Cause & Effect Matrix Plans for Fire Detection and Alarm Systems
A Cause and Effect (C&E) matrix is the logical control document that defines exactly how every input device on a fire alarm system — detectors, call points, sprinkler switches and interfaces — drives every output action, from zone alarms and sounder activation to door release, plant shutdown and fire brigade signalling. Norfolk Fire Group produces clear, fully documented C&E matrices for addressable and complex fire detection systems across Norfolk.
Our cause and effect plans are produced in accordance with BS 5839-1:2025 and are essential for the correct configuration, commissioning, verification and ongoing maintenance of any addressable or networked fire alarm system. They provide the definitive reference for installers, commissioners, maintainers and enforcing authorities, ensuring the system behaves exactly as intended on every activation.
Serving Norwich · Dereham · Kings Lynn · Swaffham · Great Yarmouth · Thetford · Wymondham · North Walsham · Downham Market · Attleborough · Fakenham · Sheringham · Cromer · Holt · Aylsham · Diss · Loddon · Bungay · All of Norfolk
What Is a Cause & Effect Matrix?
A cause and effect matrix is a structured document — typically presented as a grid or table, and supported by a cause and effect logic diagram — that maps every possible input (the “cause”) on a fire alarm system to the precise set of outputs (the “effect”) that should result. It is the single source of truth that tells the panel, the commissioner and the maintainer what the system is supposed to do when any given device operates.
On a simple conventional system the logic may be straightforward, but on an addressable or networked system — with phased evacuation, zoned alarms, smoke control interfaces, door release, lift recall, plant shutdown and fire brigade signalling — the number of input-to-output combinations can run into hundreds. A properly constructed matrix makes every one of those relationships explicit, testable and defensible.
BS 5839-1:2025 requires that the cause and effect logic for any system with more than one zone, or with any non-standard operation, be documented and agreed with the relevant enforcing authority before installation is completed. The matrix is also the document against which the system is commissioned and against which future modifications are validated.
A C&E matrix typically defines:
- Each input device and the zone/area it represents
- Which sounders, beacons and alarm zones activate on each input
- Phased or staged evacuation sequences and timing
- Outputs to fire doors, hold-open devices and access control
- Interfaces to smoke control, ventilation and plant shutdown
- Lift recall, sprinkler flow switches and suppression interfaces
- Fire brigade signalling and remote monitoring outputs
- Manual call point and fault signal behaviour
Standards & Frameworks We Work To
BS 5839-1:2025
The principal British Standard for fire detection and fire alarm systems in non-domestic premises. Requires that the cause and effect logic of any system with more than one zone, or with any non-standard operation, be documented and agreed with the enforcing authority.
BS EN 54 Series
European product standards for fire detection and fire alarm system components — control and indicating equipment, detectors, sounders and input/output devices — referenced for the configuration and behaviour of the devices in the matrix.
BAFE SP203-1
The BAFE scheme for the design, installation, commissioning and maintenance of fire detection and fire alarm systems. Our C&E matrices form part of the documented evidence required for BAFE SP203-1 third-party certification.
BS 9999:2017
Code of practice for fire safety in the design, management and use of buildings — referenced where the matrix supports phased evacuation, simultaneous evacuation or staff alarm strategies in larger or more complex premises.
BS 7273-6:2022
Code of practice for the operation of fire detection and alarm systems — including the interface to other fire protection systems and equipment. Governs how outputs from the panel are actioned by connected building systems.
RRFSO 2005
The Regulatory Reform (Fire Safety) Order 2005 — the legislative framework requiring that fire alarm systems be properly designed, commissioned and maintained, with the C&E matrix forming part of the responsible person’s fire safety records.
When Is a Cause & Effect Matrix Required?
BS 5839-1:2025 requires a documented cause and effect matrix for any fire alarm system with more than one zone, and for any system where the operation of the alarm is not simply “all sounders on, building evacuate”. In practice, this means almost every addressable system and most multi-zone conventional systems need one.
The matrix is also the document that Building Control, the Fire and Rescue Service and your insurer will ask to see as evidence that the system has been properly designed and will behave correctly in a fire. Without it, commissioning cannot be fully verified and future modifications cannot be validated against the original design intent.
Our Cause & Effect Matrix Services
C&E Matrix Development
Full cause and effect matrices produced from the system design, agreed with the responsible person and presented for approval to the enforcing authority.
Logic Diagrams
Clear cause and effect logic diagrams alongside the tabular matrix, giving installers and commissioners an at-a-glance view of every input-to-output relationship.
Commissioning Support
Verification of the installed system against the agreed matrix, confirming every cause produces the correct effect before the system is signed off.
Modification & Update
Updating the matrix when the building layout, occupancy, devices or interfaces change, so the documented logic always reflects the system as installed.
Gap Analysis
Review of existing matrices against the as-built system to identify missing, incorrect or undocumented logic and provide a prioritised remediation plan.
Stakeholder Liaison
Coordination with designers, installers, Building Control and the Fire and Rescue Service to secure agreement on the cause and effect logic before installation.