Part 2 book “Occupational safety and health for technologists, engineers, and managers” has contents: Pressure hazards, electrical hazards, industrial hygiene and confined spaces, radiation hazards, noise and vibration hazards, promoting safety, preparing for emergencies and terrorism, and other contents. | Page 371 16/05/14 2:17 PM user /205/PH01353_GE/9781292061993_GOETSCH/GOETSCH_OCCUPATIONAL_SAFETY_AND_HEALTH_FOR_ CHAPTER SE V E N T EE N Pressure Hazards Major Topics Pressure Hazards Defined Sources of Pressure Hazards Boilers and Pressure Hazards High-Temperature Water Hazards Hazards of Unfired Pressure Vessels Hazards of High-Pressure Systems Cracking Hazards in Pressure Vessels Nondestructive Testing of Pressure Vessels Pressure Dangers to Humans Decompression Procedures Measurement of Pressure Hazards Reduction of Pressure Hazards Pressure Hazards Defined Pressure is defined in physics as the force exerted against an opposing fluid or thrust distributed over a surface. This may be expressed in force or weight per unit of area, such as pounds per square inch (psi). A hazard is a condition with the potential of causing injury to personnel, damage to equipment or structures, loss of material, or lessening of the ability to perform a prescribed function. Thus, a pressure hazard is a hazard caused by a dangerous condition involving pressure. Critical injury and damage can occur with relatively little pressure. The Occupational Safety and Health Administration (OSHA) defines highpressure cylinders as those designated with a service pressure of 900 psi or greater. We perceive pressure in relation to the earth’s atmosphere. Approximately 21 percent of the atmosphere is oxygen, with most of the other 79 percent being nitrogen. In addition to oxygen and nitrogen, the atmosphere contains trace amounts of several inert gases: argon, neon, krypton, xenon, and helium. At sea level, the earth’s atmosphere averages 1,013 H (hydrogen) or 10 N/m2 or millibars or 760 mm Hg ( inches), or psi, depending on the measuring scale The international system of measurement utilizes newtons per square meter (N/m2). However, in human physiology studies, the typical unit is .
