Constructability?

[hvacpiper]

This is a general question posed to the mechanical engineers on here, about constructability of design,and who is inherintly responsible for it.Some background first,I'm just a dumb plumber,I'm not a contractor,I just install pipe for a living, at an hourly rate.That being said, after spending years going through construction documents......Who deserves the blame for documents that cannot be built?

At a recent ASPE meeting I attended,a question was posed to the panel asking ,who the ultimate responsibility lies with,to ensure a system can be constructed and installed per design.The AIA guidelines were mentioned,and that most engineering firm's designs "should" adhere to the "AIA Guidelines".I have not yet been able to read through said documents,and I wonder,if they do in fact place responsibility on anyone's shoulder.Being the end user of construction documents,I feel as though,I am proctoring dialogue between engineers and architects,that should have happened long before,I,the pipefitter was going to drill a 5" hole to put a 4" pipe in a 3-5/8" stud wall.

So is it, Architects lack of knowledge of construction methods and materials? Or is it the Engineers who place 4" risers in 4" walls? I'm going to assume it's the architects,but I'm curious as to how much back and forth the disciplines actually have in the design end of construction.4" pipe in a 4" wall is an over-simplification,but I do see that quite often,even from AE firms...

 

[317069]

Design engineer, contractor, and general review during construction share responsibilty of the project.
in your case before you drill this 5" hole, you have to read the drawings and give your comment, there is a person who provide general review during the construction and his job to solve such problems, even if you think from your experiance that there is an oversizing or undersizing, you have to share this knowledge before starting or during construction.

 

[EnergyProfessional]

I don't know the AIA document, and it will depend how the contract is written. the contractor (you) has responsibility to review plans before bidding and to point out issues. I understand you can't review everything before bidding.

In this case I would say it is the responsibility of the designer and it is not reasonable to expect you have to check that before bidding. this would lead to a change to route the pipe differently.

I bet they drew the pipe not in real size (5") but just as a thin line and on paper it fits. they also do that with ducts to have 3 20"ducts drawn is skinny lines so it all fits, on paper anyway

If the designers would have used Revit properly, they would have seen that.

Who is to blame? Always the other guy.......

 

[MTES93]

I'm a design engineer. If I told a contractor to fit a 5-inch square peg in a 4-inch round hole I would humbly admit my drafter screwed up. Just kidding. I don't care what AIA document you are referring to I would expect the designer to own up to that one, I would. Yes, we as designers on big projects have much more intense things to worry about, but you as a bidder have a very short time to price and put together your stuff. And a pipe not fitting in or down a wall could be a big deal on a project. And you wouldn't see that when your bidding the project. Hell if the engineers can't see the architectural dwgs in time to correct this during design; how would you in the time it takes you to bid the project???

The big culprit is the time line owners are putting all of us under. What took 6-months to design and 24-months to build is not compressed to 9-months total. Crazy. Programs like Revit help but remember that SI=SO.

 

[PEDARRIN2]

There is responsibility on all parts.

1. The engineer is not going to catch all the mistakes - but he needs to realize that he has to understand how things are installed in the field. I am glad the designer who works for me was a journeyman plumber before he came into the office. I bounce a lot of things off of him. He has saved me a lot of change orders.
2. The contractor is not going to catch all the mistakes. But sometimes he does, and bids the job as it is displayed to get the job and gets a hefty change order rather than bringing it up during bidding.
3 The architect/client/owner is not going to pay for all the mistakes. But they push the schedule and the fee and the expectations so things get missed then wonder why there is so much contention when it comes time to build it.

 

[EnergyProfessional]

I think the owner could force the designer to use Revit or some other tool that can detect clashes and designs in 3-D.
The problem often is that designers still design in 2-D without actual sizes.

If they used Revit they would find it very hard to place a 5"pipe into a 4" wall (people still manage that, though)

Designers that try to design the easy way (i.e. place a 5"x5" rectangle to represent a transformer that actually is 3'x3') and should pay up for that.

 

[PEDARRIN2]

From experience, the 5" pipe in a 4" wall is sometimes a pipe that I forgot to coordinate needing a larger wall with the architect. Lots of times this gets fixed in the field.

Revit is great at detecting clashes and showing the possibility of mistakes. It has made designs more precise. We often take the Autocad backgrounds we get from architects and/or structural consultants and bring them into Revit and do our mechanical design from there.

But you still have to show the design on a 2d drawing.

I can show the piping an inch apart, which will work in the field, but will not present well in a drawing. But if I show it on the drawing so the contractor can read it, my piping is running through the duct work beside it. Then I look like a bad designer to the client and the contractor gets more money because now he has to coordinate more than he had in his bid.

We hand over the model to the contractors who then have to produce a coordination model, which is what they build from. Most of the time this results in seeing conflicts we didn't see in design before they become unconstructable and cost a lot of money and fingers start pointing.

 

[Drazen]

right, pedarrin, in plans we need to show piping separated and most of time piping distance is not up to scale because of that.

in general, there are either written instructions about piping distances in specifications or some generic cross sections are shown, but most trouble comes from situation where you need to present number of parallel lines within confined width, and lines cannot fit in width. written notes on drawing remain the only resort than.

what you show in larger scale plans is actually symbolic presentation rather than scaled drawing, but you need to check available space. in that respect cad tools do not help much. they are indispensable in detail drawings of mechanical rooms, but not so useful for large plans.

as to the original question, i believe that contract and referred trade rules are focal points on decisions who is to be blamed. such issued are rarely one-dimensional.