Steamfitter Technical Standards and Specifications 2 — Questions and Answers
Question 1: According to ASME B31.1, what is the minimum required wall thickness formula component that accounts for manufacturing tolerances?
- Corrosion allowance (c)
- Mill tolerance (y) (Correct answer)
- Pressure design thickness (t)
- Mechanical allowance (m)
Correct answer: Mill tolerance (y)
ASME B31.1 requires adding a mill tolerance (typically 12.5% of nominal wall) to account for manufacturing variations when calculating minimum required wall thickness.
Question 2: Which ASTM specification covers seamless and welded black and hot-dipped zinc-coated (galvanized) steel pipe for ordinary use?
- ASTM A53 (Correct answer)
- ASTM A106
- ASTM A120
- ASTM A312
Correct answer: ASTM A53
ASTM A53 covers seamless and welded black and hot-dipped galvanized steel pipe for ordinary use in steam, water, gas, and air service.
Question 3: What does the 'Schedule' number of a pipe indicate?
- The pipe's outside diameter in inches
- The approximate value of 1000 times the ratio of working pressure to allowable stress (Correct answer)
- The pipe's weight per linear foot
- The pipe's inside diameter in millimeters
Correct answer: The approximate value of 1000 times the ratio of working pressure to allowable stress
Schedule number approximates 1000 times the ratio of the internal working pressure to the allowable fiber stress, providing a standardized measure of wall thickness.
Question 4: Under ASME B31.3 Process Piping, what category applies to piping that is highly toxic or flammable and could cause irreversible harm?
- Category D
- Category M (Correct answer)
- Category N
- Category H
Correct answer: Category M
Category M (lethal service) under ASME B31.3 applies to fluids that are so toxic or flammable that even a small leak could cause serious harm to personnel.
Question 5: When threading pipe per ANSI/ASME B1.20.1, what taper rate is specified for NPT threads?
- 1/8 inch per inch
- 1/16 inch per inch (Correct answer)
- 3/32 inch per inch
- 1/32 inch per inch
Correct answer: 1/16 inch per inch
NPT (National Pipe Taper) threads per ANSI/ASME B1.20.1 have a taper of 1/16 inch per inch (or 3/4 inch per foot) of thread length.
Question 6: Which standard governs the pressure-temperature ratings for steel pipe flanges and flanged fittings?
- ASME B16.5 (Correct answer)
- ASME B16.9
- ASME B16.11
- ASME B16.21
Correct answer: ASME B16.5
ASME B16.5 covers pressure-temperature ratings, materials, dimensions, tolerances, marking, and testing for steel pipe flanges and flanged fittings from NPS 1/2 through NPS 24.
Question 7: What does the 'A' in ASTM A106 Grade B seamless carbon steel pipe signify?
- The pipe is made in America
- The material is ferrous (iron-based) (Correct answer)
- The pipe has been annealed
- The pipe is approved for steam service
Correct answer: The material is ferrous (iron-based)
In ASTM designations, the letter 'A' indicates a ferrous (iron-based) material standard, distinguishing it from 'B' (nonferrous) or 'C' (concrete/masonry) standards.
Steamfitter Technical Standards and Specifications 2
According to ASME B31.1, what is the minimum required wall thickness formula component that accounts for manufacturing tolerances?