Aspirating smoke detector

Last updated
A TOP-SENS2 ASD unit made by Wagner (Germany) Top-sens 2 inside.jpg
A TOP-SENS2 ASD unit made by Wagner (Germany)

An aspirating smoke detector (ASD) is a system used in active fire protection, consisting of a central detection unit which draws air through a network of pipes to detect smoke. [1] The sampling chamber is based on a nephelometer that detects the presence of smoke particles suspended in air by detecting the light scattered by them in the chamber. ASDs can typically detect smoke before it is visible to the naked eye.

Contents

In most cases aspirating smoke detectors require a fan unit to draw in a sample of air from the protected area through its network of pipes. [2]

History

In 1970 the Australian Commonwealth Scientific and Industrial Research Organisation (CSIRO) used a nephelometer to carry out research into forest fires. Subsequently, the Australian Postmaster-General's Department engaged the CSIRO to investigate technologies that could prevent service interruption due to fire. After selecting a sample site to carry out research, the CSIRO suggested that the nephelometer should be used as the benchmark for the APO fire tests. This was installed to monitor smoke levels within the return-air ducts of the mechanical ventilation system, utilising a chart-recorder output display. [3]

At the conclusion of several weeks of testing, it was discovered that there no commercially available fire detection technology suitable for preventing damage to telephone equipment. One technology that did show great promise however was the nephelometer itself. [4]

In 1979, Xtralis, then IEI Pty Ltd., produced and sold an air sampling device they called VESDA (Very Early Smoke Detection Apparatus). The company redesigned the detector in 1982 to provide the reliability, features, size and reduced cost for export markets. ASD systems have gained popularity due to their ability to sense smoke long before a catastrophic incident. [5]

Design

ASD design corrects shortcomings of conventional smoke detectors by using a sampling pipe with multiple holes. The air samples are captured and filtered, removing any contaminants or dust to avoid false alarms and then processed by a centralized, highly sensitive laser detection unit. If smoke is detected, the systems alarm is triggered, and signals are then processed through centralized monitoring stations within a few seconds. [6]

Unlike passive smoke detection systems, including spot detectors, ASD systems actively draw smoke to the detector through bore holes within a piping system that runs throughout the protected area. Furthermore, ASD systems incorporate integrity monitoring to ensure an alert is raised at any time the ASD's ability to detect smoke is compromised. This is not the case with passive devices that are generally only electrically monitored with no ability to determine if smoke can actually reach the detection element.

ASD systems incorporate more than one level of alarm. This allows an ASD system to provide very early warning of an event, prompting investigation at the earliest smouldering stage of a fire when it is easily addressed. Other alarm levels may be configured to provide fire alarm inputs to fire systems as well as releasing suppression systems. ASD alarm sensitivities are configurable and can be programmed to levels ranging from thousands of times more sensitive than a conventional detector, to much less sensitive. The detectors work best in non-volatile environments. [7] [8] [9] They can also be used in computer cabinets to alert users to the overheating of computer cables or individual computer components. [10]

Installation and placement

An example of how a simple ASD unit with a single pipe could cover a five-room area ASD 5 room example.png
An example of how a simple ASD unit with a single pipe could cover a five-room area

ASDs are suitable for environments where a highly sensitive rapid smoke detection capability is required. This makes them suitable in clean rooms; areas which contain goods easily damaged by fire, such as tobacco, electronic rooms and highly flammable liquid and gases. Often, normal point detectors will recognise the danger too late, as smoke often does not reach the ceiling quickly enough for a fire to be detected in a timely fashion. [11]

As they can be easily hidden, pipe networks are suitable in environments where point detectors can be considered aesthetically displeasing, such as offices, apartments and hotel rooms. This factor also makes them suitable in locations where point detectors can be easily tampered with, such as in correctional facilities. [12]

Despite their high sensitivity ASDs can be used in dusty or dirty environments as long as correct design, installation and maintenance processes are followed. Most ASD products can accommodate a broad range of environments and applications – from both confined and open spaces to the cleanest or dirtiest environment, including telecomm, control rooms, waste treatment, mining and more. [13]

See also

Related Research Articles

<span class="mw-page-title-main">Nephelometer</span> Instrument for measuring the concentration of suspended particulates

A nephelometer or aerosol photometer is an instrument for measuring the concentration of suspended particulates in a liquid or gas colloid. A nephelometer measures suspended particulates by employing a light beam and a light detector set to one side of the source beam. Particle density is then a function of the light reflected into the detector from the particles. To some extent, how much light reflects for a given density of particles is dependent upon properties of the particles such as their shape, color, and reflectivity. Nephelometers are calibrated to a known particulate, then use environmental factors (k-factors) to compensate lighter or darker colored dusts accordingly. K-factor is determined by the user by running the nephelometer next to an air sampling pump and comparing results. There are a wide variety of research-grade nephelometers on the market as well as open source varieties.

<span class="mw-page-title-main">Smoke detector</span> Device that detects smoke, typically as an indicator of fire

A smoke detector is a device that senses smoke, typically as an indicator of fire. Smoke detectors are usually housed in plastic enclosures, typically shaped like a disk about 150 millimetres (6 in) in diameter and 25 millimetres (1 in) thick, but shape and size vary. Smoke can be detected either optically (photoelectric) or by physical process (ionization). Detectors may use one or both sensing methods. Sensitive alarms can be used to detect and deter smoking in banned areas. Smoke detectors in large commercial and industrial buildings are usually connected to a central fire alarm system.

<span class="mw-page-title-main">Security alarm</span> System that detects unauthorised entry

A security alarm is a system designed to detect intrusions, such as unauthorized entry, into a building or other areas, such as a home or school. Security alarms protect against burglary (theft) or property damage, as well as against intruders. Examples include personal systems, neighborhood security alerts, car alarms, and prisons.

<span class="mw-page-title-main">Fire alarm control panel</span> Controlling component of a fire alarm system

A fire alarm control panel (FACP), fire alarm control unit (FACU), fire indicator panel (FIP), or simply fire alarm panel is the controlling component of a fire alarm system. The panel receives information from devices designed to detect and report fires, monitors their operational integrity, and provides for automatic control of equipment, and transmission of information necessary to prepare the facility for fire based on a predetermined sequence. The panel may also supply electrical energy to operate any associated initiating device, notification appliance, control, transmitter, or relay. There are four basic types of panels: coded panels, conventional panels, addressable panels, and multiplex systems.

A false alarm, also called a nuisance alarm, is the deceptive or erroneous report of an emergency, causing unnecessary panic and/or bringing resources to a place where they are not needed. False alarms may occur with residential burglary alarms, smoke detectors, industrial alarms, and in signal detection theory. False alarms have the potential to divert emergency responders away from legitimate emergencies, which could ultimately lead to loss of life. In some cases, repeated false alarms in a certain area may cause occupants to develop alarm fatigue and to start ignoring most alarms, knowing that each time it will probably be false. Intentionally falsely activating alarms in businesses and schools can lead to serious disciplinary actions, and criminal penalties such as fines and jail time.

<span class="mw-page-title-main">Passive infrared sensor</span> Electronic sensor that measures infrared light

A passive infrared sensor is an electronic sensor that measures infrared (IR) light radiating from objects in its field of view. They are most often used in PIR-based motion detectors. PIR sensors are commonly used in security alarms and automatic lighting applications.

Building automation(BAS), also known as building management system (BMS) or building energy management system (BEMS), is the automatic centralized control of a building's HVAC (heating, ventilation and air conditioning), electrical, lighting, shading, access control, security systems, and other interrelated systems. Some objectives of building automation are improved occupant comfort, efficient operation of building systems, reduction in energy consumption, reduced operating and maintaining costs and increased security.

<span class="mw-page-title-main">Carbon monoxide detector</span> Device that measures carbon monoxide (CO)

A carbon monoxide detector or CO detector is a device that detects the presence of the carbon monoxide (CO) gas to prevent carbon monoxide poisoning. In the late 1990s Underwriters Laboratories changed the definition of a single station CO detector with a sound device to carbon monoxide (CO) alarm. This applies to all CO safety alarms that meet UL 2034 standard; however for passive indicators and system devices that meet UL 2075, UL refers to these as carbon monoxide detectors. Most CO detectors use a sensor with a defined, limited lifespan, and will not work indefinitely.

<span class="mw-page-title-main">Heat detector</span> Type of fire alarm

A heat detector is a fire alarm device designed to respond when the convected thermal energy of a fire increases the temperature of a heat sensitive element. The thermal mass and conductivity of the element regulate the rate flow of heat into the element. All heat detectors have this thermal lag. Heat detectors have two main classifications of operation, "rate-of-rise" and "fixed temperature". The heat detector is used to help in the reduction of property damage.

<span class="mw-page-title-main">Fire alarm system</span> A system, that works using multiple devices to warn of a fire or other types of emergencies

A fire alarm system is a building system designed to detect and alert occupants and emergency forces of the presence of smoke, fire, carbon monoxide, or other fire-related emergencies. Fire alarm systems are required in most commercial buildings. They may include smoke detectors, heat detectors, and manual fire alarm activation devices, all of which are connected to a Fire Alarm Control Panel (FACP) normally found in an electrical room or panel room. Fire alarm systems generally use visual and audio signalization to warn the occupants of the building. Some fire alarm systems may also disable elevators, which under most circumstances, are unsafe to use during a fire.

<span class="mw-page-title-main">Autonomous detection system</span> Automated biohazard detection system

Autonomous Detection Systems (ADS), also called biohazard detection systems or autonomous pathogen detection systems, are designed to monitor air in an environment and to detect the presence of airborne chemicals, toxins, pathogens, or other biological agents capable of causing human illness or death. These systems monitor the air continuously and send real-time alerts to appropriate authorities in the event of an act of bioterrorism or biological warfare.

A gas detector is a device that detects the presence of gases in an area, often as part of a safety system. A gas detector can sound an alarm to operators in the area where the leak is occurring, giving them the opportunity to leave. This type of device is important because there are many gases that can be harmful to organic life, such as humans or animals.

Materials MASINT is one of the six major disciplines generally accepted to make up the field of Measurement and Signature Intelligence (MASINT), with due regard that the MASINT subdisciplines may overlap, and MASINT, in turn, is complementary to more traditional intelligence collection and analysis disciplines such as SIGINT and IMINT. MASINT encompasses intelligence gathering activities that bring together disparate elements that do not fit within the definitions of Signals Intelligence (SIGINT), Imagery Intelligence (IMINT), or Human Intelligence (HUMINT).

The Centre for Fire, Explosive and Environment Safety (CFEES) is an Indian defence laboratory of the Defence Research and Development Organisation (DRDO). Located in Timarpur, Delhi, its main function is the development of technologies and products in the area of explosive, fire and environmental safety. CFEES is organised under the Armaments Directorate of DRDO. The present director of CFEES is Arvind Kumar

A flame detector is a sensor designed to detect and respond to the presence of a flame or fire, allowing flame detection. Responses to a detected flame depend on the installation, but can include sounding an alarm, deactivating a fuel line, and activating a fire suppression system. When used in applications such as industrial furnaces, their role is to provide confirmation that the furnace is working properly; it can be used to turn off the ignition system though in many cases they take no direct action beyond notifying the operator or control system. A flame detector can often respond faster and more accurately than a smoke or heat detector due to the mechanisms it uses to detect the flame.

The EN 54 Fire detection and fire alarm systems is a series of European standards that includes product standards and application guidelines for fire detection and fire alarm systems as well as voice alarm systems.

<span class="mw-page-title-main">Negative room pressure</span> Health care isolation technique wherein some air is forced in to prevent disease spread

Negative room pressure is an isolation technique used in hospitals and medical centers to prevent cross-contamination from room to room. It includes a ventilation that generates negative pressure to allow air to flow into the isolation room but not escape from the room, as air will naturally flow from areas with higher pressure to areas with lower pressure, thereby preventing contaminated air from escaping the room. This technique is used to isolate patients with airborne contagious diseases such as: influenza (flu), measles, chickenpox, tuberculosis (TB), severe acute respiratory syndrome (SARS-CoV), Middle East respiratory syndrome (MERS-CoV), and coronavirus disease 2019 (COVID-19).

Home safety is the awareness of risks and potential dangers in and around a home which may cause bodily harm, injury, or even death to those living there.

Xtralis, now part of Honeywell, was a privately held firm. It manufactures smoke detection, gas detection and video surveillance security products for the early detection, visual verification, and prevention of fire and intrusion threats.

<span class="mw-page-title-main">Optical beam smoke detector</span>

An optical beam smoke detector is a device that uses a projected beam of light to detect smoke across large areas, typically as an indicator of fire. They are used to detect fires in buildings where standard point smoke detectors would either be uneconomical or restricted for use by the height of the building. Optical beam smoke detectors are often installed in warehouses as a cost-effective means of protecting large open spaces.

References

  1. ↑ "Aspirating Smoke Detectors (ASD)". Siemens. Retrieved 2012-08-09.
  2. ↑ "VESDA Systems". Fire Security Services. Archived from the original on October 14, 2008. Retrieved 2009-05-11.
  3. ↑ Journal of Applied Fire Science, Volume 2. Baywood Publishing Company. 1993. Retrieved May 29, 2013.
  4. ↑ "The HISTORY of VESDA and MONITAIR". Cole Innovation & Design. Archived from the original on November 18, 2008. Retrieved 2009-05-11.
  5. ↑ Weadock, Megan (5 October 2009), A Dangerous Blind Spot, Security Products Magazine, retrieved 5 October 2009
  6. ↑ Do You Have (Fire) Protection, Strategic Facilities
  7. ↑ Shengwei Wang (2009). Intelligent Buildings and Building Automation. Taylor & Francis. p. 236. ISBN   9780203890813 . Retrieved May 29, 2013.
  8. ↑ Landwards, Volumes 55-58. Institution of Agricultural Engineers. 2000. p. 49.
  9. ↑ Sam Kubba (2009). LEED Practices, Certification, and Accreditation Handbook. Butterworth-Heinemann. p. 369. ISBN   9780080958590 . Retrieved May 29, 2013.
  10. ↑ Andrew Furness and Martin Muckett (2007). Introduction to fire safety management. Routledge. p. 228. ISBN   9780750680684 . Retrieved November 29, 2013.
  11. ↑ "VESDA: Clean Rooms". xtralis. Archived from the original on 15 April 2009. Retrieved 2009-05-11.
  12. ↑ "VESDA: Correctional Facilities". xtralis. Archived from the original on 15 April 2009. Retrieved 2009-05-11.
  13. ↑ "What is CCD Aspriating Smoke Detection" Archived 2016-01-13 at the Wayback Machine , Safe Fire Detection Inc, Retrieved 2010-03-23
This page is based on this Wikipedia article
Text is available under the CC BY-SA 4.0 license; additional terms may apply.
Images, videos and audio are available under their respective licenses.