ISO 7240-27:2025

Overview

ISO 7240-27:2025 (Third edition) defines requirements, test methods and performance criteria for point-type multi-sensor fire detectors that combine a smoke sensor with a carbon monoxide (CO) sensor and, optionally, one or more heat sensors. Intended for use in building fire detection and alarm systems (see ISO 7240-1), the standard covers design, performance verification and laboratory testing for these combined smoke/CO/(heat) detectors. It is not intended for specialty detectors developed for specific risks, though it can be used as guidance for other detector principles.

Keywords: ISO 7240-27, fire detection, multi-sensor detectors, smoke and CO detectors, point-type fire detectors, fire alarm systems, carbon monoxide sensor, heat sensor, testing methods.

Key Topics and Requirements

• Scope and applicability: Defines which multi-sensor point detectors are covered and exclusions for detectors with special characteristics.
• General requirements: Conformance, individual alarm indication, monitoring of detachable detectors, manufacturer and on-site adjustment of response behaviour, and protection against ingress of foreign bodies.
• Sensor response and thresholds: Methods for measuring smoke response (scattered/transmitted light), CO response and optional heat response; requirements for rate-sensitive CO response and smoke response to slow-developing fires.
• Software-controlled detectors: Requirements for software design, storage of programs/data and related verification.
• Comprehensive test methods: Laboratory tests for repeatability, reproducibility and directional dependence of smoke/CO/heat responses; long-term stability of CO response; saturation behaviour; exposure to environmental chemical agents; variation in supply parameters; air movement and dazzling effects; dry heat operational testing.
• Test reporting and tolerances: Test schedules, atmospheric and mounting conditions, tolerances and provisions for test records and conformity assessment.

Practical Applications - Who Uses This Standard

• Manufacturers: For design validation, type testing and to demonstrate compliance for product certification and market access.
• Test laboratories: To perform standardized type and performance testing of multi-sensor point detectors.
• System designers and specifiers: To select appropriate detectors for building fire detection systems and to align products with ISO requirements.
• Authorities having jurisdiction / certification bodies: To assess conformity and approve detectors for use in buildings.
• Facility managers and installers: To understand detector capabilities, limitations and expected on-site adjustment/commissioning practices.

Practical benefits include improved detection performance for a range of fire scenarios (smoldering to flaming), reduced false alarms through multi-sensor logic, and consistent, verifiable test evidence for procurement and compliance.

Related Standards

• ISO 7240-1 - General requirements for system aspects of fire detection and alarm systems (referenced for system-level integration).
• Other parts of ISO 7240 series - for detector types, alarm transmission, and installation practices.

For product development, procurement or certification work involving combined smoke/CO/(heat) point detectors, ISO 7240-27:2025 is the authoritative resource for testing and performance criteria.