Miscellaneous
Building Information Management (BIM) involves the use of information-rich 3D models and their data collaboratively, improving the quality and exchange of information throughout the design, construction, and post-construction phases. Put simply, BIM requires the delivery of the correct data, to the relevant people, at the right time, in the appropriate format.
​
Duct Leakage
Delivering Predictable Outcomes through Design Coordination
A picture may be worth a thousand words, but a digital model is worth a thousand pictures. The information and value represented in the model sums up why Virtual Design and Construction (VDC) should be used on every project – especially during the design and preconstruction phases.
VDC services like design coordination are enabled by a data-rich Building Information Model (BIM) and applied design integration processes, which we use to identify and resolve issues before construction begins. In the early design phase, better collaboration and information enables project teams to make more informed decisions about design intent and constructability. When issues are addressed at this stage of the project, it leads to better predictability, productivity and quality.
We leveraged the data-rich virtual model to conduct equipment and overhead MEP coordination on a recent large pharmaceutical project.
Duct Cleaning
Just as important as the proper installation of an HVAC system are the troubleshooting and maintenance. HVAC systems, like any component, can sustain wear or damage over time and should be maintained with regularity in order to ensure optimal efficiency. Ducts are especially important to check, since their wall- or ceiling-mounted positioning makes it important that they are made of relatively light materials. This means they can be more vulnerable to damage than some other building components. A technician, such as our qualified technicians here at HVAC Engineering, can help recommend any needed maintenance after performing some tests to check the performance of your system.
​
Duct leakage testing is a method that allows for the measurement of air leaks in an HVAC system, which can be responsible for losses of temperature-controlled air. Since it takes valuable energy to heat and cool air to a comfortable temperature, duct leakage testing can help reduce energy waste and save on recurring costs. Counter-intuitively, duct leakage testing can involve not just a duct leakage tester, but other key equipment such as a blower door or a flow hood. The method is relatively straightforward: “[j]ust as when you’re testing for airtightness, each cubic foot of air that leaks out (of the duct system in this case) must be made up by a cubic foot of air blown in by the fan”.1 What this means is that we’re able to test an HVAC system by measuring the flow of air entering and leaving the system, and the difference between the two readings indicates the magnitude of leakage within the ducts. As in any good experiment, however, it is important to control for other variables, such as the pressure already present in the HVAC system. For this reason, duct leakage testing is often preceded by a pressurization of the system using a fan with a known flowrate, so that any flexure of the duct walls is not erroneously included in the leakage reading.
​
Duct Cleaning
However, duct leakage testing is not entirely this simple. As stated in “Duct Leakage Testing, Basic Procedure”, it’s important to make the distinction between leaks that are truly wasting valuable energy- dubbed “malignant” leaks- and those which are more “benign”. For a leak to be causing a total loss of conditioned air, it must be leaking to an area outside the building envelope. In order to test for malignant leaks alone, benign leaks must be controlled. This can be achieved by pressurizing the duct system and the interior of the building envelope to the same level, thereby eliminating the pressure imbalance that causes air to leak out of the duct system and into the lower pressure building interior. As you might remember if you’ve taken a Physics class, gases naturally move from areas of higher pressure to areas of lower pressure if given a channel between the two. Once the equal pressurization is achieved, gases will only have a pressure differential between inside the building envelope and outside of it- thereby making it possible to separate out which leaks are malignant. Once the duct leakage testing has been completed, the results can be analyzed to help optimize your HVAC system to its best performance.
Indoor Air Quality
Most people are aware that outdoor air pollution can impact their health, but indoor air pollution can also have significant and harmful health effects. EPA studies of human exposure to air pollutants indicate that indoor levels of pollutants may be two to five times — and occasionally more than 100 times — higher than outdoor levels.1 These levels of indoor air pollutants are of particular concern, because most people spend about 90 percent of their time indoors. For the purposes of this guidance, the definition of good indoor air quality (IAQ) management includes:
-
Good IAQ contributes to a favorable environment for students, performance of teachers and staff, and a sense of comfort, health and well-being. These elements combine to assist a school in its core mission — educating children.
Control of airborne pollutants;
-
Introduction and distribution of adequate outdoor air; and
-
Maintenance of acceptable temperature and relative humidity.
Temperature and humidity cannot be overlooked, because thermal comfort concerns underlie many complaints about "poor air quality." Furthermore, temperature and humidity are among the many factors that affect indoor contaminant levels.
Outdoor sources should also be considered since outdoor air enters school buildings through windows, doors and ventilation systems. Thus, transportation and grounds maintenance activities become factors that affect indoor pollutant levels as well as outdoor air quality.
Testing Services
