on:** October 16, 2020, 06:37:13 PM »

I would think, guessing a bit about the rockwool stiffness, that a mesh of even 150x would be fine, more like concrete reo than a mesh fabric. I guess you wouldn't get it in galvanised, but a coat of spray paint would fix that as well as seal the rockwool preventing fibre shedding.

-russ

tom osselton · « **Reply #80 on:** October 16, 2020, 07:49:53 PM »

You could try one of these off of Amazon I’ve been looking at them for a while. ( thinking canvas)

https://www.amazon.ca/YaeMarine-Cobbler-Repair-Machine-Mending/dp/B07NC3F3M6/ref=sr_1_9?crid=MAHNLMGR4CIS&dchild=1&keywords=hand+crank+sewing+machine&qid=1602891750&sprefix=Hand+crank+sew%2Caps%2C199&sr=8-9

awemawson · « **Reply #81 on:** October 17, 2020, 06:31:34 AM »

A burst of intense sheet metal bashing this morning produced a radiator cowl to be fixed to the the west wall of the stable when I've cut a suitable hole.

When it is in situ and therefore somewhat more rigid I will add either some louvers or a mesh to stop wild life entering.

I've spot welded pre-drilled flanges on with the upper one 1-1/2" displaced from the lower one to make the horizontal surfaces of the cowl actually slope outwards to shed rain.

Next job - mark out and cut a darn great hole in the stable wall

awemawson · « **Reply #82 on:** October 17, 2020, 08:32:13 AM »

Measuring up the wall to cut a hole for the cowl showed me that the generator was not quite parallel to the south wall - the radiator end needed to move south two inches, and if it did that the required hole EXACTLY lined up with four of the stable wall planks.

So shift the generator - it's only about three tons and the direction of travel is slightly up hill - just do it

Roller crow bar to the rescue and it's amazing what you can shift single handed with a bit of grunt

So now the potential hole is in a more conveient place cut it out - so I did with my jigsaw.

Not only was the hole in the right place but the cowl actually fitted through it, so I set too screwing the flanges in place.

. . it was then the I discovered a major cock up - I'd offset the flanges in the wrong direction so the 'horizontal' surfaces slope towards the wall not away from it

Theoretically it's just a case of 'un-spot-welding' three of the flanges and re-fixing them in the right place, but I was rather enthusiastic welding them and they are rather robust welds.

. . I'll cogitate on it for a bit, and maybe experiment undoing spot welds on some scrap - you can get a special drill to remove spot welds, but I don't have one.

awemawson · « **Reply #83 on:** October 17, 2020, 01:23:24 PM »

My experiments removing spot welds confirmed that buying the proper drill was sensible so I have some on order.

I also in anticipation of removing the wrongly located flanges bent up the replacements

Then I started blocking up the slits in the Yorkshire boarded stable by over boarding with 25 x 50 roofing battens, and as it's not practical to get them under the barge board to keep rain out of the upper end grain I've given each of them a little lead rain cap.

Obviously I can't complete this until the cowl issue is resolved as the battens interfere with the cowl, but I've managed to do all the rest.

hermetic · « **Reply #84 on:** October 17, 2020, 01:45:34 PM »

My preffered spot welding removal tool was the "zipcut". It has a spring loaded hardened centre pin, surrounded by a double ended screw on cutter with some wickedly hard and sharp teeth which cut round the outside of the spot weld, which means you only have a hole in the upper panel, and you can grind the weld off the lower panel, refit it and plug weld them back together.
Phil

awemawson · « **Reply #85 on:** October 18, 2020, 07:05:21 AM »

Thanks Phil, yes that's the sort I've ordered along with a conventional stubby flat ended drill.

. . . .BUT . . .do I fancy removing 40 odd spot welds and possibly end up with a messed up main cowl body . . NO !

So I decided just to abandon the original and make another - I had the materials and it undoubtedly took less time than drilling out the spot welds. So it's (re) made and fitted and the Yorkshire boarding weather strips are finished.

Now I'm off to measure up for ceiling mesh

(anyone want a redundant cowl ???)

awemawson · « **Reply #86 on:** October 18, 2020, 11:22:37 AM »

This afternoon I finished off fixing the Rockwool acoustic slabs to the lower half of the south wall.

I'd been putting this off as the substrate is rather variable cement blocks peppered with hard bits of slag and I knew that it wasn't going to be straightforward.

The fixings I'm using are miniature 'frame fixings' 5 mm diameter by 50 mm long and are intended to be inserted into a 5 mm drilled hole, and the metal screw tapped home to expand the plastic plug. I rapidly found that the screws all too easily bend when even lightly tapped and that driving them home with an electric screwdriver improved the success rate enormously !

Just the west wall round the recently installed cowl to be lined and when that's done I can start the ceiling. Six 1250 x 2400 x 5 mm galvanised weld mesh ordered from F H Brundel which should arrive in the coming week.

awemawson · « **Reply #87 on:** October 19, 2020, 04:36:27 AM »

I've been cogitating on how to seal off the lower edge of the west wall. In its original incarnation as a stable the Yorkshire Boarding deliberately didn't stretch down to the concrete floor. This was to prevent rain wicking up the end grain and rotting out. The planks stop about four inches short, with the lowest horizontal beam being about seven inches from it's lower edge.

I considered a couple of courses of brickwork and a bit of damp proof course under the timber, but water will still puddle on the DPC.

Then I remembered that I had a few spare lengths of six inch 'twin wall' electric cable ducting that not only had an outer diameter of seven inches (ideal!) but was obviously made from rot proof plastic, AND the curvature would shed water from outside BACK outside. Perfect

Cutting a suitable length this morning it proved to fit very nicely. Just in case it wants to pop out I've run some expanding foam along the inner / lower edge to keep it in place. This can be trimmed later today when it's 'gone off'

Unconventional I suppose but I think that it will be effective.

awemawson · « **Reply #88 on:** October 19, 2020, 01:24:57 PM »

Later this morning, in a nod to Health and Safety, I built a safety barrier round the projecting cowl to stop people bumping into it. (Pete. you will recognise the bits !!!)

Then after lunch I was able to finish the bits of the South and North walls abutting the West wall that previously I'd had to leave, and then finally finished fixing acoustic slabs to the West Wall.

So that's all vertical surfaces covered in 25 mm Rockwool Acoustic Slab - just the ceiling to do which is going to require a bit of ingenuity, but that will have to wait until the 50 x 50 mm mesh arrives so time to think about it.

(That's 58 slabs fitted or 41.76 square metres, the ceiling is a further theoretical 23.4 square metres or another 32 slabs which is lucky as I have 38 left!)

The canvas for the 'radiator exhaust air tunnel' has arrived, but I won't fit that until the ceiling is done or it will get in the way of ladders etc.

kayzed1 · « **Reply #89 on:** October 19, 2020, 07:34:53 PM »

one assumes a grill and mesh to keep out the critters..

awemawson · « **Reply #90 on:** October 20, 2020, 02:45:10 AM »

Oh yes !

russ57 · « **Reply #91 on:** October 20, 2020, 03:08:14 AM »

Are you sure it's not just a padded cell....

-russ

AdeV · « **Reply #92 on:** October 20, 2020, 04:04:29 AM »

Quote from: russ57 on October 20, 2020, 03:08:14 AM

Are you sure it's not just a padded cell....

A padded cell with a honking great diesel engine in it! Luxury!

awemawson · « **Reply #93 on:** October 20, 2020, 05:43:05 AM »

It does sound very peculiar in there when the Generator is not running, and if your ear is within about a foot of the wall it’s even stranger

All that disappears though when the engine starts !

I thought that I had thinking time before the ceiling mesh is delivered, but Brundels have email to say it’s coming today

awemawson · « **Reply #94 on:** October 20, 2020, 10:19:13 AM »

True to their promise, Brundles have just delivered a bankrupting load of steel to me

The six 50 x 50 x 2400 x 1220 galvanised mesh panels to hold the ceiling acoustic material up, but also . .

Three off 6 mm x 100 mm x 6 metre mild steel bars and . .
Two off 25 mm x 25 mm x 3 mm x 6 metres angles

. . .to make Copes and Drags for the Foundry - but more of that later in an another thread probably.

Meanwhile I feel singularly disinclined to start fixing the mesh, and anyway first I need to reduce the three light fittings to dangling cables in order to get the mesh up (lights will fix up under the mesh)

AdeV · « **Reply #95 on:** October 20, 2020, 02:05:22 PM »

Quote from: awemawson on October 20, 2020, 10:19:13 AM

...a bankrupting load of steel...

I know the feeling: I recently bought 7 lengths of 25mm square box, a length of 25mm equal angle & a 25x3mm flat bar; nearly £200 delivered! I misheard him on the phone, thought it was £90odd (thinking, that's quite reasonable)... didn't hear the 1 on the front of it!!

Still... all my orange "B&Q-like" shelving no longer sags, with 3 steel reinforcement bars under each shelf

awemawson · « **Reply #96 on:** October 20, 2020, 02:22:34 PM »

That lot listed above, plus two off 2 metre x 1 metre x 1.6 mm Zintec steel sheets was £247

Steel has risen enormously in the last couple of years.

awemawson · « **Reply #97 on:** October 21, 2020, 08:13:38 AM »

As soon as I could escape from other duties this morning I isolated the lighting supply to the generator room and took down the two LED strip lights and one LED flood light. Leaving the cables dangling (but taped off) I will have to work the mesh sheets round them.

To start the first mesh I put screws into the side of the two joists near the west wall, and fixed short lengths of fencing wire to them to initially suspend the mesh (trimmed to width) at an angle so that I could then 'load' it with Rockwool, pivot it into place and screw it up. To help this process I made a suitable temporary prop.

Needless to say it wasn't quite as simple as that - but I got a tolerable result fixing the first too meshes. The mesh size is about 50 mm longer than the Rockwool length so 1200 mm x 50 mm bits have to be packed on the exposed edge as I work from West to East.

The next mesh will incorporate the lighting cables, and I'm tempted to cut it lengthwise where the cable emerges and put it up as two bits.

awemawson · « **Reply #98 on:** October 21, 2020, 12:31:39 PM »

This afternoon when I was released from Puppy sentry duty I managed to get a further one and a half more meshes up.

As I thought that I might have to, I ran a partial sheet up to the lighting cables and a full sheet beyond which worked out quite well, though obviously the room must taper a bit as the sheets are getting too long - next one wil need to be shorter by one mesh I think to avoid scaring the walls too much as it's moved into place.

Muzzerboy · « **Reply #99 on:** October 21, 2020, 02:58:23 PM »

Quote from: awemawson on October 21, 2020, 12:31:39 PM

....avoid scaring the walls too much as it's moved into place.

Yes, they must be petrified by now ;-)

IIRC, the building regs for noise control recommend / require a gap between rockwool and the next panel for most effective noise reduction. So the gap between the panels and the roof certainly wouldn't be a bad thing on that basis, assuming they are correct.

Looking forward to the acid test ie dBA measurement of the final system! I suppose you might argue the acid test is avoiding a bad review on Tripadvisor or whatever.

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Author Topic: Trying to Quieten the 110KVA Generator (Read 49093 times)