Smoke detector
A smoke detector is a device that senses smoke as an indicator of fire. Commercial security devices issue a signal to a fire alarm control panel as part of a fire alarm system, while household smoke detectors known as smoke alarms issue a local audible or visual alarm from the detector itself. Smoke detectors are housed in plastic enclosures shaped like a disk about 150 millimetres in diameter and 25 millimetres thick, but shape and size vary. Smoke can be detected either optically or by physical process. Sensitive alarms can be used to detect, thus deter, smoking in areas where it is banned. Smoke detectors in large commercial and residential buildings are powered by a central fire alarm system, powered by the building power with a battery backup. Domestic smoke detectors range from individual battery-powered units, to several interlinked mains-powered units with battery backup; the risk of dying in a home fire is cut in half in homes with working smoke alarms. The US National Fire Protection Association reports 0.53 deaths per 100 fires in homes with working smoke alarms compared to 1.18 deaths in homes without.
Some homes do not have any smoke alarms, some alarms do not have working batteries. The first automatic electric fire alarm was patented in 1890 by Francis Robbins Upton, an associate of Thomas Edison. George Andrew Darby patented the first European electrical heat detector in 1902 in Birmingham, England. In the late 1930s Swiss physicist Walter Jaeger tried 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 did not meet its purpose: small concentrations of gas had no effect on the sensor's conductivity. Frustrated, Jaeger lit a cigarette and was soon surprised to notice that a meter on the instrument had registered a drop in current. Smoke particles from his cigarette had done what poison gas could not. Jaeger's experiment was one of the advances. In 1939 Swiss physicist Ernst Meili devised an ionization chamber device capable of detecting combustible gases in mines.
He invented a cold cathode tube that could amplify the small signal generated by the detection mechanism to a strength sufficient to activate an alarm. Ionization smoke detectors were first sold in the United States in 1951. In 1955 simple home "fire detectors" for homes were developed; the United States Atomic Energy Commission granted the first license to distribute smoke detectors using radioactive material in 1963. The first low-cost smoke detector for domestic use was developed by Duane D. Pearsall in 1965, an individual replaceable battery-powered unit that could be installed; the "SmokeGard 700" was a strong fire-resistant steel unit. The company began mass-producing these units in 1975. Studies in the 1960s determined that smoke detectors respond to fires much faster than heat detectors; the first single-station smoke detector was made public the next year. It was an ionization detector powered by a single 9-volt battery, they sold at a rate of a few hundred thousand per year. Several technological developments occurred between 1971 and 1976, including the replacement of cold-cathode tubes with solid-state electronics, which reduced the detectors' sizes and made it possible to monitor battery life.
The previous alarm horns, which required specialty batteries, were replaced with horns that were more energy-efficient, enabling the use of available batteries. These detectors could function with smaller amounts of radioactive source material, the sensing chamber and smoke detector enclosure were redesigned for more effective operation; the rechargeable batteries were replaced by a pair of AA batteries along with a plastic shell encasing the detector. The 10-year-lithium-battery-powered smoke alarm was introduced in 1995; the photoelectric smoke detector was invented by Donald Steele and Robert Emmark of Electro Signal Lab and patented in 1972. An ionization smoke detector uses a radioisotope americium-241, to ionize air. Ionization detectors are more sensitive to the flaming stage of fires than optical detectors, while optical detectors are more sensitive to fires in the early smouldering stage; the smoke detector has two ionization chambers, one open to the air, a reference chamber which does not allow the entry of particles.
The radioactive source emits alpha particles into both chambers. There is a potential difference between pairs of electrodes in the chambers; the currents in both chambers should be the same as they are affected by air pressure and the ageing of the source. If any smoke particles enter the open chamber, some of the ions will attach to the particles and not be available to carry the current in that chamber. An electronic circuit detects that a current difference has developed between the open and sealed chambers, sounds the alarm; the circuitry monitors the battery used to supply or back up power, sounds an intermittent warning when it nears exhaustion. A user-operated test butto
Emergency management
Emergency management is the organization and management of the resources and responsibilities for dealing with all humanitarian aspects of emergencies. The aim is to reduce the harmful effects including disasters; the World Health Organization defines an emergency as the state in which normal procedures are interrupted, immediate measures need to be taken to prevent that state turning into a disaster. Thus, emergency management is crucial to avoid the disruption transforming into a disaster, harder to recover from. Emergency management should not be equated to disaster management. Emergency planning, a discipline of urban planning and design, first aims to prevent emergencies from occurring, failing that, should develop a good action plan to mitigate the results and effects of any emergencies; as time goes on, more data become available through the study of emergencies as they occur, a plan should evolve. The development of emergency plans is a cyclical process, common to many risk management disciplines, such as business continuity and security risk management, as set out below: Recognition or identification of risks Ranking or evaluation of risks Responding to significant risks Tolerating Treating Transferring Terminating Resourcing controls and planning Reaction planning Reporting and monitoring risk performance Reviewing the risk management frameworkThere are a number of guidelines and publications regarding emergency planning, published by professional organizations such as ASIS, National Fire Protection Association, the International Association of Emergency Managers.
There are few emergency management specific standards, emergency management as a discipline tends to fall under business resilience standards. In order to avoid or reduce significant losses to a business, emergency managers should work to identify and anticipate potential risks. In the event that an emergency does occur, managers should have a plan prepared to mitigate the effects of that emergency, as well as to ensure business continuity of critical operations after the incident, it is essential for an organization to include procedures for determining whether an emergency situation has occurred and at what point an emergency management plan should be activated. An emergency plan must be maintained, in a structured and methodical manner, to ensure it is up-to-date in the event of an emergency. Emergency managers follow a common process to anticipate, prevent, prepare and recover from an incident. Cleanup during disaster recovery involves many occupational hazards; these hazards are exacerbated by the conditions of the local environment as a result of the natural disaster.
While individual workers should be aware of these potential hazards, employers are responsible for minimizing exposure to these hazards and protecting workers, when possible. This includes identification and thorough assessment of potential hazards, application of appropriate personal protective equipment, the distribution of other relevant information in order to enable safe performance of the work. Maintaining a safe and healthy environment for these workers ensures that the effectiveness of the disaster recovery is unaffected. Flood-associated injuries: Flooding disasters expose workers to trauma from sharp and blunt objects hidden under murky waters causing lacerations, as well as open and closed fractures; these injuries are further exacerbated with exposure to the contaminated waters, leading to increased risk for infection. When working around water, there is always the risk of drowning. In addition, the risk of hypothermia increases with prolonged exposure to water temperatures less than 75 degrees Fahrenheit.
Non-infectious skin conditions may occur including miliaria, immersion foot syndrome, contact dermatitis. Earthquake-associated injuries: The predominant injuries are related to building structural components, including falling debris with possible crush injury, trapped under rubble and electric shock. Chemicals can pose a risk to human health. After a natural disaster, certain chemicals can be more prominent in the environment; these hazardous materials can be released indirectly. Chemical hazards directly released after a natural disaster occur concurrent with the event so little to no mitigation actions can take place for mitigation. For example, airborne magnesium, chloride and ammonia can be generated by droughts. Dioxins can be produced by forest fires, silica can be emitted by forest fires. Indirect release of hazardous chemicals can be unintentionally released. An example of intentional release is insecticides used after a flood or chlorine treatment of water after a flood. Unintentional release is.
The chemical released is toxic and serves beneficial purpose when released to the environment. These chemicals can be controlled through engineering to minimize their release when a natural disaster strikes. An example of this is agrochemicals from inundated storehouses or manufacturing facilities poisoning the floodwaters or asbestos fibers released from a building collapse during a hurricane; the flowchart to the right has been adopted from research performed by Stacy Young, et al. and can be found here. Exposure limits Below are TLV-TWA, PEL, IDLH values for common chemicals workers are exposed to after a natural disaster. Direct release Magnesium Phosphorus Ammonia SilicaIntentional release Insecticides Chlorine dioxideUnintentional release Crude oil components Benzene, N-hexane, hydrogen sulfi
Flame detector
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, 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. A flame detector can respond faster and more than a smoke or heat detector due to the mechanisms it uses to detect the flame. Ultraviolet detectors work by detecting the UV radiation emitted at the instant of ignition. While capable of detecting fires and explosions within 3–4 milliseconds, a time delay of 2–3 seconds is included to minimize false alarms which can be triggered by other UV sources such as lightning, arc welding and sunlight. UV detectors operate with wavelengths shorter than 300 nm to minimize the effects of natural background radiation; the solar blind UV wavelength band is easily blinded by oily contaminants.
Near infrared array flame detectors known as visual flame detectors, employ flame recognition technology to confirm fire by analyzing near IR radiation using a charge-coupled device. A near infrared sensor is able to monitor flame phenomena, without too much hindrance from water and water vapour. Pyroelectric sensors operating at this wavelength can be cheap. Multiple channel or pixel array sensors monitoring flames in the near IR band are arguably the most reliable technologies available for detection of fires. Light emission from a fire forms an image of the flame at a particular instant. Digital image processing can be utilized to recognize flames through analysis of the video created from the near IR images. Infrared or wideband infrared flame detectors monitor the infrared spectral band for specific patterns given off by hot gases; these are sensed using a specialized fire-fighting thermal imaging camera, a type of thermographic camera. False alarms can be caused by background thermal radiation in the area.
Water on the detector's lens will reduce the accuracy of the detector, as will exposure to direct sunlight. A special frequency range is 4.3 to 4.4 µm. This is a resonance frequency of CO2. During burning of a hydrocarbon much heat and CO2 is released; the hot CO2 emits much energy at its resonance frequency of 4.3 µm. This can be well detected. Moreover, the "cold" CO2 in the air is taking care that the sunlight and other IR radiation is filtered; this makes the sensor in this frequency "solar blind". By observing the flicker frequency of a fire the detector is made less sensitive to false alarms caused by heat radiation, for example caused by hot machinery. A severe disadvantage is that all radiation can be absorbed by water or water vapour. From approx. 3.5 µm and higher the absorption by water or ice is 100%. This makes infrared sensors for use in outdoor applications unresponsive to fires; the biggest problem is our ignorance. A salt film is harmful, because salt absorbs water. However, water vapour, fog or light rain makes the sensor blind, without the user knowing.
The cause is similar to what a fire fighter does if he approaches a hot fire: he protects himself by means of a water vapour screen against the enormous infrared heat radiation. The presence of water vapor, fog, or light rain will also "protect" the monitor causing it to not see the fire. Visible light will, however be transmitted through the water vapour screen, as can been seen by the fact that a human can still see the flames through the water vapour screen; the usual response time of an IR detector is 3–5 seconds. MWIR infrared cameras can be used to detect heat and with particular algorithms can detect hot-spots within a scene as well as flames for both detection and prevention of fire and risks of fire; these cameras can operate both inside and outside. These detectors are sensitive to both UV and IR wavelengths, detect flame by comparing the threshold signal of both ranges; this helps minimize false alarms. Dual IR flame detectors compare the threshold signal in two infrared ranges. One sensor looks at the 4.4 micrometer carbon dioxide, while the other sensor looks at a reference frequency.
Sensing the CO2 emission is appropriate for hydrocarbon fuels. Multi-infrared detectors make use of algorithms to suppress the effects of background radiation, again sensitivity is reduced by this radiation. Triple-IR flame detectors compare three specific wavelength bands within the IR spectral region and their ratio to each other. In this case one sensor looks at the 4.4 micrometer range while the other sensors look at reference wavelengths both above and below 4.4. This allows the detector to distinguish between non-flame IR sources and actual flames which emit hot CO2 in the combustion process; as a result, both detection range and immunity to false alarms can be increased. IR3 detectors can detect a 0.1m2 gasoline pan fire at up to 6
Heat detector
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 damaged property. It is triggered; this is the most common type of heat detector. Fixed temperature detectors operate when the heat sensitive eutectic alloy reaches the eutectic point changing state from a solid to a liquid. Thermal lag delays 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 58°C. Technological developments have enabled the perfection of detectors that activate at a temperature of 47°C, increasing the available reaction time and margin of safety.
Rate-of-Rise heat detectors operate on a rapid rise in element temperature of 6.7° to 8.3°C 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 thermistors. One thermocouple monitors heat transferred by convection or radiation while the other responds to ambient temperature; the detector responds. Rate of rise detectors may not respond to low energy release rates of developing fires. To detect developing fires combination detectors add a fixed temperature element that will respond when the fixed temperature element reaches the design threshold. Heat detectors have a label on them that reads "Not a life safety device"; that is because heat detectors are not meant to replace smoke detectors in 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, e.g. laundry room, garage, or attic, where smoke detectors should not be installed as dust or other particles would affect the smoke detector and cause false alarms.
This will allow extra time 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, 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, it cannot be said that one type of heat detector should always be used instead of another. If one were to place a rate-of-rise heat detector above a large, closed oven 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 be best. If a room filled with combustible materials is protected with a fixed heat detector a fast-flaming fire could exceed the alarm threshold due to thermal lag.
In that case the rate-of-rise heat detector may be preferred
James Madison University
James Madison University is a public research university in Harrisonburg, Virginia. Founded in 1908 as the State Normal and Industrial School for Women at Harrisonburg, the institution was renamed Madison College in 1938 in honor of President James Madison and James Madison University in 1977; the university is situated in the Shenandoah Valley, with the campus quadrangle located on South Main Street. Founded in 1908 as a women's college, James Madison University was established by the Virginia General Assembly, it was called The State Normal and Industrial School for Women at Harrisonburg. In 1914, the name of the university was changed to the State Normal School for Women at Harrisonburg. At first, academic offerings included only today's equivalent of technical training or junior college courses. During this initial period of development, the campus plan was established and six buildings were constructed; the university became the State Teachers College at Harrisonburg in 1924 and continued under that name until 1938, when it was named Madison College in honor of James Madison, the fourth President of the United States whose Montpelier estate is located in nearby Orange, Virginia.
In 1976, the university's name was changed to James Madison University. The first president of the university was Julian Ashby Burruss; the university opened its doors to its first student body in 1909 with an enrollment of 209 students and a faculty of 15. Its first 20 graduates received diplomas in 1911. In 1919, Julian Burruss resigned the presidency to become president of Virginia Polytechnic Institute. Samuel Page Duke was chosen as the second president of the university. During Duke's administration, nine major buildings were constructed. Duke served as president from 1919 to 1949. In 1946, men were first enrolled as regular day students. G. Tyler Miller became the third president of the university in 1949, following the retirement of Samuel Duke. During Miller's administration, from 1949 to 1970, the campus was enlarged by 240 acres and 19 buildings were constructed. Major curriculum changes were made and the university was authorized to grant master's degrees in 1954. In 1966, by action of the Virginia General Assembly, the university became a coeducational institution.
Ronald E. Carrier, JMU's fourth president, headed the institution from 1971 to 1998. During Carrier's administration, student enrollment and the number of faculty and staff tripled, doctoral programs were authorized, more than twenty major campus buildings were constructed and the university was recognized by national publications as one of the finest institutions of its type in America. Carrier Library is named after him. During the first decade of the 21st century, during the administration of JMU's fifth President Linwood H. Rose, the university continued to expand, not only through new construction east of Interstate 81, but on the west side of campus. In early 2005, JMU purchased the Rockingham Memorial Hospital campus just north of the main JMU campus for over $40 million; the hospital has since moved to a new location, JMU now occupies the former hospital site after having made substantial renovations to the previous hospital campus. Additionally in June 2005, the university expanded across South High Street by leasing the former Harrisonburg High School building from the City of Harrisonburg.
In May 2006, the university purchased the property. The sale was approved in June 2005 for $17 million; the university named the old HHS building Memorial Hall. Completed projects include the Rose Library located on the east side of campus, which opened on August 11, 2008; the John C. Wells Planetarium, first opened in 1974, underwent a $1.5 million renovation in 2008. It is now the only one of its kind in the world; the mission of the JMU Planetarium is public outreach. As such, it offers free shows to the public every Saturday afternoon and hosts annual summer space camps in July; the 175,000-square-foot Forbes Center for the Performing Arts opened in June 2010, serves as the home to JMU's School of Theatre and Dance. It provides major performance venues and support spaces for the School of Music, the administrative office for the Dean of the College of Visual and Performing Arts; the rapid expansion of JMU's campus has at times created tension in the city-university relationship. In 2006, the local ABC affiliate reported that the university had nearly doubled in size in the last 20 years, including purchases of several local properties.
The university has experienced tension with local residents with occasional clashes between local police and students at a popular off-campus block party. In 2000, the party with about 2,500 students grew out of hand and required a police presence at the Forest Hills townhouse complex on Village Lane. Ten years police equipped with riot gear used force to disperse a group of 8,000 college-aged individuals at the party. Several participants were airlifted to a medical center in Charlottesville to treat their injuries; the university has condemned the behavior of the block party attendees. James Madison University is considered "More Selective" by the Carnegie Foundation for the Advancement of Teaching. For the Class of 2012, the university received 22,648 applications, for an entering freshmen class of 4,325 for the 2012–2013 academic year; the retention rate for the 2011–2012 freshman class was 91.4%, the ratio of female to male students is 60/40. 38% of students are from out-of-state, representing all 50 states and 89 foreign countries.
James Madison University offers 115 degree programs on the bac
Fire blanket
A fire blanket is a safety device designed to extinguish incipient fires. It consists of a sheet of a fire retardant material, placed over a fire in order to smother it. Small fire blankets, such as for use in kitchens and around the home are made of fiberglass and sometimes kevlar, are folded into a quick-release contraption for ease of storage. Fire blankets, along with fire extinguishers, are fire safety items that can be useful in case of a fire; these nonflammable blankets are helpful in temperatures up to 900 degrees and are useful in smothering fires by not allowing any oxygen to the fire. Due to its simplicity, a fire blanket may be more helpful for someone, inexperienced with fire extinguishers. Larger fire blankets, for use in laboratory and industrial situations, are made of wool; these blankets are mounted in vertical quick-release container so that they can be pulled out and wrapped round a person whose clothes are on fire. Some older fire blankets were are not NFPA rated; this can pose a hazard during the decommissioning of old equipment.
After initial investigation in 2013, in 2014, the Netherlands Food and Consumer Product Safety Authority issued a statement that fire blankets should never be used to extinguish an oil/fat fire such as a chip pan fire if the icons or text on the blanket indicates the blanket may be used in such a case. This includes fire blankets which have been tested according to BS EN 1869. In the investigation out of the 22 tested fire blankets, 16 of the fire blankets themselves caught fire. In the other 6 the fire reignited; the Dutch Fire Burn foundation reported several accidents involving the use of fire blankets when extinguishing oil/fat fires. Consumers may send in their existing fire blankets, which will receive a sticker stating'niet geschikt voor olie- en vetbranden'. New products will have this text printed, rather than stickered. For a fire to burn, all three elements of the fire triangle must be present: heat and oxygen; the fire blanket is used to cut off the oxygen supply to the fire. The fire blanket must be sealed to a solid surface around the fire.
Fire blankets have two pull down tails visible from outside the packaging. The user should place one hand on each tag and pull down removing the blanket from the bag; the tails are located near the top of the fire blanket which allows the top lip of the fire blanket to fold back over the users' hands, protecting them from heat and direct contact burns. Cover the fire with the fire blanket, it will help cut the oxygen supply and extinguish the fire. You can use this method when a part of the body catches fire; the fire blanket must be sealed to a solid surface around the fire. The Fire Industry Association publish a "Code of Practice for the Commissioning and Maintenance of Fire Blankets Manufactured to BS EN 1869"; the FIA's code of practice recommends that the responsible person ensures that such fire blankets are subject to annual maintenance by a competent service provider. It recommends that consideration should be given to the replacement of fire blankets after seven years from the date of commissioning.
Welding blanket
