Certified Pipefitter Instrumentation and Process Measurement

Question 1

On a P&ID, a circle with the letter 'FIC' and a tag number represents which type of instrument?

Accepted Answer

Flow Indicating Controller — an instrument that measures, displays, and controls flow rate

Answer

On a P&ID, instrument tag letters follow ISA 5.1 standard: the first letter identifies the measured variable (F = Flow), and subsequent letters indicate the function (I = Indicating, C = Controlling). FIC therefore means Flow Indicating Controller — it measures, displays, and controls flow.

Question 2

What is the difference between gauge pressure (psig) and absolute pressure (psia)?

Accepted Answer

Gauge pressure is referenced to atmospheric pressure (reads zero at atmosphere); absolute pressure is referenced to a perfect vacuum

Answer

Gauge pressure (psig) reads zero at local atmospheric pressure — it measures pressure above or below atmosphere. Absolute pressure (psia) equals gauge pressure plus atmospheric pressure (~14.7 psia at sea level) and is measured from an absolute zero reference (perfect vacuum). Many process calculations require absolute pressure.

Question 3

A pipefitter is installing an orifice plate in a flow measurement run. Which orientation requirement is critical?

Accepted Answer

The beveled (sharp) edge of the orifice must face upstream (into the flow)

Answer

An orifice plate creates a calibrated pressure drop across a sharp-edged restriction. The sharp (beveled) edge must face upstream so the flow contracts cleanly through the orifice. Reversing the plate distorts the flow coefficient and introduces significant measurement error.

Question 4

What is the purpose of a thermowell when installing a temperature sensor in a pressurized process pipe?

Accepted Answer

To provide a closed-end protective tube that lets the sensor be installed or removed without depressurizing the pipe

Answer

A thermowell is a closed-end tube welded or threaded into the pipe. The temperature sensor slides inside it and senses process temperature through the well wall, but remains physically isolated from the process fluid. This allows sensor replacement under pressure without process interruption.

Question 5

Which flow meter type operates with no moving parts and measures flow using Faraday's law of electromagnetic induction?

Accepted Answer

Magnetic flow meter (magmeter)

Answer

A magnetic flow meter (magmeter) applies a magnetic field across the pipe and measures the voltage induced in the conductive flowing fluid. Because voltage is proportional to velocity by Faraday's law, flow rate can be calculated. Magmeters have no moving parts, no restrictions, and work well with slurries and corrosive fluids.

Certified Pipefitter Practice Test

Certified Pipefitter Practice Test

Certified Pipefitter Instrumentation and Process Measurement