Enhancing Mechanical Engineering Productivity with BIM (ST-16-C071)

Many engineering companies have used Revit and have already crossed the first major hurdles of implementation, standards, and productivity. However, firms are not using data and metrics from connected systems in Revit for design, coordination, and quality control. Time is being spent entering data and getting families to schedule as opposed to actually reviewing and using data in the model.

One of the larger sets of external information for a project is the HVAC cooling and heating loads. By exporting space properties (i.e. Name, No., Floor Area, etc.) from Revit thru gbXML to load & energy analysis software, data entry time and errors are reduced.  Once HVAC loads are completed the calculated results can be brought back into the Revit model. This allows a Space Airflow Schedule in Revit to be utilized by engineers to also show diffuser airflows.  Calculated airflows are calculated from the Load software. This removes the need to go to each view/sheet and edit and sum airflows. Once diffusers have airflows, then the ductwork sizes can be reviewed and adjusted by using velocity and pressure drop diagrams in Revit. These color coded ductwork diagrams can be setup to flag or highlight a section of duct that falls out of a company’s design standard tolerance range. The airflow from all the diffusers that connects to a piece of equipment is also able to be verified and checked in a Schedule against the scheduled airflow value. The gas load in a schedule for any piece of equipment can also be used to drive gas flow (CFH) thru the gas piping systems.  This process is dynamic which saves the time of adding up CFH values. Revit also provides the ability to perform ASHRAE 62.1-2007 ventilation calculations for constant volume single zone systems.  The setup is very easy at the beginning of a project and also dynamically updates if the design changes.

The calculations and design workflows outlined above are just the beginning of the potential productivity gains.  Other gains come from Fixture Unit propagation for Sanitary and Vent systems, and even the area served by roof drains.  These productivity gains require some investment time to set up workflows, schedules and views.  This investment will not only provide additional productivity and consistency, but also better quality control resulting from all of the information residing in one location.