Wet deposition
Removal of gas and aerosol pollutants by rain or cloud droplets.
What-If Analysis
A scenario-based hazard evaluation procedure using a brainstorming approach in which typically a team that includes one or more persons familiar with the subject process asks questions or voices concerns about what could go wrong, what consequences could ensue, and whether the existing safeguards are adequate.
What-If/Checklist Analysis
A What-If Analysis that uses some form of checklist or other listing of broad categories of concern to structure the what-if questioning.
Wind Rose
A plan view diagram that shows the percentage of time the wind is blowing in a particular direction.
Wind tunnel
Used for fluid modeling experiments at small scale.
Witness
A person who has facts related, directly or indirectly, to the accident or incident.
Word
A data element of length 16 bits.
Work force
A general term used to refer to employees and contractors at a facility. This term is often, but not exclusively, used to refer to operators, maintenance employees, and other employees or contractors who are not in a supervisory or technical role.
Work Function
The minimum energy required to extract the weakest bound electron from a particle surface and remove it to infinity.
Workforce involvement
A PSM program element that consists of a series of work activates that (1) solicit input from the entire work force (including contractors), (2) foster a consultative relationship between management and workers at all levels of the organization, and (3) help sustain a strong process safety culture.
Working papers
Field notes used in preparation of the final report documenting work performed, techniques used, and conclusions reached while conducting the audit.
Workplace Environmental Exposure Levels (WEELs)
Similar to TLVs, but for materials not address by ACGIH or OSHA. Developed by the American Industrial Hygiene Association (AIHA).
World-Class Manufacturing
A position of international manufacturing excellence, achieved by developing a culture based on factors such as continuous improvement, COO/OD, problem prevention, zero defect tolerance, customer-driven just-in-time production, and total quality management.
Worst Case
A conservative (high) estimate of the consequences of the most severe incident identified.
Worst Case Consequence
A conservative (high) estimate of the consequences of the most severe accident identified. For example, the assumption that the entire contents of a contained volume of toxic material is released to the most vulnerable area in such a way (all at once or continuous) as to have the maximum effect on the public or employees in that area. The contained volume could be chosen as the containers and pipes between shutoff valves or the entire process unit but probably not the entire plant.
Worst Credible Case
The most severe consequences, considering all scenarios and their outcomes, that is considered plausible or reasonably believable.
Worst Credible Incident
The most severe plausible or reasonably believable incident, considering only incident outcomes and their consequences, of all identified incidents and their outcomes.
Worst Possible Incident
The most severe incident, considering only incident outcomes and their consequences of all identified incidents and their outcomes
Worst-Case Scenario (WCS)
A release involving a hazardous material that would result in the worst (most severe) off-site consequences.
Written program
A description of a management system that defines important aspects such as purpose and scope, roles and responsibilities, tasks and procedures, necessary input information, anticipated results and work products, personnel qualifications and training, activity triggers, desired schedule and deadlines, necessary resources and tools, continuous improvement, management review, and auditing.
Zone
Classification system for electrical and electronic equipment and wiring for all voltages in locations where fire or explosion hazards may exist, as defined in Article 505 of NFPA 70 National Electrical Code.
Zone of Security
Grouping of logical or physical elements that share common security requirements.