CCPS Process Safety Glossary

Failure in one system that propagates to another.

Software written by the Device manufacturer which defines the operation of the Device with or without an Application Program. typically a collection of subroutines which acts as an interpreter in converting the instructions of the user entered Application Program into the machine code required by the Device hardware.

Converting from one isomer into another in organic compounds that differ from one another in the position of a hydrogen atom and a double bond.

The precise address of a data cell as defined by the classification scheme of the CCPS Taxonomy.

An equipment condition requiring further technical evaluation to determine suitability for continued service.

A person who is formally appointed to be responsible for maintaining the collective knowledge regarding a process, including process safety-related knowledge.

The temperature at which the rate of heat generation of a reaction or decomposition is equal to the maximum rate of cooling available. Barton and Rogers 1997

A substance or agent to which exposure of a pregnant female can result in malformations in the fetus. Importance: If a substance is known to be a teratogen, a potential health hazard exists and special protection and precaution sections should be checked on a MSDS.

No one definition of terrorism has gained universal acceptance. Terrorism is defined in the Homeland Security Act of 2002 as any activity that "(A) involves an act that (i) is dangerous to human life or potentially destructive of critical infrastructure or key resources; and (ii) is a violation of the criminal laws of the United States or of any State or other subdivision of the United States; and (B) appears to be intended (i) to intimidate or coerce a civilian population; (ii) to influence the policy of a government by intimidation or coercion; or (iii) to affect the conduct of a government by mass destruction, assassination, or kidnapping."

Verifying that the sampled information is valid. Testing can be performed by retracing data or information (i.e., physically checking against the status of the sampled information against equipment, operations, etc.), independent computation of results, and confirmation using another source of data or information.

Data associated with the aspects of a reaction that are based on the thermodynamic laws of energy, such as Gibb's free energy, and the enthalpy (heat) of reaction.

Any indication, circumstance, or event with the potential to cause the loss of, or damage to, an asset. Threat can also be defined as the intention and capability of an adversary to undertake actions that would be detrimental to critical assets.

A term used by ACGIH to express the airborne concentration of a material to which nearly all persons can be exposed day after day without adverse effect. ACGIH expresses TLV's in three ways; TLV-TWA, TLV-STEL, and TLV-CL. TLV's are reviewed and revised annually where necessary by the ACGIH. If a TLV is exceeded, a potential health hazard exists and corrective action is necessary. Also see "Skin" relative to TLV's.

A 15-minute, time -weighted average concentration to which workers may be exposed up to four times per day with at least 60 minutes between successive exposures with no ill effect if the TLV-TWA (see below) is not exceeded. The limit supplements the TLV-TWA where there are recognized acute effects from a substance with toxic effects that result primarily from chronic exposures. Developed by the ACGIH.

Time from that moment when equipment installation is complete, the time period for equipment commissioning, and the operating time thereafter.

A failure that is primarily due to the degradation over the time that a device or system is in service. For example, the failure of a pump after 2000 hours of continuous service due to wear on the bearings would be considered a time-related failure.

An estimation of the time required for an exothermic reaction, in an adiabatic container, (that is, no heat gain or loss to the environment), to reach the point of thermal runaway. (ASTM E 1445)

The delay encountered by the signal (*) as it passes through the input filter (from the Field Input Terminal(S) to the input conversion circuit boundary).

The time required, following the initiation of a specified stimulus to a system, for an output going in the direction of necessary corrective action to first reach a specified value. (EANSI/IEEE Standard 100-1977.)

For digital input, sum of TID and TIT. For analog input, sum of TAID and TAIT.

The time elapsed between a change input signal state at the Field Input Terminals and the corresponding change in the output signal(s) state(s) at the Field Output Terminals. TRT is the sum of all individual (partial) times encountered by the signal (information) as it pass through the PES from the field Input Interface to the Field Output Interface. Generally all partial times may vary depending upon many conditions such as the hardware configuration (e.g., RIOSs communication links that may affect TIT and TQT, the method used to acquire and process data such as periodic scan interrupts, and the instantaneous load of the application program.

The time required by the signal to pass (transfer) from the data storage in a MPU memory (since it is elaborated by the Application Program) to the output storage at the output interface boundary.

Unless a different definition or explanation of this term is provided in a chapter within a specific context, timely shall mean the following: the resolution or implementation of recommendations, action items, and other follow-up activities are promptly determined, performed, or conducted. This means that they are completed in a reasonable time period given the complexity of the actions or activities decided upon and their difficulty of implementation, and that the timing should be evaluated on a case-by-case basis.

A function block delaying a bosian input signal a specified Duration when changing from zero to one.