Life Safety Zone

A Life Safety Zone object groups Life Safety Point objects and other zones into one area, such as a floor or a fire compartment. It reports one combined life-safety state for the area. A safety panel exposes zones so an operator can see and silence a whole area at once.

Typical uses

• Show the alarm state of a whole floor
• Silence all horns in a fire compartment
• Group smoke detectors by area
• Report a zone in test mode

Key properties

Property	What it holds
Present_Value	The zone’s life-safety state, such as quiet, pre-alarm or alarm. It may stay latched until reset.
Zone_Members	The points and zones in this zone, as object references.
Mode	The operating mode of the zone. Accepted_Modes lists the modes it allows.
Silenced	Whether the zone’s signals are silenced.
Operation_Expected	The next operation the zone expects, such as reset or silence.

How it behaves

The zone is not commandable; clients act on it through the LifeSafetyOperation service and by writing Mode. Where it reports events itself, the standard pairs it with the CHANGE_OF_LIFE_SAFETY algorithm, which uses the alarm value lists, the Mode and Operation_Expected. A fault algorithm can set Reliability from Fault_Values.

With the CAS BACnet Stack

Enable it with the STACK_OPTION_OBJECT_TYPE_LIFE_SAFETY_ZONE build option and add each object with BACnetStack_AddObject. Serve Present_Value with the callback you register with BACnetStack_RegisterCallbackGetPropertyEnumerated and the BACnetStack_RegisterCallbackSetPropertyEnumerated callback, and Object_Name with the BACnetStack_RegisterCallbackGetPropertyCharacterString callback. Handle silence and reset requests with BACnetStack_RegisterCallbackLifeSafetyOperation. Arm alarms with BACnetStack_SetAlarmsAndEventsForObjectEnabled, then BACnetStack_SetIntrinsicChangeOfLifeSafetyAlgorithm, and add BACnetStack_SetFaultLifeSafetyAlgorithm for fault values.

Related object types

Life Safety Point, Notification Class, Structured View

Properties

The properties ASHRAE 135-2024 clause 12.16 defines for this object type.

How to read the table:

• Conformance is what the standard asks of every object of this type: R is required, W is required and writable by a client, O is optional. A digit after the letter marks a condition in the standard that decides when the property is present or writable, such as support for intrinsic reporting.
• Present by default: yes means the stack presents the property as soon as you add the object; no means it is optional and you turn it on with BACnetStack_SetPropertyEnabled. This is the stack’s starting setup, so it can differ from the conformance code.
• Writable is whether a client can write the property by default. Change it with BACnetStack_SetPropertyWritable.
• not in profile means the stack does not offer this property for this object type.
• Value when your callback does not answer: “Held by the stack” means the stack stores and serves the value itself and does not ask your callbacks. Otherwise it is the value the stack answers when your callback declines or is not registered.

Property	Datatype	Conformance	Present by default	Writable	Value when your callback does not answer
Object_Identifier	BACnetObjectIdentifier	R	yes	no	Held by the stack.
Object_Name	CharacterString	R	yes	no	"Object <type>,<instance>", such as "Object 0,1" for Analog Input 1.
Object_Type	BACnetObjectType	R	yes	no	Held by the stack.
Present_Value	BACnetLifeSafetyState	R	yes	no	No default: value-not-initialized.
Tracking_Value	BACnetLifeSafetyState	R1	yes	no (yes while Out_Of_Service is true)	0
Description	CharacterString	O	no	no	""
Device_Type	CharacterString	O	no	no	""
Status_Flags	BACnetStatusFlags	R	yes	no	Built by the stack from your callbacks.
Event_State	BACnetEventState	R	yes	no	0
Reliability	BACnetReliability	R1	yes	no (yes while Out_Of_Service is true)	0
Out_Of_Service	Boolean	R	yes	no	false
Mode	BACnetLifeSafetyMode	W	yes	yes	0
Accepted_Modes	BACnetLIST of BACnetLifeSafetyMode	R	yes	no	0
Time_Delay	Unsigned	O2,4	no	no	0
Notification_Class	Unsigned	O2,4	no	no	0
Life_Safety_Alarm_Values	BACnetLIST of BACnetLifeSafetyState	O2,4	no	no	0
Alarm_Values	BACnetLIST of BACnetLifeSafetyState	O2,4	no	no	0
Fault_Values	BACnetLIST of BACnetLifeSafetyState	O	no	no	0
Event_Enable	BACnetEventTransitionBits	O2,4	no	no	An empty bit string.
Acked_Transitions	BACnetEventTransitionBits	O2,4	no	no	An empty bit string.
Notify_Type	BACnetNotifyType	O2,4	no	no	0
Event_Time_Stamps	BACnetARRAY[3] of BACnetTimeStamp	O2,4	no	no	No default: the read fails.
Event_Message_Texts	BACnetARRAY[3] of CharacterString	O4	no	no	""
Event_Message_Texts_Config	BACnetARRAY[3] of CharacterString	O4	no	no	""
Event_Detection_Enable	Boolean	O2,4	no	no	false
Event_Algorithm_Inhibit_Ref	BACnetObjectPropertyReference	O4	no	no	No default: the read fails.
Event_Algorithm_Inhibit	Boolean	O4,5	no	no	false
Time_Delay_Normal	Unsigned	O4	no	no	0
Reliability_Evaluation_Inhibit	Boolean	O	no	no	false
Silenced	BACnetSilencedState	R	yes	no	0
Operation_Expected	BACnetLifeSafetyOperation	R	yes	no	0
Maintenance_Required	Boolean	O	no	no	false
Zone_Members	BACnetLIST of BACnetDeviceObjectReference	R	yes	no	No default: the read fails.
Member_Of	BACnetLIST of BACnetDeviceObjectReference	O	no	no	No default: the read fails.
Floor_Number	Unsigned8	O	no	no	0
Property_List	BACnetARRAY[N] of BACnetPropertyIdentifier	R	yes	no	Held by the stack.
Value_Source	BACnetValueSource	O6,7,8	no	no	No default: the read fails.
Audit_Level	BACnetAuditLevel	O9	not in profile	not in profile	No default: the read fails.
Auditable_Operations	BACnetAuditOperationFlags	O9	not in profile	not in profile	No default: the read fails.
Tags	BACnetARRAY[N] of BACnetNameValue	O	no	no	No default: the read fails.
Profile_Location	CharacterString	O	no	no	""
Profile_Name	CharacterString	O	no	no	""