Elbow fitting question 5

[Ultganon2437]

Hi I had a question in the image below. Is that setup possible with a Long Radius 90 deg elbow? Of course the elbow would have to be cut down in order to match the degrees but the thing is that a subcontractor is saying that a Long Radius elbow will not work given the length 3-9/16" that they would need Short radius 90 elbows instead. This is entirely new to me so if someone could please explain how this works or why a long radius elbow is unable to help I would really appreciate it. I know this is more of a pipefitter question but I couldnt find any forums of pipefitters.

 

[LittleInch]

Not sure "a race to the bottom" is the best phrase when talking about ships.....

Remember - More details = better answers
Also: If you get a response it's polite to respond to it.

 

[LittleInch]

Ult...

Isometrics work on the basis that piping, in general is designed and built either horizontally or vertically.

So you have dimensions in x,y and Z.

These are your principal planes of reference.

Now piping isn't always like that so to show where the angle is relevant to you need to show the principal plane (horizontal or vertical as a hatched area and show where the angle comes from.

Your iso is particularly complex as there are strange angles going on and you are not using standard 45 or 90 degree elbows, but something more like a 60 or 70 degree angle elbow.

If an elbow is not shown going horizontally or vertically then it it referred to as "rolled".

So lets say you have a horizontal nozzle and you roll a 90 elbow 45 degrees then it will go at 45 degrees to the horizontal plane using one fitting instead of a 90 vertically then a 45.

Bottom line - that Iso is not fit for purpose.

Remember - More details = better answers
Also: If you get a response it's polite to respond to it.

 

[Texas Piper]

@Tug,

Thank you for the insight. "A lot of design in these systems is left up to the pipe fitters themselves", I'll keep that in mind the next time I step on a ship

@Ult,

"So even though in the 3d model it looks like it works it doesn't necessarily mean that it is feasible in the real world?"

YES!

A 3D model is only as good as the information put into it: Garbage In, Garbage Out. A good piping designer/engineer knows and designs to (among other things) the "-ilities"; constructability, accessibility, maintainability. This is knowledge that can only be obtained from years of working with senior engineers and designers and working in the field.

 

[Gator]

Here's a quick animation of a rolled 90 degree elbow:

https://streamable.com/xs84dd

As an aside, I too very much dislike the “high value” “engineering” done by these overseas firms. Anybody with half a brain can run a piping CAD program, but it takes a true piping engineer/designer with years and years of experience to know the how and the why. Drafting and designing plant piping was an art form before CAD came along.

Agreed! Some of the stuff coming out of software is appalling, and drawing quality is not important any more apparently.