TABLE OF CONTENTS This chapter will help you understand the units used in pressure measurements and become familiar with the most common methods of using the various pressure measurement standards.
Discussed in this chapter are
The terms - pressure, specific weight, specific gravity (SG), and buoyancy
The difference between atmospheric, absolute, gauge, and differential pressure values
Various pressure units in use, i.e., British units versus SI (metric) units
Various types of pressure measuring devices
Difference in static, dynamic, and impact pressures
Laws applied to pressure
Application considerations
Pressure is the force exerted by gases and liquids due to their weight, such as the pressure of the atmosphere on the surface of the earth and the pressure containerized liquids exert on the bottom and walls of a container.
Pressure units are a measure of the force acting over a specified area. It is most commonly expressed in pounds per square inch (psi), sometimes pounds per square foot (psf) in English units, or pascals (Pa or kPa) in metric units.
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The liquid in a container has a total weight of 250 lb; the container has a 3.0 ft 2 base. What is the pressure in pounds per square inch?
Density ? is defined as the mass per unit volume of a material, i.e., pound (slug) per cubic foot (lb (slug)/ft 3) or kilogram per cubic meter (kg/m 3).
Specific weight ? is defined as the weight per unit volume of...
