DESIGNING FOR SAFETYDESIGNING FOR SAFETY

CHAPTER 9CHAPTER 9

IMPORTANCE OF DESIGNING FOR SAFETYIMPORTANCE OF DESIGNING FOR SAFETY

In the near future, the level of safety that companies and industries achieve In the near future, the level of safety that companies and industries achieve will relate directly to the quality of the initial design of their facilities, will relate directly to the quality of the initial design of their facilities, equipment and machinery, tools, workplace layouts, overall work equipment and machinery, tools, workplace layouts, overall work environment, and work methods. environment, and work methods.

Included in this effort will be a design review process and redesign decisions Included in this effort will be a design review process and redesign decisions as companies seek to achieve continuous improvement in safety. This as companies seek to achieve continuous improvement in safety. This approach can not only benefit workers but improve productivity and cost approach can not only benefit workers but improve productivity and cost effectiveness for the company. effectiveness for the company.

General Principles and DefinitionsGeneral Principles and Definitions

Designing for safety can be defined as the application of the concepts of Designing for safety can be defined as the application of the concepts of safety through design to processes, the workplace, work methods, and safety through design to processes, the workplace, work methods, and products to achieve a state of operation for which the risks are judged to be products to achieve a state of operation for which the risks are judged to be acceptable. acceptable.

Risk is defined as a measure of the probability that a hazard may cause an Risk is defined as a measure of the probability that a hazard may cause an incident and the severity of the unpleasant effects. Risks are acceptable if incident and the severity of the unpleasant effects. Risks are acceptable if they are judged to be tolerable. For any company operation to succeed, its they are judged to be tolerable. For any company operation to succeed, its risks must be acceptable. risks must be acceptable.

If a system – the facilities, equipment, and work methods – is not designed to If a system – the facilities, equipment, and work methods – is not designed to minimize risk, companies cannot achieve superior results with respect to minimize risk, companies cannot achieve superior results with respect to safety, even if management and personnel factors approach the ideal.safety, even if management and personnel factors approach the ideal.

Order of Design PriorityOrder of Design Priority

To achieve the greatest effectiveness in hazard avoidance, To achieve the greatest effectiveness in hazard avoidance, elimination, or control, companies should apply the following elimination, or control, companies should apply the following priorities to all design and redesign processes.priorities to all design and redesign processes.

First priority:First priority: Design for minimum riskDesign for minimum risk

From the very beginning, the top priority should be to eliminate From the very beginning, the top priority should be to eliminate hazards in the design process. hazards in the design process.

If an identified hazard can not be eliminated, the associated risk If an identified hazard can not be eliminated, the associated risk is to be reduced to an acceptable level through design decisions. is to be reduced to an acceptable level through design decisions.

Second priority: Second priority: Incorporate safety devicesIncorporate safety devices

If hazards cannot be eliminated or their risks effectively reduced If hazards cannot be eliminated or their risks effectively reduced through design selection, the next step is to reduce risks to an through design selection, the next step is to reduce risks to an acceptable level. acceptable level.

Companies can accomplish this step through the use of fixed, Companies can accomplish this step through the use of fixed, automatic, or other protective safety design features or devices. automatic, or other protective safety design features or devices.

Third priority: Third priority: Provide warning devicesProvide warning devices

In some cases, identified hazards cannot be eliminated or their risks In some cases, identified hazards cannot be eliminated or their risks reduced to an acceptable level through initial design decisions or reduced to an acceptable level through initial design decisions or through the built-in safety devices. through the built-in safety devices.

Under these conditions, companies should develop systems to detect Under these conditions, companies should develop systems to detect hazardous conditions and warn personnel of the hazards. hazardous conditions and warn personnel of the hazards.

Warning signals should be designed to help workers react promptly and Warning signals should be designed to help workers react promptly and correctly to a hazardous situation and should be standardized within all correctly to a hazardous situation and should be standardized within all systems.systems.

Fourth priority: Fourth priority: Develop and implement operating procedures and Develop and implement operating procedures and employee training programs employee training programs

Where it is impractical to eliminate hazards or reduce their risks to an Where it is impractical to eliminate hazards or reduce their risks to an acceptable level through design selection, incorporating safety devices, acceptable level through design selection, incorporating safety devices, or warning devices. or warning devices.

Companies should develop and implement safe operating procedures Companies should develop and implement safe operating procedures and use safety training programs.and use safety training programs.

Fifth priority: Fifth priority: Use personal protective equipmentUse personal protective equipment

When all other techniques cannot eliminate or control a hazard, When all other techniques cannot eliminate or control a hazard, employees should be given personal protective equipment to prevent employees should be given personal protective equipment to prevent injuries and illnesses.injuries and illnesses.

Role of the Safety ProfessionalRole of the Safety Professional

The safety practitioner can influence the design of the workplace and work The safety practitioner can influence the design of the workplace and work methods at three critical points:methods at three critical points:

In the pre-operational design stageIn the pre-operational design stage. .

Before a building system, or piece of equipment becomes operational, the Before a building system, or piece of equipment becomes operational, the safety professional has the greatest opportunity to identify and analyze safety professional has the greatest opportunity to identify and analyze hazards and to help engineers and architects design ways to avoid, control, hazards and to help engineers and architects design ways to avoid, control, or eliminate them. or eliminate them.

This stage can avoid costly redesigning, or replacing elements of the This stage can avoid costly redesigning, or replacing elements of the workplace.workplace.

In the operational stageIn the operational stage. .

After a building system, or piece of equipment becomes operational, the After a building system, or piece of equipment becomes operational, the safety professional can seek to make them safer through the process of safety professional can seek to make them safer through the process of continuous improvement. continuous improvement.

In the post incident stageIn the post incident stage. .

After an incident has occurred, the safety professional can still work to After an incident has occurred, the safety professional can still work to improve safety: By investigating the hazards related to the incident, he can improve safety: By investigating the hazards related to the incident, he can determine the causal factors involved and can review the possible impact determine the causal factors involved and can review the possible impact of design decisions on the incident. of design decisions on the incident.

These data can then be used to improve future designs and eliminate the These data can then be used to improve future designs and eliminate the factors that led to the current incident.factors that led to the current incident.

Behavior Modification versus Workplace RedesignBehavior Modification versus Workplace Redesign

Management and safety professionals tend to focus on behavior Management and safety professionals tend to focus on behavior modification or training as solutions when the problem is workplace modification or training as solutions when the problem is workplace or work methods design. or work methods design.

Although behavior modification and training are important elements Although behavior modification and training are important elements of a safety and health plan, such measures are misdirected when of a safety and health plan, such measures are misdirected when applied to solve workplace or work methods design problems.applied to solve workplace or work methods design problems.

If the design of the work is overly stressful or if the work situation If the design of the work is overly stressful or if the work situation encourages employees to take risks, then the causal factors are encourages employees to take risks, then the causal factors are principally universal. principally universal.

To label the causal factors as "To label the causal factors as "employee erroremployee error" or "" or "unsafe actunsafe act" " would be inappropriate and ineffective, as the following actual case would be inappropriate and ineffective, as the following actual case histories illustrate.histories illustrate.

Bags weighing 100 lb (45 kg) were delivered to work stations on pallets. Bags weighing 100 lb (45 kg) were delivered to work stations on pallets. Workers open the bags and lifted them to shoulder height to pour the Workers open the bags and lifted them to shoulder height to pour the contents into hoppers. contents into hoppers.

The job required a fast work pace, with workers bending down and The job required a fast work pace, with workers bending down and twisting to lift the bags. Back injuries were frequent. Investigative reports twisting to lift the bags. Back injuries were frequent. Investigative reports always listed the causal factors as improper lifting. always listed the causal factors as improper lifting.

The corrective action was always "The corrective action was always "re-instruct the worker in proper lifting re-instruct the worker in proper lifting techniquestechniques."."

Objectives of Designing for SafetyObjectives of Designing for Safety

The following objectives should be considered when The following objectives should be considered when companies are developing a safety-through-design companies are developing a safety-through-design process.process.

Safety, consistent with goalsSafety, consistent with goals, is to be designed into all , is to be designed into all processes, the workplace, work methods, and products in a processes, the workplace, work methods, and products in a proactive, cost-effective manner.proactive, cost-effective manner.

Risk assessmentRisk assessment is to be an integral part of the design is to be an integral part of the design processes.processes.

A fundamental design purposeA fundamental design purpose is to have processes and is to have processes and products that are error proof or error tolerant. products that are error proof or error tolerant.

Hazards must be identified and evaluatedHazards must be identified and evaluated, and then avoided, , and then avoided, eliminated, or controlled so that the associated risks are at an eliminated, or controlled so that the associated risks are at an acceptable level throughout the entire life cycle of processes, acceptable level throughout the entire life cycle of processes, equipment, and products.equipment, and products.

Conducting Hazard Analysis / Risk AssessmentConducting Hazard Analysis / Risk Assessment

To determine what actions are to be taken to avoid, eliminate, or control To determine what actions are to be taken to avoid, eliminate, or control hazards, a system to determine risk levels must be applied. hazards, a system to determine risk levels must be applied.

A good risk assessment model will enable decision makers to understand A good risk assessment model will enable decision makers to understand and categorize the risks and to determine the methods and costs to reduce and categorize the risks and to determine the methods and costs to reduce risks to an acceptable level. risks to an acceptable level.

For these purposes, risk is a measure of the probability and severity of For these purposes, risk is a measure of the probability and severity of adverse effects deriving from hazards.adverse effects deriving from hazards.

From this risk assessment, the company can choose which of the priority From this risk assessment, the company can choose which of the priority hazard control methods it will use to address the hazards that still remain.hazard control methods it will use to address the hazards that still remain.

In each of the following steps, management and the safety professional In each of the following steps, management and the safety professional must seek the counsel and expertise of qualified, experienced personnel must seek the counsel and expertise of qualified, experienced personnel who are knowledgeable about the work or process. who are knowledgeable about the work or process.

This process is more effective if a hazard analysis/risk assessment scenario This process is more effective if a hazard analysis/risk assessment scenario is written covering each of the steps. Such a scenario would include the is written covering each of the steps. Such a scenario would include the following:following:

1.1. Establish the analysis parametersEstablish the analysis parameters. .

The team would select a manageable task, system, or process to be analyzed The team would select a manageable task, system, or process to be analyzed and define its relationship with other tasks or systems, if appropriateand define its relationship with other tasks or systems, if appropriate ..

2.2. Identify the hazardsIdentify the hazards. .

Members of the team should concentrate on identifying hazards that could be Members of the team should concentrate on identifying hazards that could be the cause of incidents. the cause of incidents.

They should then determine each hazard's potential for harm or damage, They should then determine each hazard's potential for harm or damage, arising out of the characteristics of a job, piece of equipment, system, and arising out of the characteristics of a job, piece of equipment, system, and the like, and the actions or inactions of employees. the like, and the actions or inactions of employees.

At this point, the team should keep an assessment of hazard potential At this point, the team should keep an assessment of hazard potential separate from an assessment of hazard severity.separate from an assessment of hazard severity.

3.3. Consider the failure modesConsider the failure modes. .

The team should define the possible failure modes that would realize the The team should define the possible failure modes that would realize the hazard's potential and result in an incident.hazard's potential and result in an incident.

4.4. Describe the exposureDescribe the exposure. .

The purpose of this step is to establish the number of people, the type of The purpose of this step is to establish the number of people, the type of property, and the aspects of the environment that could be harmed or property, and the aspects of the environment that could be harmed or damaged, and how frequently they might be exposed to danger should the damaged, and how frequently they might be exposed to danger should the hazard be realized. hazard be realized.

5.5. Assess the severity of consequencesAssess the severity of consequences..

The team makes calculated guesswork regarding the number of fatalities, The team makes calculated guesswork regarding the number of fatalities, injuries, illnesses, value of property damaged, and extent of environmental injuries, illnesses, value of property damaged, and extent of environmental damage that might result should hazard-related incidents occur. damage that might result should hazard-related incidents occur.

Historical data are of great value as a baseline. On a subjective basis, the team Historical data are of great value as a baseline. On a subjective basis, the team would need to agree on a classification system for the severity of hazard related would need to agree on a classification system for the severity of hazard related consequences: e.g., catastrophic, critical, marginal, and negligible. consequences: e.g., catastrophic, critical, marginal, and negligible.

6. 6. Determine the probability of the hazard being realizedDetermine the probability of the hazard being realized..

Unless empirical data are available, the process of selecting the probability of Unless empirical data are available, the process of selecting the probability of an incident occurring is subjective. an incident occurring is subjective.

Probability has to be related to intervals of some kind, such as a unit of time or Probability has to be related to intervals of some kind, such as a unit of time or activity, events, units produced, or life cycle. activity, events, units produced, or life cycle.

Commonly used categories for assigning probability include frequent, probable, Commonly used categories for assigning probability include frequent, probable, occasional, remote, and unlikely.occasional, remote, and unlikely.

7. 7. Write a concluding statementWrite a concluding statement. .

The team would conclude with a statement that addresses both the probability The team would conclude with a statement that addresses both the probability of an incident occurring and the expected severity of its adverse results.of an incident occurring and the expected severity of its adverse results.

8. 8. Develop proposals to remedy the hazardsDevelop proposals to remedy the hazards. .

The team would then concentrate on the design and operational changes The team would then concentrate on the design and operational changes necessary to achieve an acceptable risk level.necessary to achieve an acceptable risk level.