Chemical Equipment Design with 2D and 3D Drafting Tools

Ward’s 2D and 3D Drawing Capabilities Eliminate Mistakes Before They Happen.

Engineers fabricating equipment for the CPI, Oil & Gas, and associated industries have depended on two dimensional drawings in the design of plant equipment for decades. Getting these designs right can mean the difference between delivering dependable equipment on-time and on-budget and making expensive, time-consuming mistakes. A small error, like a dimensionally incorrect nozzle, can lead to big problems when it’s time for equipment installation. Therefore, it’s very important to understand the strengths and weaknesses of both two and three dimensional drawings in the design and fabrication of Processing Industry equipment. 

Fabricator Ward Vessel and Exchanger uses a traditional two-dimensional drafting tool (Autodesk AutoCAD), mostly for vessel designs, and a three-dimensional parametric drafting tool (Autodesk Inventor), primarily for heat exchangers.  “There are pros and cons to both tools but using both gives us the flexibility and lets us take advantage of each platform’s strengths,” according to Bill Huffman, Director of Engineering at Ward.

There are several advantages to drafting in two dimensions. First, the programs are much simpler to understand and use. This is the computer version of drafting on paper with pencils and T-squares. Two dimensional drafting has been used for decades and is well understood. The drafting program is intuitive to learn and little training is required. Costs are lower for this type of program, in terms of hardware and software. Also, due to the simplicity of these programs, any equipment, from simple to complex, can be designed relatively quickly. In addition, file handling is relatively easy for this type of design — a single drawing file can be copied, pasted, and emailed in an instant. Two-dimensional drawings can also be reviewed, altered, and changed in a matter of hours. Not only are they easier to change, but this can be a much more cost-effective process, as long as there are no mistakes.

Three-dimensional models are more complicated and expensive to produce, but they can uncover more potential problems prior to fabrication. These could include interferences that are next to impossible to spot in a 2D drawing. 3D models take out the guesswork. “You can spin the 3D model around until you can see where those components are located and determine that ‘yes, those are definitely going to clear,’ points out Huffman.   “Checking for interferences at strange angles is going to be really hard to do on a 2D drawings. You can eyeball it in 2D, but to be sure everything is going to fit properly, you have to put the physical parts together during fabrication and see if they interfere with each other or not.”  The two photos side by side below are showing that the potential lift lug repad to nozzle interference can be clearly seen and dispositioned on the 3D model.

The three-dimensional design starts with a virtual model of the equipment that Ward will be fabricating. Drawings are then created from various ‘views” of that model.  If the underlying model is revised, then all the drawing views of the model are automatically updated, since they are linked to the main model. This is called parametric design.

The associativity of parts in the parametric design method virtually eliminates drafting errors. If a part is changed, then all views of the same part will be updated to match automatically. In the 2-D drafting world, each view of the part would need to be updated separately. “You can also turn off certain parts of the drawing, such as hiding the shell to see the internals,” adds Huffman.

Processing Industry companies also increasingly rely on 3D modeling in their own plants. “When we make our vessel in a 3D model, you can output a certain format that is compatible with other programs,” says Huffman. “So we can send them this 3D model and they can drop that right into their plant model. They can make sure all the piping is going to line up correctly.” Once the design is approved, Ward’s team is able to work from 3D drawings that enable them to fabricate a vessel accurately, minimizing the risk of problems down the road.

Three dimensional models save time and avoid potential problems by providing the whole picture. “The shop doesn’t have to stop when there’s an interference and come ask us ‘Okay, which one do you want to move?’ notes Huffman. “With these 3D models, there won’t be drawing inaccuracies and interferences in the first place.”

Ward understands the advantages and drawbacks of both design techniques and applies them to meet its customers’ needs dependable equipment delivered on-time. “In some ways two dimensional drawings help us, and in other ways, the three dimensional drawings help us,” says Huffman. “There are projects where we use both,” says Huffman. “Sometimes simplicity is a better answer than something that’s more complicated. It might be overkill if it’s just a shell and two heads. You can just draw that in two dimensions and get it in for review pretty quickly, and it will be right.”

Knowing when to use these tools, can make all the difference in the world in a successful fabrication project and a premature failure. For more information about Ward Vessel & Exchanger and its custom equipment design and fabrication capabilities, contact us at 704.568.3001 or email Put our technology and know-how to work for you on your next project.