Building information modeling (BIM) is the process of generating and managing building data that can be used from the planning stage, through construction, and well into all stages of a building’s life-cycle. Typically, it uses three-dimensional, real-time, dynamic building modeling software to increase productivity in building design and construction.
Drafting’s Evolution to Building Information Modeling
When computer-aided design (CAD) was introduced, it brought a new dimension to creating line drawings. Rather than needing a compass or triangle, one could type a command, and a circle could be drawn in any size and any scale. A line could be given any length or angle. Even with the slow speed of early computers, copying and deleting could happen at a pace only previously imagined. Building layouts could be changed much more quickly than on the drafting board.
However, this speed came at a price. When plans were designed on the drafting board, architects and engineers met before the building design started to coordinate mechanical room sizes, water heater locations, electrical panel locations, etc. All members of the design team focused on completing the project with as few changes as possible.
Building information modeling software has developed as the next step in CAD’s progression. BIM software has taken the approach of creating the model within a database. This allows higher functions to be applied through the use of parameters. Parameters can input more information than units of measurement. They can be used to apply text, graphic overlay for rendering, and referencing information from other databases. The entire model has the ability to be parametric. Rather than lines representing a pump, the pump now has become a virtual object with the ability to contain real-world information such as plan location, elevation, weight, volume, horsepower, pressure loss, and much more (see Figure 1).
The ability to contain a wide variety of data types gives the BIM program the ability to perform calculations and display the information in multiple views in real time (see Figure 2). Several different products on the market today are used to create BIM models (see sidebar).
HOW BIM Will Change Plumbing Design
When a company decides to commit to BIM, the plumbing designers will be tasked with learning the new software to produce their designs. The company may need to invest in new computer hardware to run the software effectively. The transition will require training to use the software and might require more time to develop content. This endeavor can take six months to a year before plumbing personnel actually become efficient.
The International Code Council is in the process of developing new standards to incorporate BIM in the code review process. This new project is called SmartCodes. This can have a major effect on plumbing design if plumbing designers and engineers are not involved in the development of this process. There have been numerous discussions about how industry societies need to be more involved in the development of plumbing standards. I believe BIM can be a catalyst. Within BIM’s format, plumbing calculations can be produced to help show building sustainability. Plumbing engineered systems then would have more credibility. (If you would like to learn more about SmartCodes, visit www. iccsafe.org/SMARTcodes.)
Advantages of Using BIM in Plumbing Design
Coordination with other disciplines always has been at the top of our list when designing a system. Being able to work in a virtual 3D environment really helps detect conflicts. Most BIM solutions have a means of performing conflict detection and will highlight the areas in question. Since BIM solutions are normally databases, the ability to track items such as mechanical equipment, plumbing fixtures, fixture unit counts, and gas loads is much easier. Creation of the final documentation is quicker. BIM models normally contain parametric objects, and information can be added to adjust the physical attributes of these objects. If any piece of information needs to be scheduled, a parameter can be created to allow the object to share information with a schedule.
The 3D view of the BIM model can be rotated to different directional planes to produce plumbing isometrics (see Figure 4). Since most BIM software creates the model using databases, streamlining construction specifications can be done through third-party software such as e-Specs. Cost estimating for plumbing systems becomes more accurate due to the requirement for a more accurate layout within the BIM model. Most BIM software allows CAD files to be imported and models to be exported to CAD so other groups that are not using BIM can coordinate.
Disadvantages of Using BIM in Plumbing Design
Training on the MEP portions of these solutions is very hard to find due to the specialized nature of our fields. Some engineers also state that the quality of contract documents is not as good as CAD-produced documents. The linetypes that contain text styles that currently are used in CAD are not available in some BIM programs. Also, when a designer is routing piping inside a vertical
wall cavity from a section view, the floor plan view may not show the single line piping correctly. However, this will improve as these programs mature.
The main objective of BIM is to produce a more accurate representation of the building and all of its components, thus providing better engineered systems. More time is required to lay out an accurate BIM model in plumbing due to all of the virtual pipe the designer is modeling. If proper workflow is not followed, results can be untimely delays or increased change orders. Most of the plumbing content for these solutions, such as objects for traps or valves, must be created due to the current development stage of BIM software, which can be very time consuming.
Also, if other disciplines are using 2D CAD, coordination becomes much more involved because the plumbing designer no longer can take advantage of designing in the 3D environment and cannot run any automated interference checks, increasing the chances for error and liability due to the accuracy of the model.
Tips for Using BIM Successfully in a Project
First, research what product would best suit your needs. Have vendors send a trainer to demonstrate how their software works. A good test is plumbing two water closets with cold water, sanitary, and vent. Ask others about their experience, cost impact, training requirements, and vendor software support. Ask the vendors about the computer system requirements to run their software. Since most modeling software programs are databases, the system requirements are much greater than that of standard business class machines. BIM software requirements can affect the network infrastructure of your office. Upgrading to a BIM software package is like buying an old house—do your homework and research and be prepared to do a lot of repairs and customizations.
When you finally decide what software you will be using and have updated your computers to handle the software, make sure to purchase proper training. As stated earlier, training seems to be hard to find when looking for plumbing solutions for BIM. BIM software can be self-taught, but the learning curve can be very steep. Vendors normally recommend searching online for forums dealing with the software package that you have chosen. The personnel chosen for training should have a positive attitude and specific experience in your type of design work.
Once training is complete, start developing a template containingyour company’s standards. This template will continue to evolve as you develop more content for other projects. Converts much information from CAD as possible to your BIM software and, if time allows, create this information from scratch. When trying to import information from one software to another, databases can become unstable or corrupt.
When you are ready to start using BIM on a project, it is preferable to select a pilot project, such as a small job that can take a loss. Don’t use BIM for the first time on a project with a short deadline. This can be counterproductive and can ruin morale. When your pilot project is complete, make a list of things that did not work properly and a list of things that did work properly and use this as a benchmark for your next project. As your team develops their skills, the list of issues will grow smaller, and your team will have the confidence to complete any project.
Figure 4 Since the model is in a 3D environment, waste and water isometrics become easier to produce.
Marvin Titlow has been working in the HVAC, plumbing, and fire protection design field since 1987. In 2004 Michael Brady Inc., located in Knoxville, Tennessee, hired Marvin as a senior plumbing/fire protection designer. In 2008 Marvin was promoted to technologies administrator and BIM manager. For more information or to comment on this article, e-mail firstname.lastname@example.org
J.A. Croson LLC
Nashville Machine Co.
elements) takes too long and is cumbersome to say the least. Fourth, opening a project in Revit takes a considerable amount of time. Fifth, setting up sheets is cumbersome. Sixth, there’s not enough flexibility in the final presentation. Next, changing symbology to match a company’s standard is time consuming and in some cases impossible. Program bug fixes are slow to nonexistent. The software company has time to add content but not enough time to go back and fix
what doesn’t work. It seems their interest lies in creating content just good enough so they can advertise that it does more to get companies to buy a ‘new’ and ‘improved’ version. Lastly, creating the information in elements so you can use the dynamic schedules is too cumbersome.
“I think 2D is more stable and faster (therefore cheaper for the client) to use. Unless you have a client that insists on BIM, wait about 10 years to buy it until it becomes useful. As a bare minimum, quadruple your time estimates for project completion in BIM versus 2D CAD.”
David Faubion, CPD
“On the other hand, it can be quite tedious at times and very time consuming. The more work you have on your model, the longer it takes to regenerate. I haven’t had a lot of formal training, so there can be a steep learning curve. The out-of-the-box fixtures are not good. You have to look around forums and websites to get the fixtures and fittings you need or create them yourself.
where the line work can get busy, space is tight, and coordination is paramount.
“For example, there was a corporate office building that we just completed. Revit certainly helped when it came to the coordination with the structural beams. There was a restroom/locker room in the basement garage, and there were beams overhead that pretty much boxed us in. By looking at various angles of the 3D model and sections, we could coordinate with the architect to get the furring and chases needed to get though the structure and avoid a possible RFI and/or change order.
“We use AutoCAD Revit because we felt it was the best for the overall firm. It offered the best local support.
“For example, in designing a 12-story hotel, the architect located some floormounted, tank-type water closets over a corridor below. By looking at the section, we realized that the architect had only allowed 9 inches of ceiling space for the corridor below. If we weren’t already looking at that section to check the pipe and fittings, we may not have caught this ceiling space issue as early as we did. Also, on the same project, because of the amount of work and pipe in a hotel, the model became so large that it would take a minimum of 15 minutes just to open the drawing. At one point it took almost an entire day to draw one storm line from a roof drain down to below the slab and out the building. As more information is put in the model, the slower it gets. Eventually the file crashed, and all work from the previous day’s backup had to be exported to AutoCAD to be able to complete the project on time. As I previously stated, BIM is great for coordination but awfully slow in the real world.”
CHP and Associates
“We use Autodesk Building Systems. We already use AutoCAD extensively, so this was the easiest transition. We are currently testing Revit MEP but are not convinced of its capability for piping design.