SAFETY

Safety

Safety is the state of being "safe" (from French sauf), the condition of being protected against physical, social, spiritual, financial, political, emotional, occupational, psychological, educational or other types or consequences of failure, damage, error, accidents, harm or any other event which could be considered non-desirable. This can take the form of being protected from the event or from exposure to something that causes health or economical losses. It can include protection of people or of possessions.

There also are two slightly different meanings of safety, for example, home safety may indicate a building's ability to protect against external harm events (like weather, home invasion, etc), and the second that its internal installations (like appliances, stairs, etc) are safe (not dangerous or harmful) for its habitants.

Safety can be limited in relation to some guarantee or a standard of insurance to the quality and un harmful function of an object or organization. It is used in order to ensure that the object or organization will do only what it is meant to do.

It's important to realize that safety is relative. Eliminating all risk, if even possible, would be extremely difficult and very expensive. A safe situation is one where risks of injury or property damage are low and manageable

Types of safety

It is important to distinguish between products that meet standards, that are safe, and those that merely feel safe. The highway safety community uses these terms:

Normative safety is a term used to describe products or designs that meet applicable design standards.

Substantive safety means that the real-world safety history is favorable, whether or not standards are met.

Perceived safety refers to the level of comfort of users. For example, traffic signals are perceived as safe, yet under some circumstances, they can increase traffic crashes at an intersection. Traffic roundabouts have a generally favorable safety record, yet often make drivers nervous.

Risks and responses

Safety is generally interpreted as implying a real and significant impact on risk of death, injury or damage to property. In response to perceived risks many interventions may be proposed with engineering responses and regulation being two of the most common.

Probably the most common individual response to perceived safety issues is insurance, which compensates for or provides restitution in the case of damage or loss.

System safety and reliability engineering

System safety and reliability engineering is an engineering discipline. Continuous changes in technology, environmental regulation and public safety concerns make the analysis of complex safety-critical systems more and more demanding.

A common fallacy, for example among electrical engineers regarding structure power systems, is that safety issues can be readily deduced. In fact, safety issues have been discovered one by one, over more than a century in the case mentioned, in the work of many thousands of practitioners, and cannot be deduced by a single individual over a few decades. A knowledge of the literature, the standards and custom in a field is a critical part of safety engineering. A combination of theory and track record of practices is involved, and track record indicates some of the areas of theory that are relevant. (In the USA, persons with a state license in Professional Engineering in Electrical Engineering are expected to be competent in this regard, the foregoing notwithstanding, but most electrical engineers have no need of the license for their work.)

Safety is often seen as one of a group of related disciplines: quality, reliability, availability, maintainability and safety. (Availability is sometimes not mentioned, on the principle that it is a simple function of reliability and maintainability.) These issues tend to determine the value of any work, and deficits in any of these areas are considered to result in a cost, beyond the cost of addressing the area in the first place; good management is then expected to minimize total cost.

Safety measures are activities and precautions taken to improve safety, i.e. reduce risk related to human health. Common safety measures include:

Visual examination for dangerous situations such as emergency exits blocked because they are being used as storage areas.

Visual examination for flaws such as cracks, peeling, loose connections.

Chemical analysis

X-ray analysis to see inside a sealed object such as a weld, a cement wall or an airplane outer skin.

Destructive testing of samples

Stress testing subjects a person or product to stresses in excess of those the person or product is designed to handle, to determining the "breaking point".

Safety margins/Safety factors. For instance, a product rated to never be required to handle more than 200 pounds might be designed to fail under at least 400 pounds, a safety factor of two. Higher numbers are used in more sensitive applications such as medical or transit safety.

Implementation of standard protocols and procedures so that activities are conducted in a known way.

Training of employees, vendors, product users

Instruction manuals explaining how to use a product or perform an activity

Instructional videos demonstrating proper use of products

Examination of activities by specialists to minimize physical stress or increase productivity

Government regulation so suppliers know what standards their product is expected to meet.

Industry regulation so suppliers know what level of quality is expected. Industry regulation is often imposed to avoid potential government regulation.

Self-imposed regulation of various types.

Statements of Ethics by industry organizations or an individual company so its employees know what is expected of them.

Drug testing of employees, etc.

Physical examinations to determine whether a person has a physical condition that would create a problem.

Periodic evaluations of employees, departments, etc.

Geological surveys to determine whether land or water sources are polluted, how firm the ground is at a potential building site, etc.

Standards organizations

A number of standards organizations exist that promulgate safety standards. These may be voluntary organizations or government agencies.

American National Standards Institute

A major American standards organization is the American National Standards Institute (ANSI). Usually, members of a particular industry will voluntarily form a committee to study safety issues and propose standards. Those standards are then recommended to ANSI, which reviews and adopts them. Many government regulations require that products sold or used must comply with a particular ANSI standard.

Testing laboratories

Product safety testing, for the United States, is largely controlled by the Consumer Product Safety Commission. In addition, work-place related products come under the jurisdction of OSHA^[which certifies independent testing companies as Nationally Recognized Testing Laboratories (NRTL), .

For other countries, there are many other organizations that have accreditation to test and/or submit test reports for safety certification. These are typically referred to as a Notified or Competent Body. The most common is the IECEE Certification Body Scheme,

Electricity (from New Latin ēlectricus, "amber-like") is a general term that encompasses a variety of phenomena resulting from the presence and flow of electric charge. These include many easily recognisable phenomena such as lightning and static electricity, but in addition, less familiar concepts such as the electromagnetic field and electromagnetic induction.

In general usage, the word 'electricity' is adequate to refer to a number of physical effects. However, in scientific usage, the term is vague, and these related, but distinct, concepts are better identified by more precise terms:

Electric charge – a property of some subatomic particles, which determines their electromagnetic interactions. Electrically charged matter is influenced by, and produces, electromagnetic fields.

Electric current – a movement or flow of electrically charged particles, typically measured in amperes.

Electric field – an influence produced by an electric charge on other charges in its vicinity.

Electric potential – the capacity of an electric field to do work, typically measured in volts.

Electromagnetism – a fundamental interaction between the electric field and the presence and motion of electric charge.

Electricity has been studied since antiquity, though scientific advances were not forthcoming until the seventeenth and eighteenth centuries. It would remain however until the late nineteenth century that engineers were able to put electricity to industrial and residential use, a time which witnessed a rapid expansion in the development of electrical technology. Electricity's extraordinary versatility as a source of energy means it can be put to an almost limitless set of applications which include transport, heating, lighting, communications, and computation. The backbone of modern industrial society is, and for the foreseeable future can be expected to remain, the use of electrical pow.

Charge on a gold-leaf electroscope causes the leaves to visibly repel each other

The presence of charge gives rise to the electromagnetic force: charges exert a force on each other, an

A fire extinguisher is an active fire protection device used to extinguish or control small fires, often in emergency situations. Typically, a fire extinguisher consists of a handheld cylindrical pressure vessel containing an agent which can be discharged to extinguish a fire.

The typical steps for operating a stored pressure fire extinguisher (described by the acronym "PASS") are the following:

P - Pull the safety pin

A - Aim the nozzle at the base of the fire, from a safe distance (*about 1 to 3 meters (4 to 10 feet) away)

S - Squeeze the handle

S - Sweep the extinguisher from side to side while aiming at the base of the fire

The approximate starting distance varies by the size and type of the extinguisher.

If using a cartridge operated extinguisher you must push down on the cartridge puncturing lever to pressurize the extinguisher after pulling the pin.

CO₂ fire extinguishers usually have a horn-shaped nozzle. Do not touch this horn (or the pipe linking it to the extinguisher) when attempting to put out a fire - your hand may freeze to the extinguisher, unless it is equipped with what is called a Frost Horn.

There are various types of extinguishers, which are used for different types of fires; using the wrong type can worsen the fire hazard, but using the right one can better the situation.

The first automatic fire extinguisher of which there is any record was patented in England in 1723 by Ambrose Godfrey, a celebrated chemist. It consisted of a cask of fire-extinguishing liquid containing a pewter chamber of gunpowder. This was connected with a system of fuses which were ignited, exploding the gunpowder and scattering the solution. This device was probably used to a limited extent, as Bradley's Weekly Messenger for November 7, 1729, refers to its efficiency in stopping a fire in London.

Fire classes

In firefighting, fires are organized into several fire classes that describe what kind of fuel or heat source it has, and by extension what methods will be necessary to contain it or put it out.

This article primarily deals with the United States system of classifying fires. See the section below for the European and Australasian classifications, and note the table to the right which indicates the relationship between the two sets.

Class-A fires:

Class-A fires are the most common type of fire, that occurs when a material such as wood becomes sufficiently hot, and has oxygen available to it, causing combustion. At this point the material bursts into flame, and will continue burning as long as the fire tetrahedron (heat, fuel, oxygen, and chemical reaction) continues to be available to it.

Class-A fires are used all around buildings and everywhere in the world in controlled circumstances, such as a campfire, lighter, match, or candle. This makes an example easy to come by. For example, a campfire has a fire triangle - the heat is provided by another fire (such as a match or lighter), the fuel is the wood, and the oxygen is naturally available in the open-air environment of a forest. This fire is not dangerous, because the fire is contained to the wood alone and is usually isolated from the ground by rocks. However, when a class-A fire burns in an environment where fuel and oxygen are in accessible positions, the fire can quickly grow out of control; this is the case where firefighting and fire control techniques are required.

Class-A fires are fairly simple to fight and contain - by simply removing the heat or oxygen (or in some cases fuel), the fire triangle collapses and the fire dies out. The most common way to do this is by removing heat and oxygen by spraying the burning material with water. Other means of control or containment would be to "smother" the fire with carbon dioxide or nitrogen from a fire extinguisher, cutting off its oxygen and causing the fire to die.

Class-A fires are the most commonly encountered fires, and as such most fire departments have equipment to handle them specifically. While this is acceptable for most ordinary conditions, most firefighters find themselves having to call for special equipment such as foam in the case of other fires.

Class-B fires: Class-B fires involve flammable or combustible fuels. These fires follow the same basic fire triangle (heat, fuel, and oxygen) as class-A fires, except that the fuel in question is a flammable liquid such as gasoline. A solid stream of water should never be used to extinguish this type because it can cause the fuel to scatter, spreading the flames. The most effective way to extinguish a class B fire is by inhibiting the chain reaction of the fire, which is done by dry chemical and halon extinguishing agents, although smothering with CO2 or foam is also effective. Some newer clean agents designed to replace halon work by cooling the liquid below its flash point, but these have limited class B effectiveness.

Class-C fires: Class-C fires are electrical fires, where the heat side of the fire triangle is caused by, for example, short-circuiting machinery or overloaded electrical outlets. These fires can be a severe hazard to firefighters using water: when the solid stream of water hits the electrical fire, the electricity is conducted through it and into the hose, then into the firefighter's body. Electrical shocks have caused many firefighter deaths.

There are two main ways of fighting a class-C fire: cutting off its oxygen, or simply turning off the electricity to the fire from a breaker. A class-C fire can be put out with a fire extinguisher rated for class-C fires, or with protein foam, but the primary approach is to simply turn off the power as noted above. This causes the fire to become an ordinary class-A fire, or perhaps to die out entirely. The agents used to extinguish fire of class-c are sodium bicarbonate, carbon dioxide, halons, potassium bicarbonate and PKP.

Class-D fires: Class-D fires are metal fires. Certain metals, such as sodium, titanium, magnesium, potassium, uranium, lithium, plutonium, calcium and others are flammable. Magnesium and titanium fires are common. When one of these combustible metals ignites, it can easily and rapidly spread to surrounding class-A materials.

Generally, masses of combustible metals do not represent unusual fire risks because they have the ability to conduct heat away from hot spots so efficiently that the heat of combustion cannot be maintained - this means that it will require a lot of heat to ignite a mass of combustible metal. Generally, metal fire risks exist when sawdust, machine shavings and other metal 'fines' are present. Generally, these fines can be ignited by the same types of ignition sources that would start other common fires.

Water and other common firefighting materials can excite metal fires and make them worse. The NFPA recommends that class D fires be fought with 'dry powder' extinguishing agents. Dry Powder agents work by smothering and heat absorption. The most common of these agents are sodium chloride granules and graphite powder. In recent years powdered copper has also come into use.

Some extinguishers use dry chemical extinguishing agents. This is easily confusable with dry powder. They are quite different, and using one of these extinguishers in error in place of dry powder can actually increase the size of a class D fire much like water.

Class-D fires represent a unique hazard because people are often not aware of the characteristics of these fires and are not properly prepared to fight them. Therefore, even a small class-D fire can spread class-A fires to the surrounding combustible materials. Most fire stations do not have class-D extinguishing agents available to them, making fighting these fires a logistical problem - however, in most places where these materials are found there is a hopper filled with the proper extinguishing agent.

Class-K fires: Class-K fires are fires that involve cooking oils.

Though by definition, Class-K is a subclass of Class-B, the special characteristics of these types of fires are considered important enough to recognize. Saponification can be used to extinguish such fires.

Appropriate fire extinguishers may also have hoods over them that help extinguish the fire.

Types of extinguishing agents

Dry Chemical Powder based agent that extinguishes by separating the four parts of the fire tetrahegon. It prevents the chemical reaction between heat, fuel and oxygen. Thus extinguishing the fire. Contrary to some beliefs dry chemical agents do not cool or smother a fire.

Ammonium phosphate, used on class A, B, and C fires. It receives its class A rating from the agents ability to melt and flow at 177 °C (350 °F) to smother the fire. More corrosive than other dry chemical agents. ABC Dry Chemical

Sodium bicarbonate, used on class B and C fires. Interrupts the fire's chemical reaction.

Potassium bicarbonate (aka Purple-K), used on class B and C fires. About two times as effective on class B fires as sodium bicarbonate. The preferred dry chemical agent of the oil and gas industry. The only dry chemical agent certified for use in AR-FF by the NFPA.

Potassium bicarbonate & Urea Complex (aka Monnex), used on Class B and C fires. More effective than all other powders due to its ability to decrepitate (where the powder breaks up into smaller particles) in the flame zone creating a larger surface area for free radical inhibiton.

Foams: Applied to fuel fires as either an aspirated (mixed & expanded with air in a branch pipe) or non aspirated form to form a frothy blanket or seal over the fuel, preventing oxygen reaching it. Unlike powder, foam can be used to progressively extinguish fires without flashback

AFFF (aqueous film forming foam), used on A and B fires and for vapor suppression. The most common type in portable extinguishers. It contains flour tensides  which can be accumulated in human body.

AR-AFFF (Alcohol-resistant aqueous film forming foams), used on fuel fires containing alcohol. Forms a membrane between the fuel and the foam preventing the alcohol from breaking down the foam blanket.

FFFP (film forming fluoroprotein) contains naturally occurring proteins from animal fats to create a foam blanket that is more heat resistant then the synthetic AFFF foams.

CAFS (compressed air foam system) Any APW style extinguisher that is charged with a foam solution and pressurized with compressed air. Generally used to extend a water supply in wildland operations. Used on class A fires and with very dry foam on class B for vapor suppression.

Arctic Fire is a liquid fire extinguishing agent that emulsifies and cools heated materials quicker than water or ordinary foam. It is used extensively in the steel industry. Effective on classes A, B, and D.

FireAde, a foaming agent that emulsifies burning liquids and renders them non-flammable. It is able to cool heated material and surfaces similar to CAFS. Used on A and B (said to be effective on some class D hazards, although not recommended due to the fact that fireade still contains amounts of water which will react with some metal fires).

Water:Cools burning material

APW (Air pressurized water) cools burning material by absorbing heat from burning material. Effective on only Class A fires, but has the advantage of being cheap, harmless, and relatively easy to clean up.

Water Mist uses a fine misting nozzle to break up a stream of deionized water to the point of not conducting electricity back to the operator. Class A and C rated. Used widely in Hospitals.

Water Additives

Wet Chemical (potassium acetate) extinguishes the fire by forming a soapy foam blanket over the burning oil(saponification)and by cooling the oil below its ignition temperature. Generally class A and K (F in Europe) only.

Wetting Agents Detergent based additives used to break the surface tension of water & improve penetration of Class A fires. Enables a 3 litre water extinguisher to achieve the fire fighting capacity of a 9 litre plain water type

Clean Agents

Agent does not extinguish by smothering, but displaces oxygen, or inhibits chemical chain reaction. They are labeled clean agents because they do not leave any residue after discharge which is ideal for sensitive electronics and documents.

Halon (including Halon 1211 and Halon 1301), a gaseous agent that inhibits the chemical reaction of the fire. Classes B:C for lower weight fire extinguishers (2.3 kg ; 5 lbs or less) and A:B:C for heavier weights (4.1-7.7 kg ; 9-17 lbs). Banned from new production, except for military use, as of January 1, 1994 as its properties contribute to ozone depletion and long atmospheric lifetime, usually 400 years. Halon was completely banned in Europe resulting in stockpiles being sent to the United States for reuse. Although production has been banned, the reuse is still permitted. Halon 1301 and 1211 are being replaced with new halons which have no ozone depletion properties and low atmospheric lifetimes, but are less effective.

CO₂, a clean gaseous agent which displaces oxygen. Highest rating for 7.7 kg (20 pound) portable CO₂ extinguishers is 10B:C. Not intended for Class A fires.

Mixtures of inert gases, including Inergen and Argonite.

Class D

Sodium Chloride/Bicarbonate Urea Graphite and Copper forms a crust over the burning metal and performs like a heat sink to draw heat away from the burning material, also smothers to a degree. Copper dry powder was developed by the U.S. Navy for lithium fires and will cling to vertical surfaces.

Australia

Type	Pre-1997	Current	Class
Water	Solid red		A
Foam	Solid blue	Red with a blue band	A	B
Dry Chemical (Powder)	Red with a white band		A	B	C	E
Carbon dioxide	Red with a black band		A (limited)	B	C	E	F
Vapourising liquid (not halon)	Red with a yellow band		A	B	C	E
Halon	Solid yellow	—	A	B		E
Wet Chemical	Solid oatmeal	Red with an oatmeal band	A				F

UK

Type	Old Code	BS EN 3 Colour Code	Fire Class
Water	Signal Red	Signal Red	A
Foam	Cream	Red with a Cream panel above the operating instructions	A	B			sometimes E
Dry Powder	French Blue	Red with a Blue panel above the operating instructions	A	B	sometimes C		E
Carbon Dioxide CO2	Black	Red with a Black panel above the operating instructions		B			E
Halon	Emerald Green	Pre-03- Signal red with a green panel	A	B			E
Wet Chemical	No F Class	Red with a Canary Yellow panel above the operating instructions	A					F
Class D Powder	French Blue	Red with a Blue panel above the operating instructions				D

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

Fire alarm systems have devices connected to them to detect smoke and heat, or to alert the occupants of an emergency. Below is a list of common devices found on a fire alarm.

Manual pull stations/manual call points - Devices to allow people to manually activate the fire alarm. Usually located near exits. Also called "manual pull boxes". Other countries have different devices as standard, for example the UK uses 'break-glass callpoints', when people break a small pane of glass to activate the alarm.

Smoke detectors - Spot type: Photoelectric and Ionization; Line type: Projected Beam Smoke Detector; Air-Sampling type: Cloud Chamber

Water Flow Switches - Detect when water is flowing through the fire sprinkler system

Rate-of-Rise and Thermostat (heat) Detectors - Detect heat changes

Valve Supervisory Switch - Indicates that a fire sprinkler system valve that is required to be open, is now closed (off-normal).

Carbon Monoxide Detectors - Detects poisonous carbon monoxide gas and usually only connected to household fire alarm systems. Very rarely seen in commercial systems.

A fire sprinkler is the part of a fire sprinkler system that discharges water when the effects of a fire have been detected, such as when a predetermined temperature has been reached.

Fire sprinklers can be automatic or open orifice. Automatic fire sprinklers operate at a predetermined temperature, utilizing a fusible link, a portion of which melts, or a frangible glass bulb containing liquid which breaks, allowing the plug in the orifice 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 directions and 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.

Gaseous fire suppression is a term to describe the use of inert gases and chemical agents to extinguish a fire. The system typically consists of the agent, agent storage containers, agent release valves, fire detectors, fire detection system (wiring control panel, actuation signaling), agent delivery piping, and agent dispersion nozzles.

Less typically, the agent may be delivered by means of solid propellant gas generators that produce either inert or chemically active gas.

Canisters containing Argon gas for use in extinguishing fire in a server room without damaging equipment

A heat detector is a device that detects heat and can be either electrical or mechanical in operation. The most common types are the thermocouple and the electro-pneumatic, both respond to changes in ambient temperature. Typically, if the ambient temperature rises above a predetermined threshold, then an alarm signal is triggered.

Heat detectors can also be further broken down into two main classifications, "rate-of-rise" and "fixed" or "rate compensated."

Electro-pneumatic heat detector, rate of rise and fixed temperature operation.

A smoke detector or smoke alarm is a device that detects smoke and issues an alarm to alert nearby people that there is a potential fire. A household smoke detector will typically be mounted in a disk shaped plastic enclosure about 150mm in diameter and 25mm thick, but the shape can vary by manufacturer.

A fire drill is a method of practicing the evacuation of a building for a fire or other emergency. Generally, the emergency system (usually an alarm) is activated and the building is evacuated as though a real fire had occurred. Usually, the time it takes to evacuate is measured to ensure that it occurs within a reasonable length of time.

Security

Security is the condition of being protected against danger or loss. In the general sense, security is a concept similar to safety. The nuance between the two is an added emphasis on being protected from dangers that originate from outside. Individuals or actions that encroach upon the condition of protection are responsible for the breach of security.

The word "security" in general usage is synonymous with "safety," but as a technical term "security" means that something not only is secure but that it has been secured. In telecommunications, the term security has the following meanings:

A condition that results from the establishment and maintenance of protective measures that ensure a state of inviolability from hostile acts or influences.

With respect to classified matter, the condition that prevents unauthorized persons from having access to official information that is safeguarded in the interests of national security.

Measures taken by a military unit, an activity or installation to protect itself against all acts designed to, or which may, impair its effectiveness.

Security has to be compared and contrasted with other related concepts: Safety, continuity, reliability. The key difference between security and reliability is that security must take into account the actions of active malicious agents attempting to cause destruction.

Security concepts:

Certain concepts recur throughout different fields of security.

Risk - a risk is a possible event which could cause a loss

Threat - a threat is a method of triggering a risk event that is dangerous

Vulnerability - a weakness in a target that can potentially be exploited by a threat

Exploit - a vulnerability that has been triggered by a threat - a risk of 1.0 (100%)

Countermeasure - a countermeasure is a way to stop a threat from triggering a risk event

Defense in depth - never rely on one single security measure alone

Assurance - assurance is the level of guarantee that a security system will behave as expected

A security guard or security officer is usually a privately and formally employed person who is paid to protect property, assets, and/or people. Often, security officers are uniformed and act to protect property by maintaining a high visibility presence to deter illegal and/or inappropriate actions, observing (either directly, through patrols, or by watching alarm systems or video cameras) for signs of crime, fire or disorder; then taking action and/or reporting any incidents to their client, employer and emergency services as appropriate. Since at least the Middle Ages in Europe, the term watchman was more commonly applied to this function.

"detect, deter, observe and report" methodology

Occupational safety and health (OSH) is a cross-disciplinary area concerned with protecting the safety, health and welfare of people engaged in work or employment and entrants. As a secondary effect, OSH may also protect co-workers, family members, employers, customers, suppliers, nearby communities, and other members of the public who are impacted by the workplace environment.

Since 1950, the International Labour Organization (ILO) and the World Health Organization (WHO) have shared a common definition of occupational health. It was adopted by the Joint ILO/WHO Committee on Occupational Health at its first session in 1950 and revised at its twelfth session in 1995. The definition reads: "Occupational health should aim at: the promotion and maintenance of the highest degree of physical, mental and social well-being of workers in all occupations; the prevention amongst workers of departures from health caused by their working conditions; the protection of workers in their employment from risks resulting from factors adverse to health; the placing and maintenance of the worker in an occupational environment adapted to his physiological and psychological capabilities; and, to summarize, the adaptation of work to man and of each man to his job."

The reasons for establishing good occupational safety and health standards are frequently identified as:

Moral - An employee should not have to risk injury at work, nor should others associated with the work environment.

Economic - many governments realize that poor occupational safety and health performance results in cost to the State (e.g. through social security payments to the incapacitated, costs for medical treatment, and the loss of the "employability" of the worker). Employing organisations also sustain costs in the event of an incident at work (such as legal fees, fines, compensatory damages, investigation time, lost production, lost goodwill from the workforce, from customers and from the wider community).

Legal - Occupational safety and health requirements may be reinforced in civil law and/or criminal law; it is accepted that without the extra "encouragement" of potential regulatory action or litigation, many organisations would not act upon their implied moral obligations.

The terminology used in OSH varies between states, but generally speaking:

A hazard is something that can cause harm if not controlled.

The outcome is the harm that results from an uncontrolled hazard.

A risk is a combination of the probability that a particular outcome will occur and the severity of the harm involved.

“Hazard”, “risk”, and “outcome” are used in other fields to describe e.g. environmental damage, or damage to equipment.

Modern occupational safety and health legislation usually demands that a risk assessment be carried out prior to making an intervention. This assessment should:

Identify the hazards

Identify all affected by the hazard and how

Evaluate the risk

Identify and prioritise the required actions

The calculation of risk is based on the likelihood or probability of the harm being realised and the severity of the consequences. This can be expressed mathematically as a quantitative assessment (by assigning low, medium and high likelihood and severity with integers and multiplying them to give a risk factor), or as a description of the circumstances by which the harm could arise i.e. qualitative

Workplace hazards are often grouped into physical hazards, physical agents, chemical agents, biological agents, and psychosocial issues.

Physical hazards include:

Slips and trips

Falls from height

Workplace transport

Dangerous machinery

Electricity

Heavy metals

Physical agents include:

noise

vibration

ionizing radiation

heat and cold stress

lighting

Chemical agents, include

solvents

Biological agents

Psychosocial issues include:

Work related stress, whose causal factors include excessive working time and overwork

Violence from outside the organisation

Bullying (sometimes called mobbing) which may include emotional, verbal, and Sexual harassment

Other issues include:

Reproductive hazards

Work environment factors, such as temperature, humidity, lighting, welfare

Avoidance of musculoskeletal disorders by the employment of good ergonomic design

Inhalation of small particles

Prevention of fire often comes within the remit of health and safety professionals as well.

Government organizations

Occupational Safety and Health Administration (US)

European Agency for Safety and Health at Work (EU)

Canadian Centre for Occupational Health and Safety (Canada)

WSIB (Ontario, Canada)

Australian Safety and Compensation Council (ASCC) (Australia)

International Labour Organisation (United Nations)

Health and Safety Executive (UK)

National Institute for Occupational Safety and Health (US)

Process Safety Management is a regulation, promulgated by the U.S. Occupational Safety and Health Administration (OSHA), intended to prevent an incident like the 1984 Bhopal Disaster. A process is any activity or combination of activities including any use, storage, manufacturing, handling or the on-site movement of Highly Hazardous Chemicals (HHC's). A process includes any group of vessels which are interconnected or separate and contain HHC's which could be involved in a potential release. A process safety incident is the "Unexpected release of toxic, reactive, or flammable liquids and gases in processes involving highly hazardous chemicals. Incidents continue to occur in various industries that use highly hazardous chemicals which exhibit toxic, reactive, flammable, or even explosive properties, or may exhibit a combination of these properties. Regardless of the industry that uses these highly hazardous chemicals, there is a potential for an accidental release any time they are not properly controlled. This, in turn, creates the possibility of disaster. To help assure safe and healthy workplaces, OSHA has issued the Process Safety Management of Highly Hazardous Chemicals regulation (Title 29 of CFR Section 1910.119)^[1] which contains requirements for the management of hazards associated with processes using highly hazardous chemicals.

A great many industrial facilities must comply with OSHA's Process Safety Management (PSM) regulations as well as the quite similar EPA Risk Management Program (RMP) regulations (Title 40 CFR Part 68). The EPA has published a model RMP plan for an ammonia refrigeration facility^[3] which provides excellent guidance on how to comply with either OSHA's PSM regulations or the EPA's RMP regulations.

The Center for Chemical Process Safety (CCPS) of the American Institute of Chemical Engineers (AIChE) has published a widely used book that explains various methods for identifying hazards in industrial facilities and quantifying their potential severity