What is safety engineering pdf

Translate PDF. Established in to spearhead the safety and health culture at the workplace in Malaysia. Vision: To cultivate OSH culture in every workplace and to make every job and task safe and healthy for the worker. Identify the hazard 2. Eliminate 2. Engineering Control 5. Eliminate Completely remove the hazard from the workplace so that it is not there. Substitute Replace the material or process with a less hazardous one.

Isolate Place a barrier or similar between the hazard and people within the workplace e. Engineering Install or using additional machinery. Administrative Safety briefings, safety trainings, work procedure, safety controls awareness signage.

Heinrich Frank E. Safety engineering usually begins during the design of a system or product development. Safety engineers often make use of computer models, prototypes, or recreations of a situations to assess the hazards and risks.

Safety engineers consider a number of factors that may affect the safety of a situation or product, including design, technical safety, material reliability, legislation, and human factors. Subscribe to the Safeopedia newsletter to stay on top of current industry trends and up-to-date know-how from subject matter authorities. Our comprehensive online resources are dedicated to safety professionals and decision makers like you. By: Daniel Clark. By: Jonathan Sharp. By: Tamara Parris CD. Dictionary Dictionary Term of the Day.

Time Required: 1 hours 30 minutes can be split into two minute sessions. Safety engineers develop procedures, systems, products and regulations to keep people safe at their workplaces.

They influence lives on a daily basis by preventing construction workers from falling, keeping hospital workers from contracting infectious diseases, preventing office workers from developing compressed nerves while working on computers, and more.

For instance, technology and engineering TE students must learn procedures associated with lab safety before they may use the machinery and equipment in TE labs. This activity teaches students vital safety rules in order to be successful and safe in engineering labs. This activity also teaches students to analyze and evaluate existing systems and procedures—skills that are central to engineering.

Each TeachEngineering lesson or activity is correlated to one or more K science, technology, engineering or math STEM educational standards. In the ASN, standards are hierarchically structured: first by source; e.

View aligned curriculum. Do you agree with this alignment? Thanks for your feedback! Have you ever been injured? Or have you ever witnessed an injury? Have you or your parents ever been injured at the workplace? Think back and consider the circumstances. Could anything have been done to prevent the injury? If you could go back in time, could somebody have done something differently to prevent the injury? By considering these changes, you are already thinking like a safety engineer! As between 1 American Institute of Chemical Engineers, its consultants, CCPS Technical Steering Committee and Subcommittee members, their employers, their employers' officers and directors, and Aon Energy Risk Engineering, and its employees and 2 the user of this document, the user accepts any legal liability or responsibility whatsoever for the consequences of its use or misuse.

Auto-ignition Temperature The autoignition temperature of a substance, whether solid, liquid, or gaseous, is the minimum temperature required to initiate or cause self-sustained combustion, in air, with no other source of ignition. Basic Event An event in a fault tree that represents the lowest level of resolution in the model such that no further development is necessary e.

Batch Reactor Reactor in which all reactants and solvents are introduced prior to setting the reaction conditions temperature, pressure. Products are only taken from the reactor upon conclusion of the reaction process. Both heat generation and concentrations in the batch reactor vary during the reaction process. Boiling LiquidExpanding Vapor Explosion BLEVE A type of rapid phase transition in which a liquid contained above its atmospheric boiling point is rapidly depressurized, causing a nearly instantaneous transition from liquid to vapor with a corresponding energy release.

Bonding The process of connecting two or more conductive objects together by means of a conductor. Proper authorization, controlled via administrative procedures, must be obtained before operating the valve. The physical seal should have suitable mechanical strength to prevent unauthorized valve operation. Combustible Capable of burning. Combustible Liquid A term used to classify certain liquids that will burn on the basis of flash points.

Common Mode Failure An event having a single external cause with multiple failure effects which are not consequences of each other. Continuous Reactors Reactors that are characterized by a continuous flow of reactants into and a continuous flow of products from the reaction system e. The vessel tank is continuously stirred to maintain a uniform concentration within the vessel. Critical Event A critical event is an event with a specified, high consequence such as an event involving an offsite community impact, critical system damage, a severe injury or a fatality.

Critical Event Frequency The frequency of occurrence of a critical event. The energy input from the deadheaded pump increases the temperature and pressure of the fluid in the pump. Deflagration The chemical reaction of a substance in which the reaction front advances into the unreacted substance at less than sonic velocity. Where a blast wave is produced that has the potential to cause damage, the term explosive deflagration may be used.

Deflagration to Detonation Transition DDT The transition phenomenon resulting from the acceleration of a deflagration flame to detonation via flame-generated turbulent flow and compressive heating effects. At the instant of transition a volume of precompressed, turbulent gas ahead of the flame front detonates at unusually high velocity and overpressure.

Detonation A release of energy caused by the propagation of a chemical reaction in which the reaction front advances into the unreacted substance at greater than sonic velocity in the unreacted material. Distributed Control System DCS A system which divides process control functions into specific areas interconnected by communications normally data highways , to form a single entity.

It is characterized by digital controllers and typically by central operation interfaces. Analysts calculate various hazard and explosion indexes using material characteristics and process data. Emergency Relief Device A device that is designed to open during emergency or abnormal conditions to prevent rise of internal fluid pressure in excess of a specified value.

The device also may be designed to prevent excessive internal vacuum. The device may be a pressure relief valve, a nonreclosing pressure relief device, or a vacuum relief valve.

Emergency Shutdown Device A device that is designed to shutdown the system to a safe condition on command from the emergency shutdown system. Emergency Shutdown System The safety control system that overrides the action of the basic control system and shuts down the process when predetermined conditions are violated. Explosion A release of energy that causes a pressure discontinuity or blast wave.

Fail-Safe Design features which provide for the maintenance of safe operating conditions in the event of a malfunction of control devices or an interruption of an energy source e. A feature incorporated for automatically counteracting the effect of an anticipated possible source of failure.

A system is fail-safe if failure of a component, signal, or utility, initiates action that return the system to a safe condition. Failure An unacceptable difference between expected and observed performance.

Fire Point The minimum temperature at which a flammable or combustible liquid, as herein defined, and some volatile combustible solids will evolve sufficient vapor to produce a mixture with air that will support sustained combustion when exposed to a source of ignition, such as a spark or flame.

Fireball The atmospheric burning of a fuel-air cloud in which the energy is mostly emitted in the form of radiant heat. The inner core of the fuel release consists of almost pure fuel whereas the outer layer in which ignition first occurs is a flammable fuel-air mixture. As buoyancy forces of the hot gases begin to dominate, the burning cloud rises and becomes more spherical in shape. Flammability Limits The range of gas or vapor amounts in air that will burn or explode if a flame or other ignition source is present.

Importance: The range represents an unsafe gas or vapor mixture with air that may ignite or explode. Generally, the wider the range the greater the fire potential. NFPA Flash Fire The combustion of a flammable vapor and air mixture in which flame passes through that mixture at less than sonic velocity, such that negligible damaging overpressure is generated.

Flash Point The temperature at which the vapor-air mixture above a liquid is capable of sustaining combustion after ignition from an external energy source. Fugitive Emissions Those emissions which could not reasonably pass through a stack, chimney, vent or other functionally-equivalent opening. Grounding The process of connecting one or more conductive objects to ground so that each is at the same potential as the earth.

By convention, the earth has zero potential. In practice, grounding is the process of providing a sufficiently small resistance to ground so that a static hazard cannot be created at the maximum credible charging current to a system. Grounding may be referred to as "earthing" in Europe.

Hazard An inherent chemical or physical characteristic that has the potential for causing damage to people, property, or the environment. In this document it is the combination of a hazardous material, an operating environment, and certain unplanned events that could result in an accident.

Hazard Analysis The identification of undesired events that lead to the materialization of a hazard, the analysis of the mechanisms by which these undesired events could occur and usually the estimation of the consequences. A HAZOP is used to question every part of a process to discover what deviations from the intention of the design can occur and what their causes and consequences may be.

This is done systematically by applying suitable guidewords. This is a systematic detailed review technique, for both batch and continuous plants, which can be applied to new or existing processes to identify hazards. Hazard Identification The identification of causes that lead to hazardous events and an estimation of the event consequence.

Hazardous Material In a broad sense, any substance or mixture of substances having properties capable of producing adverse effects to the health or safety of human beings or the environment. Material presenting dangers beyond the fire problems relating to flash point and boiling point. These dangers may arise from, but are not limited to, toxicity, reactivity, instability, or corrosivity Human Factors A discipline concerned with designing machines, operations, and work environments so that they match human capabilities, limitations, and needs.

Includes any technical work engineering, procedure writing, worker training, worker selection, etc. Inert Gas A nonflammable, nonreactive gas that can be used to render the combustible material in a system incapable of supporting combustion. Inherently Safer A condition in which the hazards associated with the materials and operations used in the process have been reduced or eliminated, and this reduction or elimination is permanent and inseparable.

Interlock System A system that detects out-of-limits or abnormal conditions or improper sequences and either halts further action or starts corrective action. A protection technique based upon the restriction of electrical energy within apparatus and of interconnecting wiring, exposed to a potentially explosive atmosphere, to a level below that which can cause ignition by either sparking or heating effects. Because of the method by which intrinsic safety is achieved, it is necessary to ensure that not only the electrical apparatus exposed to the potentially explosive atmosphere but also other electrical apparatus with which it is interconnected is suitably constructed.

Likelihood A measure of the expected frequency with which an event occurs. This may be expressed as a frequency e. Limiting Oxygen Concentration LOC The limiting oxygen concentration LOC is that concentration of oxygen, below which a deflagration flame propagation in the gas, mist, suspended dust, or hybrid mixture cannot occur. The LOC for dusts is dependent on the composition and particle size distribution of the solid.

Minimum Ignition Energy MIE Initiation of flame propagation in a combustible mixture requires an ignition source of adequate energy and duration to overcome heat losses to the cooler surrounding material.

Dust and vapor clouds may be readily ignited if exposed to electric discharges that exceed the minimum ignition energy MIE for the combustible mixture.

Oxidant Any gaseous material that can react with a fuel gas, dust, or mist to produce combustion. Oxygen in air is the most common oxidant. Plug Flow Reactor PFR A plug flow reactor is a tubular reactor where the feed is continuously introduced at one end and the products continuously removed form the other end. Pool Fire The combustion of material evaporating from a layer of liquid at the base of the fire. The valve opens normally in proportion to the pressure increase over opening pressure.

A relief valve is normally used with incompressible fluids. Pressure Safety Valve PSV A safety valve is a spring loaded pressure relief valve actuated by static pressure upstream if the valve and characterized by rapid opening or pop action. A safety valve is normally used with compressible fluids. Process Flow Diagram PFD A diagram that shows the material flow from one piece of equipment to the other in a process. It usually provides information about the pressure, temperature, composition, and flow rate of the various streams, heat duties of exchangers, and other such information pertaining to understanding and conceptualizing the process.

Process Hazard Analysis PHA An organized effort to identify and evaluate hazards associated with chemical processes and operations to enable their control. This review normally involves the use of qualitative techniques to identify and assess the significance of hazards. Conclusions and appropriate recommendations are developed. Occasionally, quantitative methods are used to help prioritized risk reduction. Process Safety A discipline that focuses on the prevention of fires, explosions, and accidental chemical releases at chemical process facilities.

Process Safety System PSS A process safety system comprises the design, procedures, and hardware intended to operate and maintain the process safely. Programmable Logic Controller PLC A microcomputer-based solid-state control system which receives inputs from user-supplied control devices such as switches and sensors, implements them in a precise pattern determined by instructions stored in the PLC memory, and provides outputs for control or user-supplied devices such as relays and motor starters.

Purge Gas A gas that is continuously or intermittently added to a system to render the atmosphere noncombustible. The purge gas can be inert or combustible. Quenching Rapid cooling from an elevated temperature, e. Risk Based Process Safety The CCPS's process safety management system approach that uses risk-based strategies and implementation tactics that are commensurate with the risk-based need for process safety activities, availability of resources, and existing process safety culture to design, correct, and improve process safety management activities.

Runaway Reactions A thermally unstable reaction system which exhibits an uncontrolled accelerating rate of reaction leading to rapid increases in temperature and pressure.

Safety Instrumented System SIS The instrumentation, controls, and interlocks provided for safe operation of the process. In a semi-batch reactor, some reactants are added to the reactor at the start of the batch, while others are fed continuously during the course of the reaction. For vapor dispersion modeling, it is the estimation, based on the release specification, of the actual cloud conditions of temperature, aerosol content, density, size, velocity and mass to be input into the dispersion model.

Task Analysis A human error analysis method that breaks down a procedure or overall job description into individual work tasks. If ignited, the flame speed may accelerate to high velocities and produce significant blast overpressure. Upper Flammable Limit UFL The highest concentration of a vapor or gas the highest percentage of the substance in air that will produce a flash of fire when an ignition source heat, arc, or flame is present.

See also Lower Flammable Limit. At concentrations higher then the UFL, the mixture is too "rich" to burn. The position of failure must be carefully selected so as to bring the system to, or leave the system in a safe operating state. Vapor Density The weight of a vapor or gas compared to the weight of an equal volume of air; an expression of the density of the vapor or gas. Materials lighter than air have vapor densities less than 1. Materials heavier than air examples: propane, hydrogen sulfide, ethane, butane, chlorine, sulfur dioxide have vapor densities greater then 1.

Importance: All vapors and gases will mix with air, but the lighter materials will tend to rise and dissipate unless confined. Heavier vapors and gases are likely to concentrate in low places - along or under floors, in sumps, sewers and manholes, in trenches and ditches - and can travel great distances undetected where they may create fire or health hazards. Vapor Pressure The pressure exerted by a vapor above its own liquid.

The higher the vapor pressure, the easier it is for a liquid to evaporate and fill the work area with vapors which can cause health or fire hazards. Venting Emergency flow of vessel contents out of a vessel. The pressure is controlled or reduced by venting, thus avoiding a failure of the vessel by overpressurization. The emergency flow can be one-phase or multi-phase, each of which results in different flow characteristics.

Before publication, all CCPS books are subjected to a thorough peer review process. CCPS gratefully acknowledges the thoughtful comments and suggestions of the peer reviewers.

Their work enhanced the accuracy and clarity of these guidelines. Although the peer reviewers have provided many constructive comments and suggestions, they were not asked to endorse this book and were not shown the final draft before its release.

To a certain extent, this is an appropriate description of the tools of engineering - those techniques that we use to translate a concept in the mind of the designer into a physical object. But, where does that mental image of the object to be built come from? At its heart, engineering is intuitive, and an art form. By intuitive and creative problem solving processes, the engineer develops and refines a conceptual design, and uses the mathematical and scientific tools of engineering to translate a mental concept into reality.

The selection of the design basis for a process safety system is a problem like any other engineering problem. There is no equation or formula, no scientific principle, which will define the "best" design. Yes, there are scientific and mathematical tools which will help convert a design concept into something which can actually be constructed. But there is no general answer to the question "What is the best design? The number of potential solutions to any engineering problem is large, as anybody who has ever visited an automobile show quickly realizes.

Sometimes, for a specific problem, there will be some solutions which clearly meet the overall objectives of nearly all stakeholders better than others.

In these situations it is easy to select an optimum design. However, in other cases, different stakeholders have significantly different objectives, or will differ significantly in the relative importance of the different objectives of the design. This is one of the reasons why there are so many different kinds of cars at the automobile show, giving each potential purchaser a chance to find a design that best meets his or her objectives.

But this is not possible in the design of a process plant - there is one plant which impacts many stakeholders with their different objectives and priorities. How can we best find the optimal solution? While this is not entirely a technical question, but also includes social and political aspects, I believe that the critical first step is to consider a large number of potential solutions. This increases the likelihood that the solution most acceptable to as many stakeholders as possible will be among those identified.

Where do we get those potential solutions? One important source is accumulated experience our own, and that of others who have faced similar problems in the past.

This book collects much of that accumulated experience from a large number of experts in the chemical process industry. Use of the tables which make up the heart of this book will allow the reader to take advantage of many years of practical experience. This book, a combination, update, and expansion of two earlier CCPS Guideline publications, emphasizes a risk-based approach to the evaluation of safety system design.

Inherently safer approaches are often preferred, but there can be no general answer to the question of which approach or specific solution is best for a particular situation. Instead, the design engineer must take a very broad and holistic approach to the complete design, accounting for the many different, and often competing, objectives which the design must accomplish.

Safety, health effects, environmental impact, loss prevention, economic and business factors, product quality, technical feasibility, and many other factors must be considered. This book challenges the engineer to adopt a risk-based approach to evaluating many competing goals when deciding among a number of potential design alternatives.

This book can be extremely useful in conducting process hazard analysis studies. The failure mode tables in Chapter 6 can be the basis for hazard identification checklists and also offer a variety of potential solutions for identified concerns. However, the book will be even more beneficial if used by the individual engineer at the earliest stages of the design process, before any formal hazard reviews.

It should be consulted frequently in the course of the designer's day-to-day work in specifying and designing process facilities. If you are a process safety professional, make sure that all of the process design engineers in your organization read and use this book.

It will make your job a lot easier! Dennis C. Encouraging the use of such information by dissemination through publications, seminars, symposia and continuing education programs for engineers. The intent was to produce a book that presented the process safety design issues needed to address all stages of the evolving design of a facility. The first edition discussed the impact that various engineering design choices have on the risk of a catastrophic accident, starting with the initial selection of the process and continuing through its final design.

Little Inc. This book described the ways that major processing equipment could fail, causing a catastrophic accident. By capturing industry experience in how major processing equipment can fail, this book provided a very useful tool for the selection of process safety systems.

The inherently safer solutions that were suggested may, in some cases, have come as a surprise to the process and design engineer because they may have been the most costeffective solution. In , both the Technical Steering Committee and the Planning Committee of CCPS recognized the need to consolidate these two works into one combined, expanded and updated volume. The result of this effort is the book you now hold in your hand. Chapter 6 contains updated equipment failure tables from the Design Solutions book.

This book focuses on engineering design to reduce risk due to process hazards. It does not focus on operations, maintenance, transportation, or personnel safety issues, although improved process safety can benefit each area. Detailed engineering designs are outside the scope of this book, but the authors have provided an extensive guide to references and other literature to assist the designer who wishes to go beyond safety design philosophy to the specifics of a particular safety system design.

Originally published in , the purpose of Guidelines for Engineering Design for Process Safety was to shift the emphasis on process safety to the earliest stage of the design where process safety issues could be addressed at the lowest cost and with the greatest effect. Almost 20 years later, this 2nd edition of Guidelines for Engineering Design for Process Safety continues to stress the importance of emphasizing process safety during Front-End Engineering and Design FEED to achieve the greatest risk reduction at the lowest cost - and also emphasizes the benefits of diligence to process safety design issues through the life of the facility.

This book focuses on process safety issues in the design of chemical, petrochemical, and hydrocarbon processing facilities. The scope is limited to selecting appropriate designs to prevent or mitigate the release of flammable or toxic materials that could lead to a fire, explosion, and impact to personnel and the community. Process safety issues affecting operations and maintenance are limited to cases where design choices impact system reliability.

These Guidelines are intended to be applicable to the design of a new facility, as well as modification of an existing facility. For example, Section 7. It is clear that choices made early in design can reduce both the potential for large releases of hazardous materials and the severity of such releases, if they should occur. Process safety has been defined in previous publications as: A discipline that focuses on the prevention and mitigation of fires, explosions, and accidental chemical releases at process facilities.

Excludes classic worker health and safety issues involving working surfaces, ladders, protective equipment, etc. Hazard evaluations are one method used to identify, evaluate, and control hazards involved in chemical processes. Hazards can be defined as characteristics of systems, processes, or plants that must be controlled to prevent occurrence of specific undesired events. Hazard evaluation is a technique that is applied repeatedly throughout the design, construction, and operation phases of a facility Figure 1.

Engineering design for process safety should be considered within the framework of a comprehensive process safety management program as described in Plant Guidelines for Technical Management of Chemical Process Safety Ref. Hazard evaluation is synonymous with process hazard analysis and process safety review. From conceptual design to decommissioning, no single method of hazard evaluation applies to all of the stages of a project. Different methods are required for different stages of a project, such as research and development, conceptual design, startup and operation.

Table 1. An objective shown for one stage may be applicable to another. As illustrated in Table 1. Findings from the Baker Panel report Ref. Personal or occupational safety hazards give rise to incidents—such as slips, falls, and vehicle accidents—that primarily affect one individual worker for each occurrence. Process safety hazards can give rise to major accidents involving the release of potentially dangerous materials, the release of energy such as fires and explosions , or both.

Process safety incidents can have catastrophic effects and can result in multiple injuries and fatalities, as well as substantial economic, property, and environmental damage. Process safety refinery incidents can affect workers inside the refinery and members of the public who reside nearby. Process safety in a refinery involves the prevention of leaks, spills, 1.

Process safety programs focus on the design and engineering of facilities, hazard assessments, management of change, inspection, testing, and maintenance of equipment, effective alarms, effective process control, procedures, training of personnel, and human factors. The Texas City tragedy in March was a process safety accident.

Figure 1. Specifically, implementation of these guidelines requires the application of sound engineering judgment because the concepts may not be applicable in all cases. Identifying and addressing relevant process safety standards, codes, regulations, and laws over the life of a process is one of the five elements in the Risk Based Process Safety pillar of committing to process safety Ref.

Companies should establish a process for maintaining adherence to applicable standards, codes, regulations, and laws. The primary objective of establishing a standards system is to ensure that a facility remains in conformance with applicable standards, codes, regulations, and laws, including voluntary ones adopted by the company over the life of the facility.

Long-term conformance to such standards of care helps ensure that the facility is operated in a safe and legal fashion.

For detailed information on establishing a system to comply with standards, readers are referred to Chapter 4, Compliance with Standards, of Guidelines for Risk Based Process Safety Ref.

For example, the State of California's Accidental Release Prevention Program requires compliance by facilities with over a threshold quantity of lb of chlorine, while the U. Process safety is an important part of risk management and loss prevention.

Although these Guidelines do not provide all the "answers," they do highlight the process safety issues that must be addressed in all stages of design. These Guidelines will benefit many different people within an organization: Corporate Leadership - Senior executives define the basis for the development of design philosophies. Their commitment and recognition of the value of integrating process safety at all levels of the design process is essential.

A Project Manager is responsible for determining the basic protection design concepts to apply in the execution of a project. The Project Manager is responsible for implementing the decisions and abiding by the process safety systems associated with the design. This still leaves room for making decisions when designing process units and protection systems. Each chapter has been updated to include state-of-the-art information, industry experience, and references to other CCPS publications.

Specific references and applicable industry standards are listed at the end of each chapter. It is not the intent of this book to make specific design recommendations, but to provide a good source of references where the interested reader can obtain more detailed information. How can this book help me? When is process safety incorporated into engineering design?