Pipefitter Valves, Fittings, and Pipe Materials

Question 1

What is the primary advantage of a 'full port' (full bore) ball valve over a 'standard port' (reduced bore) ball valve?

Accepted Answer

Full port valves have a bore equal to the pipe ID, allowing pigging, full flow, and minimal pressure drop; standard port has a reduced bore that increases velocity and pressure drop

Answer

Full port valves have higher pressure ratings

Answer

Full port valves are always less expensive

Answer

Full port valves can be used for throttling; standard port cannot

Question 2

What material is ASTM A312 TP316L stainless steel pipe best suited for compared to TP304?

Accepted Answer

Chloride-containing or acidic service where extra corrosion resistance is needed; the 'L' designates low carbon to resist sensitization during welding

Answer

Higher pressure applications due to its higher tensile strength

Answer

Cryogenic service below -320 degrees F

Answer

High-temperature service above 1000 degrees F

Question 3

What do the designations 'LR' and 'SR' indicate for pipe elbows?

Accepted Answer

Long Radius (1.5D) and Short Radius (1.0D), defining the centerline radius of the elbow relative to pipe diameter

Answer

Left Run and Short Run, indicating pipe routing direction

Answer

Low Resistance and Standard Resistance, pressure drop classifications

Answer

Long Range and Short Range, referring to the elbow's temperature rating range

Question 4

What is the purpose of a 'Victaulic' (grooved mechanical) coupling in piping systems, and what are its advantages over welded or flanged connections?

Accepted Answer

It is a mechanical pipe coupling using a rubber gasket and housing that clamps onto grooved pipe ends, allowing faster installation, easier maintenance disassembly, and some pipe movement flexibility

Answer

It permanently fuses two pipe ends together with higher strength than welding

Answer

It is used only on plastic pipe systems, not for steel pipe

Answer

It provides a flanged connection with full ASME B16.5 pressure rating

Question 5

What is the difference between a 'concentric reducer' and an 'eccentric reducer,' and when is each used?

Accepted Answer

Concentric reducers have the pipe centerlines aligned (centered); eccentric reducers are offset so one side is flat. Eccentric reducers are used on pump suctions (flat side up) to prevent air pockets.

Answer

Concentric reducers are for gas lines; eccentric reducers are for liquid lines

Answer

Concentric reducers allow pigging; eccentric do not

Answer

Eccentric reducers are for horizontal pipe; concentric for vertical pipe only

Question 6

What does 'ASTM A106 Grade B' designate for seamless carbon steel pipe?

Accepted Answer

ASTM A106 is the specification for seamless carbon steel pipe for high-temperature service; Grade B indicates specific mechanical properties (minimum 60,000 psi tensile, 35,000 psi yield)

Answer

Grade B indicates the pipe is butt-weld only (not seamless)

Answer

Grade B means the pipe is rated for 300 psi service only

Answer

ASTM A106 Grade B is an electric resistance welded pipe for general service