I am often asked why BAS terminology is so confusing, and whether there should be a standard to address this issue. My answers to these questions are “because” and “no.” Cynicism aside, a lack of standardized BAS terminology makes it very difficult to specify, procure, and commission a BAS that meets the owner’s needs.
Standards benefit our industry greatly. BACnet is a perfect example of a standard that was needed and has helped our industry, though it is also an example of how we can never standardize BAS into complete clarity. We also cannot expect the BAS manufacturers to work together to standardize terminology that is rooted in the unique names given to their products. So, who is responsible for working through this terminology “Tower of Babel?” We all are!
Tower of Babel, Part 1: BAS Products
Everyone in our industry has their own set of terms for the various components in a BAS. The key here is to never assume that your terms are universal and that they mean the same thing to everyone else. Is the software and hardware that allows a user to interact with a BAS a “workstation,” “operator interface,” “HMI,” etc.? Who knows without a definition, and to make matters worse, each of these terms could refer to different components that go into the making of a user’s overall interaction with a BAS.
Tower of Babel, Part 2: Integration and BACnet
Open protocol and integration terminology is probably the area in our industry that leads to the most terminology confusion. I still read project requirements such as “fully and seamlessly integrate.” The problem is that the only integration that can ever come close to the goal of “fully and seamlessly” is that which occurs between the BAS products made by a single manufacturer, which is not the context in which it is ever used. In all other cases, there is no chance that this requirement can ever be met to even a far less optimistic degree.
The funny thing is that integration is one issue where we do have some amount of standardization, which is via BACnet. The BACnet standard goes into great detail about what it defines as “integration.” Namely, the standardization of the messaging services and data formats used for the sharing of real-time control information. What BACnet does not include in its definition of “integration” or standardization of any other BAS issues is anything about sequences, points lists, programming languages, system setup and diagnostics, and even what information must be shared. Yet many uses of the term “integration” that I see today still seem to include various combinations of the items not defined within BACnet.
Unfortunately, most in our industry do not have the IT training needed to translate BACnet’s detail into a clear definition of “integration” (which can then be specified, but not by just saying “see BACnet”). ASHRAE does offer classes to assist us in gaining this clarity, but anecdotal evidence would indicate that these are not widely attended classes.
Tower of Babel, Part 3: The Specification
Given the above, it is clear that a BAS specification must include definitions of the terms used in the specification. However, there is little reason to spend a lot of time trying to pick terminology based on what seems to be most widely used (i.e., de facto standard terms). Instead, a BAS specification merely needs to clearly define each term and then be internally consistent about the use of that term. I use terms “operator interface,” “DDC router,” “DDC panel,”, “DDC controller,” and “application specific controller” to specify the hierarchy of BAS products common to most manufacturers’ systems. Are these universally accepted terms? No. Do I even consider these the best possible terms for a given system’s products? No, but they are well-defined within my spec and then used in an internally consistent manner.
A Final Word
Standards cannot help simplify all aspects of engineering, especially for something that deals with a subject that isn’t taught to mechanical engineers. Continuing education, research, and critical thinking is what is needed to help resolve this Tower of Babel.