Process Safety Management Concepts PDF

# Domain IV: Advanced Safety Concepts ## 4.1 Process Safety Management ### Introduction - The advent of complex and high-energy hazardous processes has made process safety management an integral element of process design and operation. - Catastrophic events such as Flixboro explosion, Seveso Diox...

# Domain IV: Advanced Safety Concepts ## 4.1 Process Safety Management ### Introduction - The advent of complex and high-energy hazardous processes has made process safety management an integral element of process design and operation. - Catastrophic events such as Flixboro explosion, Seveso Dioxin release and Bhopal toxic plume release, and a host of others are examples of disasters that could have been prevented by proper application of process safety management techniques. - The Flixboro event showed the importance of proper controls when administering changes in plant design such as engineering verification of changes and effects of vapor cloud explosion. - The Bhopal event showed the importance of maintenance and administrative controls. - The major objective of process safety management is to prevent unwanted releases of hazardous chemicals especially into locations, which could expose employees and others to serious hazards. - An effective process safety management program requires a systematic approach to evaluating the whole process. - The process design, process technology, operational and maintenance activities and procedures, non-routine activities and procedures, emergency preparedness plans and procedures, training programs and other elements which impact the process are all considered in the evaluation. - The various lines of defense that have been incorporated into the design and operation of the process to prevent or mitigate the release of hazardous chemicals need to be evaluated and strengthened to assure their effectiveness at each level. - Process safety management is the proactive identification, evaluation and mitigation or prevention of chemical releases that could occur as a result of failures in process, procedures or equipment. ### Elements of Process Safety Management (PSM) 1. **Employee Participation** - A successful Process Safety Management program must be based on the concept of teamwork between management and employees. - Management must consult with their employees regarding the management's efforts in the development and implementation of the PSM program elements and hazard assessments. - A sound management approach to employee participation allows more and more employees to influence decisions and have access to process information. 2. **Process Safety Information** - Complete and accurate written information on process definition and design criteria, process and equipment design, documentation of risk management decisions, protective systems, normal and upset conditions, and chemical and occupational health hazards is essential to an effective PSM program. - This information is a necessary resource to a variety of users including the team that will perform the process hazard analysis. - This information must be comprehensive and provide accurate assessment of the fire and explosion characteristics, reactivity hazards, the safety and health hazards to workers and the corrosion and erosion effects on the process equipment and monitoring tools. 3. **Process Hazard Analysis** - A process hazard analysis is one of the most important elements of the Process Safety Management program. - This is an organized and systematic effort to identify and analyze the significance of potential hazards associated with the processing or handling of hazardous chemicals. - The selection of a process hazard analysis methodology or technique will be influenced by many factors including the amount of existing knowledge about the process. - Is it a process that has been operated for a long period of time with little or no innovation? Or, is it a new process or one that has been changed frequently by the inclusion of innovative features? Also, the size and complexity of the process will influence the selection of the appropriate process hazard analysis methodology. - For a review of Hazard Evaluation Methodologies, see domain 2 Study Session under "System Safety". 4. **Risk Analysis** - Before selection and application of any process hazard analysis methodology, a comprehensive risk assessment must be conducted. - This assessment must provide information on the degree of risk as a result of system component failures. - Although risk analysis can be conducted either on a quantitative or qualitative basis, the important issue is that both the severity and probability (frequency) of the undesirable events must be taken into account. - The combination of probability and severity of undesirable events must provide the management with the information on whether the risk is acceptable or not. - In the event that risk is unacceptable, the system must be modified to reduce the probability, severity or both the probability and severity of the undesirable events. - For example, consider a high-pressure jacketed reactor with a highly exothermic reaction. - Assume that the heat of reaction is removed by pumping a coolant through the reactor jacket. - A risk assessment of this process reveals that failure of the pump can result in a runaway chemical reaction and explosion. - This is, obviously, an unacceptable risk. - Adding a spare pump can modify the system. - This lowers the probability of an explosion as a result of pump failure because two pumps must fail for the system to fail. - Once a risk assessment has been completed, the appropriate process hazard analysis methodology can be selected and applied to the process. - This analysis must identify different types of hazards within the system components and to propose possible solutions to eliminate the hazards. - These procedures are extremely useful in identifying system modes and failures that can contribute to occurrence of accidents, and should be an integral part of different phases of process development from conceptual design to installation, operation and maintenance. 5. **Employee Training** - All employees, including maintenance and contractor employees, involved with highly hazardous chemicals need to fully understand the safety and health hazards of the chemicals and processes they work with for the protection of themselves, their fellow employees and the citizens of nearby communities. - Training in subjects such as operating procedures and safe work practices, emergency evacuation and response, safety procedures, routine and non-routine work authorization activities and other areas pertinent to process safety and health will need to be covered. - In establishing the training programs, we must clearly define the employees to be trained and what subjects are to be covered in their training. - In setting up the training program, we need to clearly establish the goals and objectives we wish to achieve with the training that is provided. - The learning goals or objectives should be written in clear measurable terms before the training begins. - These goals and objectives need to be tailored to each of the specific training modules or segments. 6. **Contractors** - Employers, who use contractors to perform work in and around processes that involve highly hazardous chemicals, will need to establish a screening process so that they hire and use contractors who accomplish the desired job tasks without compromising the safety and health of employees at a facility. 7. **Pre-Startup Safety Review** - For new processes, the employer will find a process hazard analysis helpful in improving the design and construction of the process from a reliability and quality point of view. - Making use of the recommendations before final installations are completed will enhance the safe operation of the new process. - The Piping & Instrumentation Diagrams (PID) are to be completed along with having the operating procedures in place and the operating staff trained to run the process before startup. - The initial startup procedures and normal operating procedures need to be fully evaluated as part of the pre-startup review to assure a safe transfer into the normal operating mode for meeting the process parameters. - For existing processes that have been shut down for turnaround, or modification, etc., the management must assure that any changes other than "replacement in kind" made to the process during shutdown go through the management of change procedures. 8. **Mechanical Integrity** - Management will need to review their maintenance programs and schedules to see if there are areas where "breakdown" maintenance is used rather than an ongoing mechanical integrity program. - Equipment used to process, store, or handle highly hazardous chemicals needs to be designed, constructed, installed and maintained to minimize the risk of releases of such chemicals. - This requires that a mechanical integrity program be in place to assure the continued integrity of process equipment. - Elements of a mechanical integrity program include the identification and categorization of equipment and instrumentation, inspections and tests, testing and inspection frequencies, development of maintenance procedures, training of maintenance personnel, the establishment of criteria for acceptable test results, documentation of test and inspection results, and documentation of manufacturer recommendations as to meantime to failure for equipment and instrumentation. 9. **Non-routine Work Authorizations** - Non-routine work that is conducted in process areas needs to be controlled by the management in a consistent manner. - The hazards identified involving the work that is to be accomplished must be communicated to those doing the work, but also to those operating personnel whose work could affect the safety of the process. - A work authorization notice or permit must have a procedure that describes the steps the maintenance supervisor, contractor representative or other person needs to follow to obtain the necessary clearance to get the job started. 10. **Management of Change** - To properly manage changes to process chemicals, technology, equipment and facilities, one must define what is meant by change. - Change includes all modifications to equipment, procedures, raw materials and processing conditions other than "replacement in kind”. - These changes need to be properly managed by identifying and reviewing them prior to implementation of the change. - For example, the operating procedures contain the operating parameters (pressure limits, temperature ranges, flow rates, etc.) and the importance of operating within these limits. - While the operator must have flexibility to maintain safe operation within the established parameters, any operation outside of these parameters requires review and approval by a written management of change procedure. 11. **Investigation of Incidents** - Incident investigation is the process of identifying the underlying causes of incidents and implementing steps to prevent similar events from occurring. - The intent of an incident investigation is to learn from past experiences and thus avoid repeating past mistakes. 12. **Emergency Preparedness** - Management must address what actions employees are to take when there is an unwanted release of highly hazardous chemicals. - Management will need to decide if they want employees to handle and stop small or minor incidental releases. - Whether they wish to mobilize the available resources at the plant and have them brought to bear on a more significant release; or whether employers want their employees to evacuate the danger area and promptly escape to a pre-planned safe zone area, and allow the local community emergency response organizations to handle the release; or whether the employer want to use some combination of these actions. - Employers will need to select how many different emergency preparedness procedures they plan to have and then develop the necessary plans and procedures, and appropriately train employees in their emergency duties and responsibilities and then implement these lines of defense. 13. **Audits** - Management needs to select a trained individual or assemble a trained team of people to audit the process safety management system and program. - A small process or plant may need only one knowledgeable person to conduct an audit. - The audit is to include an evaluation of the design and effectiveness of the process safety management system and a field inspection of the safety and health conditions and practices to verify that the systems are effectively implemented. - The audit should be conducted or led by a person knowledgeable in audit techniques and who is impartial towards the facility or area being audited. - The essential elements of an audit program include planning, staffing, and conducting the audit, evaluation and corrective action, follow-up and documentation. ## Conclusion - Application of the Process Safety Management techniques to processes that use, produce, or store highly hazardous chemicals can greatly reduce the probability of a catastrophic accident. - These techniques are designed to aid management in their efforts to prevent or mitigate chemical releases that could lead to a catastrophe in the workplace and in the surrounding community. - To control these types of hazards, the management needs to develop the necessary expertise, experiences, judgement, and proactive initiative within the workplace to properly implement and maintain an effective Process Safety Management program. ## 4.2 Personal Protective Equipment (Respirators) ### Respirators - Under OSHA regulations (29CFR1910.134), an employer who utilizes respirators in their operation must have a written respiratory protection program prior to use of respirators in the work place. - This program must address Standard Operating Procedures (SOP's) for the selection and use of respirators, training issuers and users, disinfecting respirators, and maintenance, as well as storage requirements and inspection of respirators. - Respirators can be categorized in these major types: Air Purifying Respirators and Atmosphere Supplying Respirators. - An atmosphere is considered to be oxygen deficient if the concentration of oxygen is less than 19.5 per cent by volume. (ACGIH considers an atmosphere with less than 18% oxygen to be oxygen deficient.) - Air purifying respirators can only remove the contaminants for which they are designed. - Air purifying respirators must not be used in atmospheres which are oxygen deficient. - Air purifying respirators must not be used in atmospheres where the type and concentration of the contaminants are unknown. - Air purifying respirators remove contaminant gases and vapors from the air by the process of "adsorption." This process refers to removal of a component of a gaseous mixture on a solid bed. - Air purifying respirators must not be used in atmospheres that are Immediately Dangerous to Life or Health (IDLH) because in such atmospheres even smallest leaks can not be tolerated and for contaminants which do not have odor thresholds above PEL or TLV. - Supplied air respirators have their own supply of air, and therefore, are independent of the atmosphere in which they are used. - OSHA limits the length of the airline to a maximum of 300 feet. - The advantage of the supplied air respirators is that they can provide to the user breathing air for a long period of time. - The disadvantage of this type of respirator is that it limits the mobility of the user. - Self Contained Breathing Apparatus (SCBA) can be open circuit or closed circuit. - The former exhausts the used air from the user while the latter recycles the air after removal of carbon dioxide and water and addition of make up oxygen. - The advantage of closed loop SCBA is that it can provide breathing air to the user for a much longer period of time compared to the open loop SCВА. - Positive pressure demand SCBA's maintain a positive pressure in the face mask and reduce the possibility of inward leakage from surrounding contaminated air. ## 4.3 Example Questions 1. Placing a shield between an ionizing radiation source and an employee is an example of: a. Engineering control b. Administrative or management control c. Management control d. Only (a) and (b) above 2. A stock insurance company is best defined by which of the following statements? a. Insurance company which is profit motivated b. Insurance company with at least 100,000 shares of stock c. Insurance company protected by FDIC d. Insurance company that is not allowed to sell Workers' Compensation insurance 3. The BEST method to reduce employee exposure to airborne chemicals to an acceptable level is by means of: a. Administrative controls b. Using a respirator c. Reducing the number of exposure hours d. Engineering controls 4. Point source airborne contaminants are best controlled by: a. Dilution ventilation b. Local exhaust ventilation c. General ventilation d. General ventilation with a compression ratio of 10 or more 5. Which of the following is an example of engineering noise control? a. Use of earmuffs b. Reducing the number of hours of exposure c. Use of sound absorbing materials d. Audiometric testing 6. Which of the following insurance coverage is used to provide liability coverage for a company engaged in the cleanup of a hazardous waste site? a. Premium and medical coverage b. Chemical exposure coverage c. Manufacturers' and contractors' coverage d. Strict liability coverage 7. The preferred angle range for fixed industrial stairs is: a. 30 to 35 degrees b. 15 to 25 degrees c. 10 to 25 degrees d. 5 to 15 degrees 8. In ventilation design, the number of room air changes per unit time can be obtained by: a. Multiplying the room volume by the volumetric flow rate of air in the ventilation system. b. Dividing the room volume by the volumetric flow rate of air in the ventilation system. c. Dividing volumetric flow rate of air in the ventilation system by the room volume. d. Subtracting the volumetric flow rate of air in the ventilation system from the room volume. 9. Which of the following organizations mandates lockout/tagout programs for service or maintenance of certain types of equipment? a. NIOSH b. OSHA c. FEMA d. CPSC 10. Which of the following statements is NOT true in regard to chemical labels? a. Labels are used on drums of hazardous chemicals. b. Labels are used on transportation vehicles carrying hazardous materials. c. Labels are used on gas cylinders. d. Labels are used on bottles of hazardous chemicals. 11. In liability insurance coverage, the term “OCP” is an acronym for: a. Operation and Chemical Protection b. Owners and Contractors Protection c. Operators and Contractors Protection d. Operators and Constructors Protection 12. Insurance coverage falls into four broad categories. Which of the following is NOT one of these categories? a. Property insurance b. Liability insurance c. Life insurance d. Fire insurance 13. Business Income Coverage (BIC) insurance addresses the loss exposures relating to loss of income and/or extra expense to operate. Which of the following is NOT one of the three elements of the loss exposure covered by the basic BIC form? a. Property b. Health c. Perils d. Consequences 14. Ground Fault Circuit Interrupters (GFCI) work on the principal of sensing a difference in the amount of electric current entering and leaving a circuit. The difference is considered to be electric current that is leaking to the ground. Once a difference has been detected, a GFCI opens the circuit in: a. 0.02 to 0.03 seconds b. 0.2 to 0.3 seconds c. 2 to 3 seconds d. 0.5 to 1.5 seconds 15. Which of the following fall protection systems absorb the energy of an actual fall? a. Fall arrest systems b. Fall depression systems c. Fall suppression systems d. Fall prevention systems 16. Ozone (O3) is a powerful oxidizing agent and is considered to be a hazardous gas. Which of the following operations is most likely to produce ozone? a. Paint spraying b. Electric arc welding c. Catalytic reforming d. Catalytic cracking 17. Hexavalent chromium, which is toxic, can most likely be produced as a result of which of the following operations? a. Arc welding cast iron b. Distilling chromium oxide c. Welding stainless steel d. Precipitating hydrochromic salts 18. The total pressure in a/an ______ ventilation system is equal to the sum of velocity pressure and static pressure. a. Open b. Atmospheric c. Dynamic d. Closed 19. Which of the following markings is used on many products manufactured in Europe, indicating that the product meets the health and safety standards? a. CE b. ES c. ESH d. EHS 20. Per DOT regulations, ______ drivers are not allowed to consume alcohol within four hours before starting their driving shift. a. All b. Commercial c. Hazardous materials truck d. Commercial hazardous materials truck 21. The type of liability insurance that helps protect individuals and companies that provide professional advice and services from bearing the full cost of defending against a negligence claim made by a client is called: a. Professional liability insurance b. Professional indemnity insurance c. Errors and omissions insurance d. All of the above 22. Which of the following statements is NOT true in regard to course of construction insurance? a. It covers a building under construction. b. It covers perils such as fire, wind, and theft. c. The policy will pay for damages up to the coverage limit. d. The coverage limit must accurately reflect the total value of the structure, including labor costs and land value. 23. Per DOT regulations, the post-accident drug and alcohol test applies to all drivers who are involved in fatal crashes. The test must also be conducted on all CDL drivers who are cited for moving violations arising in a crash that requires a vehicle being towed or an injury requiring medical attention away from the scene. The alcohol test must be conducted within ______ hours and the controlled substances test must be conducted within ______ hours of the crash. a. 10, 25 b. 8, 32 c. 4, 8 d. 15, 45 24. All of the following are components of an insurance contract EXCEPT: a. Exclusions b. Conditions c. Declarations d. Privity 25. Incorporation of safety at the design stage of a potentially hazardous industrial process, rather than after it is operating, is important because: a. OSHA regulations requires a place of employment free of all hazards. b. It has an economic advantage to the company. c. It decreases management liability before plant operation. d. It educates design engineers in safety standards. 26. In facility design, the responsibility for identifying and controlling hazards associated with equipment lies with: a. Mechanical engineers b. Purchasing agents c. Design team d. Equipment manufacturer 27. A pump is sending cooling water to a reactor. Loss of cooling water to this reactor would cause the reactor to explode. A fail-safe design for the system is BEST portrayed by: a. Activation of a spare pump on failure of the cooling water pump. b. Automatic shut down of process on failure of the cooling water pump. c. Relieve pressure in the reactor. d. All of the above. 28. The concept of Energy Theory in safe design of processing facilities states that the severity of an accident is related to: a. Amount of energy release b. Rate of energy release c. Means of energy transfer d. All of the above 29. Floor slipperiness is measured by: a. Slip meter b. Friction meter c. Viscometer d. Hydrometer 30. One of the more commonly encountered hazards for ground supported scaffolds is: a. Breakage at a given leg b. Over-pressurizing the scaffold c. Breakage at the surface d. Tipping 31. Drums containing Polychlorinated Biphenyls (PCB) must be made of: a. Metal b. Polyethylene c. Ceramic d. PVC 32. The severity of electric shock primarily depends on: a. The electric current flowing through the body b. The body capacitance to absorb electrical energy c. The body transmittance for electrical conductivity d. All of the above 33. Ventricular fibrillation caused as a result of electric shock refers to: a. Blockage of the heart muscles b. Fibers of the heart contract separately c. Fibers of the heart contract simultaneously d. Fibers of the heart expand beyond limit of elasticity 34. Interlocks used in electrical equipment must meet which of the following criteria? a. Lockout-tagout b. Fail-active c. Fail-passive d. Fail-safe 35. An electrical circuit protective device such as a fuse or circuit breaker protects the circuit from overload by: a. Closing the circuit b. Dissipating excess heat c. Opening the circuit d. Electrical bonding 36. "Arcing" refers to: a. Flow of electrons through air b. Welding of metal parts c. Type of protective helmet d. Process of bending metal sheets 37. Electrical bonding: a. Eliminates the electrical charges between two conductors b. Eliminates the potential difference between two conductors c. Sends electrical charges to the ground d. Reduces electrical power consumption 38. The electrolytic fluid in lead-acid batteries during charging can produce: a. Poisonous lead gas b. Lead oxide gas c. Hydrogen gas d. Lead hydride gas 39. An electrical system is considered to be de-energized (no potential difference in any component of the system): a. When the power to the circuit has been shut off b. After the system has been shut off and tested c. After the power has been shut off and proper lockout/tagout has been performed d. When it is grounded 40. For control of electrostatic hazards which one of the following types of clothing is preferable? a. Non-conductive b. Semi-conductive c. Conductive d. Type of clothing has no effect 41. The surface conductivity of an electrostatically charged surface: a. Will increase with an increase in humidity b. Will decrease with an increase in humidity c. Humidity has no effect on surface conductivity d. Will increase with an increase in temperature 42. Which of the following is associated with equipment failure for facility design and operation? a. Poor maintenance program b. Lack of fail-safe instrumentation c. Metal fatigue d. All of the above 43. Which of the following is NOT associated with plant layout for facility design and operation? a. Direction of wind b. Number of people required to operate the plant c. Cost of process control instruments d. Cost of future revision 44. In new chemical plant layout where most processing equipment is located outdoors, which of the items listed below should be considered first? a. To group similar equipment in one location b. To determine the direction of the prevailing wind c. To provide room for maintenance d. To minimize piping and pumping costs 45. In designing outdoor plant layout, all equipment that may spill flammable materials should be located: a. In an isolated area on the upwind side b. On the downwind side c. Near fire stations and on the upwind side d. Close to the receiving area 46. The areas for containment of relatively large spills of liquefied petroleum gases must always be constructed below grade because: a. These gases have a vapor density that is greater than one. b. A person on the grade level or above will not be asphyxiated. c. Spilled material can flow to these areas by gravity. d. Only (a) and (b) above. 47. Which of the following is the leading cause of work related injuries and deaths? a. Electrical shock b. Falls and slips c. Motor vehicle accidents d. Exposure to toxic chemicals 48. When a source emits light that reaches a given surface, the surface can: a. Absorb the light b. Transmit the light c. Reflect the light d. All of the above 49. The quantity of illumination is measured by which of the following instruments? a. Foot-candle meter b. Illuminometer c. Transmitter d. Light meter 50. Which of the following organizations set forth standards for eye and face protection? a. CPSC b. FDA c. NIOSH d. ANSI 51. Most personal devices used in fall protection: a. Prevent a person from falling b. Minimize the impact of a fall c. Interrupt falls already in progress d. Shield an individual from falling objects 52. All of the following are effective measures for fall protection EXCEPT: a. Remove slipping and tripping hazards b. Barriers c. Hard hat d. Guard rails 53. Which one of the following is NOT an administrative control of hazards? a. Discipline an employee for unsafe work practices b. Provide periodic training c. Provide work rotation to reduce fatigue d. Provide personal protective equipment 54. Before an employer can assign an employee to jobs requiring the use of a respirator, the employer: a. Must consult with employee and obtain his/her consent to use a respirator. b. Must test employee's reactions and performance while using a respirator in a non-hazardous atmosphere. c. Must obtain written permission from a physician on employee's ability to use a respirator. d. Document employee's performance while using a respirator for a period of no less than 10 days. 55. The stress generated in an object as a result of application of a force is equal to the: a. Value of the compression stress minus the tensile stress b. Value of the compression stress minus the shear stress c. Value of the compression stress divided by the shear stress d. Value of the force divided by the area upon which it acts 56. The term "creep" is referred to as: a. The ability of a given material to resist tensile stress b. Slow but permanent deformation of a material under a given load c. The ability of a material to withstand shear stresses d. An individual with uncivilized, and at times, unusual behavior 57. Shoring is required for all the trenches more than 4 feet deep unless: a. They are sloped to an angle of repose b. The trench is in a stable rock c. A ladder is provided d. Only (a) and (b) above 58. A trench is: a. A narrow excavation b. Deeper than it is wide c. Never wider than 15 feet d. All of the above 59. The guard on a grinding wheel must: a. Completely enclose the wheel b. Cover the wheel as completely as the nature of the work permits c. Be adjustable d. Only (b) and (c) above 60. Which of the following organizations has the most number of standards for unfired pressure vessels? a. ANSI b. NFPA c. ASME d. OSHA 61. The recommended maximum allowable slope for a ramp is: a. 45 degrees b. 25 degrees c. 20 degrees d. 15 degrees 62. An indoor warehousing operations, the preferred type of powered truck is: a. Liquefied petroleum gas trucks b. Electric trucks c. Diesel trucks d. Gasoline trucks 63. The most common occupational injuries resulting from manual materials handling are injuries to the: a. Foot b. Hand c. Eyes d. Back 64. Many powered materials handling vehicles have a high center of gravity. This means that: a. The maximum load rating of the vehicle is increased compared to an identical low center of gravity vehicle. b. The pressure exerted on tires is less than an identical vehicle with a low center of gravity. c. The gravitational force exerted on the center of the vehicle is less than that of an identical vehicle with a low center of gravity. d. When the vehicle operated in a turn, it has a greater potential for rollover compared to an identical vehicle with a low center of gravity. 65. One of the problems associated with safety inspections is: a. Regulations may not be updated b. Control methods may not be economical c. Hazards are allowed to accumulate between inspections d. Lost time cases cannot be detected 66. One of the disadvantages to an external safety inspection is: a. Its objectivity b. High cost c. Several follow-up inspections d. All of the above 67. During a safety inspection of your facility, you have discovered an unsafe act being committed by an employee. Your best course of action is: a. To stop the unsafe act and instruct how the job can be done safely. b. To report an unsafe act to employee's supervisor. c. Provide adequate training. d. All of the above. 68. Accident causes can be classified into basic, indirect, and direct causes. An unsafe act by an employee which results in an accident is an example of which one of the following accident causes? a. Basic b. Indirect c. Direct d. Basic and direct 69. There are four different types of machine guarding: fixed, adjustable, interlocked, and self-adjusting. Which of the following is NOT an advantage of fixed guards? a. Can be constructed to suit many applications b. Can provide a high level of protection c. Low maintenance d. Adjustment and repair may require removal 70. ______ machine guards shut off or disengage power and prevent the machine from starting when the guard is opened. a. Fixed b. Adjustable c. Interlocked d. Self-adjusting 71. OSHA requires [1910.212(a)(1)] that the employer must provide one or more methods of machine guarding to protect the operator and other employees from hazardous mechanical motion or action. Which of the following IS NOT an example of hazardous mechanical motion or action requiring machine guarding? a. Point of operation b. Ingoing nip points c. Rotating parts d. Vibrating parts 72. Which of the following is NOT true in regard to Class A hard hats? a. These helmets are for general services. b. They provide good impact protection but limited voltage protection. c. They are used mainly in mining, building construction, shipbuilding, lumbering, and manufacturing. d. They provide limited impact protection but good voltage protection. 73. Which of the following statements IS NOT true in regard to Class B hard hats? a. Choose Class B helmets if your employees are engaged in electrical work. b. They protect against falling objects and high-voltage shock and burns. c. The shells are water resistant and slow burning. d. They do not have to meet ANSI standards. 74. Which of the following statements is true in regard to Class C hard hats? a. They offer limited head protection. b. They protect against falling objects and high-voltage shock and burns. c. They provide good impact protection. d. Both (b) and (c). 75. Which of the following colors are used on the coverings of grounded conductors? a. Red b. White or natural gray c. Green d. Yellow 76. Many combustible gas devices burn the contaminants catalytically. This causes an increase in temperature, resulting in an increase in the resistance of the filament. Which of the following BEST describes the principle used in these devices? a. Wheatstone bridge b. Catburner c. Combustion chamber d. Catcomb 77. Which of the following statements in NOT true in regard to cathodic protection? a. It is used to control the corrosion of a metal surface b. It makes the metal surface the cathode of an electrochemical cell c. It makes the metal surface the anode of an electrochemical cell d. It connects protected metal to a more easily corroded sacrificial metal acting as the anode 78. Which of the following statements is NOT true regarding a ground fault circuit interrupter (GFCI)? a. It is a fast-acting circuit breaker designed to shut off electric power in the event of a ground fault. b. It can shut off power in as little as 1/40 of a second. c. It works by comparing the amount of current going to and returning from the equipment along circuit conductors. d. It protects the user from line contact hazards. 79. CAD is an acronym for: a. Construction and design b. Cumulative anxiety disorders c. Computer aided design d. Construction and development 80. The two most common software packages used in occupational health and safety departments are: a. Industrial hygiene and occupational safety b. Occupational safety and regulatory compliance c. Word processing and database management d. Industrial hygiene and regulatory compliance 81. The principle of receiving value (i.e. quality, safety, etc.) for an original purchase of a product is called: a. Caveat emptor b. Caveat venditor c. Caveat privitor d. Caveat vendor 82. If a product fails to meet a warranty, then: a. The manufacturer must be negligent b. The manufacturer can be held liable c. The consumer must prove unreasonable risk to receive compensation d. The consumer must prove negligence in design to receive compensation 83. A retailer has made an oral promise concerning a product's life expectancy. Which one of the following best describes this concept? a. Warranty of use b