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92.5 degree bend : the half? Really? Honestly?


ToughButterCup

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6 hours ago, dpmiller said:

it's the opposite angle- they add up to 180...

 

I couldn't immediately think where you would do that?

 

I mean if you have a pipe run that descends vertically, then goes horizontally (with a fall), then descends vertically again you need two 92.5 degree bends not one of each.

 

Perhaps if you were going around three sides of a building?

Edited by Temp
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On 05/03/2020 at 16:07, Temp said:

[...]

if you have a pipe run that descends vertically, then goes horizontally (with a fall), then descends vertically again you need two 92.5 degree bends not one of each.

[...]

 

Thanks @Temp

Caught a naiscent  error for me ... 

 

I'm try to plumb this bit of soil pipe from upstairs, through the wall down through the wet room and thence outside (follow the blue line)

 

CrossSectionCorrected.thumb.jpg.7970bd0e8662af8e9c13afd9049c53f4.jpg

The top  bend is 92.5 (just below the POSI - although the angle is not drawn to scale) and once the pipe is through the concrete from the office  into the Wet Room, the next bend will be a 92.5. The next two are also 92.5s. Double sockets I think.

 

So you stopped me making three errors. Thanks.

I thought the next bend after a 92.5 should automatically be an 87.5 (following the logic pointed out by @dpmiller). Its my inability to see what a packed lunch needs to do on its way from the loo to the digester..... not @dpmiller's explanation of the obvious once its been pointed out.

Ian

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Erm, if you have a 92.5 degree (more than a right angle) bend at the top "stuff" will surely collect in a small pool. Wouldn't you want all those bends in the marvellous drawing  to be around 45 degrees each?

 

Edit: Doh!! Put's on dunces cap and shuffles into the corner ?

Edited by BotusBuild
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Unless this a joke and I don't "get" it, 92.5 and 87.5 degree bends are the same - they are slightly less than a right angle.  One measurement is the bend itself, the other is between the original direction and the new one.  Just like a 45 degree is the same as a 135 degree.

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Hmmmm, got me worried for a minute, but have a look at this ....

 

The blue line is the line of flow.

The office and wetroom walls are parallel, so each pair of angles on each wall must add up to 180

 

flowangles.thumb.jpg.428dc706eb86604120ef228d97f65d3b.jpg

Unless I'm missing something, and that wouldn't be the first time either.....

Instinctively I thought 45s would do the job . It was only this morning that I tried to make the damn thing work - and found that a 45 degree bend , wouldn't lead the pipe through the hole I had cut in the concrete.... the hole was too 'square' to the floor.

 

20190903_102830.thumb.jpg.284f21f1b31f6c5e7faa19fa79b435a2.jpg20190903_103222.thumb.jpg.a472e96cd89bf5365caddbed82b16801.jpg

In this case 2 lots of 92.5 double sockets should do the job(bie) . But if I get a rush of blood to the head, then with a load more concrete hammering , 45s will do just as well.

 

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The waste only has about 300mm to travel at 2.5 degrees ..... but that would tend to be noisier than a couple of 45s wouldn't it? And knowing my luck if it has a tendency to block more easily, it will.

 

Merde, Scheisse, Poo, Merda.? 'Nother steep shitty  learning curve innit? Bugger.

Thanks @joe90 : its obvious, you are right.

 

Coffe and then the SDS. Damn!

Cant take a joke? Don't start a self-build.

 

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You might get away with it, after all, a soil stack usually has a swept 92.5° bend at the base.  If you can fit a swept bend in at the bottom of the top vertical bit, then the second 92.5° bend turning that back down to the vertical isn't a problem. 

 

Blockages occur when the velocity slows right down, and although bends do slow things a lot, the vertical bit will mean that the velocity at the bend will be pretty high to start with.  I've only ever seen bends cause a serious flow problem when they are near-horizontal, not when they are vertical, TBH.

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Well @joe90, here's what I did last night.... making the hole slope at 45 degrees took much longer than I thought it would

 

betterreducedsize.thumb.jpg.e429e0389c5aa3012f2ca87ede3554b6.jpg

While I agree with @Jeremy Harris point that in terms of flow, I might have got away with two 92.5 degree bends, might have  isn't good enough. And when I considered the noise aspect - the prospect of living for ever more with a noisy loo flush all because I couldn't be bothered to make a bit more effort ... 

 

Whats the point of doing it on your own and cutting corners? Exerience shows me I can pay other people and have corners cut aplenty. 

Harsh way of find out what 92.5 degree bends are for innit? ?

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19 hours ago, Mr Punter said:

Unless this a joke and I don't "get" it, 92.5 and 87.5 degree bends are the same - they are slightly less than a right angle.  One measurement is the bend itself, the other is between the original direction and the new one.  Just like a 45 degree is the same as a 135 degree.

Got my 87.5 (less than 90) and 92.5 (more than 90) the wrong way round. I am wearing the dunces cap for the day

 

But I see that my suggestion of using 45 degree bend has been adopted ?

Edited by BotusBuild
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On 09/03/2020 at 14:02, AnonymousBosch said:

walls are parallel, so each pair of angles on each wall must add up to 180

 

I'm a bit late to this party. But this sounds similar to the missing pound riddle. 

 

You don't want to get to 180. Else you would be going straight back up,  (in that case you would want the 87 bend) 

 

You want to get back to 0. Hence a 92 and a - 92 being what you want. 

 

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On 12/03/2020 at 06:53, Oz07 said:

We are all aware you can link the pipe in the fitting probably 5 degrees each way! ...!

 

Thanks for that.

I didn't know that the tolerance was quite so great. I spent an hour yesterday chipping out concrete all for a couple of degrees misalignment.

Bloody German heritage....it's a curse sometimes 

 

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