Fire alarm system
A fire alarm system is an active fire protection system that detects fire or
the effects of fire, and as a result provides one or more of the following:
notifies the occupants, notifies persons in the surrounding area, summons the fire service,
and controls all the fire alarm components in a building. Fire alarm systems can include
alarm initiating devices, alarm notification appliances, control units, fire safety control
devices, annunciators, power supplies, and wiring.
Design
The design of the overall goals, general system type, and integration into the
other facility systems (active fire suppression, HVAC, lighting, electrical power, fire barriers, etc.)
is performed by competent engineers with experience in fire protection, who are licensed within the
geographical area of practice, such as a US State or a Canadian Province. This is done in conjunction
with the Archtitect's design team during the design phase of the building project. The detailed component
selection and layout is provided by a technician as hired by the contractor during the construction phase.
In the United states, that person is usually certified for fire alarm design by the National Institute for
Certification of Engineering Technologies (NICET).
The design is typically provided in compliance with the model building codes having jurisdiction
in that area. In the United States, NFPA 72, The National Fire Alarm Code is usually used for
the installation methods, testing and maintenance. Property insurance company recommendations
are also sometimes incorporated.
Extensions of existing systems is done considering the originally installed
fire alarm system, and more than likely will be proprietary to match the existing equipment
Fundamental design
A fire alarm system is composed of components which can be classified into the following categories.
Fire Alarm Control Unit (Panel) - any panel providing required functions, and has inputs and outputs. NAC Power booster panels are the most common example.
Burglar alarm
Burglar (or intrusion), fire and safety alarms are found in electronic form today.
Sensors are connected to a control unit via either a low-voltage hardwire or
narrowband RF signal, which is used to interact with a response device.
The most common security sensors indicate the opening of a door or window or
detect motion via passive infrared (PIR). In new construction systems are predominately
hardwired for economy while in retrofits wireless systems may be more economical and certainly
quicker to install. Some systems are dedicated to one mission, others handle fire, intrusion,
and safety alarms simultaneously. Sophistication ranges from small, self-contained noisemakers,
to complicated, multi-zoned systems with color-coded computer monitor outputs. Many of these concepts
also apply to portable alarms for protecting cars, trucks or other vehicles and their contents (i.e., "car alarms").
See also fire alarm control panel for specific fire system issues. Burglar alarms are sometimes referred to as
alarm systems, see burglar alarm control panel for a discussion of hard-wired burglar alarm system design.
System connections
The trigger signal from each sensor is transmitted to one or more control unit(s) either through
wires or wireless means (radio, line carrier, infrared). Wired systems are convenient when sensors
(such as smoke detectors) require power to operate correctly, however, they may be more costly to install.
Entry-level wired systems utilize a Star network topology, where the panel is at the center logically,
and all devices "home run" its wire back to the panel. More complex panels use a Bus network topology
where the wire basically is a data loop around the perimeter of the facility, and has "drops" for
the sensor devices which must include a unique device identifier integrated into the sensor device itself.
Wired systems also have the advantage, if wired properly, of detecting tampering with the wiring connections.
Wireless systems, on the other hand, often use battery-powered transmitters which are easier to install,
but may reduce the reliability of the system if the sensors are not supervised, or the batteries maintained.
Depending on distance, construction materials, or one or more wireless repeaters may be required to get the signal
reliably back to the alarm panel. Hybrid systems utilize both wired and wireless sensors to achieve the benefits of both.
Transmitters, or sensors can also be connected through the premises electrical circuits to transmit
coded signals to the control unit (line carrier). The control unit usually has a separate channel or
zone for burglar and fire sensors, and better systems have a separate zone for every different sensor,
as well as internal "trouble" indicators (mains power loss, low battery, wire broken, etc).
Alarm connection and monitoring
The desired result of an alarm system is to cause an appropriate alarm output and response when the sensors
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Depending upon the application, the alarm output may be local or remote or a combination.
Local alarms do not include monitoring, though may include indoor and/or outdoor sounders
(e.g. motorized bell or electronic siren) and lights (e.g. strobe light) which may be
useful for signaling an evacuation notice for people during fire alarms, or where one hopes
to scare off an amateur burglar quickly. However, with the widespread use of alarm systems
(especially in cars), false alarms are very frequent and many urbanites tend to ignore alarms
rather than investigating, let alone contacting the necessary authorities. In short,
there may be no response at all. In rural areas (e.g., where nobody will hear the fire bell
or burglar siren) lights or sounds may not make much difference anyway, as the nearest
responders could take so long to get there that nothing can be done to avoid losses.
Remote alarm systems are used to connect the control unit to a predetermined monitor of
some sort, and they come in many different configurations. High-end systems connect to a
central station or responder (eg. Police/ Fire/ Medical) via a direct phone wire
(or tamper-resistant fiber optic cable), and the alarm monitoring includes not only the sensors,
but also the communication wire itself. While direct phone circuits are still available in some
areas from phone companies, because of their high cost they are becoming uncommon.
Direct connections are now most usually seen only in Federal, State, and Local Government buildings,
or on a school campus that has a dedicated security, police, fire, or emergency medical department.
More typical systems incorporate a digital telephone dialer unit that will dial a central station
(or some other location) via the Public Switched Telephone Network (PSTN) and raise the alarm, either
with a synthesized voice or increasingly via an encoded message string that the central station decodes.
These may connect to the regular phone system on the system side of the demarcation point, but typically
connect on the customer side ahead of all phones within the monitored premises so that the alarm system can
seize the line by cutting-off any active calls and call the monitoring company if needed.
Encoders can be programmed to indicate which specific sensor was triggered, and monitors can show
the physical location (or "zone") of the sensor on a list or even a map of the protected premises,
which can make the resulting response more effective. For example, a water-flow alarm, coupled with a
flame detector in the same area is a more reliable indication of an actual fire than just one or the other
sensor indication by itself. Many alarm panels are equipped with a backup dialer capability for use when the
primary PSTN circuit is not functioning. The redundant dialer may be connected to a second phone line,
or a specialized encoded cellular phone, radio, or internet interface device to bypass the PSTN entirely,
to thwart intentional tampering with the phone line(s). Just the fact that someone tampered with the line
could trigger a supervisory alarm via the radio network, giving early warning of an imminent problem (e.g., arson).
In some cases a remote building may not have PSTN phone service, and the cost of trenching and running
a direct line may be prohibitive. It is possible to use a wireless cellular or radio device as the primary
communication method. There is controversy within the alarm industry as to the usage of the Internet
as a primary signaling method, due to the twin issues of the immediacy and urgency of an alarm signal,
and the lack of quality of service within the current design of the public internet.
Monitored alarms and speaker phones allow for the central station to speak with the homeowner and/or intruder.
This may be beneficial to the owner for medical emergencies. For actual break-ins, the speaker phones allow the
central station to urge the intruder to cease and desist as response units have been dispatched.
The list of services to be monitored at a Central Station has expanded over the past few years to include:
Intrusion Alarm Monitoring; Fire Alarm & Sprinkler Monitoring; Critical Condition Monitoring;
Medical Response Monitoring; Elevator Telephone Monitoring; Hold-Up or Panic Alarm Monitoring;
Duress Monitoring; Auto Dialer tests; Open & Close Signal Tracking, or Supervision; Open & Close
Reporting; Exception Reports; and PIN or Passcode Management. Increasingly, the Central Stations are
making this information available directly to end users via the internet and a secure log-on to
view and create custom reports on these events themselves.
Bodyguard
A bodyguard (or "close protection officer") is a type of security guard or government agent
who protects a person—usually a government leader, celebrity, CEO, or other public figure—from assault,
kidnapping, assassination, loss of confidential information, or other threats.
Most important public figures such as heads of state or governors are protected by several bodyguards
or by a team of bodyguards from an agency, security forces, or police forces (e.g., in the US,
the United States Secret Service or the Bureau of Diplomatic Security). Less-important public figures,
or those with lower risk profiles, are often accompanied by a single bodyguard who may double as a driver.
Some celebrities also use bodyguards to protect themselves from aggressive fans or violent stalkers.
Roles
Bodyguards may be armed, depending on the laws in their jurisdiction, and in some cases,
they may wear body armour. Bodyguards often have training in firearms tactics, unarmed combat,
tactical driving, and first aid. In multi-agent units (like those protecting a head of state)
one or more bodyguards may specialize in specific tasks, such as providing a protective escort,
crowd screening and control, or searching for explosives or electronic surveillance devices.
Bodyguards may also work with other security personnel to conduct threat or risk assessment and
analyze potential security weaknesses.
Bodyguards often examine a premises or venue before their clients arrive, to determine where
the exits and entrances are, find potential security weaknesses, and meet the staff (so that a would-be
attacker cannot pose as a staff member). As well, some bodyguards do research to be aware of potential
threats to their client, such as a protest by a radical group or the release from custody of person who
is a known threat. While escorting a client, bodyguards have to remain alert so that they are able to react
quickly to threatening situations. In some cases, bodyguards also drive their clients, which means that
they have to be aware of suspicious vehicles and prepared to practice evasive driving techniques.
Job requirements
Bodyguards often work long shifts in order to provide 24-hour protection, and shifts
often include evenings, weekends, and holidays. Since bodyguards follow their clients,
the work locations may range from indoor office meetings or social events to outdoor rallies or
concerts. Bodyguards often have to travel by car, train, and plane to escort their client,
and in some cases, international travel is required.
Bodyguards often have backgrounds in the Armed Forces, police services, prison guard services
or martial arts, although this is not required. Bodyguards must be physically fit, with good
eyesight and hearing. Bodyguards need to have a presentable appearance, especially for close
protection work for dignitaries and heads of state. However, bodyguards protecting celebrities
or pop stars may be able to have tattoos and facial piercings. A driving licence is usually required.
In the UK and some other countries, bodyguards have to have a licence or certification,
which involves identity and criminal record checks.
Bodyguards need to be observant and possess quick reflexes. As well, they need to be able to
work as member of a bodyguard team, with assigned tasks, or be able to act independently,
and adapt and improvise an appropriate response if the need arises. Bodyguards need to be able
to recognise potentially dangerous situations and remain calm under pressure. As well, they need
good interpersonal and communications skills and strong decision-making and planning skills. Since
bodyguards accompany their client throughout their day, the bodyguard will be privy to the private life
of the client, which means that a bodyguard has to show discretion and maintain confidentiality.
Fictional individuals
Brave and fiercely protective bodyguards have long been depicted in fiction.
The character of the Scottish hero Quentin Durward appears in stories as the
bodyguard of the king of France. The character Charles d'Artagnan appears in
stories as the bodyguard of the French crown. The character Atticus Kodiak is a
professional bodyguard who acts as narrator and protagonist in a series of novels by Greg Rucka.
Bodyguards also appear in Usagi Yojimbo - Stan Sakai's anthropomorphic-rabbit samurai based upon
Miyamoto Musashi and in the Artemis Fowl series of children's books.
Bodyguards are also depicted in a number of films. Japanese director Akira Kurosawa's film
Yojimbo depicts a samurai bodyguard in Japan. The Bodyguard is a film about a bodyguard who
protects a celebrity singer. Gogo Yubari is O-Ren Ishii's bodyguard in the film Kill Bill 1.
In the science-fiction/fantasy Star Wars films, MagnaGuard is General Grievous's bodyguard.
In the film Lord of War, the main character's brother protects him while he makes arms deals
in war-torn countries. In the film Man on Fire, John Creasy (Denzel Washington) is a burnt-out
ex-CIA officer and counter-insurgency operative who grudgingly becomes the bodyguard of a young
girl (played by Dakota Fanning). Several films have been made about guarding the President of the US,
such as In the Line of Fire and The Sentinel.
Bodyguards are also depicted in television shows, comics, and other media. Bodyguard is a
Japanese television series starring Reiko Takashima. In the UK, Bodyguards is a television series.
Sheeva is the personal protector of Sindel. Suki is aJapanese manga about a relationship
between a teenaged girl and a 32-year old bodyguard. Kevin Nash is Shawn Michaels' bodyguard.
The Human Target is an American comic book and television series.