Vessel Orientation on Drawing Sheet

[DDDRUMS]

After 30+ years of detailing I now have to argue about fundamental drafting practices....

Somebody help!!!

In general the following is correct, I used to believe!

[1] On a plan view North is up the page
North is 0 deg
East is 90 deg
South is 180 deg
West is 270 deg

Just like a clock or compass-rose north is up and reading clockwise

[2] Vessels (and Structures) are built from the ground up,
Measuring tapes read left to right,
Therefore Vertical Vessels rotated horizontal on a drawing sheet have base at the left - top at the
right.....

(Regardless of CAD defualt settings!)

Any comments?

Comments

 

[ctopher]

To me up is up. The top of the vessel will be up on the dwg. I had never rotated a vessel as you mentioned. I had worked on various dwgs from refineries, to pipelines to valves to aircraft to small parts, nothing rotated.
UNLESS, there was a need to show a certain detail or view rotated to be more clear.

Chris
SolidWorks 07 3.0/PDMWorks 07
AutoCAD 06
ctopher's home (updated 04-21-07)

 

[TheTick]

To me, a part is just a controlled shape until it is installed in something. For most small mechanical parts, orientation in a drawing does little to convey use. Besides, that's what installation drawings are for.

I can see how this convention would be more appropriate to architectural or plant drawings.

 

[ewh]

I agree with The Tick on this. Orientation is generally subject to making a clear, concise definition of the part. There are exceptions, such as buildings and assembled platforms, but most mechanical parts do not have this restriction. I wouldn't waste the paper space in trying to detail a vertical i-beam and having to use an unreasonably small scale to get it to fit on the page. I would detail it horizontally.
In aerospace, a part may be catty-wumpus in space, and trying to force the detail views to reflect the normal view projections of an aircraft is a wasted exercise in futility which gains nothing in the quality of the drawing.
Modeling parts, however, is a different issue subject to different arguments.

 

[CorBlimeyLimey]

DDDRUMS ... In general I agree with your statements, especially "bottom to the left, top to the right" when rotated. I had to follow that convention when involved with architectural glazing components. However, on more than just a few occasions I was at odds with office supervisors when I did not adhere to that practice for the reasons ewh stated.

Standards are good for the most part, but they do not and cannot cover all situations. If clarity and unambiguity of details require going against standards, then IMO the standard should be ignored. If need be, a simple note explaining the view/detail should more than suffice for non-compliance.

 

[11echo]

Well I guess I have to disagree, half way anyway, at least in my discipline. Yes north is normally "up" ...but it can be right or left too (again in my discipline – process piping). SO when we generate a dwg. where there is suppose to be an orientation, we put a "Plant North Arrow" at the upper right or left on the dwg. This saves alot of heart ache when construction rolls around. Doesn’t structural and architectural people do the same, or do you just assume? *G*

 

[aardvarkdw]

DDRUMS,

Look up Orthographic Projection. Then determine if your company/country/industry prefers to detail in First Angle or Third Angle Orthographic Projection.

As far as orientation of your primary view goes, it doesn't matter what the installed orientation will be (Like the Tick said, that is what assembly and installation drawings are for.), what matters is that the primary view is the best view for describing the part and that it is orientated so that the dimensions on the drawing can be understood.

David

 

[DDDRUMS]

Perhaps I wasn't specific enough but I was asking about large pressure vessel type details, not small mechanical widgets.

 

[ewh]

Large pressure vessels I would use front, top, etc. Large pressure vessel type details (parts) I would use whatever orientation is most efficient, and not force the views to maintain the parent assemblies orientation. An exception is if the detail views are taken from the parent assembly views, which would require a note explaining the orientation difference if it has been changed (i.e. "Rotated 90 Degrees CCW").

 

[tk369]

I used to work in the pulp and paper making industry, designing continuous wood-pulp digesters. These vertical silos, 200-320 feet high and anywhere from 16-25 ft i.d. at the bottom were a real challange to detail-especially the elevation on a standard E-size-on a drafting board. (Yeah, I'm that old!)

I showed the elevation rotated with the top to the left and bottom to the right, and showed all connections in the same plane, measured from the bottom or base

Then, I used sections at each different elevation to define the orientation of each fitting relative to 'north' or any customer-defined location.

Our fabricators and erectors all used these prints without any problems.

Good luck in your situation.

 

[danielthb]

Orient everything so a drawing's user is able to read it from either the bottom or from the right side of the sheet.

Dan (all caps on drawings) Blackwell