Physical Address
304 North Cardinal St.
Dorchester Center, MA 02124
BS ISO 7240 — Fire Detection and Alarm Systems: General Requirements, Detectors and Control Equipment
Fire detection and alarm systems (BS ISO 7240 series)
🔥 BS ISO 7240 is the British Standard implementing the ISO 7240 series, the core international standard system for fire detection and alarm systems. The series specifies general requirements and terminology, performance requirements and test methods for various fire detectors, and general requirements for fire alarm control equipment, providing a unified basis for the design, selection, installation and acceptance of automatic fire alarm systems in buildings.
💡 The automatic fire alarm system is the “sentry” of building fire protection. Whether a detector alarms reliably in the early stage of a fire and whether the control equipment processes signals correctly determine the success of evacuation and initial fire-fighting. ISO 7240 sets quantitative thresholds for detector sensitivity, response time and false-alarm immunity.
1. Series Overview and Scope 📌
The BS ISO 7240 series is split by function, covering overall system requirements and requirements for each component:
- Part 1 (general requirements and definitions): system general requirements, terminology and definitions, and general requirements for system components (detectors, control equipment, alarm devices).
- Part 15 (point-type smoke and heat detectors): performance requirements and test methods for point detectors using smoke and heat sensors (point-type combined smoke/heat detectors).
- Part 28 (fire alarm control equipment): general requirements and tests for fire alarm and fire control equipment (control panel).
The series also includes parts for other detector types and components, forming a complete fire alarm system standard.
2. Series Structure and Key Points 📋
The series comprises four documents; the core readable parts are ISO 7240-1, 15 and 28, while Part 8 is a scanned version summarised here from public domain knowledge.
| Standard | Title | Main Content | Status |
|---|---|---|---|
| BS ISO 7240-1:2014 | Fire detection and alarm systems — General and definitions | System general requirements, terminology and component general requirements | Readable |
| BS ISO 7240-15:2014 | Point-type detectors using smoke and heat sensors | Performance and tests for combined smoke/heat point detectors | Readable |
| BS ISO 7240-28:2014 | Fire alarm control equipment | Control-panel general requirements and test methods | Readable |
| BS ISO 7240-8:2014 | (Related detector, scanned) | Summarised from public domain knowledge | Scan |
⚠️ Part 8 of this series is a scanned version; the related technical content here is written from public domain knowledge. Consult the official BSI publication for clause details.
3. Key Technical Requirements 🔬
3.1 General requirements and definitions (Part 1)
ISO 7240-1 specifies system general requirements and definitions: system structure, terminology, general requirements for components (marking, protection, power supply, function), and environmental adaptability requirements, as the common basis for each part.
3.2 Point-type smoke and heat detectors (Part 15)
ISO 7240-15 specifies performance requirements and test methods for point detectors using smoke and heat sensors (combined type): response threshold (sensitivity) tests, response time, and environmental and reliability tests (temperature, humidity, vibration, EMC), ensuring reliable early response and false-alarm immunity.
3.3 Fire alarm control equipment (Part 28)
ISO 7240-28 specifies general requirements and tests for fire alarm control equipment: signal processing, alarm and fault indication, power-source switching, self-test function, and environmental and EMC tests, so the control equipment works correctly under fire and fault conditions.
🚨 Detector false alarms and missed detections are major problems in fire alarm systems. Selection, installation position and maintenance directly affect performance: avoid installing in areas with high air flow, steam or dust, and maintain, clean and functionally test regularly to prevent failure or false alarm.
4. Engineering Practice and Application 🛠️
- 🔍 Design selection: choose smoke, heat or combined detectors by fire type (smoke/temperature rise) and interior finish, and lay out by protected area and mounting height.
- 🔧 Installation control: install detectors away from air-flow disturbance, steam and dust sources; install control equipment where easy to operate and observe.
- 📊 Maintenance and testing: perform functional tests, cleaning and sensitivity checks periodically and keep maintenance records to keep the system in good condition.
- 📋 Interconnection: alarm control equipment should interconnect with fire pumps, smoke exhaust, public-address and other facilities, and undergo joint commissioning and acceptance per code.
5. Frequently Asked Questions ❓
❓ Q: What is the difference between smoke and heat detectors?
A: A smoke detector responds to smoke in the early fire stage — fast but susceptible to steam/dust interference; a heat detector responds to temperature rise — fewer false alarms but slower. Combined (smoke+heat) detectors balance both with higher reliability.
A: A smoke detector responds to smoke in the early fire stage — fast but susceptible to steam/dust interference; a heat detector responds to temperature rise — fewer false alarms but slower. Combined (smoke+heat) detectors balance both with higher reliability.
❓ Q: What is the difference between point and linear detectors?
A: A point detector monitors smoke/temperature near one point, for ordinary rooms; a linear detector (e.g. beam smoke detector) monitors a path, for high spaces and long corridors.
A: A point detector monitors smoke/temperature near one point, for ordinary rooms; a linear detector (e.g. beam smoke detector) monitors a path, for high spaces and long corridors.
❓ Q: Why do detectors false alarm?
A: Steam, oil mist, dust, air flow and decoration dust can trigger false alarms. Select and position detectors correctly and maintain/clean to reduce non-fire triggering.
A: Steam, oil mist, dust, air flow and decoration dust can trigger false alarms. Select and position detectors correctly and maintain/clean to reduce non-fire triggering.
🔍 Q: What functions should fire alarm control equipment have?
A: At least fire-alarm indication, fault indication, signal processing, automatic main/standby power switching and self-test, and ability to interconnect relevant fire-fighting facilities on fire.
A: At least fire-alarm indication, fault indication, signal processing, automatic main/standby power switching and self-test, and ability to interconnect relevant fire-fighting facilities on fire.