Chapter 06: Final Review & Key Terms

1. Ready for Review

• A workplace hazard refers to any workplace condition that has the potential to cause damage to equipment and vehicles, injure workers, or cause adverse health effects or death.
• Engine work on commercial vehicles has its own unique hazards, including the release of stored energy, exhaust emissions, rotating hazards, and the engine as a source of ignition.
• Hazard management involves different methods or strategies to eliminate or control the threat that any hazard poses.
• New workers and novice technicians have not developed the skills to identify or anticipate hazards, nor do they understand how to minimize potential dangers to themselves and others. These skills need to be taught, and experienced technicians should make special efforts to help new workers develop these skills.
• It is vitally important that technicians are adequately familiar with a vehicle’s steering and braking systems and have the skills to operate them and to safely move vehicles in and out of a shop and road test them, if necessary.
• Never undertake moving a vehicle unless you are confident that you can properly handle it or have received instruction prior to operating the vehicle.
• Respectfully care for a customer’s vehicle by installing seat covers and protective floor mats before beginning any service work, and install seat covers before entering the cab for any reason.
• To protect equipment, vehicles, and people from consequential damage from inadvertently starting, moving, or operating, LOTO procedures are used.
• Lockout and tagout are two interchangeable terms describing an administrative safety procedure to prevent the use of tools, equipment, or materials that are determined to be unsafe or potentially unsafe and to prevent vehicles from starting during service.
• LOTO procedures are commonly used to disable machinery or equipment, to prevent them from starting, or to prevent the release of hazardous energy while employees perform servicing and maintenance activities.
• LOTO protocols are included in legislation called the Control of Hazardous Energy . This standard requires the release of hazardous energy prior to the service and maintenance of machinery and equipment.
• Pressurized air, hydraulic or other gas pressure, electricity stored in capacitors or available from batteries, and objects such as a raised dump box acted upon by gravity are common examples of stored energy sources.
• High-voltage hazards refer to current levels above 60 VDC and 30 VAC. These are considered minimum thresholds for risk of significant personal injury or even death from electrical energy.
• Gloves used as PPE to control high-voltage hazards should be rated for a minimum of 1000 volts. The ANSI Class 0 is the accepted standard when working on electric vehicles.
• Exhaust from diesel engines, especially older ones, can contain noxious gases and very small particles that can create a health hazard when inhaled.
• Prolonged exposure to diesel exhaust and particulate matter can increase the risk of cardiovascular, cardiopulmonary and respiratory disease, and lung cancer.
• Noxious ammonia can (under some conditions) be released from newer exhaust aftertreatment systems and add to the hazard of breathing diesel exhaust emissions.
• An engine can become an ignition source when intake air is blended with another fuel source, such as natural gas or lubricating oil. Increased cylinder fueling can cause the engine to have uncontrolled acceleration and overspeed or run away.
• Runaway engines can explode and seriously injure or kill nearby workers.
• The exhaust aftertreatment system can become a source of ignition and ignite nearby flammable debris or dry grass.
• Exhaust spark arresters are required by diesel engines working off-road in forests and fields.
• A turbocharger compressor wheel that has sharp spinning blades is a rotating hazard that can quickly sever fingers.
• Fan blades, pulleys, gears, and flywheels are examples of rotating hazards that can injure workers in contact with the rotating energy. Rotating devices can turn falling objects, such as parts and fasteners, into dangerous projectiles.
• Employers are obligated by legislation to provide a safe workplace free from serious and recognizable hazards and to comply with standards, rules, and regulations issued under occupational health and safety regulations.
• Before a technician enters a workplace, it is the responsibility of the employer to determine the appropriate use of PPE, which protects the worker from bodily harm by preventing hazardous material, a material that can cause damage or injury to a person, or particles from entering the worker’s body or physically injuring the worker.
• Wearing employer-designated PPE is a major obligation of employees under health and safety legislation.
• Fire extinguishers are rated by the type of fire for which they are suitable: A, B, C, D, or K. There are pictograms on the fire extinguisher indicating for which type of fire they are suitable.
• Diesel engines and fuel systems are highly sensitive to contaminants, such as dirt and water. Smaller operating clearances, higher injection system pressures, and use of electrohydraulic components (a result of advanced technology) cause even the smallest amount of contaminants to be more destructive in today’s engines.
• Clean care shop practices extend the service life of replacement parts and major components. From a business perspective, clean care practices have the added benefit of increasing resale value and ROI and lowering the overall lifetime costs of operation while increasing productivity; the vehicle will provide more efficient service with improved reliability.

1.1. Key Terms

clean care practices Shop policies and procedures to enhance engine and fuel system service life by eliminating contaminant entry points.

positive intake shutoff valve A safety device that mechanically shuts off intake airflow to prevent engine overspeed.