Fire Alarm System Design

The overall design objective of a fire detection and alarm system is to detect fire as early as possible. However it also needs to resist environmental influences and other potential sources of false activation. Once a fire is detected, the actions taken by the system must be consistent with the building’s overall design, its evacuation plan, and the integrated fire protection strategy for the premises.

For all but the simplest of buildings and risks, fire alarm system design is a specialized activity. It should be performed by a competent engineer with experience in fire protection, and who is trade-certified to act in this capacity. The overall fire safety design for a building is usually done in conjunction with the Architect’s design team during the design phase of the building project, and detailed in a “fire report.” The detailed component selection and final equipment layout and configuration/programming for a fire alarm system is typically performed by a certified fire alarm contractor, in accordance with the requirements of the fire report, during the building’s construction and fit-out phases. 

The design of building fire alarm systems in New Zealand is almost always required to be in compliance with New Zealand Standard NZS 4512:2010 Fire Detection and Alarm Systems in Buildings. This national standard covers design, installation, extension, modification, commissioning, testing and maintenance. It also sets down minimum levels of trade qualification for those working on fire alarm systems, and requires independent third-party inspection/audit of all new systems, and all significant system alterations and extensions. 

NZS 4512:2010 is the only “Acceptable Solution” for fire detection and alarm systems under the NZ Building Code Compliance Documents. Confirmation by an independent third party inspector of full compliance with this standard generally ensures acceptance under the Building Code regime by the Building Consent Authority (local council). Alternative “Engineered Solutions” are permitted, however these require a building-specific Professional Fire Engineer’s design which must undergo a series of professional reviews in order to be accepted by the Building Consent Authority. In general, such engineered solutions are invoked to allow trade-offs between one compliance parameter and another, or to accommodate unusual building features or occupancy. 

Extensions of existing systems should be performed with the same attention to design, but must also consider the capabilith of the originally-installed fire alarm system. The Standard has strict rules about the intermixing of system components, so the equipment used for extensions will generally need to have listed compatibility with the existing equipment. NZS 4512:2010 also has requirements for independent third party inspection of significant system extensions (adding zones or changing the control panel).