Process safety focuses on preventing

fire Fire is the rapid oxidation of a material (the fuel) in the exothermic chemical process of combustion, releasing heat, light, and various reaction Product (chemistry), products. At a certain point in the combustion reaction, called the ignition ...

explosion An explosion is a rapid expansion in volume associated with an extreme outward release of energy, usually with the generation of high temperatures and release of high-pressure gases. Supersonic explosions created by high explosives are known ...

s and

chemical accidents A chemical accident is the unintentional release of one or more chemical hazard substances which could harm human health and the environment. Such events include fires, explosions, leakages or release of toxic or hazardous materials that can caus ...

chemical process In a scientific sense, a chemical process is a method or means of somehow changing one or more chemicals or chemical compounds. Such a chemical process can occur by itself or be caused by an outside force, and involves a chemical reaction of some ...

facilities or other facilities dealing with

hazardous material Dangerous goods, abbreviated DG, are substances that when transported are a risk to health, safety, property or the environment. Certain dangerous goods that pose risks even when not being transported are known as hazardous materials ( syllabi ...

s such as

refineries A refinery is a production facility composed of a group of chemical engineering unit processes and unit operations refining certain materials or converting raw material into products of value. Types of refineries Different types of refineries ar ...

, and oil and gas ( onshore and offshore) production installations.

Occupational safety and health Occupational safety and health (OSH), also commonly referred to as occupational health and safety (OHS), occupational health, or occupational safety, is a multidisciplinary field concerned with the safety, health, and welfare of people at wor ...

primarily covers the management of

personal safety Human security is a paradigm for understanding global vulnerabilities whose proponents challenges the traditional notion of national security through military security by arguing that the proper referent for security should be at the human rather th ...

. Well developed management systems also address process safety issues. The tools, techniques, programs etc. required to manage both process and occupational safety can sometimes be the same (for example a work permit system) and in other cases may have very different approaches. LOPA (

Layers of Protection Analysis Layer or layered may refer to: Arts, entertainment, and media * ''Layers'' (Kungs album) * ''Layers'' (Les McCann album) * ''Layers'' (Royce da 5'9" album) *"Layers", the title track of Royce da 5'9"'s sixth studio album *Layer, a female Maveric ...

) or QRA ( Quantified Risk Assessment) for example focus on process safety whereas PPE (

Personal Protective Equipment Personal protective equipment (PPE) is protective clothing, helmets, goggles, or other garments or equipment designed to protect the wearer's body from injury or infection. The hazards addressed by protective equipment include physical, elec ...

) is very much an individual focused occupational safety issue. A common tool used to explain the various different but connected systems related to achieving process safety is described by James T. Reason's

Swiss cheese model The Swiss cheese model of accident causation is a model used in risk analysis and risk management, including aviation safety, engineering, healthcare, emergency service organizations, and as the principle behind layered security, as used in com ...

. In this model, barriers that prevent, detect, control and mitigate a major accident are depicted as slices, each having a number of holes. The holes represent imperfections in the barrier, which can be defined as specific performance standards. The better managed the barrier, the smaller these holes will be. When a major accident happens, this is invariably because all the imperfections in the barriers (the holes) have lined up. It is the multiplicity of barriers that provide the protection. Process safety generally refers to the prevention of unintentional releases of chemicals, energy, or other potentially dangerous materials (including

steam Steam is a substance containing water in the gas phase, and sometimes also an aerosol of liquid water droplets, or air. This may occur due to evaporation or due to boiling, where heat is applied until water reaches the enthalpy of vaporization ...

) during the course of chemical processes that can have a serious effect to the plant and environment. Process safety involves, for example, the prevention of

leak A leak is a way (usually an opening) for fluid to escape a container or fluid-containing system, such as a tank or a ship's hull, through which the contents of the container can escape or outside matter can enter the container. Leaks are usuall ...

s, spills, equipment malfunction, over-pressures, over-temperatures,

corrosion Corrosion is a natural process that converts a refined metal into a more chemically stable oxide. It is the gradual deterioration of materials (usually a metal) by chemical or electrochemical reaction with their environment. Corrosion engine ...

, metal

fatigue Fatigue describes a state of tiredness that does not resolve with rest or sleep. In general usage, fatigue is synonymous with extreme tiredness or exhaustion that normally follows prolonged physical or mental activity. When it does not resolve ...

and other similar conditions. Process safety programs focus on design and engineering of facilities, maintenance of equipment, effective alarms, effective control points, procedures and training. It is sometimes useful to consider process safety as the ''outcome'' or ''result'' of a wide range of technical, management and operational disciplines coming together in an organised way. Process safety chemists will examine both: # Desired

chemical reaction A chemical reaction is a process that leads to the IUPAC nomenclature for organic transformations, chemical transformation of one set of chemical substances to another. Classically, chemical reactions encompass changes that only involve the pos ...

, using a

reaction calorimeter A reaction calorimeter is a calorimeter that measures the amount of energy released ( exothermic) or absorbed (endothermic) by a chemical reaction. These measurements provide a more accurate picture of such reactions. Applications When consider ...

: this will allow a good measure of not only the reaction heat to be ascertained, but also to examine how much heat is "accumulated" during the various additions of chemicals (i.e. How much heat could be evolved if anything went wrong. The chemist will then (if necessary) vary the reactions conditions to arrive at a process that the proposed plant can control (i.e. the heat output is significantly less than the cooling capacity of the plant), and has low accumulation (meaning that in the event of any problem, the current addition can be stopped without any danger of overheating) # Undesired chemical reaction, using one or more of: :*

Differential scanning calorimeter Differential scanning calorimetry (DSC) is a thermoanalytical technique in which the difference in the amount of heat required to increase the temperature of a sample and reference is measured as a function of temperature. Both the sample and ref ...

Reactive screening device Reactive may refer to: *Generally, capable of having a reaction (disambiguation) *An adjective abbreviation denoting a bowling ball coverstock made of reactive resin *Reactivity (chemistry) *Reactive mind *Reactive programming See also *Reactanc ...

:* Adiabatic calorimeter ::These instruments are typically used for examining crude materials that are intended to be purified by

distillation Distillation, or classical distillation, is the process of separation process, separating the components or substances from a liquid mixture by using selective boiling and condensation, usually inside an apparatus known as a still. Dry distilla ...

- these results will allow the chemist to decide on a maximum temperature limit for a process, that will not give rise to a

thermal runaway Thermal runaway describes a process that is accelerated by increased temperature, in turn releasing energy that further increases temperature. Thermal runaway occurs in situations where an increase in temperature changes the conditions in a way t ...

References

External links

*{{Commonscatinline