DESIGNING FOR SAFETY

1. DESIGNING FOR SAFETY CHAPTER 9

2. IMPORTANCE OF DESIGNING FOR SAFETY • 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, equipment and machinery, tools, workplace layouts, overall work environment, and work methods. • Included in this effort will be a design review process and redesign decisions as companies seek to achieve continuous improvement in safety. This approach can not only benefit workers but improve productivity and cost effectiveness for the company. General Principles and Definitions • Designing for safety can be defined as the application of the concepts of 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 acceptable. • 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 they are judged to be tolerable. For any company operation to succeed, its risks must be acceptable. • If a system – the facilities, equipment, and work methods – is not designed to minimize risk, companies cannot achieve superior results with respect to safety, even if management and personnel factors approach the ideal.

3. Order of Design Priority • To achieve the greatest effectiveness in hazard avoidance, elimination, or control, companies should apply the following priorities to all design and redesign processes. First priority:Design for minimum risk • From the very beginning, the top priority should be to eliminate hazards in the design process. • If an identified hazard can not be eliminated, the associated risk is to be reduced to an acceptable level through design decisions. Second priority: Incorporate safety devices • If hazards cannot be eliminated or their risks effectively reduced through design selection, the next step is to reduce risks to an acceptable level. • Companies can accomplish this step through the use of fixed, automatic, or other protective safety design features or devices.

4. Third priority: Provide warning devices • In some cases, identified hazards cannot be eliminated or their risks reduced to an acceptable level through initial design decisions or through the built-in safety devices. • Under these conditions, companies should develop systems to detect hazardous conditions and warn personnel of the hazards. • Warning signals should be designed to help workers react promptly and correctly to a hazardous situation and should be standardized within all systems. Fourth priority: Develop and implement operating procedures and employee training programs • Where it is impractical to eliminate hazards or reduce their risks to an acceptable level through design selection, incorporating safety devices, or warning devices. • Companies should develop and implement safe operating procedures and use safety training programs. Fifth priority: Use personal protective equipment • When all other techniques cannot eliminate or control a hazard, employees should be given personal protective equipment to prevent injuries and illnesses.

5. Role of the Safety Professional • The safety practitioner can influence the design of the workplace and work methods at three critical points: In the pre-operational design stage. • Before a building system, or piece of equipment becomes operational, the safety professional has the greatest opportunity to identify and analyze hazards and to help engineers and architects design ways to avoid, control, or eliminate them. • This stage can avoid costly redesigning, or replacing elements of the workplace. In the operational stage. • After a building system, or piece of equipment becomes operational, the safety professional can seek to make them safer through the process of continuous improvement. In the post incident stage. • After an incident has occurred, the safety professional can still work to improve safety: By investigating the hazards related to the incident, he can determine the causal factors involved and can review the possible impact of design decisions on the incident. • These data can then be used to improve future designs and eliminate the factors that led to the current incident.

6. Behavior Modification versus Workplace Redesign • Management and safety professionals tend to focus on behavior modification or training as solutions when the problem is workplace or work methods design. • Although behavior modification and training are important elements of a safety and health plan, such measures are misdirected when applied to solve workplace or work methods design problems. • If the design of the work is overly stressful or if the work situation encourages employees to take risks, then the causal factors are principally universal. • To label the causal factors as "employee error" or "unsafe act" would be inappropriate and ineffective, as the following actual case histories illustrate. • 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 contents into hoppers. • The job required a fast work pace, with workers bending down and twisting to lift the bags. Back injuries were frequent. Investigative reports always listed the causal factors as improper lifting. • The corrective action was always "re-instruct the worker in proper lifting techniques."

7. Objectives of Designing for Safety • The following objectives should be considered when companies are developing a safety-through-design process. • Safety, consistent with goals, is to be designed into all processes, the workplace, work methods, and products in a proactive, cost-effective manner. • Risk assessment is to be an integral part of the design processes. • A fundamental design purpose is to have processes and products that are error proof or error tolerant. • Hazards must be identified and evaluated, and then avoided, eliminated, or controlled so that the associated risks are at an acceptable level throughout the entire life cycle of processes, equipment, and products.

8. Conducting Hazard Analysis / Risk Assessment • To determine what actions are to be taken to avoid, eliminate, or control hazards, a system to determine risk levels must be applied. • A good risk assessment model will enable decision makers to understand and categorize the risks and to determine the methods and costs to reduce risks to an acceptable level. • For these purposes, risk is a measure of the probability and severity of adverse effects deriving from hazards. • 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. • In each of the following steps, management and the safety professional must seek the counsel and expertise of qualified, experienced personnel who are knowledgeable about the work or process. • 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 following:

9. Establish the analysis parameters. • The team would select a manageable task, system, or process to be analyzed and define its relationship with other tasks or systems, if appropriate. • Identify the hazards. • Members of the team should concentrate on identifying hazards that could be the cause of incidents. • 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 the like, and the actions or inactions of employees. • At this point, the team should keep an assessment of hazard potential separate from an assessment of hazard severity. • Consider the failure modes. • The team should define the possible failure modes that would realize the hazard's potential and result in an incident. • Describe the exposure. • 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 damaged, and how frequently they might be exposed to danger should the hazard be realized.

10. 5.Assess the severity of consequences. • The team makes calculated guesswork regarding the number of fatalities, injuries, illnesses, value of property damaged, and extent of environmental damage that might result should hazard-related incidents occur. • 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 consequences: e.g., catastrophic, critical, marginal, and negligible. 6. Determine the probability of the hazard being realized. • Unless empirical data are available, the process of selecting the probability of an incident occurring is subjective. • Probability has to be related to intervals of some kind, such as a unit of time or activity, events, units produced, or life cycle. • Commonly used categories for assigning probability include frequent, probable, occasional, remote, and unlikely. 7. Write a concluding statement. • The team would conclude with a statement that addresses both the probability of an incident occurring and the expected severity of its adverse results. 8. Develop proposals to remedy the hazards. • The team would then concentrate on the design and operational changes necessary to achieve an acceptable risk level.