SHEL (Safety, Health,
Environmental, and Loss Prevention Reviews) These reviews are performed
during design. The purpose of the reviews is to have an outsider’s evaluation
of the process and layout from safety, industrial hygiene, environmental, and
loss prevention points of view. It is often desirable to combine these reviews
to improve the efficiency of the use of time for the reviewers.
Checklists Checklists are
simple means of applying experience to designs or situations to ensure that the
features appearing in the list are not overlooked. Checklists tend to be
general and may not be appropriate to a specific situation. They may not handle
adequately the novel design or unusual process.
What-if At each process
step, what-if questions are formulated and answered to evaluate the effects of
component failures or procedural errors. This technique relies on the
experience level of the questioner.
Failure Mode and Effect Analysis
(FMEA) This is a systematic study of the causes of failures and their
effects. All causes or modes of failure are considered for each element of a
system, and then all possible outcomes or effects are recorded. This method is
usually used in combination with fault tree analysis, a quantitative technique.
FMEA is a complicated procedure, usually carried out by experienced risk
analysts.
Cause-Consequence Diagram These
diagrams illustrate the causes and consequences of a particular scenario. They
are not widely used because, even for simple systems, displaying all causes and
outcomes leads to very complex diagrams. Again, this technique is employed by
experienced risk analysts.
Reactive Chemicals Reviews The process chemistry is reviewed for evidence of exotherms, shock sensitivity, and other instability, with emphasis on possible exothermic reactions. It is especially important to consider pressure effects—“Pressure blows up people, not temperature!” The purpose of this review is to prevent unexpected and uncontrolled chemical reactions. Reviewers should be knowledgeable people in the
Industrial Hygiene Reviews These reviews evaluate the potential of a process to cause harm to the health of people. It is the science of the anticipation, recognition, evaluation, and control of health hazards in the environment. It usually deals with chronic, not acute, releases and is involved with toxicity.
Toxicity is the ability to cause biological injury. Toxicity is a property of all materials, even salt, sugar, and water. It is related to dose and the degree of hazard associated with a material. The amount of a dose is both time and duration dependent. Dose is a function of exposure (concentration) and duration and is sometimes expressed as dose = (concentration)n × duration, where n can vary from 1 to 4.
Industrial hygiene deals with hazards caused by chemicals, radiation, and noise. Routes of exposure are through the eyes, by inhalation, by ingestion, and through the skin. An industrial hygiene guide is based on exposures for an 8-hour day, 40-hour week and is to be used as a guide in the control of health hazards. It is not to be used as a fine line between safe and dangerous conditions. Types of controls used include:
• Engineering, such as containment, ventilation, and automation
• Administrative, such as use of remote areas and job rotation
• Protective equipment
No comments:
Post a Comment