Friday, December 23, 2016

ASME B16 latest 2016

ASME B16 latest (2016-12-19)

ASME B16.1 (2015)
ASME B16.3 (2016)
ASME B16.4 (2016)
ASME B16.5 (2013)
ASME B16.9 (2012)
ASME B16.10 (2009)
ASME B16.11 (2011)
ASME B16.12 (2009 R2014)
ASME B16.14 (2013)
ASME B16.15 (2013)
ASME B16.18 (2012)
ASME B16.20 (2012)
ASME B16.21 (2011)
ASME B16.22 (2013)
ASME B16.23 (2011)
ASME B16.24 (2016)
ASME B16.25 (2012)
ASME B16.26 (2013)
ASME B16.29 (2012)
ASME B16.33 (2012)
ASME B16.34 (2013)
ASME B16.36 (2015)
ASME B16.38 (2012)
ASME B16.39 (2014)
ASME B16.40 (2013)
ASME B16.42 (2011)
ASME B16.44 (2012)
ASME B16.47 (2011)
ASME B16.48 (2015)
ASME B16.49 (2012)
ASME B16.50 (2013)
ASME B16.51 (2013)

SHELL DEP (Design and Engineering Practice) V3.4

SHELL DEP (Design and Engineering Practice)




MSS Sp standrds

MSS Sp standrds

  • SP-65-1999
  • SP-67-2002
  • SP-68-1997
  • SP-69-2003
  • SP-70-1998
  • SP-71-1997
  • SP-72-2010a
  • SP-73-2003
  • SP-75-2008
  • SP-78-1998
  • SP-79-2009
  • SP-80-2008
  • SP-81-2006
  • SP-82-1992
  • SP-83-2006
  • SP-85-2002
  • SP-88-2010
  • SP-90-2000
  • SP-91-2009
  • SP-92-1999
  • SP-93-1999
  • SP-94-2008
  • SP-95-2000
  • SP-96-2001
  • SP-97-2012
  • SP-98-2005
  • SP-99-2010
  • SP-101-1989 (R 2001)
  • SP-102-1989 (R 2001)
  • SP-104-1995
  • SP-105-1996
  • SP-106-1990
  • SP-109-1997
  • SP-110-2010
  • SP-111-2005
  • SP-112-1999
  • SP-113-2001
  • SP-114-2007
  • SP-115-1999
  • SP-116-2003
  • SP-117-2006
  • SP-119-1996
  • SP-120-2006
  • SP-121-2006
  • SP-122-2005
  • SP-124-2001
  • SP-125-2000
  • SP-126-2007
  • SP-127-2001a
  • SP-130-2003
  • SP-132-2004
  • SP-133-205
  • SP-134-2006
  • SP-135-2010
  • SP-136-2007
  • SP-137-2007
  • SP-138-2009

  • ASME B31 latest (2016-12-19)

    ASME B31 latest (2016-12-19)

    ASME B31 latest (2016-12-19)
    ASME B31.1 (2016)
    ASME B31.3 (2014)
    ASME B31.4 (2016)
    ASME B31.5 (2016)
    ASME B31.8 (2016)
    ASME B31.8S (2016)
    ASME B31.9 (2014)
    ASME B31.12 (2014)
    ASME B31E (2008)
    ASME B31G (2012)
    ASME B31J (2008 R2013)
    ASME B31Q (2016)
    ASME B31T (2015)

    Distillation-Ebooks - Operation-Design-Troubleshooting - Henry Kister

    Distillation-Ebooks - Operation-Design-Troubleshooting - Henry Kister

    ASTM Special Technical Publications* Manual Series

    ASTM Special Technical Publications* Manual Series

    Basic Rubber Testing: Selecting Methods for a Rubber Test Program
    Bearing Steel Technology 
    Concrete Pipe for the New Millennium
    Constructing and Controlling Compaction of Earth Fills
    Dimension Stone Cladding: Design* Construction* Evaluation* and Repair
    Dimension Stone Use in Building Construction*
    Fracture Resistance Testing of Monolithic and Composite Brittle Materials
    Gate Dielectric Integrity: Material* Process* and Tool Qualification
    Joining And Repair Of Composite Structures
    Manual on Chlorosilane Emergency Response Guidelines
    Manual on Elastic-Plastic Fracture: Laboratory Test Procedures 
    Manual on Hydrocarbon Analysis
    Manual on the Building of Materials Databases

    Pipeline pressure profile

    PD5500 2015 edition

    Epcon Chempro v9.2 With Api Technical Data Book v9.1

    Epcon Chempro v9.2 With Api Technical Data Book v9.1 | 319.3 Mb

    API Standard 650 12th Mar. 2013* Ad 1 & 2* Er 1 & 2 Jan. 2016 Welded Tanks for Oil Storage

    API Standard 650 12th Mar. 2013* Ad 1 & 2* Er 1 & 2 Jan. 2016 Welded Tanks for Oil Storage

    zip* Pass:

    Pipeline Pigging Handbook* 3RD Edition by Jim Cordell* Hershel Vanzant

    ASME B30 STD latest (2016-12-19)

    ASME B30 STD latest (2016-12-19)

    ASME B30 latest (2016-12-19)

    ASME B30.1 (2015)
    ASME B30.2 (2011)
    ASME B30.3 (2016)
    ASME B30.4 (2015)
    ASME B30.5 (2014)
    ASME B30.6 (2015)
    ASME B30.7 (2016)
    ASME B30.8 (2015)
    ASME B30.9 (2014)
    ASME B30.10 (2014)
    ASME B30.11 (2010)
    ASME B30.12 (2011)
    ASME B30.13 (2011)
    ASME B30.14 (2015)
    ASME B30.16 (2012)
    ASME B30.17 (2015)
    ASME B30.18 (2016)
    ASME B30.19 (2016)
    ASME B30.20 (2013)
    ASME B30.21 (2014)
    ASME B30.22 (2016)
    ASME B30.23 (2011)
    ASME B30.24 (2013)
    ASME B30.25 (2013)
    ASME B30.26 (2015)
    ASME B30.27 (2014)
    ASME B30.28 (2015)
    ASME B30.29 (2012)

    Tuesday, November 8, 2016

    HVAC Solution Professional

    HVAC Solution Professional

    HVAC Solution Professional allows you to drag-and-drop super-intelligent objects to design air systems including both air handlers and rooftops. It also provides you with tools to build hydronic, steam and control systems. The software includes all the necessary piping and ductwork components to model most systems with unparalleled flexibility. Top this off with the capability to select equipment from one of our many equipment manufacturers that meet your design capacities. Create equipment and control schedules, bill of materials, schematic in dxf format, an electrical coordination matrix and more

    Structural engineering Library - ENERCALC

    Structural engineering Library then ENERCALC 

    ENERCALC provides Structural Engineering Library since 1983 when it was released first set of 26 Lotus 1-2-3 templates. Although it goes by one name, the Structural Engineering Library is actually dozens of structural engineering design and analysis modules all in one system. It provides the practicing engineer with a large toolkit of capabilities to design the elements of structures and also provides an environment to develop sets of project engineering calculations that contain non-ENERCALC items such as EXCEL spreadsheets, WORD documents, PDF files, scanned images, and general project information. The Structural Engineering Library is a versatile toolkit for the practicing engineer. Small projects of 5 stories or less dominate the structures built nationwide and this is where our software excels. A frame analysis program has its place but all structures require design and analysis of dozens or hundreds of smaller elements that make up the building project. The Structural Engineering Library provides structural capabilities for all common design tasks in steel, concrete, masonry, timber and dozens of other design modules.

    3D Systems Geomagic Design X

    3D Systems Geomagic Design X

    Geomagic Design X, the industry's most comprehensive reverse engineering software, combines history-based CAD with 3D scan data processing so you can create feature-based, editable solid models compatible with your existing CAD software.

    Instead of starting from a blank screen, start from the real world. Goemagic Design X is the easiest way to create editable, feature-based CAD models from a 3D scanner and integrate them into your existing engineering design workflow.

    Reuse existing designs wihtout having to manually update old drawings or painstakingly measure and rebuild a model in CAD. Reduce costly errors related to poor fit with other components.

    Geomagic Design X is easy to learn and use. In fact, if you can design in CAD, you can start using Geomagic Design X right away. It uses familiar history-based modeling tools found in all major CAD products, along with automated feature extraction from scan data.

    Dassault Systems SolidWorks

    Dassault Systemes SolidWorks v2017

    Dassault Systemes SolidWorks -. Computer-aided design, engineering analysis and manufacture of products of any complexity and purpose Dassault Systemes SolidWorks is the core of an integrated set of enterprise automation, through which the support life cycle of the product in accordance with the concept of CALS -technologies, including bi-directional data exchange with other Windows-based applications and the creation of online documentation. Complex solutions Dassault Systemes SolidWorks based on advanced technologies of hybrid parametric modeling and a wide range of specialized modules. The software operates on a platform of the Windows , has the support of the Russian language, and, accordingly, supports the GOSTand ESKD .

    Build "chamfers and fillets"
    The user may specify assemblies fillet and a chamfer which are useful in preparation for welding. As with assembly with other characteristics of these features can be extended to parts for which they affect.
    Showing welds
    For assemblies, you can add simplified weld beads. Simplified weld beads provide a lightweight simple representation of welds.
    In previous versions of the software SolidWorks welds had to be added as components of the assembly. This method is no longer used. However, you can continue to edit existing components welds.
    Remove items for assembly
    Tool Defeature lets you remove elements of part or assembly and save the results to a new file in which the details are replaced by dumb solids (that is, without a solid definition of the elements or stories). You can then use the new file without revealing all the design model.

    Drawings and Detailing
    Options align to the size of the palette
    Tools are available on the alignment palette sizes when selecting more than one size. To display a palette of sizes, select dimensions and move the pointer over the button-switch sizes palette.
    Auto-post sizes
    Tool Auto-place dimensions has dimensions quickly and easily. When using the Auto-place sizes selected dimensions are placed as follows:
    • From the smallest to the largest.
    • Aligned and centered, if possible.
    • Arranged considering the distances defined in Document Properties - Dimensions.
    • Arranged so as to avoid overlapping.
    • Located intermittently, if necessary.
    Support for double units
    Now it is possible to display a double unit in the hole table. For example, you can display the size of the hole in illimetrah and inches.
    To display dual dimensions in hole tables, click Tools> Options> Document Properties> Tables> holes. In the double-size, select Display double sizes. To display units, select Show units double.
    You can also click the right mouse button in the hole table and click Show dual dimensions. When the double-size, you can click the right mouse button in the hole table and click Show units of double size.
    Support welds in the drawings
    The drawings can be inserted bidirectional weld symbol attached to the welding paths. Click Insert> Model Items and Notes section, click Weld Symbol.
    You can insert weld symbols, crawler seams and ends processing for welds in specific types. Click Insert> Model Items and under Source / Destination, click Selected Item for the Source. In the Notes section, select the weld symbols, caterpillars, or End Treatment. Move the cursor to highlight the way welding and click to place notes.
    It is also possible to select the characteristics of the weld seam of the wood construction FeatureManager team model elements.

    Menu Enterprise PDM
    New client-side menu SolidWorks Enterprise PDM make it easier to find the most frequently used commands. All commands are grouped into four menus Enterprise PDM at the top of the file view pane.
    The new menus reduce the length of the context menu. However, the most frequently used commands are still available by right-clicking the mouse. Available commands depend on the user's choice. Click Actions to access to perform actions, such as the registration and de-registration files.
    Model Display
    SolidWorks DisplayManager is a central location for managing external views, inscriptions, scenes, cameras, lights and walk. Use DisplayManager to view, edit and delete items applied to the current model.
    PhotoView 360
    PhotoView 360 is now the standard photorealistic rendering solution for the SolidWorks . The PhotoWorks is no longer supported. The functionality of the drawing are identical to the functionality of the previous versions. The underlying technology has been updated to improve the user experience and improve outcomes.

    Parts and tools
    Defeature for Parts
    Tool Defeature lets you remove elements of part or assembly and save the results to a new file in which the details are replaced by dumb solids (that is, without a solid definition of the elements or stories). You can then use the new file without revealing all the design model.
    General use of the equations in the various models
    Equations and global variables can be used in several models.
    You export selected equations and variables from the model to an external text file (.txt). You can also create a text file manually using programs such as Notepad. Then, you import data from a text file into other models. You can associate a model with a text file that you've made in the text file changes updated the equations and variables in the models.
    Conditions of repayment and components
    The equations can be used to control the state of maturity of elements of parts and assembling components.
    In the dialog box, use the Add function equation Visual Basic IIf to specify the conditions of repayment or cancellation of the repayment element or component.
    Elongated surface of the two-dimensional or three-dimensional face
    You can create extruded surfaces from models that include two-dimensional or three-dimensional face, and bind extruded surfaces to surrounding elements.

    The new study "2D simplification" (Professional)
    It is possible to simplify some of the three-dimensional models by simulating them in 2D. The two-dimensional simplification is available for static, nonlinear studies, the design of pressure vessels and thermal studies. The time for analysis can be saved through the use of two-dimensional simplification of the respective models. For two-dimensional grid patterns requires less components and simpler contact conditions than for the corresponding three-dimensional models.

    You can add simplified weld beads to the welded parts and assemblies, and multibody parts.
    Benefits of simplified weld:
    • Uniform implementation in parts and assemblies.
    • Compatibility with all types of geometry, including a body with clearances.
    • Light simplified mapping welds.
    • Turning weld characteristics in the drawings by welds tables.
    • Selection Tool Smart Weld to select faces welding paths.
    • Binding symbols welds to the weld seams.
    • Tools that simplify the definition of the welding paths (length).
    • Inclusion in the folder welds in the design tree, the FeatureManager .
    Furthermore, the user can specify the properties for the subfolders welds, including:
    • weld material.
    • The welding process.
    • weld mass per unit length.
    • Welding cost per unit weight.
    • Welding time per unit length.
    • The number of welding passes.
    Showing welds
    Welds are displayed as graphical representations in models. Welds are lightweight and do not affect the performance.
    Chamfers and fillets
    The user may specify assemblies fillet and a chamfer which are useful in preparation for welding. As with assembly with other characteristics of these features can be extended to parts for which they affect.

    Intergraph CAESAR II 2017

    Intergraph CAESAR II 2017 

    Piping stress analysis software



    Only for study purpose

    Thursday, October 27, 2016

    GPSA - Engineering Data Book (13th Ed) SI 2012

    Slug Flow Analysis Using Dynamic Spectrum Method in Caesar II

    Slug Flow Analysis Using Dynamic Spectrum Method in Caesar II

    For dynamic analysis Caesar II software provides a very nice module, dynamic module where we have to simply provide the input parameters to get the output result. Before you start the dynamic analysis you have to perform conventional static analysis of the system (without using any slug force) and qualify the system from all criteria. To open the dynamic module in Caesar II click on dynamic analysis button

    When you click on the dynamic analysis button following window (Fig.2) will open. Select Slug Flow (Spectrum) from drop down menu. The window will be filled with some pre-existing data. For clarity simply select all those and delete. Now we have to provide inputs for analysis

    During dynamic analysis our first input will be the generation of spectrum profile. Slug load is one type of impulse load. So the magnitude of load varies from zero to some maximum value, remains constant for a time and then reduces to zero again. The force profile can be represented by a curve

    So from the profile it is clear that in addition to slug force (Refer Static method of Slug Flow using Caesar II for calculation of slug force), we need to calculate two additional parameters, a) Slug Duration and b) Slug Periodicity.
    1. Slug Duration: Slug duration is defined as the time required for the slug to cross the elbow. Mathematically it can be denoted as, Slug Duration=Length of Liquid Slug/Velocity of Flow.
    2. Slug Periodicity: Slug Periodicity can be defined as the time interval for two consecutive slugs hitting the same elbow. So mathematically it can be denoted as, Slug Periodicity = (Length of Liquid Slug + Length of Gas Slug)/Velocity of Flow.
    Let’s assume that the calculated slug duration is 8 milliseconds and periodicity is 400 milliseconds as shown in Fig. 3. We will use these data for generation of spectrum profile.

    When you click on Enter Pulse data it will open the window where we have to enter the data for spectrum profile generation. From the above curve at time 0 the force is 2120 N the same force will be active for next 8 milliseconds till the slug crosses the elbow. Then at time 8.1 forces will be reduced to zero. And the same zero force will be there till 400 milliseconds. Then the next cycle will start. i.e, at time 400.1 seconds the force will be again 2120 N. That way enter data for at least two cycles
    • Clicking Save / Continue button will convert the time history into its equivalent force response spectrum in terms of Dynamic Load Factor versus Frequency and the screen “Spectrum Table Values “as shown in Fig. 5 will appear.
    • Be sure to specify a unique spectrum name, as this processor will overwrite any existing files of the same name.
    • By clicking OK, the processor will load the appropriate data in the Spectrum Definitions tab in Dynamic Input and move the data to the dynamic input
    Once the spectrum profile is generated click on force sets button and enter the slug force with proper direction in the fields

    • Click on the + button to add more rows and – button to delete rows.
    • In force set field input a numeric id which will be used to construct dynamic load cases.
    After that click on Spectrum load cases menu and create the required load cases for dynamic analysis. You have to specify at least two load cases as shown.
    • Operating + Dynamic for nozzle and support load checking.
    • Sustained + Dynamic for stress checking.
    For full details refer below link 

    3D Video Boiler Presentation

    Cathodic Corrosion Protection Hand book

    Handbook of Cathodic Corrosion Protection by Walter von Baeckmann, Wilhelm Schwenk, W

    Duplex material - Materials Literature Collection 022/200 - Zeron 100

    Materials Literature Collection 022/200 - Zeron 100

    43 files about this duplex material

    Materials Literature Collection 019/200 -Alloy 625

    Materials Literature Collection 019/200 -Alloy 625

    73 documents about this nickel-based alloy

    Defect Sizing Using Non-destructive Ultrasonic Testing: Applying Bandwidth-Depend

    Defect Sizing Using Non-destructive Ultrasonic Testing: Applying Bandwidth-Depend

    Functions of Gaskets for leak proof Flanged joints

    Functions of Gaskets for leak proof Flanged joints

    Gasket is one of the basic elements for flanged joints in piping system of process plants. A gasket can be defined as a material or combination of materials clamped between two separable mechanical members of a mechanical joint (flanged joint) which produces the weakest link of the joint. Gaskets are used to create a static seal between two stationary members of a mechanical assembly (the flanged joint). The gasket material flows (interpose a semi-plastic material between the flange facings) into the imperfections between the mating surfaces by an external force (bolt tightening force) and maintain a tight seal (seals the minute surface irregularities to prevent leakage of the fluid) under operating conditions. The amount of flow (seal) of the gasket material that is required to produce a tight seal is dependent upon the roughness of the surface. The gasket must be able to maintain this seal under all the operating conditions of the system including extreme upsets of temperature and pressure. Therefore, it is important to ensure proper design and selection of the gaskets to prevent flange-leakage problems and avoid costly shutdowns of the process plants. The following article will try to explain the main points related to gaskets.
    Working philosophy of a gasket to prevent leakage:
    Refer the above figure which shows the three major forces acting on the gasket. Normally the gasket is seated by tightening the bolts on the flanges before the application of the internal pressure. Upon the application of the internal pressure in the joint, an end force (Hydrostatic end force) tends to separate the flanges and to decrease the unit stress (Residual stress) on the gasket. Leakage will occur under pressure if the hydrostatic end force is sufficiently great and the difference between hydrostatic end force and the bolt-load reduces the gasket load below a critical value.  To explain it in more clear language we can say that there are three principal forces acting on any gasketed joint. They are:
    •  Bolt Load which applies the initial compressive load that flows the gasket material into surface imperfections to form a seal.
    • The hydrostatic end force, that tends to separate flanges when the system is pressurized.
    • Internal pressure acting on the portion of the gasket exposed to internal pressure, tending to blow the gasket out of the joint and/or to bypass the gasket under operating conditions. 
    Even though there are other shock forces that may be created due to sudden changes in temperature and pressure. Creep relaxation is another factor that may come into the picture. The initial compression force applied to a joint must serve several purposes.
    • It must be sufficient to initially seat the gasket and flow the gasket into the imperfections on the gasket seating surfaces regardless of operating conditions.
    • Initial compression force must be great enough to compensate for the total hydrostatic end force that would be present during operating conditions.
    • It must be sufficient to maintain a residual load on the gasket/flange interface.
    Now from a practical standpoint, residual load on the gasket must be “X” times internal pressure if a tight joint is required to be maintained. This unknown quantity “X” is what is specified as the “m” factor in the ASME Pressure Vessel Code and will vary depending upon the type of gasket being used. Actually the “m” value is the ratio of residual unit stress (bolt load minus hydrostatic end force) on gasket to internal pressure of the system. The larger the value of “m”, the more assurance the designer has of obtaining a tight joint.
    Gasket Types:
    Gaskets can be grouped into three main categories as follows:
    • Non-metallic Gaskets: Usually composite sheet materials are used with flat face flanges and low pressure class applications. Non-metallic gaskets are manufactured non-asbestos material or Compressed Asbestos Fibre (CAF). Non-asbestos types include arimid fibre, glass fibre, elastomer, Teflon (PTFE) and flexible graphite gaskets. Full face gasket types are suitable for use with flat-face (FF) flanges and flat-ring gasket types are suitable for use with raised face (RF) flanges.
    • Semi-metallic Gaskets: Semi-metallic gaskets are composites of metal and non-metallic materials. The metal is intended to offer the strength and resiliency while the non-metallic portion of a gasket provides conformability and sealability. Commonly used semi-metallic gaskets are spiral wound, metal jacketed, Cam profile and a variety of metal-reinforced graphite gaskets. Semi metallic gaskets are designed for the widest range of operating conditions of temperature and pressure. Semi-metallic gaskets are used on raised face, male-and female and tongue and groove flanges.
    • Metallic Gaskets: Metallic gaskets are fabricated from one or a combination of metal to the desired shape and size. Common metallic gaskets are ring-joint gaskets and lens rings. They are suitable for high-pressure and temperature applications and require high bolt load to seal.
    Common gasket configurations:
    Aside from the choice of gasket material, the structure or configuration of the gasket is also significant. Following are descriptions of four major types.
    • Graphite foil: The physical and chemical properties of graphite foil make it suitable as a sealing material for relatively arduous operating condition. In an oxidizing environment, graphite foil can be used in the temperature range of –200 to +500°C, and in a reducing atmosphere, it can be used at temperatures between –200 and 2,000°C. Because graphite foil has no binder materials, it has excellent chemical resistance, and is not affected by most of the commercially used common chemicals. It also has very good stress-relaxation properties.
    • Spiral-wound: As the name implies, the spiral-wound gasket is made by winding a preformed-metal strip and a filler on the periphery of a metal winding mandrel. All spiral-wound gaskets are furnished with a centering ring. In addition to controlling compression, these rings serve to locate the gasket centrally within the bolt circle. Inner rings are used where the material (such as a gasket with PTFE filler) has a tendency for inward buckling. The ring also prevents the buildup of solids between the inside diameter of the gasket and the bore of pipe. Under vacuum condition, the ring protects against damage that would occur if a pieces of a broken component were drawn into the the system. Spiral-wound gaskets can operate at temperatures from –250 to 1,000°C, and pressures from vacuum to 350 bar. Spiral-wound gaskets up to 1-in. diameter and up to class number 600 require a uniform bolt stress of 25,000 psi to compress the gasket. Larger sizes and classes require 30,000 psi to compress the gasket.
    • Ring-joint: Ring-joint gaskets are commonly used in grooved flanges for high-pressure-piping systems and vessels. Their applicable pressure range is from 1,000 to 15,000 psi. These gaskets are designed to give very high gasket pressure with moderate bolt load. These joints are not generally pressure-actuated. The hardness must be less than that of the flange material so that proper flow of material occurs without damaging flange surfaces. The most widely used ring-joint gaskets are of the oval and octagonal type. Oval-type gaskets contact the flange face at the curved surface and provide a highly reliable seal. However, the curved shape makes it more difficult to achieve accurate dimensioning and surface finishing. Oval gaskets also have the disadvantage that they can only be used once, so they may not be the best choice for sealing flanges that have to be opened routinely. On the other hand, because they are constructed of only straight faces, octagonal-type gaskets are usually less expensive, they can be dimensioned more accurately, and are easier to surface finish than the oval-type gasket. However, a greater torque load is required to flow the gasket material into imperfections that may reside on the flange faces. Octagonal gaskets can be used more than once.
    • Corrugated-metal: This type of gasket is available in a wide range of metals, including brass, copper, coppernickel alloys, steel, monel, and aluminium. Corrugated metal gaskets can be manufactured to just about any shape and size required. The thickness of the metal is normally 0.25 or 0.3 mm, with corrugations having a pitch of 1.6, 3.2, and 6.4 mm. The sealing mechanism is based on point contact between the peaks of the corrugations and the mating flanges

    Gasket Standards:
    Following standards are normally adopted for specifying gaskets.
    • ASME B16.21 Non-metallic flat gaskets for pipe flanges.
    • ASME B16.20 Metallic Gaskets for steel pipe flanges, Ring Joint, Spiral Wound and Jacketed
    • IS2712 Specification for compressed Asbestos fibre jointing.
    • BS 3381 Sprial Wound Gaskets to suit BS 1560 Flanges
    Selection of Gaskets:
    • The gasket material selected should be one which is not adversely affected physically or chemically by the service conditions.
    • The two types of gaskets most commonly known are ring gaskets and full face gaskets. The latter as the name implies, covers the entire flange face and are pierced by the bolt holes. They are intended for use with flat face flanges. Ring gaskets extend to the inside of the flange bolt holes and consequently are self centering. They are usually used with raised face or lap joint flanges but may also be used with flat-faced flanges.
    • Flat-ring gaskets are widely used wherever service condition permits because of the ease with which they may be cut from flat sheet and installed. They are commonly fabricated from such materials as rubber, paper, cloth, asbestos, plastics, copper, lead, aluminum, nickel, monel, and soft iron. The gaskets are usually made in thickness from 1/64 to 1/8 in. Paper, cloth and rubber gaskets are not recommended for use above 120° C. Asbestos-composition gaskets may be used up to 350° C or slightly higher, ferrous and nickel-alloy metal gaskets may be used up to the maximum temperature rating of the flanges.
    • Upon initial compression a gasket will flow both axially and radially. The axial flow is required to fill depressions in the flange facing and prevent leakage. Radial flow serves no useful purpose unless the gasket is confined. Where a flange joint is heated, a greater gasket pressure is produced due to the difference between the flange body and the bolts. This greater pressure coupled with the usual softening of the gasket material at elevated temperatures causes additional axial and radial gasket flow. To compensate for this, the flange bolts are usually re-tightened a second or third time after the joint is heated to the normal operating temperature. A thick gasket will flow radially to a far greater extent than a thin gasket. Some thin gaskets show practically no radial flow at extremely high unit pressures. Consequently, for high temperatures a thin gasket has the advantage of maintaining a permanent thickness while a thick gasket will continue to flow radially and may leak, in time, due to the resulting reduced gasket pressure. However in attempting utmost utilization of thin gasket advantage, one may find that gasket selected has insufficient thickness to seal the irregularities, in the commercial flange faces. The spiral wound asbestos-metallic gasket combines the advantages of both the thick and thin gasket. Although a relatively thick gasket (most common types are 0.175” thick) its spirally laminated construction confines the asbestos filler between axially flexible metal layers. This eliminates the radial flow characteristics of a thick gasket and provides the resiliency to adjust to vary service conditions. Spiral wound gaskets are available with different filler materials such as Teflon, grafoil etc. to suit fluid compatibility. Spiral wound gaskets used with raised face flanges usually have an inner metal ring and an outer centering ring.
    • Laminated gaskets are fabricated with a metal jacket and a soft filler, usually of asbestos. Such gaskets can be used up to temperatures of about 400° C to 450° C and require less bolt load to seat and keep tight than solid metal flat ring gaskets.
    • Serrated metal gaskets are fabricated of solid metal and have concentric grooves machined into the faces. This greatly reduces the contact area on initially tightening thereby reducing the bolt load. As the gasket is deformed, the contact surface area increases. Serrated gaskets are useful where soft gaskets or laminated gaskets are unsatisfactory and bolt load is excessive with a flat-ring metal gasket. Smooth-finished flange faces should be used with serrated gaskets.
    • Corrugated gaskets with asbestos filling are similar to laminated gaskets except that the surface is rigid with concentric rings as with the case of serrated gaskets. Corrugated gaskets require less seating force than laminated or serrated gaskets and are extensively used in low-pressure liquid and gas service. Corrugated metal gaskets without asbestos may be used to higher temperature than those with asbestos filling.
    • Two standard types of ring-joint gaskets are available for high-pressure service. One type has an oval cross section, and the other has an octagonal cross section. These rings are fabricated of solid metal, usually soft iron, soft steel, monel, 4-6% chrome, and stainless steels. The alloy-steel rings should be heat treated to soften them.
    • It is recommended that ring joint gasket be used for class 150 flanged joints. When the ring joint or spiral wound gasket is selected, it is recommended that line flanges be of the welding neck type.
    Parameters affecting Gasket performance:
    The performance of the gasket is affected by a number of factors. All of these factors must be taken into consideration when selecting a gasket:
    • The Flange Load: All gasket materials must have sufficient flange pressure to compress the gasket enough to insure that a tight, unbroken seal occurs. The flange pressure, or minimum seating stress, necessary to accomplish this is known as the “y” factor. This flange pressure must be applied uniformly across the entire seating area to achieve perfect sealing. However, in actual service, the distribution around the gasket is not uniform. The greatest force is exerted on the area directly surrounding the bolts. The lowest force occurs mid-way between two bolts. This factor must be taken into account by the flange designer.
    • The Internal Pressure: In service, as soon as pressure is applied to the vessel, the initial gasket compression is reduced by the internal pressure acting against the gasket (blowout pressure) and the flanges (hydrostatic end force). To account for this, an additional preload must be placed on the gasket material. An “m” or maintenance factor has been established by ASME to account for this preload. The “m” factor defines how many times the residual load (original load minus the internal pressure) must exceed the internal pressure. In this calculation, the normal pressure and the test pressure should be taken into account.
    • Temperature: The effects of both ambient and process temperature on the gasket material, the flanges and the bolts must be taken into account. These effects include bolt elongation, creep relaxation of the gasket material or thermal degradation. This can result in a reduction of the flange load. The higher he operating temperature, the more care needs to be taken with the asket material selection. As the system is pressurized and heated, the joint deforms. Different coefficients of expansion between the bolts, the flanges and the pipe can result in forces which can affect the gasket. The relative stiffness of the bolted joint determines whether there is a net gain or loss in the bolt load. Generally, flexible joints lose bolt load.
    • Fluid: The media being sealed, usually a liquid or a gas with a gas being harder to seal than a liquid. The effect of temperature on many fluids causes them to become more aggressive. Therefore, a fluid that can be sealed at ambient temperature, may adversely affect the gasket at a higher temperature. The gasket material must be resistant to corrosive attack from the fluid. It should chemically resist the system fluid to prevent serious impairment of its physical properties.
    • Surface Finish of the Gasket: The surface finish of a gasket — which consists of grooves or channels pressed or machined onto the outer surface — governs the thickness and compressibility required by the gasket material to form a physical barrier in the clearance gap between the flanges. A finish that is too fine or shallow is undesirable, especially on hard gasket materials, because the smooth surface may lack the required grip, which will allow extrusion to occur. On the other hand, a finish that is too deep will yield a gasket that requires a higher bolt load, which may make it difficult to form a tight seal, especially when large flange surfaces are involved. Fine machining marks applied to the flange face, tangent to the direction of applied fluid pressure can also be helpful. Flange faces with non-slip grooves that are approximately 0.125 mm deep are recommended for gaskets more than 0.5 mm thick; and for thinner gaskets, grooves 0.065 mm deep are recommended. Under no circumstances should the flange-sealing surface be machined with tool marks extending radially across the gasket-sealing surface; such marks could allow leakage.
    • Gasket Thickness: For a given material, it is a general rule that a thinner gasket is able to handle a higher compressive stresses than thicker one. However, thinner materials require a higher surface finish quality. As a rule of thumb, the gasket should be at least four times thicker than the maximum surface roughness of the flange faces. The gasket must be thick enough to occupy the shape of the flange faces and still compress under the bolt load. In situations where vibration is unavoidable, a thicker gasket than the minimum required should be employed.
    • Gasket Width: In order to reduce the bolt load required to produce a particular gasket pressure, it is advisable not to have the gasket wider than is necessary. For a given gasket stress, a raised face flange with a narrow gasket will require less pre-load, and thus less flange strength than a full-face gasket. In general, high-pressure gaskets tend to be narrow.
    • Stress Relaxation: This factor is a measure of the material’s resiliency over a period of time, and is normally expressed as a percentage loss per unit of time. All gasket material will lose some resiliency over time, due to the flow or thinning of the material caused by the applied pressure. After some initial relaxation, the residual stress should remain constant for the gasket.
    • Gasket Outer Diameter: For two gaskets made of the same material and having the same width, the one with a larger outer diameter will withstand a higher pressure. Therefore, it is advisable to use a gasket with an external diameter that is as large as possible.
    Related Posts with Thumbnails