Steamfitter Key Skills and Knowledge Areas 3 — Questions and Answers
Question 1: What is the correct bolt torque sequence when assembling a gasketed pipe flange?
- Start at the top and work clockwise
- Tighten in a cross (star) pattern (Correct answer)
- Tighten all bolts on one side first, then the other
- Random order, then final torque
Correct answer: Tighten in a cross (star) pattern
A cross or star pattern ensures even compression of the gasket and prevents distortion of the flange faces.
Question 2: Which type of valve is best suited for throttling (regulating) steam flow in a process system?
- Gate valve
- Ball valve
- Globe valve (Correct answer)
- Check valve
Correct answer: Globe valve
Globe valves are designed for throttling service because their disc moves perpendicular to flow, allowing fine flow control.
Question 3: A pipe hanger spacing chart specifies 10-foot maximum spans for 2-inch carbon steel pipe. What is the consequence of exceeding this span?
- Increased pressure drop
- Excessive pipe sag causing condensate pooling and possible failure (Correct answer)
- Higher thermal expansion
- Reduced insulation effectiveness
Correct answer: Excessive pipe sag causing condensate pooling and possible failure
Spans that are too large allow pipes to sag, creating low points where condensate collects, risking water hammer and structural stress.
Question 4: What is the purpose of a trap on a steam condensate return line?
- To increase steam pressure
- To discharge condensate while retaining live steam (Correct answer)
- To filter particulates from the steam
- To measure flow rate
Correct answer: To discharge condensate while retaining live steam
A steam trap automatically removes condensate and non-condensable gases from the system without allowing live steam to escape.
Question 5: When performing a hydrostatic pressure test on a newly installed piping system, the test pressure is typically set at what value?
- Equal to the design operating pressure
- 1.5 times the design pressure (Correct answer)
- 2 times the design pressure
- Half the design pressure
Correct answer: 1.5 times the design pressure
ASME B31.1 and B31.3 codes typically require hydrostatic test pressure to be 1.5 times the design (maximum allowable working) pressure.
Question 6: Which type of gasket material is most appropriate for saturated steam service at 300°F and 70 psi?
- Neoprene rubber
- Spiral wound stainless steel with flexible graphite filler (Correct answer)
- Cork and rubber composite
- Teflon (PTFE) sheet
Correct answer: Spiral wound stainless steel with flexible graphite filler
Spiral wound metallic gaskets with flexible graphite filler are rated for high-temperature steam service and provide reliable sealing.
Question 7: What does 'P&ID' stand for and what is its primary use in pipefitting work?
- Pipe and Insulation Diagram — used for heat loss calculations
- Piping and Instrumentation Diagram — shows system components, flow paths, and controls (Correct answer)
- Pressure and Installation Design — used for structural support layouts
- Process and Isometric Drawing — used for field dimension verification
Correct answer: Piping and Instrumentation Diagram — shows system components, flow paths, and controls
A P&ID (Piping and Instrumentation Diagram) is the primary engineering document showing all pipes, equipment, valves, and instrumentation in a process system.
Steamfitter Key Skills and Knowledge Areas 3
What is the correct bolt torque sequence when assembling a gasketed pipe flange?