Scale on drawings? 5

[JStructsteel]

Do you folks put scales onto your drawings?

A contractor is bewildered that we don’t want them scaling dimensions.

 

[JStructsteel]

Update, so 10 days later contractor asked for some dimensions, which was a justified question, I didn’t call them out. But took 30 seconds to figure out by doing the math on the drawings.
He spent hours and hours according to him.

He just got a surcharge on his next job, costing him and client money because of his shitty attitude.

 

[driftLimiter]

Oof. This is a good post to consider when making drawings. Contracts only know how to add they don't know how to subtract

 

[le99]

An RFI from a contractor is potentially a claim later.

 

[canwesteng]

If you can figure the dimension out on the drawing, it isn't missed. I never double dimension things on drawings

 

[GeorgeTheCivilEngineer]

Definitely put the scale on the drawings.

I've always taken 'DO NOT SCALE FROM DRAWING' is as much to mean that specified dimensions always take precedence, rather than a literal 'thou shalt not measure things'.

 

[JStructsteel]

If a contractor spends hours trying to figure a dimension after we tell him to ask for dimensions, then he is a shitty contractor

 

[human909]

@ Canpro, thats weird about no dimensions. My thought when doing a detail or plan, is 'can they build this based on the dims' Granted one time it would have saved me not to dimension.

Around here we don't want them to be able to build it based on the engineering drawings. Engineering drawings are for the structure. Architectural drawings are for the dimensions. So engineering drawings will have very few dimensions except in places like typical connection details etc. Beam sizes or slab, wall thicknesses will be nominate on the drawing but generally not dimenssioned.

 

[CANPRO]

Around here we don't want them to be able to build it based on the engineering drawings. Engineering drawings are for the structure. Architectural drawings are for the dimensions. So engineering drawings will have very few dimensions except in places like typical connection details etc. Beam sizes or slab, wall thicknesses will be nominate on the drawing but generally not dimenssioned.

I get what you're saying and I agree dimensions on the architectural drawings should govern. But aren't you concerned that the architect might move a gridline and increase a beam span beyond an acceptable limit (one of the examples that come to mind). Seems to me you'd want dimensions on your drawings just to cover your ass.

 

[Enable]

I get what you're saying and I agree dimensions on the architectural drawings should govern. But aren't you concerned that the architect might move a gridline and increase a beam span beyond an acceptable limit (one of the examples that come to mind). Seems to me you'd want dimensions on your drawings just to cover your ass.

Naa that's what max limitations are for.

I'm on all sides of this issue. I'm a contractor / delegated designer / EOR in certain cases. My opinion is surely different depending on what hat I wear. It goes something like this:

As contractor: Lord in heaven put bloody dimensions here. I don't want to thumb through 100 architecturals that don't apply when all I need are some beam lengths. FFS you drew this thing in CAD...it's like 2 extra clicks from the ribbon you SOB.

As delegated designer: Sure would be nice to have some dimensions but meh i'll take rough dims and let my client (the contractor) figure the exact dimensions by field verifying.

As EOR: You want me to add dimensions so that the contractor / architect can point the finger at me for something that really isn't my ball game to begin with? Nevermind the fact that the architectural dimensions are bound to have errors...which I've just blindly copied. Screw that. I'll provide max dims and point the contractor to the architectural thanks very much.

 

[CANPRO]

Naa that's what max limitations are for

But the max limitation would need a dimension would it not? Maybe I'm misunderstanding, but I'm picturing with everything on the drawings dimensioned followed by "MAX".

I understand your view points and have similar range of experience as a contract, delegated designer, and EOR. For per personally, I believe a proper set of structural drawings requires some basic dimensions (grids/elevations)...and notes indicating the drawings aren't to be scaled, the dimensions shown are not to be used for construction, and the architectural drawings to be used for dimensions.

 

[human909]

There obviously is no right or wrong here it just comes down to local conventions and work flow approaches. Just like I find the practice of the EOR delegating responsibility of connections to others I likewise find the responsivity of dimensioning on structurals problematic.

I get what you're saying and I agree dimensions on the architectural drawings should govern. But aren't you concerned that the architect might move a gridline and increase a beam span beyond an acceptable limit (one of the examples that come to mind). Seems to me you'd want dimensions on your drawings just to cover your ass.

This issue occurred to me when I wrote my previous comment. Any gridline movement beyond a few a few dozen mm is unlikely an a significant change. Changes of any sort need appropriate engineering review.

For what it is worth I don't worry as I'm engineering for a company that does design and build. I normally follow the project a significant way through. Also many of my engineering designs do not not the fully fledged engineering drawings. (This is not uncommon here we have plenty of 'signed' design drawings from consultants that are a few sketches of critical details notepaper.)

Here is a typical drawing plan

No dimension at all. This is repeated for all plan views and elevation views.

I believe a proper set of structural drawings requires some basic dimensions (grids/elevations)...and notes indicating the drawings aren't to be scaled, the dimensions shown are not to be used for construction, and the architectural drawings to be used for dimensions.

I do agree that basic dimensions are helpful in a set of structurals. However I do see some issues. If I design a building that has 7000mm portal bay lengths and then that gets nominated on the drawings. Further down the line due to a minor change in the sheeting used or similar the end bay might require the bay length to be 6970mm spacing between grid lines. That is not a change that the engineer needs to worry about but if 7000mm is still noted on their drawings then it is a complete reissue.

I see architecturals often revised for minor details during the project as RFIs are raised about minor finishing details. Engineering drawings are less commonly revised (unless the engineers have been particularly slack).

I'm on all sides of this issue. I'm a contractor / delegated designer / EOR in certain cases.

I'm also on all sides of the issue as we design and build and it isn't uncommon for us to use external consultants. Overall I'm used to engineering drawings not having dimensions, though I am grateful if gridlines are dimensioned.

 

[Enable]

I do agree that basic dimensions are helpful in a set of structurals. However I do see some issues. If I design a building that has 7000mm portal bay lengths and then that gets nominated on the drawings. Further down the line due to a minor change in the sheeting used or similar the end bay might require the bay length to be 6970mm spacing between grid lines. That is not a change that the engineer needs to worry about but if 7000mm is still noted on their drawings then it is a complete reissue.

I see architecturals often revised for minor details during the project as RFIs are raised about minor finishing details. Engineering drawings are less commonly revised (unless the engineers have been particularly slack).

When I'm an EOR this is my biggest problem with dimensioning. I am not paid enough to follow the updates on the architectural to the point of incorporating every 25mm change here and there when a certain cabinet size gets redone or something else minor like that. And if I have dimensioned my details, that cabinet change might really impact the length of a wall or sign anchorage location or whatever. Big deal if it's not picked up and they run with what's on my sheets. When the job has only a handful of architectural I am probably amicable to following lock-step, but on the projects with 100s, you got to be kidding me. If I was paid for it I would have a different tune most likely, but honestly out of my three hats, being an EOR pays the worst

But the max limitation would need a dimension would it not? Maybe I'm misunderstanding, but I'm picturing with everything on the drawings dimensioned followed by "MAX".

I understand your view points and have similar range of experience as a contract, delegated designer, and EOR. For per personally, I believe a proper set of structural drawings requires some basic dimensions (grids/elevations)...and notes indicating the drawings aren't to be scaled, the dimensions shown are not to be used for construction, and the architectural drawings to be used for dimensions.

So when I say max dimensions I don't mean literally put only MAX and nothing else. That would be quite funny lol. When I'm acting as the EOR what I generally do is include some dimensions for every unique item where length might be critical (so columns, beams, whatever) and naturally a couple of gridlines. But on all of those I put it as a maximum value rather than the actual so 2500mm MAX or something like that (of course I've drawn it at 1:1 in CAD so it should be true unless changes occur). This provides enough for rough estimation / idea but not enough for construction, which forces contractor to use the architecturals (which is what I want of course).

I do think it's less than nice not to put any dimension on a structural though. The plan that human909 shows would annoy me as a contractor. They could put a dimension or two on the gridlines and say "dimension MAX (refer to architectural)" or something like that and still have same CYA but really help out human909 for estimating purposes. If human909 produced that for his own design/build team that's different since they already know the dims / have the CAD file and that's not a fabrication set anyways (not sure if that was from him or one of his outside consultants).