ELA 984: Inherently Safer Designs
To choose the "inherently safer" chemistry, the research team needs to take into account:
*not the environment & Worker safety & Process hazards
The Operations, Maintenance, and Modifications stage will likely last:
A decade or more
Inherently safer design is:
A way of thinking about the design of chemical processes and plants that focuses on the elimination or reduction of hazards
___ design features reduce risk, including the frequency or severity by relying on the active functioning of a device or control system.
Active
TRUE or FALSE: Once the Development stage of the process life cycle is underway, it's too late to revisit the basic chemistry of the process.
False
Both the Flixborough case and the Synthron case show the consequences of ignoring ISD in which Process Safety Management system element?
Management of Change (MOC)
With the ___ approach, if the hazard cannot be eliminated, smaller quantities of hazardous materials or energy are used. This reduces the potential severity of any associated incident (such as fire, explosion, or toxic release).
Minimize
In the handling of a flammable liquid, a facility determines that it is possible to dilute it to a 20% concentration and still operate effectively. This is an example of which inherently safer design?
Moderate
What ISD guideword is associated with this checklist question: "Can hazards be reduced via lower temperatures or pressures?"
Moderate
In general, which two strategies are the most robust and reliable?
Passive Inherent
A reaction with a maximum adiabatic reaction pressure of 200 psig conducted in a reactor with a design of 150 psig. One of the reactants is gradually added at a rate to control the reaction temperature, and the reaction stops if the reactant feed is stopped. The process operator is trained to monitor the reactor temperature and pressure, and stop the reactant feed if either gets too high. This is an example of which of the following types of control?
Procedural
In addition to inherently safer, what are the other common strategies for safety in design?
Procedural Active Passive
The inherently safer design guidewords focus on:
Process routes Materials Procedures Equipment
Documenting the exact state of the decommissioned equipment is a form of the inherently safer strategy of:
Simplification
What ISD guideword is associated with this checklist question: "Are all manuals, guides, and instructional material clear and easy to understand, especially those that are used in an emergency situation?"
Simplify
With the ___ approach, any unnecessary complexity is removed; as a result, there is a reduced risk of human error.
Simplify
What ISD guideword is associated with the checklist question: "Can pressure be used instead of a pump to move hazardous fluids from one unit operation to another?"
Substitute
TRUE or FALSE: Alternative types of process equipment have different inherently safer characteristics.
True
TRUE or FALSE: Applying the ISD approach to distillation systems designs can be evaluated during the development stage of the a process.
True
TRUE or FALSE: Hazard management programs should focus on both steady state operations and process dynamics.
True
TRUE or FALSE: Human factors have a strong relationship with the principles of inherent safety.
True
Inherently safer design optimally happens ___ in the life cycle of the process.
early
The Management of Change process should ensure that changes do not ___ change existing inherently safer barriers.
unintentionally
___ methods reduce risk by relying on personnel actions governed by operating procedures, safety rules and standards, emergency response procedures, and training.
* not active *not inherently safer
With respect to inherent safety, what issues should be addressed during the Operations, Maintenance, and Modifications phase of the process life cycle?
* not all
During Process Hazard Analyses (PHAs), each safety device or procedure should be evaluated to see if it can be eliminated or modified by applying inherently safer principles of:
* not minimize
A hazard:
*not Can be changed by changing the material & Can be changed by changing the conditions of use
From an ISD perspective, the process design basis needs to be taken into consideration in order to:
*not Reduce or eliminate risks associated with batch processes
The ___ Process Safety Management system element has ISD significance because it is an opportunity to consider incorporating ISD concepts.
*not Safe Work Practices
A process engineering group is reviewing an existing process that will be modified to improve yield. They have been asked to perform a Management of Change (MOC) review and provide potential process safety recommendations before the process moves forward t oa full safety review. These are some of the recommendations that engineering group is proposing: Which of the engineering group's recommendations below can be considered ISD actions?
*not all *not all but run the process... *not al but evaluate... & Run the process at... *not all but Provide an emergency.... /& Run the process at lower...
Although the opportunity to incorporate inherently safer strategies still exists during design and construction, many of the ___ opportunities are no longer possible at this stage because the process chemistry and the safe operating envelope will already have been specified
*not all but moderation *not all
It is inherently safer to develop processes with ___
*not all but wide safe... *not just both narrows
Changes to the process design to incorporate inherently safer strategies during the ___ stage of the life cycle can be easy to accomplish and relatively inexpensive, yet this effort can significantly affect the outcome.
*not development *not operations, maintenance...
A packaging system for an explosible powder is built with a design pressure of 200 psig (the mzximum explosion pressure from a dust explosion of the material being dried is 140 psig). This is an example of which of the following types of control.
*not inherently safer
During the detailed design stage there is an opportunity to evaluate the siting of the equipment processing hazardous material to establish if adequate separation distances have been established. This is an application of which ISD strategy?
*not moderate *not eliminate/minimize
Many opportunities still exist to apply the ___ strategy during detailed design.
*not moderation *not minimization
When the ___ stage of the process life cycle is reached, the chemistry, unit operations, and type of equipment have been set.
*not operations, maintenance and modification
The design and construction stage focuses primarily on:
*not piping... & detailed... & Unit...
Which PSM element is most important in preserving and protecting against elimination of inherently safer features during the Operations, Maintenance, and Modifications stage of the process life cycle?
*not process safety culture
Evaluating equipment required for an inherently safer process usually occurs first in which stop of the process life cycle?
*not research
What is the longest stage in the life cycle of a process?
*not research
A Process Safety Management (PSM) or Risk Management Program (RMP)-covered facility will perform Process Hazard Analyses (PHA) or similar studes at least once every:
5 years
Which of the following is NOT one of the four different safety strategies in design?
Aggressive
To choose the "inherently safer design," the team needs to take into account:
Both (a) and (b)
Of the questions listed below, which are most appropriate to ask for ISD considerations during the Development stage of the process life cycle?
Can the product yield be improved? Can a different mode of operation (continuous versus batch) be used and result in smaller accumulations of hazardous materials? Is a flammable solvent necessary?
The last stage of the process life cycle is:
Decommissioning
The ___ step is the last step at which changes can be made at moderate cost because most of the equipment is purchased after this step is approved.
Detailed design
The design basis of the process, especially those inherently safer features that are built into the design and installation of the process, must be clearly:
Documented
TRUE or FALSE: A mitigative safeguard is an example of inherently safer design.
False
TRUE or FALSE: Hazards are not inherent to a material or its conditions
False
TRUE or FALSE: ISD cannot be implemented until the Development sage of the process life cycle is completed because the chemistry and the basic hazards of the materials are not known yet.
False
TRUE or FALSE: Implementing an ISD approach always results in a process having no risk.
False
TRUE or FALSE: Inherent safety means that all hazards have been designed out of the process up front.
False
TRUE or FALSE: Inherently safer design is applicable to the chemical and process industries only.
False
TRUE or FALSE: Passive control measures, since they don't have to rely on the active intervention of devices or human operators, are considered the most robust approach to hazard control.
False
TRUE or FALSE: Since there is a substantial impact on the cost of modification after the Design and Construction stage has been completed, there can be no further ISD implementation.
False
TRUE or FALSE: The design and implementation of inherently safer chemical processes does not need to be considered for when the plant is no longer a productive unit or plant and is decommissioned.
False
In their search for the best chemistry, researchers attempt to identify and minimize which of the following hazards?
Flammability Reactivity Toxicity
Developing a complete knowledge of all the potential hazards and their severity for a material or process is key to implementing an effective inherently safer design. Which Process Safety Management system element does this apply to?
Hazard Identification and Risk Analysis
Which of the following Process Safety Management system elements are particularly well-suited for the application of ISD principles?
Hazard Identification and Risk Analysis (HIRA) Management of Change (MOC)
A hazard identification and risk analysis (HIRA) study is targeted towards determining:
How bad could it be? What can go wrong? How often might it happen?
What are the key human factor areas associated with ISD principles?
Human error assessment The operator-process/equipment interface Administrative controls
Elements of which strategies will be required for a comprehensive process safety management program when all hazards of a process and plant are considered?
Inherent Passive Active Procedural
In which order should the designer apply strategies
Inherent > Passive > Active > Procedural
___ design features minimize the hazard without relying on the active functioning of any device.
Inherently safer
Since implementation of ISD concepts is often more costly than easier procedural barriers, management support for implementation of ISD is critical. Which process Safety Management system element does this apply to?
Management Review and Continuous Improvement
The ISD concept of ____ includes review of process changes before they are implemented, documentation of changes, and revision of training as a consequence of changes.
Management of Change (MOC)
In the Flixborough case, the plant site had very large inventories of flammable material which is contrary to the ISD principle of:
Minimization
What ISD guideword is associated with the checklist question: "Are just in time deliveries used when dealing with hazardous materials?"
Minimize
When decommissioning equipment, the inherently safer strategy of ___ is used to remove the inventory of hazardous materials.
Minimize
With the ___ approach, techniques such as dilution, refrigeration or less severe process conditions are used.
Moderate
Inherently safer design strategies:
Moderate Substitute Eliminate/Minimize Simplify
If a process must be controlled with a very small temperature band in order to avoid hazardous conditions, that process would have
Narrow safe operating limits
From and ISD perspective, the process design basis needs to be taken into consideration in order to:
Reduces the potential for large releases of hazardous materials
Below are the stages of the process life cycle but they are out of order. Drag the stages up or down to arrange them into the correct order.
Research > Development > Design and construction > Operations, maintenance and modification > Decommissioning
With the ___ approach, the design could replace a hazardous material with a less hazardous alternative or use less hazardous reaction chemistry.
Substitute
The failure to design equipment to reduce the potential for error (such as complex and confusing equipment, positioning of dials, color coding, or different directions for on/off) is an issue associated with:
The operator-process/equipment interface
TRUE or FALSE: ISD features are particularly susceptible to lapses in corporate memory given that they are such a fundamental part of the design that their purpose may not be obvious, unlike an add-on device (such as high-pressure alarm).
True
TRUE or FALSE: Inherently safer design concepts can be utilized at later stages of the process life cycle.
True
TRUE or FALSE: Plant modifications during the Operations, Maintenance, and Modifications stage of the process life cycle provide an opportunity to incorporate inherently safer strategies that were overlooked or deferred during the initial design.
True
TRUE or FALSE: Process Safety Management systems accept the fact that there are inherent risks in a process.
True
TRUE or FALSE: Process control must be provided during all modes of operation, not just in the normal, steady-state operating mode.
True
TRUE or FALSE: Risk is a function of frequency and severity and it can be quite complicated due to all the various types of risks that must be considered.
True
Application of ISD principles reminds us that ___ are often the least effective control measures and that organizations should implement inherently safer controls where ever possible.
administrative controls
CCPS defines ___ as "An inherent chemical or physical characteristic that has the potential for causing damage to people, property, or the environment
hazard
During the Operations, Maintenance, and Modifications stage, conduct of operations should include an ISD approach so as to eliminate or minimize the hazards and reduce the number of ___ safeguards required.
passive procedural active
The image shown is an example of ___ which can be used to identify which chemical interactions pose potential reaction hazards.
reactivity matrix
