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.

CCST questions

1. Hydrostatic head is another way of expressing:

A. gallons.

B. pressure.

C. length.

D. mass.

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.

CCST answers

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.

Pressure difference

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 (nsheble@isa.org) explains the answers to CCST questions. For information about the CCST program, go to www.isa.org/ccst.