Every complex topic or field needs a helpful naming system. Scientists name flora and fauna by genus and species. Even astronomers have their own planetary nomenclature. Standard naming conventions do just that—they standardize how we talk about things. They’re also a convenient way to condense large amounts of information into a short form. Hence, they function like acronyms. We needn’t sound out “self-contained underwater breathing apparatus” when we can simply utter S.C.U.B.A. right?
In building automation, the same need for standards and compression applies, and BACnet gives us a convenient way to describe the functionality of devices using something called BIBBs.
What are BIBBs?
Definition: BIBBs stands for “BACnet Interoperability Building Blocks” and is a standard naming convention for representing specific device capabilities using simple acronyms. That is, it creates simple categories to describe how one device works with another.
Without short-form descriptions, listing all the capabilities and services that a device offers would turn functional descriptions into a messy scrawl of technical jargon. By condensing these functions into acronyms, BIBBs makes it easier for FMs, system integrators, and building engineers to talk about the same things. BIBBs help buyers get the minimum number of services for the job without over-engineering and spending for extraneous functionality.
BIBB Categories
The BIBB naming system starts with five broad categories that list interoperability functions. These are high level functions that host specific capabilities within them. Categories include:
Data Sharing (DS)
The data sharing function describes how devices exchange data. Data sharing is essential for reading and writing data from one device to another. For example. If you wanted to regularly check the water temp of your boiler to monitor its performance, you would need the DS functionality.
Alarm & Event Management (AE)
The alarm and event management functionality is for detecting and notifying alarms and events. For example, if your boiler temps exceeded a specified setpoint, the AE function would allow you to receive an alert.
Scheduling (SCHED)
The scheduling functionality is for scheduling values based on date, time, and calendar. For example, if you wanted to schedule your boiler to provide after-hours heating for tenants.
Trending (T)
The trending functionality is for trend logging and historical data support. For example, if you wanted to store your boiler’s temp data to create a history for your engineer.
Device Management/Network Management (DM/NM)
The DM/NM is for setting up device and network management. It allows devices to discover each other, to synchronize clocks, and to reset a device to factory settings (reinitialize). For example, if you wanted to discover a newly installed boiler temp sensor.
Specific Capabilities
Specific capabilities, or sometimes called services, are distinct functions that exist within a BIBBs category. Capabilities also have acronyms. For example, the Read Property (RP) service is under the data sharing (DS) category. The service must exist for data sharing to occur. That is, a device (e.g., controller) must be able to read data, while another device (e.g., thermostat) must be able to send it. Many devices have both capabilities. Here are some examples of services for different BIBBs categories:
Data Sharing (DS)
Read Property Multiple (RPM)
Write Property (WP)
Change of Value (COV)
Alarm & Event Management (AE)
Notification (N)
Alarm Summary (ASUM)
View Notifications (VN)
Device and Network Management
Dynamic Device Binding (DDB)
Text Message (TM)
Reinitialize Device (RD)
Find a more extensive list of device capabilities here.
Clients and Servers
BIBBs also distinguishes between clients and servers, assigning and A and B category to each respectively. Client devices (A) can initiate or call for data or service from a device that can respond to that request (B). An example of this would be a controller (A) requesting temp data from a thermostat (B), which responds with the requested data. You can remember this order by recalling that the letter “A” comes before “B” in the alphabet, just as a request must precede a response.
Putting It All Together
Now that we have all three parts of BIBBs, let’s look at a full interoperability description. The BIBBs naming syntax places the category first, specific capability second, and server/client designation third. Each acronym is separated by a dash. Consider a BACnet controller that has data sharing (DS), a read property service (RP), and client capability (A). It would be designated as DS-RP-A. Can you guess what functionality a thermostat would require to send temp data back to the controller? If you answered DS-RP-B, you’re correct!
Conclusion
As we’ve seen, BIBBs are the “building blocks” of the standardized system of naming devices and their interoperability functions. Devices can have many different functions, so there’s also a need to group them. For example, controllers, sensors, and actuators must all have a minimum number of specific functions to work. These groups of functions are called BACnet device profiles. Like BIBBs acronyms, profiles give us a shorthand way of quickly designating and describing a device. Read BACnet Basics: What are Device Profiles? to learn more or visit The BACnet Institute for free training.
If you have commercial tenants, they’ve likely scheduled heating or air conditioning outside of your building’s usual business hours. Managers and owners commonly refer to these extra hours as overtime HVAC, after-hours HVAC, after-hours air conditioning or some variation. These overtime utility services give companies the flexibility to host special events, hold annual meetings, or simply extend their workday hours.
Tenant overtime HVAC systems are online platforms that automate the scheduling and billing of those after-hours HVAC requests. These systems streamline much of the traditional steps of a tenant overtime program, including scheduling and billing. Consequently, they save property managers and their staff time and resources. In addition, overtime HVAC systems can increase tenant satisfaction and conserve energy. Modern systems operate on a software-as-a-service model (SaaS) where property managers pay a monthly subscription for the service, but one-time fees are also available.
Modern tenant overtime systems let property owners set normal business hours (blue), while tenants can schedule HVAC service outside these times (green).
After-Hours vs Standard Occupancy Times
Standard business hours or “occupancy times” for buildings vary by region, but most fall somewhere around 8 a.m. and 6 p.m. Monday to Friday. Owners and managers define their business hours within commercial leases and agree to provide heating, cooling and lighting for tenants to operate their businesses. However, many leases also allow for “after-hours” or “overtime” HVAC requests. These are defined as any times outside normal business hours, and they’re usually billed separately from normal OPEX.
To recoup the costs for providing after-hours HVAC services, managers and owners usually charge tenants a fixed hourly rate (ex: $35/hour). The rate usually includes an estimated energy cost for providing service for one hour, plus an admin fee to cover staff time.
Overtime HVAC Scheduling
Because after-hours HVAC requests are outside standard operating hours, tenants must schedule them with the manager or building engineer. Typical steps in a standard overtime program usually involve the following:
The tenant makes an overtime HVAC request via email or text.
The manager records the request in a spreadsheet and notifies the building engineer.
The engineer programs the request into the building’s BMS.
The manager invoices the tenant at the end of the month for the overtime charges.
Managing this process requires time and resources, which is why most leases require a 24 or 48-hour notice per request. The window gives staff enough time to schedule the request, but places limits on how spontaneous tenants can be with last minute schedules.
Tenant overtime HVAC systems eliminate or simplify many of the above steps. Instead of an email or phone call, tenants use an online portal and web browser to submit overtime requests. Since overtime systems link to your building’s BMS, they bypass the need for manual reporting and system programming—no managers or engineers needed. This keeps notice times shorter, and tenants benefit from the increased flexibility.
Overtime HVAC systems also come with mobile apps. Tenants use these programs to schedule after-hours services from their smartphones or tablets. The freedom of mobile scheduling tends to increase overall tenant satisfaction with a property’s after-hours program.
Common connection flow of a cloud-based tenant overtime HVAC system to a commercial property.
Overtime HVAC Billing
Billing for standard hour energy is straightforward. Tenants pay pro rata based on the building’s total utility costs for the month. The strategy essentially splits the energy costs among all tenants equally, and everyone pays their share at the end of the month. However, overtime HVAC charges add complexity to monthly billing. It would be unfair to split overtime energy costs among all tenants, since only specific ones use it, so landlords invoice tenants only for the kWh they use.
However, individual invoicing takes more time. Spreadsheets need updated. Invoices generated. Emails sent to tenants. Plus, manual entry increases the risk of mistakes, leaving tenants paying too much or too little. Tenant overtime HVAC systems automate most of these monthly billing tasks, eliminating human error and tenant disputes around charges.
Overtime systems record BMS operation histories in their servers. So, times, days, and durations of overtime services are automatically generated for any timeframe. Most platforms also automate monthly billing to tenants. Since the system tracks individual usage, it can email automated invoices to tenants, taking the paperwork off property managers.
Energy Conservation
On average, 30% of the energy used in commercial buildings is wasted. After-hour scheduling changes and cancellations happen. It’s not uncommon for tenants to walk into unheated boardrooms or for entire building floors to sit unoccupied while chillers run at full power. Such scheduling mistakes waste energy and money. The bulk of these issues stem from recording mistakes and human error. A work order was overlooked, an email went to spam. Someone was out sick. These are common, often unavoidable, situations.
Because they’re automated systems, tenant overtime platforms eliminate human error. Schedule changes and cancellations are caught more frequently and wasted energy reduced.
Overtime HVAC systems can also positively affect tenant attitudes toward energy waste. Because tenants pay for the overtime kilowatts they use, they’re more cautious about waste. In contrast, attitudes towards energy use during standard business hours can be markedly different. Those tenants often have a “use it or lose it” approach, feeling they should condition the air in their spaces, whether they’re empty or occupied. The attitude is “We’re paying for it anyway.”
Tenant Satisfaction
Aside from time and money savings, the biggest selling point of overtime HVAC systems is their value to tenant businesses. With HVAC scheduling, office managers can operate hybrid workspaces more effectively. Government agencies can use after-hours reports to report on sustainability goals. Software developers could employ overtime usage to evaluate team productivity. Marketing agencies could add overtime energy costs as a billable line item for clients. The value of tenant overtime HVAC systems is yet to be fully realized, but the heart of it lies in their ability to empower tenants to run better businesses and organisations.
