1 August 2002 Test your knowledge with CCST . . . The following
sample questions (not actual exam questions) appear in the
Certified Control System Technician (CCST) study guide published
by ISA. The content area for these questions is Domain
1—calibration. 1) If a cubic foot of water weighs 62.4 pounds,
it exerts a pressure of how many pounds per square inch (psi)?
2) Head is another way of expressing: 3) Approximately what is
the pressure, in psi, at the bottom of a 20-foot tank filled
with a fluid that has a specific gravity of 1.5? 1) Imagine a
cubic foot of water. It's 12 inches wide, 12 inches back, and 12
inches high. Because the base of this cube of water is 12 by 12,
we know that the base is 144 square inches. The question asks
how many pounds per square inch does the box exert. Put 62.4
pounds in the numerator and 144 square inches in the
denominator, divide, and you get 0.433 psi—answer C. 2) The
correct answer is B. 3) Specific gravity (SG) is the density
(mass/volume) of a substance with referenc