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WorksheetsUnit 3.1 – Pipe Sizing and Selection PART 1
Total questions: 40
Worksheet time: 20mins
Which committee sets the primary design codes for pressure piping?
ASME B16
ASME B31
API 650
ASTM A106
Different services require different pressure-piping standards. These are detailed in:
Chemical Engineer’s Handbook
ASME B31 tables
Towler & Sinnott
ISO 9001
Standards for pipe fittings such as flanges and tees are issued by:
ASME B31
ASME B16
ASTM D2000
ANSI Z223
Long pipe runs between buildings are typically carried on:
Structural trusses
Pipe racks
Expansion joints
Pressure vessels
Which joint type is normally used where frequent disassembly is expected?
Screwed joint
Welded joint
Flanged joint
Brazed joint
Small-diameter pipes often use which type of joint?
Screwed
Welded
Riveted
Bellows
Major load NOT typically significant in piping stress design is:
Thermal expansion
Dead weight
Pressure drop reaction
Vibration
Flexibility to absorb thermal expansion can be added using:
Thicker walls
Expansion loops or bellows
Higher pressure ratings
Increased velocity
Which factor does not contribute to dead-weight loads?
Pipe contents
Pipe insulation
Ancillary equipment
Sonic velocity
Pipe wall thickness is primarily selected to resist:
Vibrational fatigue
Internal pressure
Axial tension
External corrosion only
In the ASME B31.3 formula, the term c accounts for:
Casting quality factor
Mechanical plus corrosion/erosion allowances
Temperature factor
Outside diameter
Standard pipe dimensions for stainless steel are given in:
ASME B36.19
ASME B36.10M
API 610
ASTM E84
Schedule number is defined as:
(Safe working stress × 1000) / Safe working pressure
(Safe working pressure × 1000) / Safe working stress
Pressure / Diameter
Diameter / Wall thickness
Which schedule is most common for general low-pressure service?
20
40
80
160
When motive power is free (e.g., gravity flow), you normally choose the:
Largest economical diameter
Smallest diameter that meets flow
Highest schedule number
Thickest wall
For gases and vapors, velocity is normally limited to:
100% of critical
50% of critical
30% of critical
10% of critical
Maximum velocity must be below the point where:
Cavitation starts
Erosion is likely
Pump suction pressure drops
Sound waves reflect
Approximate design velocity for pump discharge is:
0.02 d + 0.1 m/s
0.06 d + 0.4 m/s
0.2 d m/s
0.6 d + 0.4 m/s
Approximate design velocity for pump suction is:
0.02 d + 0.1 m/s
0.06 d + 0.4 m/s
0.2 d m/s
0.4 d + 0.2 m/s
For steam or vapor lines, the design velocity is roughly:
0.2 d m/s
0.02 d + 0.1 m/s
0.6 d m/s
0.1 d m/s
The most economic pipe diameter minimizes:
Only pumping cost
Only capital cost
Total annualized cost
Maintenance cost
Increasing pipe diameter generally:
Increases capital cost and pumping cost
Decreases both costs
Increases capital but decreases pumping cost
Decreases capital but increases pumping cost
Towler & Sinnott formulas for A106 carbon steel (25–200 mm) are used to estimate:
Wall thickness
Optimum pipe diameter
Casting quality factor
Sonic velocity
A stainless-steel process line (250 mm) carrying liquid at moderate pressure is being sized for lowest annual cost. According to the empirical formula, you would use the coefficient:
0.550
0.465
0.664
0.534
If internal design pressure is 150 psi, outside diameter 0.3 m, S = 20,000 psi, E = 1, γ = 0, and c = 1 mm, the pressure design thickness t_m is approximately:
P d / [2(S E + P γ)] ≈ ___
Not required
Based on velocity
Based on schedule only
Thermal expansion in pipes is normally absorbed by the natural:
Wall thickness
Bends and loops in the layout
Increased pressure rating
Pipe schedule number
If natural flexibility is insufficient, engineers add:
Pipe racks
Expansion loops, bellows, or special devices
Higher-grade steel
Smaller diameters
Which load is usually negligible when calculating piping stresses?
Thermal expansion
Vibration
Reaction from fluid pressure drop
Weight of insulation
The dead-weight load of a pipe system includes all except:
Weight of the pipe itself
Weight of contained fluid
Weight of pipe supports
Weight of insulation
For high-pressure steam lines, pipes must be analyzed as:
Thin cylinders
Thick cylinders
Vacuum vessels
Double-walled tubes
The ASME B31.3 minimum required thickness tmt_m is the sum of:
Pressure design thickness + casting factor
Pressure design thickness + allowances for mechanical/corrosion
Outside diameter + temperature factor
Safe stress + temperature factor
In the formula tp=Pd2(SE+Pγ)t_p = \frac{P d}{2(S E + P \gamma)}, SS represents:
Safe working pressure
Basic allowable stress of pipe material
Sonic velocity
Schedule number
Casting quality factor EE accounts for:
Alloy composition
Quality of weld/casting
External coating
Expansion loops
Temperature factor γ\gamma corrects for:
Fluid viscosity
Elevated service temperatures
Wall roughness
Pressure drop
Standard wrought-steel pipe dimensions are specified in:
ASME B36.10M
ASME B36.19
ASTM A53
API 650
A pipe’s “schedule number” is primarily a measure of:
Outside diameter
Wall thickness
Sonic velocity
Roughness factor
If a line operates with free gravity head, what economic factor is least significant?
Pumping power
Pipe friction
Capital cost
Corrosion allowance
The critical (sonic) velocity of a vapor line is primarily a function of:
Pipe diameter
Fluid compressibility and temperature
Wall thickness
Surface roughness
For gases, the usual design velocity limit is set at roughly what fraction of sonic velocity?
10 %
30 %
60 %
90 %
Higher velocity in a liquid line mainly increases:
Corrosion allowance
Erosion potential and pressure drop
Capital cost
Casting quality factor
