Optical smoke alarm - Revision history

Editor at 12:27, 17 December 2020

2020-12-17T12:27:19Z

← Older revision		Revision as of 12:27, 17 December 2020
Line 38:		Line 38:
	* Fire detection and alarm system.		* Fire detection and alarm system.
	* Fire detector.		* Fire detector.
		+	* Fire fatalities in Scotland.
	* Heat alarm.		* Heat alarm.
	* Ionisation smoke alarm.		* Ionisation smoke alarm.

Designing Buildings at 07:27, 9 December 2020

2020-12-09T07:27:36Z

← Older revision		Revision as of 07:27, 9 December 2020
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	* The role of codes, standards and approvals in delivering fire safety.		* The role of codes, standards and approvals in delivering fire safety.

−	[[Category:~~Products_/_components~~]] [[Category:DCN_Product_Knowledge]]	+	[[Category:DCN_Definition]] [[Category:DCN_Guidance]] [[Category:DCN_Product_Knowledge]] [[Category:Products_/_components]]

Designing Buildings at 07:16, 15 September 2019

2019-09-15T07:16:37Z

← Older revision		Revision as of 07:16, 15 September 2019
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	{\|		{\|
−	~~\|width="100%"~~\| Optical smoke detectors typically use a smoke scatter chamber, which contains an LED source with a collimated lens that produces a beam. A photodiode is located at an angle to the beam. As smoke particles enter the chamber they interrupt the beam and the light is scattered and detected by the photodiode. This results in a voltage that can be used to determine an alarm condition. Optical detectors respond to smouldering fires very quickly, as the larger particles generated cause more scattering. Optical scatter chambers are less sensitive to small particles – and become progressively less sensitive as the smoke particle size approaches the LED wavelength used. Therefore optical smoke detectors are slower at detecting the small smoke particles generated from flaming fires. These detectors are less likely to produce false alarms from cooking fumes and steam than ionisation detectors.	+	\| Optical smoke detectors typically use a smoke scatter chamber, which contains an LED source with a collimated lens that produces a beam. A photodiode is located at an angle to the beam. As smoke particles enter the chamber they interrupt the beam and the light is scattered and detected by the photodiode. This results in a voltage that can be used to determine an alarm condition. Optical detectors respond to smouldering fires very quickly, as the larger particles generated cause more scattering. Optical scatter chambers are less sensitive to small particles – and become progressively less sensitive as the smoke particle size approaches the LED wavelength used. Therefore optical smoke detectors are slower at detecting the small smoke particles generated from flaming fires. These detectors are less likely to produce false alarms from cooking fumes and steam than ionisation detectors.
	\|}		\|}

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	* Carbon monoxide detector.		* Carbon monoxide detector.
		+	* Characterising smoke from modern materials and evaluating smoke detectors.
	* Domestic smoke alarms DG525.		* Domestic smoke alarms DG525.
	* Fire detection and alarm system.		* Fire detection and alarm system.
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	* The role of codes, standards and approvals in delivering fire safety.		* The role of codes, standards and approvals in delivering fire safety.

−	[[Category:Products_/_components]]	+	[[Category:Products_/_components]] [[Category:DCN_Product_Knowledge]]

Designing Buildings at 07:05, 15 September 2019

2019-09-15T07:05:09Z

← Older revision		Revision as of 07:05, 15 September 2019
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	Optical smoke alarms should conform to BS EN 14604: 2005 Smoke Alarm Devices.		Optical smoke alarms should conform to BS EN 14604: 2005 Smoke Alarm Devices.
		+
		+	Characterising smoke from modern materials and evaluating smoke detectors was written by Raman Chagger and published by BRE in 2014 states:
		+
		+	{\|
		+	\|width="100%"\| Optical smoke detectors typically use a smoke scatter chamber, which contains an LED source with a collimated lens that produces a beam. A photodiode is located at an angle to the beam. As smoke particles enter the chamber they interrupt the beam and the light is scattered and detected by the photodiode. This results in a voltage that can be used to determine an alarm condition. Optical detectors respond to smouldering fires very quickly, as the larger particles generated cause more scattering. Optical scatter chambers are less sensitive to small particles – and become progressively less sensitive as the smoke particle size approaches the LED wavelength used. Therefore optical smoke detectors are slower at detecting the small smoke particles generated from flaming fires. These detectors are less likely to produce false alarms from cooking fumes and steam than ionisation detectors.
		+	\|}
		+
		+	Ref: [https://files.bregroup.com/research/Test-Fires-Characterisation_2014-November.pdf https://files.bregroup.com/research/Test-Fires-Characterisation_2014-November.pdf]

	= Related articles on Designing Buildings Wiki =		= Related articles on Designing Buildings Wiki =

Designing Buildings at 10:49, 11 August 2019

2019-08-11T10:49:11Z

← Older revision		Revision as of 10:49, 11 August 2019
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	Optical smoke alarms should conform to BS EN 14604: 2005 Smoke Alarm Devices.		Optical smoke alarms should conform to BS EN 14604: 2005 Smoke Alarm Devices.

−	~~= Find out more =~~	+	= Related articles on Designing Buildings Wiki =
−		+
−	=== Related articles on Designing Buildings Wiki ===	+

	* Carbon monoxide detector.		* Carbon monoxide detector.
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	* Multi-sensor alarm.		* Multi-sensor alarm.
	* New requirements for fire detection and alarm network systems IP 12 13.		* New requirements for fire detection and alarm network systems IP 12 13.
		+	* Over £1 billion lost every year due to false alarms.
	* Smoke detector.		* Smoke detector.
	* The causes of false fire alarms in buildings.		* The causes of false fire alarms in buildings.

Designing Buildings at 08:36, 23 December 2017

2017-12-23T08:36:46Z

← Older revision		Revision as of 08:36, 23 December 2017
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	* Carbon monoxide detector.		* Carbon monoxide detector.
		+	* Domestic smoke alarms DG525.
	* Fire detection and alarm system.		* Fire detection and alarm system.
	* Fire detector.		* Fire detector.
−	* Fire.
	* Heat alarm.		* Heat alarm.
−	* Intruder alarm.
	* Ionisation smoke alarm.		* Ionisation smoke alarm.
	* Multi-sensor alarm.		* Multi-sensor alarm.
	* New requirements for fire detection and alarm network systems IP 12 13.		* New requirements for fire detection and alarm network systems IP 12 13.
−	* Smoke damper.
	* Smoke detector.		* Smoke detector.
	* The causes of false fire alarms in buildings.		* The causes of false fire alarms in buildings.

Editor at 18:49, 24 November 2017

2017-11-24T18:49:12Z

← Older revision		Revision as of 18:49, 24 November 2017
Line 36:		Line 36:
	* Multi-sensor alarm.		* Multi-sensor alarm.
	* New requirements for fire detection and alarm network systems IP 12 13.		* New requirements for fire detection and alarm network systems IP 12 13.
		+	* Smoke damper.
	* Smoke detector.		* Smoke detector.
	* The causes of false fire alarms in buildings.		* The causes of false fire alarms in buildings.

Designing Buildings at 09:25, 21 October 2017

2017-10-21T09:25:35Z

← Older revision		Revision as of 09:25, 21 October 2017
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	=== Related articles on Designing Buildings Wiki ===		=== Related articles on Designing Buildings Wiki ===

−	* Building regulations.
	* Carbon monoxide detector.		* Carbon monoxide detector.
−	* Combustion appliance.
−	* Fire and rescue service.
−	* Fire dampers.
	* Fire detection and alarm system.		* Fire detection and alarm system.
	* Fire detector.		* Fire detector.
−	* Fire protection engineering.
−	* Fire safety design.
	* Fire.		* Fire.
	* Heat alarm.		* Heat alarm.
Line 41:		Line 35:
	* Ionisation smoke alarm.		* Ionisation smoke alarm.
	* Multi-sensor alarm.		* Multi-sensor alarm.
−	* ~~Principal habitable room.~~	+	* New requirements for fire detection and alarm network systems IP 12 13.
−	* Scottish building standards.	+
	* Smoke detector.		* Smoke detector.
	* The causes of false fire alarms in buildings.		* The causes of false fire alarms in buildings.

Designing Buildings at 08:27, 4 October 2016

2016-10-04T08:27:56Z

← Older revision		Revision as of 08:27, 4 October 2016
Line 45:		Line 45:
	* Smoke detector.		* Smoke detector.
	* The causes of false fire alarms in buildings.		* The causes of false fire alarms in buildings.
		+	* The role of codes, standards and approvals in delivering fire safety.

	[[Category:Products_/_components]]		[[Category:Products_/_components]]

Designing Buildings at 07:15, 7 August 2016

2016-08-07T07:15:53Z

← Older revision		Revision as of 07:15, 7 August 2016
Line 33:		Line 33:
	* Fire dampers.		* Fire dampers.
	* Fire detection and alarm system.		* Fire detection and alarm system.
		+	* Fire detector.
	* Fire protection engineering.		* Fire protection engineering.
	* Fire safety design.		* Fire safety design.