Pneumatic testing is often used to test piping systems when the presence of moisture is undesirable or removal of residual water cannot be conveniently achieved. Due to incompressibe nature of hydrotest fluid, the energy stored in a piping system under hydrostatic pressure is far less in comparison to a piping system which is subjected to pneumatic pressure. 

Piping Topic: Testing
Hits: 21893

Hot tap is a pressure installation technique that allows connections to be made on existing live (operating) piping or equipment without shutdown or interruption to critical plant operation. As per API Publication 2201, "Hot tapping is the technique of attaching connections to equipment in service by welding and drilling."

Piping Topic: Hot Tapping
Hits: 24698

Online calculator for pipe weight is a convenient tool for instantly calculating the weight of steel pipes and its contents including any insulation weight if applicable. Choose the pipe size and the applicable thickness to calculate the empty pipe unit weight.

Piping Topic: Weight Calculations
Hits: 15176

Section 302.3.2 (d) of ASME B31.3 provides the basis of design stress or allowable stress for piping materials. As per this section, the basic allowable stress values at temperature for materials other than bolting materials, cast iron, and malleable iron shall not exceed the lowest of the following for temperatures below the creep range:

Piping Topic: Stress Theory
Hits: 59813

Allowable Pipe Support Span Calculation

Selecting the correct pipe support span is an important aspect of piping design. The maximum pipe support spacing is dependent on the maximum allowable deflection or sag in the piping and the maximum permissible longitudinal stress on account of the span. 

Piping Topic: Support Span Calculations
Hits: 27049

Calculation for a straight pipe under external pressure is referenced in section 304.1.3 of ASME B31.3. As per this section, to determine wall thickness and stiffening requirements for straight pipe under external pressure, the procedure outlined in the BPV Code, Section VIII, Division 1, UG-28 through UG-30 shall be followed, using as the design length L, the running centerline length between any two sections stiffened in accordance with UG-29.

Piping Topic: Wall Thickness Calculations
Hits: 25695

The application of reinforced thermosetting resin pressure piping (RTRP) has grown considerably in chemical plants, oil and gas facilities, water and sewarage systems due its corrosion resistance, strength and durability. FRP, GRP, GRE and GRV are abbreviations for specific types of RTR pipes depending on the resin systems used in the manufacture of piping system.

Piping Topic: FRP and GRP
Hits: 42364

Piping prefabrication is an important step in the construction of piping systems. Whenever feasible, sections of piping systems or piping spools are prefabricated by the contractor in the workshop. After prefabricating the spools, they are transported to the field and assembled to complete the piping system.

Piping Topic: Fabrication
Hits: 30685

Piping and Instrumentation Diagram (P&ID) is a schematic representation of a process flow between all process units or equipment's in a plant. As the name suggests the graphical representation on a P&ID includes all piping connected between equipment's and the associated instrumentation necessary to design, construct and operate a plant facility.

Piping Topic: Process Plant Layout
Hits: 56985

In the design of piping systems, the piping engineer or designer is responsible for locating the pipe supports and restraints to take care of the loads and displacements imposed on the piping system for the various load cases. A piping system may have several types of supports and restraints to take care of the various loads imposed on it and to allow the piping system to function safely under operating, design and occassional load conditions.

Piping Topic: Supports General
Hits: 45047

The installation of hot bitumen pipeline (on-lease) requires careful consideration with regards to design and construction methodology. The buried pipelines are routed through congested areas within lease boundary, hence various factors are taken into consideration including design constraints.

Piping Topic: Pipeline Design
Hits: 6391

Acoustic Induced Vibration (AIV) is a flow induced vibration phenomena that can result in fatigue failures in piping systems leading to major safety and economic consequences such as damage to assets, environmental impact and loss of life.

Piping Topic: Stress Theory
Hits: 10428

Pipeline pigging is the process of propelling a pig through a pipeline from a pig launcher and receiving the pig at the pig receiver end of the pipeline. Various types of pigs are propelled through the pipeline depending on the intended function which could be cleaning, dewatering, chemical batching, dimensioning or inspection.

Piping Topic: Pipeline Design
Hits: 23727

Piping Engineering is a specialized discipline of Mechanical Engineering which covers the design of piping and layout of equipments and process units in chemical, petrochemical or hydrocarbon facilities. Piping Engineers are responsible for the layout of overall plant facilities, the location of equipments and process units in the plot and the design of the connected piping as per the applicable codes and standards to ensure safe operation of the facilities for the design life.  

Piping Topic: Process Plant Layout
Hits: 38386

Hydrotest Procedure for Piping Systems

Testing requirements for piping systems are covered in para. 345 of ASME B31.3 code. As per ASME B31.3, prior to initial operation and after completion of applicable examinations as per para. 341, each piping system shall be tested to ensure tightness. The recommended test is a hydrostatic leak test.

Piping Topic: Testing
Hits: 30233

Double Block and Bleed (DBB) trunnion-mounted ball valves have been traditionally used on pipelines for isolation of pig traps or scraper traps. DBB design ball valves have provision for venting of the body cavity to verify that both upstream and downstream seats provide effective sealing against the line pressure.

Piping Topic: Ball Valve
Hits: 5200

A spiral wound gasket consists of spirally wound (usually V-section) metal strip with filler material and an outer metallic ring to hold the windings in place. Spiral wound gaskets are categorized as semi-metallic gaskets and their design is covered by ASME B16.20 - Metallic gaskets for pipe flanges. A spiral wound gasket is designed for one time use.

Piping Topic: Gasket Design
Hits: 12160

Most failures of bolted joints are due to poor assembly and application of incorrect bolting torque. Hence it is important to ensure correct tightening of bolts to ensure leak free joints.

The torue applied to a bolt is used to overcome the following friction:

Piping Topic: Bolt Design
Hits: 39744

Uninsulated or bare piping resting directly on structural steel have resulted in repeated corrosion problems posing high risks for pipe leaks. The geometry of bare piping resting on structural steel provides a crevice that allows water to be trapped.

Piping Topic: Supports General
Hits: 8864

The presence of hydrogen at high temperature and pressure can cause embrittlement of carbon steel and alloy steels. Atomic hydrogen is able to permeate into steel and reacts with iron carbides to form methane. The methane accumulates at the grain boundaries and cannot diffuse through the metal resulting in high internal stresses that eventually lead to cracking of the metal at the grain boundary.

Piping Topic: Materials Corrosion
Hits: 5479

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