01 December 2004
ISA Certified Control Systems Technician (CCST) Program
This question is from the Level I study guide, Domain 1, Calibration. Level I represents a professional who has a five-year total of education, training, and/or experience.
1. Hydrostatic head is another way of expressing:
2. All physical measurements arise from the fundamental quantities of:
A. mass, length, and time.
B. density, viscosity, and specific gravity.
C. flow, volume, and temperature.
D. pressure, density, and specific gravity.
1. Hydrostatic head-or simply head-is the pressure that a height of liquid sitting over a given point creates at that point. Because it measures in height, the units of head are lengths-millimeters, inches, meters, feet, and the like. Train engineers in the old days often referred to their steam engines as having a "full head of steam," meaning high pressure. The correct answer is B.
2. The scientific and engineering community widely accepts the Systeme Internationale d'Unites (SI). Its base units are length, mass, moles, time, temperature, electric current, and light intensity. The base units of the American engineering system are length (foot), mass (lbm), and time (second). A is the best answer. The other three answers have properties that derive from the base units of A.
Nicholas Sheble (firstname.lastname@example.org) explains the answers to CCST questions. For information about the CCST program, go to www.isa.org/ccst.