According to the Autodesk website, building information modeling (BIM) is an intelligent 3-D model-based process that equips architecture, engineering, and construction (AEC) professionals with the insight and tools to more efficiently plan, design, construct, and manage buildings and infrastructure. So what does that really mean? And how can the use of BIM benefit the design community, specifically in the fire protection industry?
The concept of BIM in the AEC industry has been around since the 1960s, but didn’t evolve to its current use until the early 2000s. The design community used a 2-D platform to design buildings for many years, even after the introduction of the personal computer gave way to computerized software for architectural and engineering design. Two-dimensional platforms allowed designers to use an inventory of stored symbols and line types to improve on the hand drafting that was previously used in the industry.
Then the use of 3-D design became prevalent, giving way to what is now BIM. Three-dimensional modeling allows engineers to see what they are designing before it is built, to get a feel for the layout of the space and how the various elements fit into the design. This helps designers avoid conflicts with other disciplines or trades before the system is installed.
When BIM was introduced, it allowed a database or model to be used so that an inventory of symbols can include objects. BIM is a form of 3-D modeling, but takes it even further by introducing other dimensions, such as time (for scheduling purposes) and cost (for estimating and control). It also introduces what could be considered a database to store specific information about the objects used in design. Objects are added to the model to build the database or design. The objects store information that can be used in a wide variety of ways to enhance the database or model being used to design the building. This, in turn, enhances the design tools available to the design community.
Fire protection system design
Fire protection engineers and contractors have been using 3-D modeling for many years to design systems, such as automatic sprinkler, standpipe, fire pumping, and special hazard-suppression systems. The use of 3-D design applications helps with the coordination of design and installation by showing the designers how the various components of the systems will fit into the building or space. Some applications also have integrated hydraulic calculations into the program to allow for more efficiency in design.
Most of the fire protection system shop drawings being developed today use a combination of 2-D and 3-D designs. Two-dimensional floor plans are used to show piping runs and layout as well as sprinkler locations. They also are used to show sprinkler locations on reflected ceiling plans to coordinate the layout with other ceiling devices. Three-dimensional applications are used to show riser details, floor control valve locations, fire pump rooms, and other equipment where space relationships are necessary. These are beneficial because they show how the equipment or systems fit into the spaces for which they are being designed. However, most of the applications being used to develop design and shop drawings have been 3-D applications, and are not truly BIM applications.
With BIM becoming more prevalent in the design community over the past 10 to 15 years, fire protection systems are now being designed using BIM applications. Some software programs export the information from the BIM model to 2-D for shop-drawing use. This allows for continuity in the model as the construction process begins. It also allows for continuous coordination from the design to construction phases. The BIM model allows the design team to determine space layouts for major equipment and then the contractor to avoid field conflicts with other trades and key building elements. By adapting the design model to construction, the concept design can be enhanced to shop-drawing design while keeping the original design concepts in place.
The benefits of a BIM application design through the life of the building allows the contractors to keep an inventory of equipment within the model, so that recurring maintenance and repairs can be performed on the system while knowing what equipment is in place and without having to field-verify equipment every time. This can include major equipment, such as pumps, controllers, valves, and sprinklers. The transfer of the information in the BIM model to the end user allows the use for facilities-management purposes
BIM applications for fire alarm and detection systems are not as common as for suppression systems. This may be due to the smaller size of equipment as well as wiring runs being easier to coordinate in the field, whereas suppression systems have a need for coordinating larger pipe and equipment. However, BIM applications can be of benefit to the fire alarm and detection industry as a tool for inventory and cataloging of equipment. While detailed field coordination may not be as critical with the smaller equipment, the use of BIM can help with panel locations, fire command rooms, and coordinating the placement of devices on ceilings with other trades.
The traditional applications seen for fire protection BIM design are for installed systems. However, there also can be a benefit of using BIM for fire-engineering designs. Egress plans can be automated through the use of BIM. Egress plans are used to develop the exiting scheme for buildings and take into account the occupant load of rooms and the overall building while showing the egress routes to exit the building.
BIM applications can take the architectural model and import room data into the egress model. The room data can give the type or use of the room and the size of the room. Those two factors are then used to determine the calculated occupant load of the room to determine the width and quantity of exits from the room or space, and for the overall building. Using a BIM application allows engineers to calculate the occupant load based on load factors found in the building code.
Developing egress plans in a 2-D platform often requires the use of polylines to determine the required area of the space. Once that is determined, a manual calculation is performed to determine the occupant load. Changes to the plan show up when the polylines differ from the initial layout.
With BIM applications, changes to rooms and areas can be automated using the BIM model to show deviations in the areas and calculated loads. This automation can reduce the effort typically seen when using only a 2-D model or application.
Required egress capacity also can be automated using BIM applications. While doors, stairs, and other exit components still need to be placed, the BIM application can help confirm the exit capacity is sufficient to accommodate the calculated occupant load. The designer can take the occupants of the various rooms and spaces into consideration when determining the required egress routes, and the BIM application can confirm that the capacity is within the required amounts. This allows the calculation of occupant loads and confirmation of overall and individual capacity to be streamlined, saving time and effort. When developing egress plans, the most tedious task is determining the calculated occupant loads and required capacity and verifying that all building occupants are accounted for in the exiting capacity. When dealing with very large crowds, automating this portion of the process can be of great benefit.
Using the data from the model allows the fire protection designer to automate some of the exiting process. Engineers will still need to manually determine the exit flow, but the time to determine the total occupant load and the required exit capacity is reduced. It is also very useful for streamlining the changes in design that occurs during the overall design process. By using a BIM application, more time can be spent on determining the egress routes while less time overall is needed to develop the exiting scheme for the building.