What B-ALSC Is
A BACnet device profile is a standardized capability level: a checklist of things a device must be able to do before it can wear the label. B-ALSC (BACnet Advanced Life Safety Controller) is defined in Annex L of ANSI/ASHRAE 135-2024 (clause L.5.1) as the fuller life-safety controller: like the B-LSC it generates life-safety notifications and processes silence and reset, and it adds internal scheduling and an event log.
The checklist items are BACnet Interoperability Building Blocks (BIBBs), each a named unit of capability. B-ALSC is a B-role device that answers requests and originates life-safety alarms. A device documents its claim in its PICS (Protocol Implementation Conformance Statement); to verify a claim, ask for the PICS and check the profile line.
Where It’s Used
B-ALSC fits a more capable life-safety controller that also schedules actions and keeps its own event history.
- Integrated fire and safety controllers. A device that annunciates life-safety events and runs local time-of-day logic.
- Controllers with an event log. A life-safety controller that retains its own record of events for later retrieval, not just live notification.
- Supervised safety plant. A controller managing life-safety points where local scheduling and history matter alongside alarming.
Required Services
The table below is the exhaustive service set required by the B-ALSC BIBBs. Initiates means the device sends the request or notification; Executes means the device receives and acts on it (responding, for confirmed services). BIBB codes encode the same split: a -A BIBB is the initiating side, a -B BIBB the executing side. A - means the profile does not require that direction; a device may still support it.
| Capability area | Service | Required by BIBB | Initiates | Executes |
|---|---|---|---|---|
| Data sharing | ReadProperty | DS-RP-B | - | Yes |
| Data sharing | ReadPropertyMultiple | DS-RPM-B | - | Yes |
| Data sharing | WriteProperty | DS-WP-B | - | Yes |
| Data sharing | WritePropertyMultiple | DS-WPM-B | - | Yes |
| Data sharing | SubscribeCOV | DS-COV-B | - | Yes |
| Data sharing | ConfirmedCOVNotification | DS-COV-B | Yes | - |
| Data sharing | UnconfirmedCOVNotification | DS-COV-B | Yes | - |
| Alarm and event management | LifeSafetyOperation | AE-LS-B | - | Yes |
| Alarm and event management | ConfirmedEventNotification | AE-LS-B | Yes | - |
| Alarm and event management | UnconfirmedEventNotification | AE-LS-B | Yes | - |
| Alarm and event management | AcknowledgeAlarm | AE-ACK-B | - | Yes |
| Alarm and event management | GetEventInformation | AE-INFO-B | - | Yes |
| Alarm and event management | ReadRange (event log access) | AE-EL-I-B | - | Yes |
| Device and network management | Who-Is | DM-DDB-A, DM-DDB-B | Yes | Yes |
| Device and network management | I-Am | DM-DDB-A, DM-DDB-B | Yes | Yes |
| Device and network management | Who-Has | DM-DOB-B | - | Yes |
| Device and network management | I-Have | DM-DOB-B | Yes | - |
| Device and network management | DeviceCommunicationControl | DM-DCC-B | - | Yes |
| Device and network management | TimeSynchronization ¹ | DM-TS-B | - | Yes |
| Device and network management | UTCTimeSynchronization ¹ | DM-UTC-B | - | Yes |
| Device and network management | ReinitializeDevice | DM-RD-B | - | Yes |
Several requirements are hosted objects. AE-LS-B means the device hosts Life Safety Point and Life Safety Zone objects; AE-EL-I-B means it hosts at least one Event Log object (read back with ReadRange); and SCHED-I-B means it hosts Schedule and Calendar objects that write its local objects, which adds no outbound service and so is not a row above.
¹ The profile requires one of the two time-synchronization services, not both. (Protocol_Revision is a readable property of the device’s Device object.)
Related Profiles
| Profile | How it differs from B-ALSC |
|---|---|
| B-LSC | Life Safety Controller: a step down. No internal scheduling, no event log |
| B-BC | Building Controller: the general controller, without the life-safety event model |
| B-ALSWS | Advanced Life Safety Workstation: the operator-side profile that displays and commands these devices |
What Chipkin Provides
The CAS BACnet Stack implements the BIBB set the B-ALSC profile requires, including the life-safety event model, the internal schedule engine, and the event log. Talk to us about building or integrating a B-ALSC device on the stack.