Considerations for Design of piping systems

[Freeman]

Piping Design

Piping design deals with the:


Analytical design
Material selection
Geometric layout
Fabrication
Inspection specification
Component specification
of piping and piping components.
4.1 Failure Mechanisms
Piping and piping components may fail if inadequately designed, by a number of different mechanisms. These failures, in the majority of cases are either load controlled or displacement controlled failures.
Pipe rupture due to overpressure
Bending failure in pipe span
Elbow *****ing after 10 years of service, 5000 cycles of heat up to 500 F
on heat up, a line comes into contact with adjacent header which is at ambient temperature
during startup on a cold winter day in Grande Prairie, an outdoor gas line located above grade and constructed to Z662 is suddenly subjected to full line pressure and ruptures.
a 12” Sch.40 header, bottom supported, 40 feet long runs vertically up a tower and connects to a nozzle. On steam out of the vessel, a 1’ deflection is observed in the pipe and remains after the steam out procedure is completed and the pipe returns to ambient temperature.
a header of a reciprocating compressor has been stressed checked; during operation vibration is observed in the line. During the unit turnaround, *****ing is found at midspan in the wrought piping material.
A stress check determines that a hot, high alloy line does not pass the flexibility requirements per B31.3. Twenty-five cycles are expected over the lifetime of the line.

Considerations for Design of piping systems

Design of piping systems is governed by Codes. All codes have a common theme; they are intended to set forth engineering requirements deemed necessary for safe design and construction of piping installations.
The Codes are not intended to apply to the operation, examination, inspection, testing, maintenance or repair of piping that has been placed in service. The Codes do not prevent the User from applying the provisions of the Codes for those purposes.
Engineering requirements of the Codes, while considered necessary and adequate for safe design, generally use a simplified approach. A designer capable of applying a more rigorous analysis shall have the latitude to do so, but must be able to demonstrate the validity of such analysis.
Design Conditions

Design conditions refer to the operating and design temperature and pressure that the piping system will operate at over the course of its design life.

Code Design Temperature & Design Pressure

Code

Design Temperature

Design Pressure

Code
B31.1

Design Temperature

The piping shall be designed for a metal temperature representing the maximum sustained condition expected. The design temperature shall be assumed to be the same as the fluid temperature unless calculations or tests support the use of other data, in which case the design temperature shall not be less than the average of the fluid temperature and the outside wall temperature.

Design Pressure
The internal design pressure shall be not less than the maximum sustained operating pressure (MSOP) within the piping system including the effects of static head.

Code

B31.3

Design Temperature

The design temperature of each component in a piping system is the temperature at which, under the coincident pressure, the greatest thickness or highest component rating is required in accordance with par. 301.2

Design Pressure
The design pressure of each component in a piping system shall be not less than the pressure at the most severe condition of coincident internal or external pressure and temperature expected during service, except as provided in par. 302.2.4.

Code
B31.4

Design Temperature
The design temperature is the metal temperature expected in normal operation. It is not necessary to vary the design stress for metal temperatures between –20 F and 250 F.

Design Pressure
The piping component at any point in the piping system shall be designed for an internal design pressure which shall not be less than the maximum steady state operating pressure at that point, or less than the static head pressure at that point with the line in a static condition. The maximum steady state operating pressure shall be the sum of the static head pressure, pressure required to overcome friction losses and any required back pressure.

Code
B31.8

Design Temperature
No design temperature. The Code mentions only ambient temperature and ground temperature. (1975)

Design Pressure
Design pressure is the maximum operating pressure permitted by the Code, as determined by the design procedures applicable to the materials and locations involved.

Code
Z662

Design Temperature
For restrained piping, the temperature differential shall be the difference between the maximum flowing fluid temperature and the metal temperature at the time of restraint.
For unrestrained piping, the thermal expansion range to be used in the flexibility analysis shall be the difference between the maximum and minimum operating temperatures.

Design Pressure
The design pressure at any specific location shall be specified by the designer, shall not be less than the intended maximum operating pressure at any location, and shall include static head, pressure required to overcome friction loss and any required back pressure.

[Freeman]

B31.3 Process Piping

This piping is typically found in petroleum refineries, chemical and
pharmaceutical plants, and many other process plants and terminals.
It has a high-pressure section. It recognizes different degrees of
fluids safety concerns and imposes different rules on each. It has a
nonmetallic section. It is generally considered the most broadly applicable
code.

Paragraph 300.1.3 lists the exclusions:

 Piping systems designed for pressures at or above 0 but less than
105 kPa (15 psig), provided they meet certain other requirements
including temperature ranges

 Power boilers and piping required to meet B31.1


 Tubes and so forth that are internal to a heater enclosure

 Pressure vessels and certain other equipment and piping

[Freeman]

B31.4 Pipeline Transportation Systems for liquid hydrocarbons and other liquids


This code is for the type of pipelines that transport liquids between plants
and terminals and pumping regulating and metering stations. One of
the more well-known pipelines that is predominately under the auspices
of this code is the Alaskan Pipeline from Prudhoe Bay in Alaska to
Valdez.


Paragraph 400.1.2 lists the elements to which it does not apply:

 Auxiliary piping, e.g., water, air, or steam

 Pressure vessels, heat exchangers, and similar equipment

 Piping designed at or below 1 bar (15 psig) at any temperature

•  Piping above 1 bar (15 psig) if temperature is below –30°C (–20°F) or
  

above 120°C (250°F)

 Pipe, casing, or tubing used in oil well and related assemblies

 Petroleum refinery piping with certain exceptions

 Gas transmission and distribution lines

 Most proprietary equipment

 Ammonia refrigeration piping and carbon dioxide gathering and distribution
systems

[Freeman]

B31.5 refrigeration piping and heat transfer components

This is piping used for refrigerants and secondary coolants. It is to cover
temperatures as low as –196°C (–320°F). There is a note explaining
that the other codes may have requirements in their sections.

Paragraph 500.1.3 lists the elements to which the code does not apply:

 Any self-contained unit system that is subject to Underwriters Laboratories (UL) or a similar testing laboratory

 Water piping

 Piping designed for use not exceeding 105 kPa (15 psig)

 Pressure vessel and similar equipment but starting at the first joint of any piping for refrigerant piping that is connecting such equipment

[Freeman]

B31.8 gas transmission and distribution piping systems

This code covers primarily gas transportation piping between sources and terminals. It includes gas metering, regulating, and gathering pipelines. It has rules about corrosion protection and with its supplement

B31.8S covers the management of the integrity of such pipelines.

Paragraph 802.1.3 lists the elements to which it does not apply:

 Pressure vessels covered by the BPVC

•  Piping with metal temperatures above 232°C (450°F) or below –29°C (–20°F)
  

•  Piping beyond the outlet of the customer’s meter assembly
  

 Piping in oil refineries with exceptions

 Vent piping for waste gases

 Wellhead assemblies

 Design and manufacture of proprietary equipment

 Design and manufacture of heat exchangers to Tubular Exchanger Manufacturers Association (TEMA) standards

 Liquid petroleum transportation systems, liquid slurry transportation piping, carbon dioxide transportation systems, and liquefied natural gas piping systems; it includes references to other documents for these types of systems

[Freeman]

B31.11 slurry transportation piping systems

The primary use of this code is for aqueous slurries between plants and terminals. It also covers use within those areas. One of the uses of these systems is in the mining industries in moving ores from the mines to elsewhere.

Paragraph 1100.1.2 states the elements to which it does not apply:

 Auxiliary piping such as for water, air, and similar liquids and gases

 Pressure vessels

 Piping designed for pressures below 103 kPa (15 psig) at any temperature

 Piping designed for pressures above 103 kPa (15 psig), when temperature
is below –30°C (–20°F) or above 120°C (250°F)

 Piping within the battery limits of slurry processing plants and other
nonstorage facilities

 Design and fabrication of proprietary items

A careful reading about each of the codes would find many similarities,
especially for the elements to which the piping codes do not apply.
They do not design for under 105 kPa (15 psig). They are for piping, not
pressure vessels and other elements of a project that are covered by the
ASME BPV Code.

[inzenjer]

does anyone have
Piping Stress Calculations Simplified by S.W. Spielvogle
please upload
thank you in advance

[alwaw911]

Unfortunately no inzenjer...but i have this one:

[link Point to another website Only the registered members can access]
Piping Systems & Pipeline ASME Code Simplified
ed2005 McGraw-Hill by Philipp Ellenberger.

A REAL NICE BOOK...

[sauro]

try:

[link Point to another website Only the registered members can access]

[sauro]

try:

[link Point to another website Only the registered members can access]

[inzenjer]

good job sauro
thank you for your effort and contibution

[inzenjer]

good job sauro
thank you for your effort and contribution