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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 thisthermal lag. Heat detectors have two main classifications of

operation, "rate-of-rise" and "fixed temperature."

Contents

[hide]

1 Fixed temperature heat detectors

2 Rate-of-rise heat detectors

3 Heat detector selection

4 See also

[edit]Fixed temperature heat detectors

This is the most common type of heat detector. Fixed temperature detectors operate

when the heat sensitiveeutectic alloyreaches the eutectic point changing state from a

solid to a liquid.Thermal lagdelays the accumulation of heat at the sensitive element so

that a fixed-temperature device will reach its operating temperature sometime after the

surrounding air temperature exceeds that temperature. The most common fixed

temperature point for electrically connected heat detectors is 136.4F (58C).Technological developments have enabled the perfection of detectors that activate at a

temperature of 117F (47C), increasing the available reaction time and margin of

safety. This type of technology has been available for decades without the use of

batteries or electricity as shown in the picture.

[edit]Rate-of-rise heat detectors

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Worn out Edwards 281B heat detector. Note the missing central disk which activates the fixed

temperature element.

Rate-of-Rise (ROR) heat detectors operate on a rapid rise in element temperature of

120 to 150F (67 to 83C) increase per minute, irrespective of the starting

temperature. This type of heat detector can operate at a lower temperature fire

condition than would be possible if the threshold were fixed. It has two heat-sensitive

thermocouples/ thermistor. One thermocouple monitors heat transferred by convection

or radiation. The other responds to ambient temperature. Detector responds when firsts

temperature increases relative to the other.

Rate of rise detectors may not respond to low energy release rates of slowly developing

fires. To detect slowly developing fires combination detectors ad a fixed temperature

element that will ultimately respond when the fixed temperature element reaches the

design threshold.

[edit]Heat detector selection

Heat detectors commonly have a label on them that says "Not a life safety device". That

is because heat detectors are not meant to replacesmoke detectorsin the bedrooms or

in the hallway outside of the bedrooms. A heat detector will nonetheless notify of a fire

in a kitchen or utility area (i.e., laundry room, garage, or attic), where smoke detectors

should not be installed. This will allow extra time to evacuate the building or to put out

the fire if possible.Mechanical heat detectors are independent fire warning stations that - unlike smoke

detectors - can be installed in any area of a home. Portability, ease of installation, and

excellent performance and reliability make this a good choice for residential fire

protection when combined with the required smoke detectors. Because the detectors

are not interconnected, heat activation identifies the location of the fire, facilitating

evacuation from the home.

Each type of heat detector has its advantages, and it cannot be said that one type of

heat detector should always be used instead of another. If you were to place a rate-of-rise heat detector above a large, closed oven, then every time the door is opened a

nuisance alarm could be generated due to the sudden heat transient. In this

circumstance the fixed threshold detector would probably be best. If a room filled with

highly combustible materials is protected with a fixed heat detector then a fast-flaming

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fire could exceed the alarm threshold due to thermal lag. In that case the rate-of-rise

heat detector may be preferred.

Smoke detectorFrom Wikipedia, the free encyclopedia

A smoke detector is a device that detectssmoke, typically as an indicator of fire. Commercial, industrial, and

mass residential devices issue a signal to afire alarm system, while household detectors, known as smoke

alarms, generally issue a local audible or visualalarmfrom the detector itself.

Smoke detectors are typically housed in a disk-shaped plastic enclosure about 150 millimetres (6 in) in

diameter and 25 millimetres (1 in) thick, but the shape can vary by manufacturer or product line. Most smoke

detectors work either by optical detection (photoelectric) or by physical process (ionization), while others use

both detection methods to increase sensitivity to smoke. Sensitive alarms can be used to detect, and thus

deter, smoking in areas where it is banned such as toilets and schools. Smoke detectors in large commercial,

industrial, and residential buildings are usually powered by a central f ire alarm system, which is powered by the

building power with a battery backup. However, in many single family detached and smaller multiple family

housings, a smoke alarm is often powered only by a single disposable battery.

Contents

[hide]

1 History

2 Design

o 2.1 Optical

o 2.2 Ionization

o 2.3 Air-sampling

o 2.4 Carbon monoxide and carbon dioxide detection

o 2.5 Performance differences

3 Commercial smoke detectors

o 3.1 Conventional

o 3.2 Addressable

4 Single Station Smoke Alarms

o 4.1 Batteries

o 4.2 Reliability

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o 4.3 Installation and placement

5 References

6 External links

[edit]History

The first automatic electric fire alarm was invented in 1890 byFrancis Robbins Upton(U.S. patent no.

436,961). Upton was an associate ofThomas Edison, but there is no evidence that Edison contributed to this

project.

George Andrew Darbypatented the first electricalHeat detectorand Smoke detector in 1902 inBirmingham,

England.[1]

In the late 1930s the Swiss physicistWalter Jaegertried to invent a sensor for poison gas. He expected that

gas entering the sensor would bind to ionized air molecules and thereby alter an electric current in a circuit in

the instrument. His device failed: small concentrations of gas had no effect on the sensor's conductivity.

Frustrated, Jaeger lit a cigaretteand was soon surprised to notice that a meter on the instrument had

registered a drop in current. Smoke particles had apparently done what poison gas could not. Jaeger's

experiment was one of the advances that paved the way for the modern smoke detector.

It was 30 years, however, before progress in nuclear chemistry and solid-state electronics made a cheap

sensor possible. While home smoke detectors were available during most of the 1960s, the price of these

devices was rather high. Before that, alarms were so expensive that only major businesses and theaters could

afford them.

The first truly affordable home smoke detector was invented byDuane D. Pearsallin 1965, featuring an

individual battery powered unit that could be easily installed and replaced. The first units for mass production

came from Duane Pearsalls company,Statitrol Corporation, in Lakewood, Colorado. These first units were

made from strong fire resistant steel and shaped much like a bee's hive. The battery was a rechargeable

specialized unit created by Gates Energy. The need for a quick replace battery didn't take long to show itself

and the rechargeable was replaced with a pair ofAA batteriesalong with a plastic shell encasing the detector.

The small assembly line sent close to 500 units per day before Statitrol sold its invention to Emerson Electric in

1980 and Searss retailers picked up full distribution of the 'now required in every home' smoke detector.

The first commercial smoke detectors came to market in 1969. Today they are installed in 93% of U.S. homes

and 85% of UK homes. However it is estimated that any given time over 30% of these alarms do not work, as

users remove the batteries, or forget to replace them.

[edit]Design

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[edit]Optical

Optical Smoke Detector with the cover removed.

Optical Smoke Detector

1: Optical chamber

2: Cover

3: Case moulding

4: Photodiode (detector)

5: Infrared LED

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Inside a basic ionization smoke detector. The black, round structure at the right is the ionization

chamber. The white, round structure at the upper left is thepiezoelectricbuzzer that produces the

alarm sound.

An optical detector is a light sensor. When used as a smoke detector, it includes a light source (incandescent

bulb or infrared LED), a lens to collimate the light into a beam, and aphotodiodeor other photoelectric sensor

at an angle to the beam as a light detector. In the absence of smoke, the light passes in front of the detector in

a straight line. When smoke enters the optical chamber across the path of the light beam, some light

isscatteredby the smoke particles, directing it at the sensor and thus triggering the alarm.

Also seen in large rooms, such as a gymnasium or an auditorium, are devices that detect a projected beam. A

wall-mounted unit sends out a beam, which is either received by a separate monitoring device or reflected back

via a mirror. When the beam becomes less visible to the "eye" of the sensor, it sends an alarm signal to thefire

alarm control panel.

According to the National Fire Protection Agency, "photoelectric smoke detection is generally more responsive

to fires that begin with a long period of smoldering (called smoldering fires)." Also, studies by Texas A&M and

the NFPA cited by the City of Palo Alto California state, "Photoelectric alarms react slower to rapidly growing

fires than ionization alarms, but laboratory and field tests have shown that photoelectric smoke alarms provide

adequate warning for all types of fires and have been shown to be far less likely to be deactivated by

occupants."

Although optical alarms are highly effective at detecting smoldering fires and do provide adequate protection

from flaming fires, fire safety experts and the National Fire Protection Agency recommend installing what are

called combination alarms, which are alarms that either detect both heat and smoke, or use both the ionization

and photoelectric / optical processes. Also some combination alarms may include a carbon monoxide detection

capability.

Not all optical or photoelectric detection methods are the same. The type and sensitivity of the photodiode or

optical sensor, and type of smoke chamber differ between manufacturers.

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[edit]Ionization

An Americium container from a smoke detector.

An ionization smoke detectoruses a radioisotope such asamericium-241to produce ionization in air; a

difference due to smoke is detected and an alarm is generated. Ionisation detectors are more sensitive to

flaming fires than optical detectors, while optical detectors are more sensitive to smouldering fires.[2]

The radioactiveisotopeamericium-241 in the smoke detector emits ionizingradiationin the form ofAlpha

particlesinto anionization chamberthat is open to the air and a sealed reference chamber. The

airmoleculesin the chamber becomeionizedand these ions allow the passage of a smallelectric

currentbetweenchargedelectrodesplaced in the chamber. If any smoke particles pass into the chamber the

ions will attach to the particles and so will be less able to carry the current. An electronic circuit detects the

current drop, and sounds the alarm. The reference chamber cancels effects due to air pressure, temperature,

or the aging of the source.[3]

Other parts of the circuitry monitor the battery (where used) and sound an

intermittent warning when the battery nears exhaustion. A self-test circuit simulates an imbalance in the

ionization chamber and verifies the function of power supply, electronics, and alarm device. The standby power

draw of an ionization smoke detector is so low that a small battery can provide power for months or years,

making the unit independent of AC power supply or external wiring; however, batteries require regular test and

replacement.

An ionization type smoke detector is generally cheaper to manufacture than an optical smoke detector;

however, it is sometimes rejected because it is more prone to false (nuisance) alarms than photoelectric smoke

detectors.[4][5]It can detect particles of smoke that are too small to be visible.

Americium-241, analpha emitter, has ahalf-lifeof 432 years. Alpha radiation, as opposed tobetaandgamma,

is used for two additional reasons: Alpha particles have high ionization, so sufficient air particles will be ionized

for the current to exist, and they have low penetrative power, meaning they will be stopped by the plastic of the

smoke detector or the air. About one percent of the emitted radioactive energy of 241Am isgamma radiation.

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The amount of elemental americium-241 is small enough to be exempt from the regulations applied to larger

sources. It includes about 37kBqor 1Ciof radioactive elementamericium-241(241

Am), corresponding to

about 0.3 g of the isotope.[6][7]This provides sufficient ion current to detect smoke, while producing a very low

level of radiation outside the device. The presence of americium-241 means that every decommissioned smoke

detector must be properly disposed of lest it constitute an environmental hazard.[8]

[edit]Air-sampling

An air-sampling smoke detector is capable of detecting microscopic particles of smoke. Most air-sampling

detectors areaspirating smoke detectors, which work by actively drawing air through a network of small-bore

pipes laid out above or below a ceiling in parallel runs covering a protected area. Small holes drilled into each

pipe form a matrix of holes (sampling points), providing an even distribution across the pipe network. Air

samples are drawn past a sensitive optical device, often a solid-state laser, tuned to detect the extremely small

particles of combustion. Air-sampling detectors may be used to trigger an automatic fire response, such as a

gaseous fire suppression system, in high-value or mission-critical areas, such as archives or computer server

rooms.

Most air-sampling smoke detection systems are capable of a higher sensitivity than spot type smoke detectors

and provide multiple levels of alarm threshold, such as Alert, Action, Fire 1 and Fire 2. Thresholds may be set

at levels across a wide range of smoke levels. This provides earlier notification of a developing fire than spot

type smoke detection, allowing manual intervention or activation of automatic suppression systems before a fire

has developed beyond the smoldering stage, thereby increasing the time available for evacuation and

minimizing fire damage.

[edit]Carbon monoxide and carbon dioxide detection

Some smoke alarms use acarbon dioxide sensororcarbon monoxide sensorto detect extremely dangerous

products of combustion.[9][10]However, not all smoke detectors that are advertised with such gas sensors are

actually able to warn of poisonous levels of those gases in the absence of a fire.[citation needed]

[edit]Performance differences

Photoelectric smoke detectors respond quickly to smoldering fires, which are made up of combustion particles

between 0.3 and 10.0 microns. Ionization smoke detectors, however, are superior when detecting flaming fires,

which can be characterized by combustion particles between 0.01 and 0.3 microns. Also, ionization detectors

are weaker in high air-flow environments, and because of this, the photoelectric smoke detector is more reliable

for detecting smoke in both the smoldering and flaming stages of a fire.[11]

According to fire tests conformant toEN 54, the CO2 cloud from smoke can usually be detected before

particulate.[10]

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Due to the varying levels of detection capabilities between detector types, manufacturers have designed multi-

criteria devices which cross-reference the separate signals to both rule out false alarms and improve response

times to real fires.[11]Examples include Photo/heat, photo/CO, and even CO/photo/heat/IR.

Obscurationis a unit of measurement that has become the standard definition of smoke detectorsensitivity.

Obscuration is the effect that smoke has on reducing sensorvisibility; higher concentrations of smoke result in

higher obscuration levels.

Typical smoke detector obscuration ratings[12]

Type of Detector Obscuration Level

Ionization 2.6

5.0% obs/m (0.8

1.5% obs/ft)

Photoelectric 6.513.0% obs/m (24% obs/ft)

Beam 3% obs/m (0.9% obs/ft)[citation needed]

Aspirating 0.00520.5% obs/m (0.00156.25% obs/ft)

Laser 0.066.41% obs/m (0.022.0% obs/ft)[13]

[edit]Commercial smoke detectors

This section requiresexpansion.

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An integrated locking mechanism for commercial building doors. Inside an enclosure are a locking

device, smoke detector and power supply.

Commercial smoke detectors are either conventional or analog addressable, and are wired up to security

monitoring systems orfire alarm control panels(FACP). These are the most common type of detector, and

usually cost a lot more than a household smoke alarms. They exist in most commercial and industrial facilities,

such as high rises, ships and trains. These detectors don't need to have built in alarms, as alarm systems can

be controlled by the connected FACP, which will set off relevant alarms, and can also implement complex

functions such as a staged evacuation.

[edit]Conventional

The word "conventional" is slang used to distinguish the method used to communicate with the control unit from

that used by addressable detectors whose methods were unconventional at the time of their introduction. So

called Conventional Detectors cannot be individually identified by the control unit and resemble an electrical

switch in their information capacity. These detectors are connected in parallel to the signaling path or (initiating

device circuit) so that the current flow is monitored to indicate a closure of the circuit path by any connected

detector when smoke or other similar environmental stimulus sufficiently influences any detector. The resulting

increase in current flow is interpreted and processed by the control unit as a confirmation of the presence of

smoke and a fire alarm signal is generated.

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[edit]Addressable

An addressable Simplex smoke detector

This type of installation gives each detector on a system an individual number, or address. Thus, addressable

detectors allow an FACP, and therefore fire fighters, to know the exact location of an alarm where the address

is indicated on a diagram.

Analog addressable detectors provide information about the amount of smoke in their detection area, so that

the FACP can decide itself, if there is an alarm condition in that area (possibly considering day/night time and

the readings of surrounding areas). These are usually more expensive than autonomous deciding detectors.[14]

[edit]Single Station Smoke Alarms

The main function of a single station or "standalone" smoke alarm is to alert persons at risk. Several methods

are used and documented in industry specifications published byUnderwriters Laboratories[15]Alerting methods

include:

Audible tones

Usually around 3200 Hz due to component constraints (Audio advancements for persons with hearing

impairments have been made; seeExternal links)

85dBAat 10 feet

Spoken voice alert

Visualstrobe lights 177candelaoutput

Tactile stimulation, e.g., bed or pillow shaker (No standards exist as of 2008 for tactile stimulation alarm

devices.)

Some models have a hush or temporary silence feature that allows silencing without removing the battery. This

is especially useful in locations where false alarms can be relatively common (e.g. due to "toast burning") or

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users could remove the battery permanently to avoid the annoyance of false alarms, but removing the battery

permanently is strongly discouraged.

While current technology is very effective at detecting smoke and fire conditions, the deaf and hard of hearing

community has raised concerns about the effectiveness of the alerting function in awakening sleeping

individuals in certain high risk groups such as the elderly, those with hearing loss and those who are

intoxicated.[16]Between 2005 and 2007, research sponsored by the United States'National Fire Protection

Association(NFPA) has focused on understanding the cause of a higher number of deaths seen in such high

risk groups. Initial research into the effectiveness of the various alerting methods is sparse. Research findings

suggest that a low frequency (520 Hz) square wave output is significantly more effective at awakening high risk

individuals. Wireless smoke and carbon monoxide detectors linked to alert mechanisms such as vibrating pillow

pads for the hearing impaired, strobes, and remote warning handsets are more effective at waking people with

serious hearing loss than other alarms.[17]

[edit]Batteries

Photoelectric smoke detector equipped with strobe light for the hearing impaired

Most residential smoke detectors run on 9-volt alkaline or carbon-zinc batteries. When these batteries run

down, the smoke detector becomes inactive. Most smoke detectors will signal a low-battery condition. The

alarm may chirp at intervals if the battery is low, though if there is more than one unit within earshot, it can be

hard to locate. It is common, however, for houses to have smoke detectors with dead batteries. It is estimated,

in the UK, that over 30% of smoke alarms may have dead or removed batteries. As a result, public information

campaigns have been created to remind people to change smoke detector batteries regularly. In Australia, for

example, a public information campaign suggests that smoke alarm batteries should be replaced onApril

Fools' Dayevery year.[18]

In regions usingdaylight saving time, campaigns may suggest that people change

their batteries when they change their clocks or on a birthday.

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Some detectors are also being sold with alithium batterythat can run for about 7 to 10 years, though this might

actually make it less likely for people to change batteries, since their replacement is needed so infrequently. By

that time, the whole detector may need to be replaced. Though relatively expensive, user-replaceable 9-volt

lithium batteries are also available.

CommonNiMHandNiCdrechargeable batterieshave a highself-dischargerate, making them unsuitable for

use in smoke detectors. This is true even though they may provide much more power than alkaline batteries if

used soon after charging, such as in a portable stereo. Also, a problem with rechargeable batteries is a rapid

voltage drop at the end of their useful charge. This is of concern in devices such as smoke detectors, since the

battery may transition from "charged" to "dead" so quickly that the low-battery warning period from the detector

is either so brief as to go unnoticed, or may not occur at al l.

The NFPA, recommends that home-owners replace smoke detector batteries with a new battery at least once

per year, when it starts chirping (a signal that its charge is low), or when it fails a test, which the NFPA

recommends to be carried out at least once per month by pressing the "test" button on the alarm.[19]

[edit]Reliability

In 2004,NISTissued a comprehensive report[5]

that concludes, among other things, that "smoke alarms of

either the ionization type or the photoelectric type consistently provided time for occupants to escape from most

residential fires", and "consistent with prior findings, ionization type alarms provided somewhat better response

to flaming fires than photoelectric alarms (57 to 62 seconds faster response), and photoelectric alarms provided

(often) considerably faster response to smoldering fires than ionization type alarms (47 to 53 minutes faster

response)".

The NFPA strongly recommends the replacement of home smoke alarms every 10 years. Smoke alarms

become less reliable with time, primarily due to aging of their electronic components, making them susceptible

to nuisance false alarms. In ionization type alarms, decay of the 241Am radioactive source is a negligible factor,

as its half-life is far greater than the expected useful life of the alarm unit.

Regular cleaning can prevent false alarms caused by the build up of dust or other objects such as flies,

particularly on optical type alarms as they are more susceptible to these factors. A vacuum cleaner can be

used to clean ionization and optical detectors externally and internally. However, on commercial ionisation

detectors it is not recommended for a lay person to clean internally. To reduce false alarms caused by cookingfumes, use an optical or 'toast proof' alarm near the kitchen.

[20]

A jury in the United States District Court for the Northern District of New York decided in 2006 thatFirst

Alertand its parent company, BRK Brands, was liable for millions of dollars in damages because the ionization

smoke alarm in the Hackert's house was a defective design by its nature, typically failing to detect the slow-

burning fire and choking smoke that filled the home as the family slept.[21]

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[edit]Installation and placement

A 2007 U.S. guide to placing smoke detectors, suggesting that one be placed on every floor of a

building, and in each bedroom.

In theUnited States, moststateandlocallawsregarding the required number and placement of smoke

detectors are based upon standards established inNFPA72, National Fire Alarm and Signaling Code.

Laws governing the installation of smoke detectors vary depending on the locality. Homeowners with questions

or concerns regarding smoke detector placement may contact their localfire marshalorbuilding inspectorfor

assistance. However, some rules and guidelines for existing homes are relatively consistent throughout the

developed world. For example,CanadaandAustraliarequire a building to have a working smoke detector on

every level. TheUnited StatesNFPA code cited in the previous paragraph requires smoke detectors on every

habitable level and within the vicinity of all bedrooms. Habitable levels include attics that are tall enough to

allow access.

In new construction, minimum requirements are typically more stringent. All smoke detectors must be hooked

directly to theelectrical wiring, be interconnected and have abattery backup. In addition, smoke detectors are

required either inside or outside everybedroom, depending on local codes. Smoke detectors on the outside will

detect fires more quickly, assuming the fire does not begin in the bedroom, but the sound of the alarm will be

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reduced and may not wake some people. Some areas also require smoke detectors instairways,

mainhallwaysandgarages.

Wired units with a third "interconnect" wire allow a dozen or more detectors to be connected, so that if one

detects smoke, the alarms will sound on all the detectors in the network, improving the chances that occupants

will be alerted, even if they are behind closed doors or if the alarm is triggered one or two floors from their

location. Wired interconnection may only be practical for use in new construction, especially if the wire needs to

be routed in areas that are inaccessible without cutting open walls and ceilings. As of the mid-2000s,

development has begun on wirelessly networking smoke alarms, using technologies such asZigBee, which will

allow interconnected alarms to be easily retrofitted in a building without costly wire installations. Some wireless

systems using Wi-Safe technology will also detect smoke or carbon monoxide through the detectors, which

simultaneously alarm themselves with vibrating pads, strobes and remote warning handsets. As these systems

are wireless they can easily be transferred from one property to another.

In the UK the placement of detectors are similar however the installation of smoke alarms in new builds need to

comply to the British Standards BS5839 pt6. BS 5839: Pt.6: 2004 recommends that a new-build property

consisting of no more than 3 floors (less than 200sqm per floor) should be fitted with a Grade D, LD2 system.

Building Regulations in England, Wales and Scotland recommend that BS 5839: Pt.6 should be followed, but

as a minimum a Grade D, LD3 system should be installed. Building Regulations in Northern Ireland require a

Grade D, LD2 system to be installed, with smoke alarms fitted in the escape routes and the main living room

and a heat alarm in the kitchen, this standard also requires all detectors to have a main supply and a battery

back up.

Alarm System: Smoke and HeatDetectorsSmoke & Heat Detectors

Smoke detectors are available that will interface with your security system. The

smoke detectors that are already in your home cant be tied into your

security system. The device that the builder put in your home is either electrical,

battery operated, or in some instances both, if you have the better quality

detectors. Lifesaving smoke detectors should be in every home. If you elect to

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add some to your system, your existing detectors should be left in place, as they

are still able to help give early warning in case of a fire.

If you add a smoke detector to your system it should be placed in the highest

point of your home as possible, as smoke will rise no matter where it originates.

Some homeowners elect to place one in the basement and top floor, and some

want one added to every floor.

The technology that makes most of these devices work is photoelectric

technology. This means that the detector basically takes a snapshot of the

density of smoke that enters its chamber, and wants to see a density increase as

it samples every few milliseconds. This technology makes the detector much

more discriminating then its inexpensive counterparts.

Many of these devices also detect temperature change with their built in heat

detectors. This means that the device will go into an alarm condition, if the

temperature in its area of coverage is rising rapidly, even if there is no smoke yet.

Independent heat detectors are also available, if you would like an added degree

of protection in areas such as kitchens, furnace rooms, attics and fireplaces.

(Required to meet code, in some municipalities)

There are many advantages to adding fire devices to your security system. Some

of them are:

* Your detector is on all the time, even if your alarm is disarmed.

* The devices work off the power from your alarm system and use its backup

power supplies should power fail.

* The siren will emit a tone that is audibly different then a burglary siren, so that

you can differentiate.

* Your dispatch is being made without you having to call for help yourself. This

gives you more time to gather your loved ones and pets for immediate exit.

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* A dispatch will take place even if you are not home. Typically flames will be

coming through your roof, by the time your neighbors see them, and call for help.

This early response may save your pets and a good portion of your home.

* Insurance companies often give an additional discount, off your homeowners

insurance, for having a fire system. These devices could effectively pay for

themselves, after a few years.

(INSIDE SCOOP!) Some municipalities will not dispatch their limited resources to

an automatic fire alarm, unless it is designed completely to local code. This is a

very expensive endeavor that, many homeowners in those areas cant

justify. Businesses will have to do this, in order to get an occupancy permit.

Check with your local fire authority before investing in smoke or heat detectors

that will not get a response.

A fire sprinkler is the part of afire sprinkler systemthat discharges water when the

effects of a fire have been detected, such as when a predetermined temperature has

been exceeded.

Contents

[hide]

1 History

2 US regulatory requirements

3 Operation

4 Sprinkler types

o 4.1 ESFR

5 See also

6 References7 External links

[edit]History

This unreferenced section

requirescitationsto

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ensureverifiability.

See, generally,Dana (1919).[1]

In 1812, British inventor Sir William Congreve patented a manual sprinkler system

using perforated pipes along the ceiling. When someone noticed a fire, a valveoutside the building could be opened to send water through the pipes.[2]

A large furniture factory had repeatedly burned down, andHiram Stevens

Maximwas consulted on how to prevent a recurrence. As a result, Maxim invented

the first automatic fire sprinkler. It would douse the areas that were on fire, and it

would report the fire to the fire station. Maxim was unable to sell the idea elsewhere,

but when the patent expired the idea was used.[3][4]

Henry S. Parmaleeof New Haven, CT created and installed the first automatic fire

sprinkler system in 1874, usingsolderthat melted in a fire to plug holes in theotherwise open water pipes. At the time he was the president of Mathusek Piano

Works. Parmelee invented his sprinkler system in response to exorbitantly high

insurance rates. Parmelee patented his idea and had great success with it in the

U.S. Parmelee called his invention the "automatic fire extinguisher".[5]He then

traveled to Europe to demonstrate his method to stop a building fire before total

destruction.

His invention did not get as much attention as he had planned. Most people could

not afford to install a sprinkler system. Once Parmelee realized this, he turned his

efforts on educating the insurance companies about his system. He talked about

how the sprinkler system would reduce the loss ratio, thus saving money for the

insurance companies. He knew that he could never succeed in obtaining contracts

from the business owners to install his system unless he could ensure for them a

reasonable return in the form of reduced premiums.

In this connection he was fortunate enough to enlist the sympathies of two men, who

both had connections in the insurance industry. The first of these was Major

Hesketh, who, in addition to being a cotton spinner in a large business in Bolton,

was Chairman of the Bolton Cotton Trades Mutual Insurance Company. The

Directors of this Company and more particularly its Secretary, the late Peter Kevan,

took an interest in Parmelees early experiments, and eventually it was to Major

Hesketh, its Chairman, that Parmelee owed his first order for the Sprinkler

Installations which were installed in the Cotton Spinning Mills of John Stones &

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Company, at Astley Bridge, Bolton, to be followed soon afterwards by the Alexandra

Mills belonging to Mr. John Butler of the same town.

Although he got a contract through his efforts, the Bolton Cotton Trades Mutual

Insurance Company was not a very big company outside of its local area. Parmelee

needed a wider influence. He found this influence in James North Lane, the

Manager of the Mutual Fire Insurance Corporation ofManchester. This company

was founded in 1870 by the Textile Manufacturers' Associations

ofLancashireandYorkshireas a protest against high insurance rates. They had a

policy of encouraging risk management and more particularly the use of the most

up-to-date and scientific apparatus for extinguishing fires. Even though he put

tremendous effort and time into educating the masses on his sprinkler system, by

1883 only about 10 factories were protected by the Parmelee sprinkler.

Back in the US,Frederick Grinnell, who was manufacturing the Parmelee sprinkler,

designed a newer and more effective version which became known as the Grinnell

sprinkler. He increased sensitivity by removing the fusible joint from all contact with

the water, and, by seating a valve in the center of a flexible diaphragm, he relieved

the low-fusing soldered joint of the strain of water pressure. By this means the valve

seat was forced against the valve by the water pressure, producing a self-closing

action, so that the greater the water pressure, the tighter the valve. The flexible

diaphragm had a further and most important function. It caused the valve and its

seat to move outwards simultaneously until the solder joint was completely severed.

Grinnell got a patent for his version of the sprinkler system. He also took his

invention to Europe, where it was a much bigger success than the Parmelee

version. Eventually, the Parmelee system was withdrawn, which left an open path

for Grinnell and his invention.

[edit]US regulatory requirements

Fire sprinkler application and installation guidelines, and overall fire sprinkler system

design guidelines, are provided by theNational Fire Protection Association(NFPA)

13, (NFPA) 13D, and (NFPA) 13R.

The states,California and Pennsylvania require sprinklers in at least some new

residential construction.[6]

Fire sprinklers can be automatic or open orifice. Automatic fire sprinklers operate at

a predetermined temperature, utilizing a fusible element, a portion of which melts, or

a frangible glass bulb containing liquid which breaks, allowing the plug in the orifice

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to be pushed out of the orifice by the water pressure in the fire sprinkler piping,

resulting in water flow from the orifice. The water stream impacts a deflector, which

produces a specific spray pattern designed in support of the goals of the sprinkler

type (i.e., control or suppression). Modern sprinkler heads are designed to direct

spray downwards. Spray nozzles are available to provide spray in various directionsand patterns. The majority of automatic fire sprinklers operate individually in a fire.

Contrary to motion picture representation, the entire sprinkler system does not

activate, unless the system is a special deluge type.

Open orifice sprinklers are only used in water spray systems or deluge sprinklers

systems. They are identical to the automatic sprinkler on which they are based, with

the heat sensitive operating element removed.

Automatic fire sprinklers utilizing frangible bulbs follow a standardized color coding

convention indicating theiroperating temperature. Activation temperatures

correspond to the type of hazard against which the sprinkler system protects.

Residential occupancies are provided with a special type of fast response sprinkler

with the unique goal of life safety.

[edit]Operation

Each closed-head sprinkler is held closed by either a heat-sensitive glass bulb (see

below) or a two-part metal link held together withfusible alloysuch asWood's

metal[7]and other alloys with similar compositions.[8]The glass bulb or link applies

pressure to a pip cap which acts as a plug which prevents water from flowing until

the ambient temperature around the sprinkler reaches the design activation

temperature of the individual sprinkler. Because each sprinkler activates

independently when the predetermined heat level is reached, the number of

sprinklers that operate is limited to only those near the fire, thereby maximizing the

available water pressure over the point of fire origin.

The bulb breaks as a result of thethermal expansionof the liquid inside the

bulb.[9]The time it takes before a bulb breaks is dependent on the temperature.

Below the design temperature, it does not break, and above the design temperature,

it takes less time for higher temperatures. The response time is expressed as a

response time index (RTI), which typically has values between 35 and 250 ms,

where a low value indicates a fast response.[10]Under standard testing procedures

(135 C air at a velocity of 2.5 m/s), a 68 C sprinkler bulb will break within 7 to 33

seconds, depending on the RTI.[11]The RTI can also be specified in imperial units,

http://en.wikipedia.org/wiki/Operating_temperaturehttp://en.wikipedia.org/wiki/Operating_temperaturehttp://en.wikipedia.org/wiki/Operating_temperaturehttp://en.wikipedia.org/w/index.php?title=Fire_sprinkler&action=edit&section=3http://en.wikipedia.org/w/index.php?title=Fire_sprinkler&action=edit&section=3http://en.wikipedia.org/w/index.php?title=Fire_sprinkler&action=edit&section=3http://en.wikipedia.org/wiki/Fusible_alloyhttp://en.wikipedia.org/wiki/Fusible_alloyhttp://en.wikipedia.org/wiki/Fusible_alloyhttp://en.wikipedia.org/wiki/Wood%27s_metalhttp://en.wikipedia.org/wiki/Wood%27s_metalhttp://en.wikipedia.org/wiki/Wood%27s_metalhttp://en.wikipedia.org/wiki/Fire_sprinkler#cite_note-6http://en.wikipedia.org/wiki/Fire_sprinkler#cite_note-6http://en.wikipedia.org/wiki/Fire_sprinkler#cite_note-6http://en.wikipedia.org/wiki/Fire_sprinkler#cite_note-7http://en.wikipedia.org/wiki/Fire_sprinkler#cite_note-7http://en.wikipedia.org/wiki/Fire_sprinkler#cite_note-7http://en.wikipedia.org/wiki/Thermal_expansionhttp://en.wikipedia.org/wiki/Thermal_expansionhttp://en.wikipedia.org/wiki/Thermal_expansionhttp://en.wikipedia.org/wiki/Fire_sprinkler#cite_note-8http://en.wikipedia.org/wiki/Fire_sprinkler#cite_note-8http://en.wikipedia.org/wiki/Fire_sprinkler#cite_note-8http://en.wikipedia.org/wiki/Fire_sprinkler#cite_note-9http://en.wikipedia.org/wiki/Fire_sprinkler#cite_note-9http://en.wikipedia.org/wiki/Fire_sprinkler#cite_note-9http://en.wikipedia.org/wiki/Fire_sprinkler#cite_note-10http://en.wikipedia.org/wiki/Fire_sprinkler#cite_note-10http://en.wikipedia.org/wiki/Fire_sprinkler#cite_note-10http://en.wikipedia.org/wiki/Fire_sprinkler#cite_note-10http://en.wikipedia.org/wiki/Fire_sprinkler#cite_note-9http://en.wikipedia.org/wiki/Fire_sprinkler#cite_note-8http://en.wikipedia.org/wiki/Thermal_expansionhttp://en.wikipedia.org/wiki/Fire_sprinkler#cite_note-7http://en.wikipedia.org/wiki/Fire_sprinkler#cite_note-6http://en.wikipedia.org/wiki/Wood%27s_metalhttp://en.wikipedia.org/wiki/Wood%27s_metalhttp://en.wikipedia.org/wiki/Fusible_alloyhttp://en.wikipedia.org/w/index.php?title=Fire_sprinkler&action=edit&section=3http://en.wikipedia.org/wiki/Operating_temperature

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where 1 fts is equivalent to 0.55 ms. The sensitivity of a sprinkler can be

negatively affected if the thermal element has been painted.

Maximum CeilingTemperature

TemperatureRating

TemperatureClassification

Color Code

(with Fusible

Link)

Glass BulbColor

100F / 38C135-170F / 57-

77COrdinary

Uncolored or

Black

Orange

(135F) or Red

(155F)

150F / 66C175-225F / 79-

107CIntermediate White

Yellow (175F)

or Green

(200F)

225F / 107C250-300F /

121-149CHigh Blue Blue

300F / 149C 325-375F /163-191C

Extra High Red Purple

375F / 191C400-475F /

204-246CVery Extra High Green Black

475F / 246C500-575F /

260-302CUltra High Orange Black

625F / 329C 650F / 343C Ultra High Orange Black

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From Table 6.2.5.1NFPA13 2007 Edition indicates the maximum ceiling

temperature, nominal operating temperature of the sprinkler, color of the bulb or link

and the temperature classification.

[edit]Sprinkler types

[edit]ESFR

ESFR, or ESFR Sprinkler, denotes a special type of fire

sprinkler. Early Suppression Fast Response sprinkler heads were developed in the

1990s to take advantage of the latest fast-response fire sprinkler technology to

provide fire suppression of specific high-challengefire hazards. The sprinklers are

specifically designed to fully suppress a fire that is within the design limits of the

piping system. Prior to the introduction of these sprinklers, protection systems were

designed to control fires until the arrival of thefire department.

Types Of Sprinkler HeadsThe Different Types And Uses Of Sprays,Rotors, And Impact Sprinklers

Sprinkler heads come in a variety of sizes, shapes, models, andbrands, but most of these variations fit into four main categories:

Pop-up sprinkler heads

Impact rotors

Gear-driven rotors

Large turf rotors

Pop-Up Sprinkler Heads

http://en.wikipedia.org/wiki/National_Fire_Protection_Associationhttp://en.wikipedia.org/wiki/National_Fire_Protection_Associationhttp://en.wikipedia.org/w/index.php?title=Fire_sprinkler&action=edit&section=4http://en.wikipedia.org/w/index.php?title=Fire_sprinkler&action=edit&section=4http://en.wikipedia.org/w/index.php?title=Fire_sprinkler&action=edit&section=4http://en.wikipedia.org/w/index.php?title=Fire_sprinkler&action=edit&section=5http://en.wikipedia.org/w/index.php?title=Fire_sprinkler&action=edit&section=5http://en.wikipedia.org/w/index.php?title=Fire_sprinkler&action=edit&section=5http://en.wikipedia.org/wiki/Fire_hazardhttp://en.wikipedia.org/wiki/Fire_hazardhttp://en.wikipedia.org/wiki/Fire_hazardhttp://en.wikipedia.org/wiki/Fire_departmenthttp://en.wikipedia.org/wiki/Fire_departmenthttp://en.wikipedia.org/wiki/Fire_departmenthttp://www.sprinklerwarehouse.com/DIY-How-to-choose-a-sprinkler-head-s/7027.htmhttp://en.wikipedia.org/wiki/Fire_departmenthttp://en.wikipedia.org/wiki/Fire_hazardhttp://en.wikipedia.org/w/index.php?title=Fire_sprinkler&action=edit&section=5http://en.wikipedia.org/w/index.php?title=Fire_sprinkler&action=edit&section=4http://en.wikipedia.org/wiki/National_Fire_Protection_Association

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Click here to buySprinkler Sprays

Probably the most widely used irrigation head; pop-ups are typicallyused for residential and small commercial sprinkler systems. Thereare two types of pop-up heads; stationary sprays and rotating heads,called rotors. Pop-up spray heads are designed to supply acontinuous stream of water, and are fitted with a nozzle. There arenozzles in a variety of designs; each design is for a specific spray

pattern, such as a full arc, a half-circle, or a quarter circle. Nozzles areused to distribute water in a variety of patterns to fit the contours of thelandscape. Other than a pop-up stem, pop-up spray head