A Corrosion Resistant Alloy (CRA) barrier can provide enhanced corrosion and erosion resistance. Solid Corrosion Resistant Alloys (CRA) such as UNS N06625 are expensive and hence a CRA barrier over carbon steel piping is a cost-effective solution to solid CRA piping for severe service applications. Pipe cladding provide the means for achieving this barrier by a process of bonding two dissimilar metals. 

Piping Topic: Nickel Alloys
Hits: 2577

Ring joint gaskets are heavy duty metallic ring type joint gaskets and largely used in onshore and offshore upstream and downstream petroleum and petrochemical applications where high pressures and temperatures are encountered. Ring joint gaskets are manufactured according to ASME B16.20 and API 6A standards.

Piping Topic: Gasket Design
Hits: 14078

Positive Material Identification (PMI) is a process of verifying that the nominal chemical composition of the alloy components and associated welds have been correctly supplied, installed and documented as specified, thus minimizing the risk of component failure and release of hazardous or toxic liquids and gases.

Piping Topic: Materials General
Hits: 14937

When a piping system changes its condition from installation to operating, it will expand or contract depending on the service fluid temperature. If the piping system is provided with restraints, it will try to expand or contract against its restraints resulting in internal forces, moments and stresses.

Piping Topic: Stress Theory
Hits: 7418

When a piping system experiences large vertical movements and if the variability at the point of support exceeds 25%, it is recommended to use contant support springs. As per MSS SP 58, constant support hangers shall be used on piping systems where the deviation in supporting force must be limited to 6 percent and which cannot be accommodated by a variable spring hanger. Constant support hangers are also referred to as constant effort supports.

Piping Topic: Spring Support
Hits: 5942

Hydrostatic Leak tests of welded piping systems serve the following purposes: a] qualify joints not included in the UT or radiographic examination and b] determine the leak tightness of the welded and flanged joints.

Piping Topic: Testing
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MSS SP 58 defines variable spring hanger as a spring coil device which produces a varying supporting effect while permitting vertical pipe movement. Variable Spring Hangers are provided in piping systems to support the weight of the pipe and contents while accommodating the thermal expansion or contraction of the piping normally up to about 50-75mm and in exceptionally rare cases up to about 125 mm. 

Piping Topic: Spring Support
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As a piping system undergoes thermal expansion or contraction during its operating cycle, friction forces are generated at the pipe support locations. The friction force acts opposite to the direction of pipe displacement and could contribute significantly to reduction in piping flexibility and increased loads on anchors or connected equipments.

Piping Topic: Supports General
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Secondary stress is developed in a piping system owing to constraint of the system against displacements, either due to thermal expansion or imposed anchor and restraint movements. As per ASME B31.3 section 302.3.5, the computed displacement stress range SE in a piping system shall not exceed the allowable displacement stress range SA calculated by the following equation:

Piping Topic: Stress Theory
Hits: 15118

Pipe rack can be considered as the main artery of a plant piping system. It offer a means to group and route plant piping in an organized manner. Pipe rack design is one of the significant aspects of plant design and a good design contrbutes to integrity and reliability of the plant and the associated structures. Piping inside the process plants are preferably routed on pipe racks and piping in the off-site areas are preferably routed on pipe sleepers. 

Piping Topic: Process Plant Layout
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This article discusses equipment and piping layout considerations for compressors handling hydrocarbon gases though most of these requirements will apply to other compression facilities as well. Layout of gas compression facilities shall take into cognizance the accessiblity, maintenance and safety requirements. 

Piping Topic: Process Plant Layout
Hits: 9721

Modularization involves prefabrication, installation and precommissioning of a complete plant unit at a location remote from the construction site with the objective of reducing on-site construction, cost and schedule. However, modular construction introduces certain risks in the project which need to be appropriately addressed to ensure that the benefits of modularization outweigh the risks.

Piping Topic: Process Plant Layout
Hits: 6713

When fluid flows through a pipe bend or elbow, the fluid changes direction and hence there is a change in in momentum. As per Newtons Second Law: "The rate of change of momentum of a body is equal to the net force acting on the body". Slug forces are generated when there is 'two-phase' (gaseous and liquid phase) fluid flowing through pipes and slugs of liquid that are formed intermittently travel at relatively high velocity.

Piping Topic: Stress Analysis Related Calculations
Hits: 23694

Calculations for reinforcement of welded branch for ASME B31.3 are performed using the rules defined in section 304.3.3 of the code. The rules involve calculating the area removed from the header due to perforation in the branch and determining the replacement area available in the run pipe, branch pipe and the reinforcement pad including the welds.

Piping Topic: Wall Thickness Calculations
Hits: 27699

Though the fundamental principles of plant layout such as safety, operability, maintainability, constructability, compliance to process requirements and provision for future expansion apply to offshore plant layout as well, there are profound differences in how these principles are applied to offshore plant facilities. Offshore facilities layout are governed by many other factors such as helicopter approach, pipeline approach, jack-up rigs, drilling rigs, supply boat operations, installation barge and maintenance barge access, vessel mooring requirements etc. which are not applicable to onshore plant layout.

Piping Topic: Layout Offshore Platforms
Hits: 10487

ASME B31.3 section 323.2 requires the designer to verify that the materials which meet other requirements of the code are suitable for service throughout the operating temperature range. The minimum temperature limits for various materials are provided in Table A-1 of the code and indicate the design minimum temperature for which the material is normally suitable without impact testing other than that required by the material specification.

Piping Topic: Carbon Steel
Hits: 24636

Pipe spacing calculator is a convenient tool to calculate the minimum spacing between pipes. Spacing can be calculated based on pipe OD and flange OD, between two flange ODs or between two bare pipes. Select the applicable piping configuration from the four options provided to calculate the pipe center to center spacing.

Piping Topic: Support Span Calculations
Hits: 37169

An orifice plate is a flate piece of metal with a restricted bore that is mounted between two orifice flanges for the purpose of flow measurement or is mounted between pair of standard flanges to restrict flow. An orifice plate may be considered as the simplest form of differential pressure flowmeter or flow restriction device.

Piping Topic: Process Plant Layout
Hits: 16743

Calculate minimum safe distances between piping system being pneumatically tested and personnel/plant facilities using ASME PCC-2 Mandatory Appendix 501-II and III equations. For details on the basis of this calculation and example manual calculation refer to the article on Pneumatic Testing - Safe Distances.

Piping Topic: Construction Related Calculations
Hits: 63836

This article provides a convenient tool for calculating the design wall thickness for predefined piping materials for internal pressure. The basis of calculation is section 304.1.2 of ASME B31.3. The allowable stress values are based on 2014 edition of ASME B31.3. The allowable stress values and calculated thickness may vary slightly due to differences in allowable stress values in the current version of code. The calculated design wall thickness are in mm.

Piping Topic: Wall Thickness Calculations
Hits: 23614

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