Wikipedia describes BIM as: Building information modeling (BIM) is a process involving the generation and management of digital representations of physical and functional characteristics of places. Building information models (BIMs) are files (often but not always in proprietary formats and containing proprietary data) which can be exchanged or networked to support decision making about a place. Current BIM software is used by individuals, businesses and government agencies who plan, design, construct, operate and maintain diverse physical infrastructures, such as water, wastewater, electricity, gas, refuse and communication utilities, roads, bridges and ports, houses, apartments, schools and shops, offices, factories, warehouses and prisons.
Building Information Modeling
We like to describe BIM Documentation as a virtual building. Today, our tools (BIM Software, etc) allows architects and engineers to perform drawings to a much greater level of accuracy. More and more of the products that we specify for the building are available in 3-Dimensional format, in perfect scale with all their parts and pieces. A simple list of items available to our industry includes doors, windows, plumbing fixtures, steel beams, etc. We can essentially build a computer version of a full building by assembling all the selected products. Further, these 3-Dimensional objects that we download from our selected manufacturers have all of the product information attached to them. This information can contain things like selected color, model number, weight, and even local suppliers.
Why is this a quantum shift in our industry and how might it change the future of how we deliver buildings?
Historically, architects have drawn buildings nominally. By this, we mean that a 2×4 wood stud is not 2×4. A 2×4 stud is actually 1 1/2” x 3 1/2”. This type of “nominal” discrepancy occurs throughout a set of construction documents. This leaves lots of opportunity for minor field issues. Most of the time, these field issues are resolved by the contractors during the construction process. If the issue involves the esthetics of the building, contractors will issue an RFI (Request for Information) to resolve or clarify the intent of our design. The more of these issues that occurred, the longer construction process takes.
Additionally, the construction process has always involved a large amount of waste. Contractors and Sub-Contractors always ‘allowed’ for a bit extra material on most everything they build. It is more efficient to have a little extra than it is to stop construction and wait for additional material to be delivered. Quantities can not be guaranteed for a lot of reasons. Namely, architects were drawing by hand to small scales such as 1/4” or 1/8” = 1’-0” and contractors use rulers and similar tools to closely estimate quantities required.
The Evolution in Architecture
Today, we are in a truly exciting time in architecture. In the mid to late 80’s, architects and engineers processes evolved from hand drawing to 2-dimensional computer drawing or CAD, computer aided drafting. This evolution sped the process up dramatically. It enable changes to be made quickly and efficiently. But this process was basically just as described, computer aided drafting. By the mid to late 90’s, the evolution started to take on a third dimension, we were able to take those 2 dimensional lines and bring them up. We started to draw walls instead of lines!
This evolution has today reached a point that we have the ability to create the building ‘virtually’. This virtual building can be exact in dimension, quantity, position, etc. We are able, in most cases, to select the exact toilet a client may want and place it exactly into the proper place it is required to be from the wall. The plumbing engineers are able to exactly show the piping and connections required to make sure the toilet operates correctly ……. and we all want that to work!
Anyway, the point is that we can build a building virtually. We are able to resolve conflicts earlier, at the design stage where they are much easier to resolve than in the field, where it causes people to stand around and results in long, more expensive construction times. We are able to accurately calculate quantities such as concrete, tile, and brick. While there is still a little waste required due to cutting and fitting of a standardized material to an actual condition, it starts from an accurate point, allowing for less waste.
We are also able to complete projects faster. We are able, due to the accuracy of the drawings, to release certain construction items that used to have to be field verified, prior to construction. This allows things to be built earlier and be ready for installation once the construction catches up. Since system conflicts, such as an air-conditioning duct hitting a steel been, can be resolved at the design documents stage, we no longer have expensive construction teams standing around scratching their heads. As contractors learn that through the use of our BIM documents, they are able to construct buildings faster, their expense will come down relative to the total cost. Why? Because time is money, especially in construction. And a faster building will be a less expensive building.
Cost of Building
And finally their is the cost of the building. For the most part, owners have only been able to learn the final estimated cost of a construction project at the end of the construction document phase, the completion of the drawings. If the building came in over budget, they had difficult decisions to make. Do they accept the higher cost and continue or do they try to remove items from the building in order to lower the cost? Often, if they choose to remove items, they would have to pay to have the drawings revised. They have to pay more to get a cheaper building. This is a terribly inefficient use of time and money. BIM is allowing the construction team of architects, engineers, and contractors to provide much more valuable information to the owner much earlier in the process. Most of the time, at about 40% completion of the BIM Documents, a contractor can provide a very accurate cost estimate for the construction. With this earlier information, the owner can make better decisions at a point where they are not prohibitively expensive or impacting the time schedule significantly.
BIM Documentation is allowing construction teams of architects, engineers, and contractors to work together more closely resulting in a better built building, built faster, and within the owners prescribed budget. For everyone involved, this is a win, win, win proposition.
In a future blog, we’ll discuss how this project integration may effect the construction teams of the future and the possible return of The Master Builder. Stay tuned!