Chapter 27 Hazard Analysis/Prevention and Safety Management
Major Topics • Hazard analysis • Hazard prevention and deterrence • OSHA process safety standard • Risk assessment • Best practices in safety management
Hazard • A hazard is a condition or combination of conditions that, if left uncorrected, may lead to an accident, illness, or property damage.
Preliminary hazard analysis • A preliminary hazard analysis is conducted to identify potential hazards and prioritize them according to: the likelihood of an accident or injury being caused by the hazard; and the severity of the injury, illness, or property damage that could result if the hazard caused an accident. • A useful sorting is to rate the probable level of injuries that could occur (catastrophic, critical, marginal, and nuisance). • Then with each item, indicate the probability of occurrence (considerable, probable, or unlikely). • Rate the correction of these hazards next by cost.
Preliminary hazard analysis • Experience and related expertise are important factors in conducting a preliminary review. • For example , say, a new piece of equipment such as a computer numerical control (CNC) machining center is installed. The safety and health professional may form a team that includes an experienced machinist, an electrician, a materials expert, and a computer control specialist. All members of the team are asked to look over the machining center for obvious hazards relating to their respective areas of expertise.
Cost benefit factors in hazard analysis • Every hazard typically has several different remedies. • Every remedy has a corresponding cost and corresponding benefit. • List all of the potential remedies along with their respective costs and then estimate the extent to which each will reduce the hazard (its benefit) (fig 27-4 page 609). • For the CNC machining center, after examining the matrix, the solution that makes the most sense from the prospective of both cost and impact on the hazard is the plexiglass door. It eliminates two of the hazards (spraying lubricants, and metal chips) and reduces the third (jammed stock).
Hazard Analysis: FMEA, HAZOP, HEA, FTA, and TOR. • Failure Mode Effect Analysis (FMEA): Critically examine the system in question. Divide the system into its various components. Examine each individual component and record all of the various ways in which the components may fail. Rate each potential failure according to the degree of hazard posed [0 = no hazard, 1 = slight, 2 = moderate, 3 = extreme, 4= severe]. Examine all potential failures for each individual component of the system and decide what effect the failures could have (fig 27-5 page 611). • Hazard and Operability Review (HAZOP): HAZOP consists of forming a team of experienced, knowledgeable people from a variety of backgrounds relating to the process or system and having team members brainstorm about potential hazards. • Human Error Analysis (HEA): is used to predict human error. Two approaches to HEA can be effective: Observing employees at work and noting hazards (the task analysis approach) and actually performing job tasks to get a firsthand feel for hazards. • Technic of Operation Review (TOR): is an analysis method that allows supervisors and employees to work together to analyze workplace accidents, failures and incidents. It seeks to identify systemic causes, not to assign blame.
Weakness of FMEA and HAZOP, and how it can be overcome • The limitation of FMEA (Failure mode and effective analysis) is that it does not account for human error, because it is generally the heart of a workplace accident compared to system or process failure. The weakness can be overcome by coupling human error analysis with FMEA. • HAZOP (Hazard and operability review) has the same weakness as FMEA – they do not factor human errors in the equation. HAZOPs predict problems with associated with system or process failures. The weakness can be overcome by coupling human error analysis with HAZOP.
Two approaches to HEA • Human Error Analysis (HEA): is used to predict human error. Two approaches to HEA can be effective: • 1. Observing employees at work and noting hazards (the task analysis approach) • 2. Actually performing job tasks to get a firsthand feel for hazards. • Regardless of how HEA is conducted it is a good idea to perform it in conjunction with FMEA and HAZOP analysis. This will enhance the effectiveness of all three processes.
Technic of Operation Review (TOR) • Technic of Operation Review (TOR): is an analysis method that allows supervisors and employees to work together to analyze workplace accidents, failures and incidents. It seeks to identify systemic causes, not to assign blame. • For 20 years user documentation on TOR was not readily available. Consequently wide scale use did not occur till the early 1990s.
Most important strength of TOR • Technic of Operation Review (TOR) is a hands-on analytical methodology designed to determine the root system causes of an operation failure. • Because it uses a worksheet written in simple to understand terms and follows an uncomplicated yes/no decision-making sequence, it can be used at even the lowest levels of the firm. • TOR demands careful and systematic evaluation of the real circumstances surrounding an incident, and results in isolating the specific ways in which the organization failed to prevent the occurrence.
Hazard prevention strategies • Eliminate the source of the hazard. • Substitute a less hazardous equivalent • Reduce the hazards at the source • Remove the employee from the hazard (substitute a robot or other automated system). • Isolate the hazard (enclose them in barriers) • Dilute the hazard (ventilate the hazardous substance) • Apply appropriate management strategies • Use appropriate personal protective equipment • Provide employee training • Practice good housekeeping
HAZWOPER response to chemical spill • Hazardous waste operations and emergency response (HAZWOPER) gives organizations two options for responding to a chemical spill: • The first is to evacuate all employees in the event of a spill and call in professional emergency response personnel. Employers who use this option must have an emergency action plan [EAP] in place in accordance with 29CFR 1010.38(a). • The second option is to respond internally. Employers who use this option must have an emergency response plan [ERP] in place that is in accordance with 29 CFR 1010.120.
Risk Assessment • Risk assessment is the process of quantifying the level of risk associated with the operation of a given machine. • The most widely used risk assessment technique is the decision tree (see fig 27-10 page 621), coupled with codes representing the four questions and defined levels of risk. • Question 1: Severity (S) of potential injuries S1 Slight injury (bruise, abrasion) S2 Severe injury (amputation or death) • Question 2: Frequency (F) of exposure to potential hazards F1 Infrequent exposure F2 from frequent to continuous exposure • Question 3: Possibility (P) of avoiding the hazard if it does occur P1 Possible P2 Less possible to not impossible • Question 4: Likelihood (L) that the hazard will occur L1 Highly unlikely L2 Unlikely L3 Highly likely • Associated risk factors (B) ranging from lowest (1) to highest (4) • By applying the decision tree or similar device, the risk associated with the operation of a given machine can be quantified. This allows safety personnel to assign logical priorities for machine safeguarding and hazard prevention.
Safety management concerns • Strategic planning: An organizations strategic plan should have either a broad goal or a guiding principle that speaks to maintain a safe and healthy work environment. • Safety policy: The safety policy should summarize the organization’s commitment and explain the responsibility of managers, supervisors and employees for maintaining a safe and healthy work environment. • Written procedures: Safety managers should ensure that all of the following are developed as written policies: job descriptions; general safety rules; procedures for specialized and hazardous operations; standard operating procedures; program for communicating with employees about safety information; emergency plan; employee orientation program; and safety manual. • Employee training: Safety managers are responsible for ensuring that both new and experienced employees receive the training they need to do their jobs safely. • Communication: Safety managers are responsible for ensuring that employees, supervisors, and managers are fully informed about the safety and health policies, practices, concerns, and other information. • Human resource management: Safety managers work closely with human resource management personnel on personnel issues relating to safety and health – blood testing, drug testing, wellness programs, and back-to-work programs for injured personnel. • Self assessments: Develop checklists for managers and employees for safety oriented self assessments. • Safety and health promotion: The purpose of safety programs is to remind people to think of safety first – both on and off campus. • Accident investigation and reporting: Safety managers are responsible for establishing a structured system for investigating accidents and near misses and for reporting the results of the investigations. • Ongoing monitoring: Safety managers are responsible for ensuring that workplace hazards and the requirements of applicable regulatory agencies are properly monitored on a regular basis.
Summary • Hazard analysis identifies hazards and recommends corrective action. • Hazards can be potentially catastrophic, critical, marginal, and nuisance. • Failure mode and effect analysis (FMEA) is a hazard analysis method that examines each component to determine how it may fail. • Hazard and operability review (HAZOP) is a hazard analysis method that involves forming a team and brainstorming. • Human error analysis (HEA) is used to predict human error and its effects. • Technic of operation review (TOR) allows workers to conduct the analysis. • Fault tree analysis (FTA) displays the analysis process visually. • Fundamentals of hazard prevention: eliminate the source of the hazard, reduce the hazard, and provide employee training. • Safety management includes: safety policy, employee training, safety assessments, accident investigation, reporting and monitoring.
Home work • Answer questions 2, 5, 9, and 11 on page 628. • 2. What is the purpose of a preliminary hazard analysis? • 5. Briefly describe the following detailed hazard analysis methodologies: FMEA, HAZOP, HEA, FTA and TOR. • 9. What is the most important strength of TOR? • 11. Explain the two options given to organizations by HAZWOPER for responding to a chemical spill.