Fire Index — Fire Breakdown Structure (FBS)
The Fire Breakdown Structure (FBS) is the specialized hierarchical taxonomy defined by BS 8644-1:2022 and the Building Safety Act 2022 for managing fire safety assets within built assets. Unlike standard spatial containment (LBS) or MEP system networks (SBS), the FBS organizes elements strictly by their fire compartmentation boundaries, smoke barrier integrity, and statutory protection roles.
The 4-Tier FBS Hierarchy
| Tier Level | Designation | Description | Example Metadata |
|---|---|---|---|
| Tier 0 | Facility | Root asset representing the overall building or asset complex. | Building_01, Tower Block A |
| Tier 1 | Storey | Vertical spatial level containing horizontal fire separation floors. | Level 00 - Basement, Level 01 - Ground, Level 02 |
| Tier 2 | Fire Compartment | Enclosed volume bounded by fire-resisting construction designed to prevent fire spread. | C-01-CORRIDOR, FZ-PLANT-01, PROTECTED_ESCAPE_STAIR_A |
| Tier 3 | Fire Component | Physical fire protection asset installed within or bounding the compartment. | Fire Doorsets, Compartment Partitions, Fire Dampers, Penetration Seals |
Spatial FBS vs Standard LBS (Location Breakdown Structure)
While standard LBS groups elements by architectural spaces or tenant rooms (e.g. Room 101 Office, Room 102 WC), the Fire Breakdown Structure (FBS) aggregates spaces into statutory fire separation zones:
- Compartment Boundary Designation:
- A single compartment wall may border five different architectural rooms, but in the FBS, it is recognized as a single continuous fire-separating barrier bounding
C-01-CORRIDOR.
- A single compartment wall may border five different architectural rooms, but in the FBS, it is recognized as a single continuous fire-separating barrier bounding
- Protected Escape Route Alignment:
- Stair enclosures and escape corridors are designated as protected routes requiring verified fire resistance, smoke control (
Sa/Sm), and self-closing door devices.
- Stair enclosures and escape corridors are designated as protected routes requiring verified fire resistance, smoke control (
- Penetration Seal Association:
- Cable trays, pipes, and ductwork passing through compartment walls are associated with the compartment boundary they penetrate, ensuring firestopping integrity is recorded.
Fire Component Classification in the FBS
Elements classified under Tier 3 fall into standardized fire safety families:
- Fire Doorsets & Glazing:
- Tested timber, steel, or composite assemblies with verified ratings (
FD30,FD30S,FD60,FD60S,FD120). - Required attributes: Closer mechanism, intumescent seals, acoustic rating, and test certificate reference.
- Tested timber, steel, or composite assemblies with verified ratings (
- Compartment Walls, Floors & Partitions:
- Masonry, concrete, or drywall partition systems providing certified fire resistance duration.
- Required attributes: Integrity (E), Insulation (I), and Loadbearing capacity (R).
- Fire & Smoke Dampers:
- Mechanical and motorized dampers installed in HVAC duct penetrations.
- Required attributes: Actuation mechanism, release temperature, and maintenance inspection schedule.
- Fire Stopping & Penetration Seals:
- Collars, wraps, batts, and mastic seals maintaining compartment integrity at service penetrations.
Identifying Compartment Mismatches
The FBS engine automatically validates the spatial relationship between physical elements and compartment boundaries:
- Compartment Boundary Verification: If a door is tagged with rating
FD60Sbut is located on an internal partition that is not designated as a compartment boundary, the system records an advisory notice. - Uncompartmented Fire Assets: Components requiring fire resistance that do not fall within any designated fire compartment trigger an anomaly in the Fire Quality & Issues Register.