Post on 14-Apr-2018
transcript
7/29/2019 B31.3 Process Piping Course - 09 Reactions
1/12
ASME B31.3 Process Piping Course 9. Reactions
BECHT ENGINEERING COMPANY, INC. Reactions -1
ASME B31.3 Process Piping
Charles Becht IV, PhD, PE
Don Frikken, PE
Instructors
BECHT ENGINEERING COMPANY, INC. Reactions -2
1. Establish applicable system standard(s)2. Establish design conditions3. Make overall piping material decisions
Pressure Class Reliability Materials of construction
4. Fine tune piping material decisions Materials Determine wall thicknesses Valves
5. Establish preliminary piping system layout & support
configuration6. Perform flexibility analysis7. Finalize layout and bill of materials8. Fabricate and install9. Examine and test
Piping Development Process
7/29/2019 B31.3 Process Piping Course - 09 Reactions
2/12
ASME B31.3 Process Piping Course 9. Reactions
BECHT ENGINEERING COMPANY, INC. Reactions -3
9. Reactions
General Considerations Fabricated Equipment
Rotating Equipment
Supports
Cold Spring
BECHT ENGINEERING COMPANY, INC. Reactions -4
The Material in This Section isAddressed by B31.3 in:
Chapter II - Design
7/29/2019 B31.3 Process Piping Course - 09 Reactions
3/12
ASME B31.3 Process Piping Course 9. Reactions
BECHT ENGINEERING COMPANY, INC. Reactions -5
General Considerations
Main purpose is to provide sufficientsupport and flexibility to prevent the pipingfrom exerting excessive reactions onequipment and restraints
The calculation methods are different forfabricated equipment than for rotatingequipment or supports
Reaction limits are determined differently
for fabricated equipment than for rotatingequipment or supports
BECHT ENGINEERING COMPANY, INC. Reactions -6
Fabricated Equipment Calculation Methods
Reaction Limits
Nozzle Flexibility
7/29/2019 B31.3 Process Piping Course - 09 Reactions
4/12
ASME B31.3 Process Piping Course 9. Reactions
BECHT ENGINEERING COMPANY, INC. Reactions -7
Calculation Methods
Usually the accuracy of a formal analysisusing a computer stress analysis programis required
Both sustained loads and displacementloads are considered
Failure modes for fabricated equipmentinclude:
Gross deformation or collapse
Fatigue
BECHT ENGINEERING COMPANY, INC. Reactions -8
Calculation Methods In order to evaluate fatigue, the entire
range of loads must be considered, so thetemperature range for this calculation isthe same as for calculating thedisplacement stress range
7/29/2019 B31.3 Process Piping Course - 09 Reactions
5/12
ASME B31.3 Process Piping Course 9. Reactions
BECHT ENGINEERING COMPANY, INC. Reactions -9
Reaction Limits
Reaction limits fornozzles are calculatedusing
Welding ResearchCouncil Bulletin 107Local Stresses inShells due toExternal Loadings
Finite element analysis
BECHT ENGINEERING COMPANY, INC. Reactions -10
Reaction Limits Allowable stresses values used in the
calculation are taken from the applicable Code,and stress evaluation is usually done using thestress evaluation criteria described in ASMEB&PV Code Section VIII, Division 2, AlternateRules for Pressure Vessels
Advantages to doing these calculations yourself
Cycle time is reduced considerably Easier to decide between reinforcing the
nozzle and lowering the reactions
7/29/2019 B31.3 Process Piping Course - 09 Reactions
6/12
ASME B31.3 Process Piping Course 9. Reactions
BECHT ENGINEERING COMPANY, INC. Reactions -11
Rotating Equipment
Calculation Methods Reaction Limits
BECHT ENGINEERING COMPANY, INC. Reactions -12
Calculation Methods Usually the accuracy of a formal analysis using
a computer stress analysis program is required
Failure modes for rotating equipment include:
Detrimental misalignment
Rubbing interference
In order to evaluate failure modes, only themagnitude of the loads during operation needs
to be considered, so the temperature rangefrom the installed condition to the operatingcondition is used
7/29/2019 B31.3 Process Piping Course - 09 Reactions
7/12
ASME B31.3 Process Piping Course 9. Reactions
BECHT ENGINEERING COMPANY, INC. Reactions -13
Temperature Range Examples
Outdoor cooling tower water line: Minimum water temperature is 45F (7C)
Maximum water temperature is 90F (32C)
The piping is installed during February,which has an average daily temperature of53F (12C)
Minimum average daily temperature is 30F(-1C)
Temperature range is _______ to ________
BECHT ENGINEERING COMPANY, INC. Reactions -14
Temperature Range Examples Outdoor compressed air piping
Minimum compressed air temperature isambient
Maximum compressed air temperature is150F (65C)
The piping is installed during J uly, which hasan average daily temperature of 64F (18C)
Minimum average daily temperature is -30F(-35C)
Temperature range is _______ to ________
7/29/2019 B31.3 Process Piping Course - 09 Reactions
8/12
ASME B31.3 Process Piping Course 9. Reactions
BECHT ENGINEERING COMPANY, INC. Reactions -15
Temperature Range Examples Outdoor steam traced water line:
Minimum water temperature is 40F (4C)
Maximum water temperature is 60F (16C)
The piping is installed during September,which has an average daily temperature of76F (24C)
Minimum average daily temperature is 30F(-1C)
Calculated maximum temperature for no flowcondition with steam tracing on is 280F(140C)
Temperature range is _______ to ________
BECHT ENGINEERING COMPANY, INC. Reactions -16
Reaction Limits Limits are specified by the equipment
manufacturers
Manufacturers of certain types ofequipment are required to at least meetthe allowable reaction requirements inapplicable industry standards, so
Many manufacturers refer the users tothese standards
7/29/2019 B31.3 Process Piping Course - 09 Reactions
9/12
ASME B31.3 Process Piping Course 9. Reactions
BECHT ENGINEERING COMPANY, INC. Reactions -17
Reaction Limits
API 619Positive DisplacementCompressors
API 617Centrifugal Compressors
NEMA SM-23
API 611
API 612
Steam Turbines
ASME B73.1
API 610
Centrifugal PumpsIndustry StandardEquipment
BECHT ENGINEERING COMPANY, INC. Reactions -18
Supports Calculation Methods
Reaction limits
7/29/2019 B31.3 Process Piping Course - 09 Reactions
10/12
ASME B31.3 Process Piping Course 9. Reactions
BECHT ENGINEERING COMPANY, INC. Reactions -19
Calculation Methods
Usually the accuracy of a formal analysis usinga computer stress analysis program is required
The failure modes of concern for supports iscollapse and excessive deformation
The structural codes dont recognize thedistinction between displacement and sustainedloads, so only the magnitude of the loadingextremes needs to be considered, so
The temperature range from the installedcondition to the operating condition is used
Some codes differentiate between normalloads and occasionalloads
BECHT ENGINEERING COMPANY, INC. Reactions -20
Reaction LimitsReaction limits are determined by either themaximum stress or the stability limit of thestructure.
7/29/2019 B31.3 Process Piping Course - 09 Reactions
11/12
ASME B31.3 Process Piping Course 9. Reactions
BECHT ENGINEERING COMPANY, INC. Reactions -21
Cold Spring
Cold spring is the intentional deformation of pipingduring assembly to produce a desired initialdisplacement and stress. (319.2.4)
Cold springing:
Does not change the stress range
Does not change the reaction range
Is not helpful for reducing reaction ranges at fabricatedequipment
Can be helpful for reducing reactions rotatingequipment and supports
Can be used to control displacements
BECHT ENGINEERING COMPANY, INC. Reactions -22
Cold Spring
Neutral Neutral
Cold Cold
Hot Hot
7/29/2019 B31.3 Process Piping Course - 09 Reactions
12/12
ASME B31.3 Process Piping Course 9. Reactions
BECHT ENGINEERING COMPANY, INC. Reactions -23
Cold Spring
Because cold spring is difficult to achieveaccurately in practice, B31.3 permits onlypartial credit in calculating reaction forces
For two anchor systems with no intermediaterestraints, B31.3 gives equations for estimatingreactions giving 2/3 credit for cold spring(319.5.1)
For other systems, B31.3 requires that each
case be studied to estimate reactions (319.5.2)
BECHT ENGINEERING COMPANY, INC. Reactions -24
Cold SpringNote that unintentional cold spring(misalignment) has the same effect asintentional cold spring.
The Code says Any distortion of piping tobring it into alignment for joint assembly whichintroduces a detrimental strain in equipment orpiping components is prohibited. (335.1.1)
Some owners are more restrictive than theCode on misalignment.