Probability of failure on demand (PFOD, PFD)
The probability that a system will fail to perform a specified function on demand (i.e., when challenged or needed).
Probit
A random variable with a mean of 5 and a variance of 1, which is used in various effect models. Probit-based models derived from experimental dose-response data, are often used to estimate the health effect that might result based upon the intensity and duration of an exposure to a harmful substance or condition (e.g., exposure to a toxic atmosphere, or a thermal radiation exposure).
Procedures
Written step-by-step instructions and associated information (cautions, notes, warnings) that describe how to safely perform a task.
Process
A broad term that includes the equipment and technology needed for petrochemical production, including reactors, tanks, piping, boilers, cooling towers, refrigeration systems, etc.
Process Area
An area containing equipment (e.g. pipes, pumps, valves, vessels, reactors, and supporting structures) intended to process or store materials with the potential for explosion, fire, or toxic material release.
Process Capability (Cp)
The ratio of the specification range to six standard deviations of the process.
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
An organized effort to identify and evaluate hazards associated with 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 Knowledge Management
A PSM program element that includes work activities to gather, organize, maintain, and provide information to other PSM program elements. Process safety knowledge primarily consists of written documents such as hazard information, process technology information, and equipment-specific information. Process safety knowledge is the product of this PSM element.
Process Life Cycle
The stages that a physical process or a management system goes through as it proceeds from birth to death. These stages include conception, design, deployment, acquisition, operation, maintenance, decommissioning, and disposal.
Process Media
The material (i.e., chemical substances) processed by the equipment.
Process Medium
The material processed by the equipment.
Process Safety
A disciplined framework for managing the integrity of operating systems and processes handling hazardous substances by applying good design principles, engineering, and operating practices.
Note: Process Safety focuses on efforts to reduce process safety risks associated with processes handling hazardous materials and energies. Process Safety efforts help reduce the frequency and consequences of potential incidents. These incidents include toxic or flammable material releases (loss events), resulting in toxic effects, fires, or explosions. The incident impact includes harm to people (injuries, fatalities), harm to the environment, property damage, production losses, and adverse business publicity.
Process Safety Competency
The combination of knowledge, skill, expertise, and training needed to deem someone as well-qualified and capable relating to process safety.
Process Safety Culture
The common set of values, behaviors, and norms at all levels in a facility or in the wider organization that affect process safety.
Process Safety Incident/Event
An event that is potentially catastrophic, i.e., an event involving the release/loss of containment of hazardous materials that can result in large-scale health and environmental consequences.
Process Safety Information (PSI)
Physical, chemical, and toxicological information related to the chemicals, process, and equipment. It is used to document the configuration of a process, its characteristics, its limitations, and as data for process hazard analyses.
Process Safety Management (PSM)
A management system that is focused on prevention of, preparedness for, mitigation of, response to, and restoration from catastrophic releases of chemicals or energy from a process associated with a facility.
Process Safety Management Systems
Comprehensive sets of policies, procedures, and practices designed to ensure that barriers to episodic incidents are in place, in use, and effective.
Process Safety Metric
A standard of measurement or indicator of process safety management efficiency or performance.
Process Safety Review
An inspection of a plant/process unit, drawings, procedures, emergency plans and/or management systems, etc., usually by an on-site team and usually problem-solving in nature. (See "Audit" for contrast).
Process Safety System (PSS)
A process safety system comprises the design, procedures, and hardware intended to operate and maintain the process safely.
Process Severity
The indication of the degree of aggressiveness of the process medium on the hardware; aggressiveness would include erosion, stress, corrosion, temperature, blockage, etc. Four categories of severity are used in this book: Clean, General Industry, Moderately Severe, Severe. (See Chapter 2 for further explanation of these categories.)
Product Stewardship
The management practice supporting a philosophy of service to customers and minimizing effects on health and the environment throughout the complete life cycle of a product.
Products
Chemicals produced during a reaction process
Program
A series of actions proposed in order to achieve a certain result.
Program Level 1
An implementation program level under the EPA RMP Rule. Applies to those facilities perceived to have a negligible potential for serious off-site consequences in the event of an accidental release. There are no requirements for an accidental release prevention program for this program level.
Program Level 2
An implementation program level under the EPA RMP Rule. Applies to certain facilities perceived to have the potential for offsite consequences in the event of an accidental release. The accidental release prevention program requirements for this program level are less rigorous than the Program Level 3 requirements. xiv Glossary
Program Level 3
An implementation program level under the EPA RMP Rule. Applies to certain facilities perceived to have the potential for offsite consequences in the event of an accidental release. The accidental release prevention program for this program level contains the most rigorous and detailed requirements under the RMP Rule.
Program Library
A collection of available computer programs and routines.
Program Sustainability
An ongoing commitment to managing risk, improving continuously, reacting to emerging trends, and keeping current on evolving transportation risk analysis practices.
Programmable Controller
A controller which has a human interface that allows the determination of how the PC shall perform its operating functions (e.g., logic, sequencing, timing, counting, and arithmetic, to control, through digital or analog Inputs and Outputs, various types of machines or processes) in an industrial environment. The PC and its associated peripheral are designed so that they can be integrated into an industrial control system and used in their intended functions. The PC can be based on various technologies, including but not limited to; electro-mechanical (e.g., programmable tenor drum, programmable stepping switch), electronic (e.g., programmable diode matrix), or a digitally operating electronic system which uses a programmable memory for the internal storage of user-oriented instructions (e.g., computer, micro-computer, PLC, DCS).
Programmable Controller System (PC System)
A user's built configuration consisting of a programmable controller and associated Peripherals that is necessary for the intended Automated System. It consists of units interconnected by cables or plug-in connections for Permanent Installation and by cables or other means for Portable and Transportable Peripherals.
Programmable Electronic System (PES)
An individual PE device or a series of interconnected PE devices {e.g., sensor (e.g., microprocessor based pressure transmitter), programmable electronic logic solver (e.g., PLC, DCS, single loop controller), final element (e.g., microprocessor based valve)] in a plant for the purpose of control, protection or monitoring. (Includes various types of computers, programmable logic controllers, interconnect systems, instrument distributed control system controllers, and other associated equipment). A PE system also typically includes power supplies, peripherals, non-PE sensors and final elements (e.g., motors), data highways and other communication paths.
Programmable Electronic System (PES):
A system based on a computer connected to sensors and/or actuators in a plant for the purpose of control, protection or monitoring (includes various types of computers, programmable logic controllers, peripherals, interconnect systems, instrument distributed control system controllers, and other associated equipment).
Programmable Logic Controller (PLC)
Abbreviation for programmable logic controller, microcomputer-based control device used to replace relay logic. A 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.
Programmable Logic Controller (PLC)
A PLC is a PE programmable controller (e.g, a PES device, a PE logic solver) that has its embedded software designed in such a way as to provide plant floor user oriented application programming languages, and industrial ESD and response capability similar to electro-mechanical technology. The PLC was originally designed to replace relays in the automotive manufacturing process and has been continuously updated to presently achieve many DCS capability characteristics.
Programming and Debugging Tools (PADT)
A Catalogued Peripheral to assist in programming, testing, commissioning, and troubleshooting the PES application, program documentation and storage, and possible to be used as MMIs. PADTs are said to be "Pluggable" when they may be plugged or unplugged at any time into their associated interface, without any risk to the operators and the application. In all other cases PADTs are said to be "Fixed."
Project Definition
A phase in the development of computerized systems in which a brief statement is developed as to what is to be accomplished and why.
Proof Test
Periodic test performed to detect dangerous hidden failures in a system so that, if necessary, a repair can restore the system to an “as good as new” condition, or as close as practical to this condition.
Proof Test Interval
The time interval between checking a protection system.
Proof Test Time Interval (T)
The interval of time between two successive proof tests. Dimension (Time).
Proof Testing
A run through the process substituting nonhazardous materials (e.g., water) to check for the adequacy of the equipment e.g., heating/cooling load, and to verify procedural steps.
Propagating Brush Discharge
An energetic discharge caused by electrical breakdown of the dielectric layer in a capacitor and massive lateral surface discharge resulting in dissipation of most of the stored charge. The capacitor is typically formed by charged plastic coating on a metal substrate although plastic pipe and tote bins may also form the required charged double layer. The stored energy may exceed 1000 mJ, presenting both personnel shock and ignition hazards for a wide variety of materials, including dusts in air.
Propagating Factors
Human, process, and environmental actions and influences that contribute to guiding, sustaining, continuing, transmitting, spreading, and extending the sequence of events following the initiating event.
Property Boundary
The boundary that is or can be built upon including the opposite side of a public way. (NFPA 30)
Prophylaxis
Prevention of a disease or condition.
Protected Side of Flame Arrester
The side of a flame arrester and system to which it is connected where flame is to be excluded
Protection Layer
A concept whereby a device, system, or human action is provided to reduce the likelihood and/or severity of a specific loss event.
Protective System
Systems such as pressure vessel relief valves, which function to prevent or mitigate the occurrence of an incident.