Monthly report

Monthly reportPart II - Piping

ContentsTypes of Platforms;5Fixed;5Compliant Tower:6Semi-submersible7Jack up rig;8A floating production;9Tension-leg platform;10Gravity-based structure;11Spar (platform);12Piping Systems;13Design;13Oil Field14Drilling Fluid14Drilling Rig;14Use:14Science of Materials:17Elasticity:17Strain:17Deflection:17Impact Strength:17Fatigue Stress:17Yield Strength:18Compressive Strength:18Tensile Strength:18Gas line sizing:19Pressure ratings21Gasket materials;22Valves:23Control Valves;24Pipe Expansion:25Pipe Support Spacing:25Circumferential Stress:26Thin walled assumptions:27Selecting pipe wall thickness;28Valves:29Control Valves;30Pipe Expansion:31Pipe Support Spacing:31Work Hardening:32Flanges;32Threaded flanges:32Blind Flanges;33Socket Welded Flanges;33Slip on Flanges;34Lapped Flanges;35Raised-Face Flanges;35Ring-Joint Flanges;36Fittings;37Elbows:37Reducers;37Socket Welded Fitting:37Fitting Standard;38ASME B16.938Encompasses overall dimensions, tolerances, ratings, testing and markings for wrought carbon and alloy steel factory made butt-welded fittings of 13 through 1,200mm. It also includes thickness that may be produced, except low-pressure corrosion- resistant fittings.38Valves;39Gate Valves;40Function:40Ball Valve;41Function:42Plug Valve;42Function:42Lubricated Plug Valve;44Soft-Sealed, Fire safe Plug Valve;44Selecting a type of valve suitable for process;44Valve Sizing;45Identifying Valve Inspection and Testing Requirements;45Shell Test;46Back Seat Test;46Fire safe Test;46Summary:46

Types of Platforms;Fixed;These platforms are built on concrete or steel legs, or both, anchored directly onto the seabed, supporting a deck with space for drilling rigs, production facilities and crew quarters. Such platforms are, by virtue of their immobility, designed for very long term use. Various types of structure are used: steel jacket, concrete caisson, floating steel, and even floating concrete. Steel jackets are vertical sections made of tubular steel members, and are usually piled into the seabed.Concrete caisson structures, pioneered by the Condeep concept, often have in-built oil storage in tanks below the sea surface and these tanks were often used as a flotation capability, allowing them to be built close to shore and then floated to their final position where they are sunk to the seabed. Fixed platforms are economically feasible for installation in water depths up to about 520 m (1,710 ft.)

Compliant Tower:A compliant tower (CT) is a fixed rig structure normally used for the offshore production of oil or gas. The rig consists of narrow, flexible (compliant) towers and a piled foundation supporting a conventional deck for drilling and production operations. Compliant towers are designed to sustain significant lateral deflections and forces, and are typically used in water depths ranging from 450 to 900 m. With the use of flex elements such as flex legs or axial tubes, resonance is reduced and wave forces are de-amplified. This type of rig structure can be configured to adapt to existing fabrication and installation equipment. Compared with floating systems, such as tension-leg platforms and SPARs, the production risers are conventional and are subjected to less structural demands and flexing. However, because of cost, it becomes uneconomical to build compliant towers in depths greater than 1,000 meters. In such a case a floating production system is more appropriate, even with the increased cost of risers and mooring. Despite its flexibility, the compliant tower system is strong enough to withstand hurricane conditions.

Semi-submersibleA semi-submersible (semi submerged ship) is a specialized marine vessel used in a number of specific offshore roles such as offshore drilling rigs, safety vessels, oil production platforms, and heavy lift cranes. They are designed with good stability and sea keeping characteristics. Other terms include semisubmersible, semi-sub, or simply semi.

Jack up rig; A jack up rig or a self-elevating unit is a type of mobile platform that consists of a buoyant hull fitted with a number of movable legs, capable of raising its hull over the surface of the sea. The buoyant hull enables transportation of the unit and all attached machinery to a desired location. Once on location the hull is raised to the required elevation above the sea surface supported by the sea bed. The legs of such units may be designed to penetrate the sea bed, may be fitted with enlarged sections or footings, or may be attached to a bottom mat. Generally Jack up rigs are not self-propelled and rely on tugs or heavy lift ships for transportation. Jack up platforms are used as exploratory drilling platforms and offshore and wind farm service platforms. Jack up platforms have been the most popular and numerous of various mobile types in existence.

A floating production;

A floating production, storage and offloading (FPSO) unit is a floating vessel used by the offshore oil and gas industry for the production and processing of hydrocarbons, and for the storage of oil. An FPSO vessel is designed to receive hydrocarbons produced by itself or from nearby platforms or subsea template, process them, and store oil until it can be offloaded onto a tanker or, less frequently, transported through a pipeline. FPSOs are preferred in frontier offshore regions as they are easy to install, and do not require a local pipeline infrastructure to export oil. FPSOs can be a conversion of an oil tanker or can be a vessel built specially for the application. A vessel used only to store oil (without processing it) is referred to as a floating storage and offloading vessel (FSO). There are also under construction (as at 2013) floating liquefied natural gas (FLNG) vessels, which will extract and liquefy natural gas on board.

Tension-leg platform;Tension-leg platform (TLP) or extended tension leg platform (ETLP) is a vertically moored floating structure normally used for the offshore production of oil or gas, and is particularly suited for water depths greater than 300 meters and less than 1500 meters. Use of tension-leg platforms has also been proposed for wind turbines.

The platform is permanently moored by means of tethers or tendons grouped at each of the structure's corners. A group of tethers is called a tension leg. A feature of the design of the tethers is that they have relatively high axial stiffness (low elasticity), such that virtually all vertical motion of the platform is eliminated. This allows the platform to have the production wellheads on deck (connected directly to the subsea wells by rigid risers), instead of on the seafloor. This allows a simpler well completion and gives better control over the production from the oil or gas reservoir, and easier access for down hole intervention operations.

Gravity-based structure;

A gravity-based structure (GBS) is a support structure held in place by gravity. A common application for a GBS is an offshore oil platform. These structures are often constructed in fjords since their protected area and sufficient depth are very desirable for construction. A GBS intended for use as an offshore oil platform is constructed of steel reinforced concrete, often with tanks or cells which can be used to control the buoyancy of the finished GBS. When completed, a GBS is towed to its intended location and sunk. Prior to deployment, a study of the seabed will have been done in order to ensure it can withstand the vertical load exerted on it by that structure.

Spar (platform);A spar is a type of floating oil platform typically used in very deep waters, and is named for logs used as buoys in shipping that are moored in place vertically. Spar production platforms have been developed as an alternative to conventional platforms. The deep draft design of spars makes them less affected by wind, wave and currents and allows for both dry tree and subsea production. A spar platform consists of a large-diameter, single vertical cylinder supporting a deck. The cylinder is weighted at the bottom by a chamber filled with a material that is denser than water to lower the center of gravity of the platform and provide stability. Additionally, the spar hull is encircled by helical strakes to mitigate the effects of vortex-induced motion. Spars are permanently anchored to the seabed by way of a spread mooring system composed of either a chain-wire-chain or chain-polyester-chain configuration.There are three primary types of spars; the classic spar, truss spar, and cell spar. The classic spar consists of the cylindrical hull noted above, with heavy ballast tanks located at the bottom of the cylinder.

Piping Systems;Design;There are mainly three kinds of pipes design used by dragon oil. Pipes are differentiated by their properties and are coded according to that. Code Title;

ASME B31.3 ASME B31.4 ASMEB31.8Process Piping Pipeline Transportation Systems for hydrocarbons Gas Transmission

Trunk line; Runs cross countryPipe line; few kilometers (From gathering to storage)

There are many problems that arise while installing pipelines. For example a railway, road or gas transfer pipes might start to float. To tackle each situation, different set of codes are used like RP 14E.Pipeline sleeves are a way of enforcing or repairing a pipe. Steel sleeves are effective because they restrain bulging, or accumulation of strain, in the defective area. Steel sleeves accomplish this while absorbing only 15 to 20 percent of the hoop stress in the carrier pipe. Steel sleeves are effective because the stiffness (elastic modulus) of the sleeve material is equivalent to that of the line pipe steel.

For control different types of valves are used for intended control. Ball valve is used to open and completely shut the flow of hydrocarbon or gas. There are other valves like gate valves and globe valves that restrict the flow i.e. it can be opened from 0 to 100%.

To transport gasses, compressors are used. However gas cannot maintain pressure over a certain distances and in cases of gas running cross country, pressure drop becomes a problem. To overcome that, multiple compressors are installed where the gas starts loosing pressure, this keeps the flow going.

The basic formula for determining pipe wall thickness is the general hoop stress formula for thin-wall cylinders, which is stated as;

WhereHS = hoop stress in pipe wall, psi, t = pipe wall thickness, in. L = length of pipe, ft. P = internal pressure of the pipe, psi, do = outside diameter of pipe, in.

Oil FieldAn "oil field" or "oilfield" is a region with an abundance of oil wells extracting petroleum (crude oil) from below ground. (Wikipedia, 2015)

Drilling FluidThe main functions of drilling fluids include providing hydrostatic pressure to prevent formation fluids from entering into the well bore, keeping the drill bit cool and clean during drilling, carrying out drill cuttings, and suspending the drill cuttings while drilling is paused and when the drilling assembly is brought in and out of the hole. The drilling fluid used for a particular job is selected to avoid formation damage and to limit corrosion.The three main categories of drilling fluids are water-based muds (which can be dispersed and non-dispersed), non-aqueous muds, usually called oil-based mud, and gaseous drilling fluid, in which a wide range of gases can be used.

Drilling Rig;Use:Oil and natural gas drilling rigs are used not only to identify geologic reservoirs but also to create holes that allow the extraction of oil or natural gas from those reservoirs. Primarily in onshore oil and gas fields once a well has been drilled, the drilling rig will be moved off of the well and a service rig (a smaller rig) that is purpose-built for completions will be moved on to the well to get the well on line. This frees up the drilling rig to drill another hole and streamlines the operation as well as allowing for specialization of certain services, i.e., completions vs. drilling.

Limits of Technology;Drill technology has advanced steadily since the 19th century. However, there are several basic limiting factors which will determine the depth to which a bore hole can be sunk.

All holes must maintain outer diameter; the diameter of the hole must remain wider than the diameter of the rods or the rods cannot turn in the hole and progress cannot continue. Friction caused by the drilling operation will tend to reduce the outside diameter of the drill bit. This applies to all drilling methods, except that in diamond core drilling the use of thinner rods and casing may permit the hole to continue. Casing is simply a hollow sheath which protects the hole against collapse during drilling, and is made of metal or PVC. Often diamond holes will start off at a large diameter and when outside diameter is lost, thinner rods put down inside casing to continue, until finally the hole becomes too narrow. Alternatively, the hole can be reamed; this is the usual practice in oil well drilling where the whole size is maintained down to the next casing point.

For percussion techniques, the main limitation is air pressure. Air must be delivered to the piston at sufficient pressure to activate the reciprocating action, and in turn drive the head into the rock with sufficient strength to fracture and pulverize it. With depth, volume is added to the in-rod string, requiring larger compressors to achieve operational pressures. Secondly, groundwater is ubiquitous, and increases in pressure with depth in the ground. The air inside the rod string must be pressurized enough to overcome this water pressure at the bit face. Then, the air must be able to carry the rock fragments to surface. This is why depths in excess of 500 m for reverse circulation drilling are rarely achieved, because the cost is prohibitive and approaches the threshold at which diamond core drilling is more economic.

Diamond drilling can routinely achieve depths in excess of 1200 m. In cases where money is no issue, extreme depths have been achieved, because there is no requirement to overcome water pressure. However, water circulation must be maintained to return the drill cuttings to surface, and more importantly to maintain cooling and lubrication of the cutting surface of the bit; while at the same time reduce friction on the steel walls of the rods turning against the rock walls of the hole. When water return is lost the rods will vibrate, this is called "rod chatter", and that will damage the drill rods, and crack the joints.

Without sufficient lubrication and cooling, the matrix of the drill bit will soften. While diamond is the hardest substance known, at 10 on the Mohs hardness scale, it must remain firmly in the matrix to achieve cutting. Weight on bit, the force exerted on the cutting face of the bit by the drill rods in the hole above the bit, must also be monitored.Use:Oil and natural gas drilling rigs are used not only to identify geologic reservoirs but also to create holes that allow the extraction of oil or natural gas from those reservoirs. Primarily in onshore oil and gas fields once a well has been drilled, the drilling rig will be moved off of the well and a service rig (a smaller rig) that is purpose-built for completions will be moved on to the well to get the well on line. This frees up the drilling rig to drill another hole and streamlines the operation as well as allowing for specialization of certain services, i.e., completions vs. drilling.

Science of Materials:Elasticity: Is the ability of the material to return to its previous shape after stress is released. Plasticity or plastic deformation is defined as unrecoverable strain. Most materials in the linear elastic category are usually capable of plastic deformation. Brittle materials, like ceramics, do not experience any plastic deformation and will fracture under relatively low stress, while ductile materials such as metallic, lead or polymers will plastically deform much more before a fracture initiation.Consider the difference between a carrot and a bubblegum. The carrot will stretch very little before it breaks, the chewed bubble gum, on the other hand, will plastically deform enormously before breaking.The ultimate strength is the maximum stress that a material can withstand before it breaks or weakens.Microstructure: A materials strength is dependent on its microstructure. Strengthening: Is a type of alloying that can be used to improve the strength of a pure material. This technique works by adding atoms of one element (the alloying element) to the crystalline of another element diffuses into matrix, forming a solid solution. In most binary systems, when alloyed above a certain concentration, a second phase will form.

Strain:Deformation of the material is the change in geometry created when stress is applied.-Strain is deformation per unit length.Deflection: Is a term to describe the magnitude to which a structural element is displaced when subject to an applied load.Impact Strength:Is the capability of the material to withstand a suddenly applied load and is expressed in terms of energy. In order for a material or object to have a high impact strength, the stress must be evenly distributed throughout the object. It must also have a large volume with a low modulus of elasticity and a high material yield strength.Fatigue Stress:Is a measure of the strength of the material or a component under cyclic loading, this is usually more difficult to assess than static strength measures. Fatigue stress is quoted as stress amplitude or stress range:Change in Stress= StressMax StressMin,Usually at 0 mean stress, along with number of cycles to failure under that condition of stress.Yield Strength: Lowest stress that produces a permanent deformation in a material. In some materials it is difficult to identify, thus it is usually defined as the stress required to cause 0.2% plastic strain.Compressive Strength:Is a limit state of compressive stress that leads to failure in a material in the matter of ductile failure or brittle failure.Tensile Strength: Is a limit state of tensile stress that leads to tensile failure in the matter of ductile failure or brittle failure. (Sudden breaking into two or more pieces at low stress rate)Stress= Force/AreaStrain= Change in length/Total lengthYoungs Modulus= Stress/Strain

Gas line sizing: Pressure drop is low in gas producing facilities as pipe segments are short. The pressure drop has a more significant impact on longer segments.Example: -Gas gathering pipelines-Transmission lines-Relief Pipes

Velocity in gas pipes should be less than 60 to 80ft/sec. A lower velocity of 50ft/sec should be used in presence of a known corrosives such as CO2. The minimum velocity needs to be above 10ft/sec, which minimizes liquid fallout.

Gas velocity equation:

Vg= gas flow rate MMscf/DT= gas flowing temperature, RP= flowing pressure, psia Z= compressibility factor, (dimensionless)d= pipe inner diameter (inches)

Once a design velocity is chosen, to determine the pipe size, this can be used.

Where:d = pipe ID, in.,

Z = compressibility factor, dimensionless,

R = gas/liquid ratio, ft3/bbl,

P = flowing pressure, psia,

T = gas/liquid flowing temperature, R,

V = maximum allowable velocity, ft./sec,

and

QL = liquid-flow rate, B/D.

Pressure ratings

ANSI Standard B16.5, Steel Pipe Flanges and Flanged Fittings has seven pressure classes: ANSI 150, 300, 400, 600, 900, 1500, and 2500. Table 11 illustrates the maximum, no shock working pressures for Material Group 1.1, which is the working group for most oil and gas piping and pipeline applications

Gasket materials;

Gasket materials for flat-face gaskets normally are 1/16 in. thick and made of composite materials. Asbestos was formerly used for gasket materials for both flat-faced and RF gaskets, but asbestos has been replaced because it is a hazardous material.

Spiral-wound gaskets, composed of a metal ring with wound internal composite rings, are typically used. The composite materials may include stainless steel and Teflon or other polytetrafluoroethylene (PTFE) type materials. A wide selection of winding materials is commercially available for a number of different fluids and applications. RTJ "ring" gaskets are typically made of cadmium-plated soft iron or low-carbon steel for ANSI 600 and ANSI 900 class flanges. 304 and 316 stainless-steel rings are frequently used in the higher-class ratings as well as for corrosive-service applications (such as H2S and CO2 service).

Valves:There are 4 types of check valves. (Allow flow in a single direction) Swing Split disk Lift plug/piston BallThe swing valve is suitable for non-pulsating flow and is not good for vertical flow applications.The split disk are mounted between flanges (water configuration), but the operating springs are easily subject to failure

The lift-plug and piston check valves are good for pulsating flow conditions. Excellent in vertical flow conditions. Office controls the plug or piston movement can easily be cut out in sandy service.Subject to fouling with paraffin. Slam shut upon flow reversal. Check valves are manufactured under the same code as isolating valves.

Pressure ratings, and connections, body materials, seals same as for isolation valves.Check valves should never be substituted for a positive shut off isolation valve in any piping system application. Under ideal service conditions, the best check valve in the perfect application will not guarantee a positive shut off.

Check valves may leak or fail open and allow communication of pressure from the high side to the low side.

Control valves including self-contained regulators, can be in either the open or closed position, whichever position creates the highest pressure.

Locked upon (or closed) valves can be considered always open or closed position, whichever position creates the highest pressure.

Locked upon (or closed) valves can be considered always open (or closed). If the lock and key are maintained in accordance with a proper lockout and tag-out procedure. A hazardous analysis to determine the associated risk of relying on the lockout is justified.

Control Valves;

Are used to regulate pressure, temperature and flow rate.Pressure relief valves and devices prevent the piping system from exceeding the maximum allowable pressure.They come in a variety of configurations and materials.They are rated with the ANSI/API pressure classes, flange ratings and end connections.As with isolation valves, pressure relief valves must be rated for the maximum allowable pressure.

Pipe Expansion:In the majority of oil and gas facility and pipeline applications, pipe expansion is not critical, as normal piping arrangements contain the numerous elbows and changes in direction. These make the piping system relatively flexible and allow the pipe to absorb the configuration may not be adequate to handle the expansion and contraction of the piping systems. The design must be checked to verify that the piping configuration will absorb the expansion and if not, that expansion loop will be incorporated as needed.

Pipe Support Spacing:The proper location and spacing of above ground-pipe supports can be determined as follows:-Assume that the hoop stress in the pipe is equal to the allowable stress Sh, for the material at the design temperature.-Poisson Law: Axial stress can be no more than 0.3 Sh. The stress for bending= 0.75 Sh-Assume 0.25 Sh is used for the movement caused by the pipe to allow stress for loads and concentrations.Assume pipe be modelled as fixed beam.L= [(0.25 Sh x Z) / W]^0.5L: length between supports (ft)Sh: allowable stress (psi)Z: pipe-section modulus, (in)^3W: weight of pipe filled with water (lbm/ft)

Circumferential Stress:

Hoop Stress: The hoop stress is the force exerted circumferentially (perpendicular both to the axis and radius of the object) in both directions on every particle in the cylinder wall. It can be described as

Where:F is the force exerted circumferentially on an area of the cylinder wall that has the following two lengths as sides:t is the radial thickness of the cylinderl is the axial length of the cylinder

An alternative to hoop stress in describing circumferential stress is wall stress or wall tension, which usually is defined as the total circumferential force exerted along the entire radial thickness:

Thin walled assumptions: For thin walled assumption to be valid the vessel must have a wall thickness of no more than about one tenth of its radius. This allows for testing the wall as a surface, and subsequently using the young- Laplace equation for estimating the hoop stress created by an internal pressure on a thin walled cylindrical pressure vessel.

WhereP is the internal pressuret is the wall thicknessr is the mean radius of the cylinder. is the hoop stress.

Selecting pipe wall thickness; The fluid flow equations and formulas presented thus far enable the engineer to initiate the design of a piping or pipeline system, where the pressure drop available governs the selection of pipe size. (In addition, there may be velocity constraints that might dictate a larger pipe diameter. This is discussed below in the section on velocity considerations for pipelines. Once the inner diameter (ID) of the piping segment has been determined, the pipe wall thickness must be calculated. There are many factors that affect the pipe-wall-thickness requirement, which include: The maximum and working pressures Maximum and working temperatures Chemical properties of the fluid The fluid velocity The pipe material and grade The safety factor or code design application If there are no codes or standards that specifically apply to the oil and gas production facilities, the design engineer may select one of the industry codes or standards as the basis of design. The design and operation of gathering, transmission, and distribution pipeline systems are usually governed by codes, standards, and regulations. The design engineer must verify whether the particular country in which the project is located has regulations, codes, and standards that apply to facilities and/or pipelines. The basic formula for determining pipe wall thickness is the general hoop stress formula for thin-wall cylinders, which is stated as Where:

HS = hoop stress in pipe wall, psi,

t = pipe wall thickness, in.,

L = length of pipe, ft,

P = internal pressure of the pipe, psi,

do =Outer diameter of pipe

Valves:There are 4 types of check valves. (Allow flow in a single direction) Swing Split disk Lift plug/piston BallThe swing valve is suitable for non-pulsating flow and is not good for vertical flow applications.The split disk are mounted between flanges (water configuration), but the operating springs are easily subject to failure

The lift-plug and piston check valves are good for pulsating flow conditions. Excellent in vertical flow conditions. Office controls the plug or piston movement can easily be cut out in sandy service.Subject to fouling with paraffin. Slam shut upon flow reversal. Check valves are manufactured under the same code as isolating valves.

Pressure ratings, and connections, body materials, seals same as for isolation valves.Check valves should never be substituted for a positive shut off isolation valve in any piping system application. Under ideal service conditions, the best check valve in the perfect application will not guarantee a positive shut off.

Check valves may leak or fail open and allow communication of pressure from the high side to the low side.

Control valves including self-contained regulators, can be in either the open or closed position, whichever position creates the highest pressure.

Locked upon (or closed) valves can be considered always open or closed position, whichever position creates the highest pressure.

Locked upon (or closed) valves can be considered always open (or closed). If the lock and key are maintained in accordance with a proper lockout and tag-out procedure. A hazardous analysis to determine the associated risk of relying on the lockout is justified.

Control Valves; Are used to regulate pressure, temperature and flow rate.

Pressure relief valves and devices prevent the piping system from exceeding the maximum allowable pressure.

They come in a variety of configurations and materials.

They are rated with the ANSI/API pressure classes, flange ratings and end connections.

As with isolation valves, pressure relief valves must be rated for the maximum allowable pressure.

Pipe Expansion:In the majority of oil and gas facility and pipeline applications, pipe expansion is not critical, as normal piping arrangements contain the numerous elbows and changes in direction. These make the piping system relatively flexible and allow the pipe to absorb the configuration may not be adequate to handle the expansion and contraction of the piping systems. The design must be checked to verify that the piping configuration will absorb the expansion and if not, that expansion loop will be incorporated as needed.

Pipe Support Spacing:The proper location and spacing of above ground-pipe supports can be determined as follows:-Assume that the hoop stress in the pipe is equal to the allowable stress Sh, for the material at the design temperature.-Poisson Law: Axial stress can be no more than 0.3 Sh. The stress for bending= 0.75 Sh-Assume 0.25 Sh is used for the movement caused by the pipe to allow stress for loads and concentrations.Assume pipe be modelled as fixed beam.L= [(0.25 Sh x Z) / W] ^0.5L: length between supports (ft)Sh: allowable stress (psi)Z: pipe-section modulus, (in) ^3W: weight of pipe filled with water (lbm/ft)

Work Hardening:The primary species responsible for work hardening are dislocations. Dislocations attract with each other by generating stress fields in the material. The interaction between the stress fields of dislocations can impede dislocation motion by repulsive or attractive attractions. Additionally if two dislocation cross, causing the formation line entanglement occurs, causing the formation of a jog which opposes dislocation motion. These entanglements and jogs act as piping points, which oppose dislocation motion. These entanglements and jogs act as piping points, which oppose dislocation motion. As both of these processes are more likely to occur when more dislocations are present, there is a correlation between dislocation, density and yield strength.

Where G= shear modulus, b is burgers vector and p is the dislocation density.Flanges; Threaded Flange Blind Flange Slip On Flange Lapped Flange Welding Neck Flange (Strongest) Flat Faced Flange Ring Joint Flange

Threaded flanges:A threaded flange has pipe threads machined into its bore as shown:

Threaded flanges are only used for small diameter piping systems. Up to 2 inches.Not used in large pipes because of increased difficulty of obtaining sufficient and uniform thread enlargementSlip on rather than threaded preferred based on the greater likelihood of having a leak. Blind Flanges;Is a metal plate that is used to block flow in a piping system. Its not attached to the pipe, but bolted to a mating flange.It is used for blocking flow in a piping system.

Socket Welded Flanges;Has an oversized bore that is partially machined into the end opposite the face as shown;

Based on SAES L 010, Limitations on piping joints, the maximum size socket welded joints in hazardous services shall be 1 and 0.5 (38mm)

SAES L 009 indicates that welded slip-on-type flanges are preferred over socket-welded flanges in socket.

Slip on Flanges;A slip-on flanges has an oversize bore. It is slipped over the pipes outer diameter and projects slightly beyond the pipe end. The flange is then fillet welded to the pipe outer diameter and also between the flange bore and the pipe end.

Lower cost alternate to the welding neck-type flange that will be described below. It is because it is lighter and requires less welding to attack it to the pipe.However it is not suitable for high temperature, cyclic, high pressure or high external loading situations.Based on SAES L 009 flange analysis be performed if a slip flange is used for any of the following cases Severe cyclic conditions: i.e. large and frequent temperature fluctuations, or vibration prone services Design temperature greater than 230 degrees ASME class 400 or higher rating Pipe size over (600mm) 24 inches.The analysis must consider thermal and other external piping loads and must demonstrate that flange will not be over-stressed. Because of this extra analysis requirement, it is unlikely that a slip on type flange will be used in these services because its economic attractiveness will be reduced.

Lapped Flanges;Is not physically connected to the pipe. It is slipped over a pipe stub that has a flared end and the pipe stub is welded to the major pipe section. The flared pipe end has a machined face where the gasket is sealed. The bolting holds the flanges and gasket joint together.

Raised-Face Flanges;The area where the gasket is located is higher than the surrounding flange surface, typically by 1.5 mm (1/16 in.). This raised-face portion of the flange has a specially machined, serrated finish that is suitable for the typical gasket types used in process plant applications. Any gasket type, other than a ring type, may be used with a raised-face flange. The raised face results in much less contact area and higher gasket contact stresses as compared to a flat face. The gasket is compressed and sealed only in the area of the raised face. A smooth machine finish, 3.2-6.4 micrometer AARH (arithmetic average roughness height), should be specified for use with spiral-wound gaskets.A raised-face flange is used for a very broad range of services, and is the most common type.

Ring-Joint Flanges;Consists of a groove that is machined into the flange end. The sealing surfaces of the groove are smoothly finished to 63 micro inch surface roughness, and are free of any detrimental ridges or tool marks. The presence of such surface defects will result in a leaking joint, since a very smooth contact surface is required to achieve a leak-proof, metal-to-metal seal. A solid metal ring type gasket is inserted in the groove.The ring-joint flange is used for the most severe service applications where the other possible flange face and gasket combinations will not provide acceptable performance.Typically, these are high-pressure and/or high-temperature services.Based on SAES-L-009, a ring-joint flange is required for steel flanges of Class 900 and higher, for design temperatures over 480C (900F), or for underwater pipelines in Class 300 and higher.

Fittings; Elbows:Are used to change the direction of a pipe run. Standard elbows change the direction by either 45 or 90 degrees. Long radius elbows have a bent radius of 1 0.5 times the nominal pipe size, and short radius elbows have a bent radius equal to the nominal pipe size. Returns change direction by 180 degrees.

Reducers; Change the diameter in a straight section pipe, and comes as either a concentric or eccentric type.As shown below, laterals are special types of tees

A lateral is used in situations where it is necessary for the two flow streams to combine in a less abrupt transition than provided by a standard 90 degree tee.

Socket Welded Fitting: Attachment is designed with a recess in its and to permit the pipe to be inserted, as shown in figure. The pipe is withdraw approximately 1 5 mm from the bottom of the recess, then fillet welded between the pipe outside diameter and the end of fitting. The gap is needed in order to provide space to permit differential thermal expansion, which occurs during welding and normal operation.

Fitting Standard;There are two primary design standards that are used for pipe fittings are:- ASME B16.9, Factory made wrought steel butt-weld ASME B16.11, Forged Steel Fittings, Socket welding and threaded

ASME B16.9Encompasses overall dimensions, tolerances, ratings, testing and markings for wrought carbon and alloy steel factory made butt-welded fittings of 13 through 1,200mm. It also includes thickness that may be produced, except low-pressure corrosion- resistant fittings.

Valves;

Valves are necessary for the basic function of a piping system. When a plant is designed, the types of valves and their location within a piping system are selected. Fluid flows through a pipe, and valves are used to control the flow. A valve may be used to block flow, throttle flow, or prevent flow reversal.

The block-flow function provides completely on or completely off flow control of a fluid in a piping system, generally without throttling or variable control capability. To throttle flow in a piping system may increase or decrease the amount of fluid flowing in the system and can also help control pressure at points within the system.

Various types of valves may be used for each function. The gate valve is the type that is most commonly used to block flow in a process plant. The ball-, plug-, butterfly-, diaphragm-, and globe-type valves are used to block flow to a lesser extent. The globe valve is the type most commonly used to throttle flow in a refinery. Butterfly and diaphragm valves are also used to throttle flow.

Gate Valves;About 75 percent of all valves in process plants are gate valves. Most valves in process plants function as block valves. Block valves are required only to fully shut off or fully turn on flow. The gate valve is not suitable to throttle flow because it will pass the maximum possible flow while it is only partially open, and the valve seating surfaces can erode rapidly from fluid flow when the valve is not in the fully open or fully closed position.

Function:The off/on flow control of a gate valve is achieved by moving a gate into or out of the fluid-flow stream. When the full-port gate valve is in the open (on) position, it provides a full line size, unobstructed, straight through flow passage, and thus results in a minimum-flow pressure drop. In reduced-port and Type-type gate valves, the flow area is smaller than the line size, causing slightly higher-pressure drops than a full-port valve. The gate valve shuts off flow by forcing the gate against the valve body seating surfaces, which creates a pressure-tight seal in both directions.

Ball Valve;Ball valves usually function as block valves to fully shut off or fully open flow. Ball valves are well suited for conditions where quick on/off and/or bubble-tight service are required. Soft-sealed ball valves are not normally used for throttling service because the valve soft seats are subject to erosion or distortion/displacement caused by fluid flow when the valve is not in the fully open or fully closed position.The soft-sealed ball valve is a good choice as a block valve when used within the limitations previously mentioned and when bubble-tight shutoff, double-block and bleed capability, or the quick on/off feature is required. Where such capabilities are not required, the ball valve is usually not the best choice in most sizes, because of its higher cost relative to gate valves.

Function:The ball valve is quick-opening and requires only a quarter-turn from full open to fully close. A ball is used to permit or block flow. A hole, provided through one axis of the ball, connects with the inlet and outlet ports of the valve body. With the ball in the open position, straight-through flow is accomplished. When the ball is turned 90, flow is blocked. In the closed position, tight shutoff is obtained by resilient, seat-to-metal ball-sealing contact, and to a lesser degree, by metal-to-metal contact in metal-seated models.

Plug Valve;Plug valves usually function as block valves to fully shut off or fully open flow. They are well suited for conditions where quick on/off and/or bubble-tight shutoff are required. Most plug valve styles are available in the full range of pipe sizes and materials that are needed in process plant applications. Soft-sealed styles with full cylindrical plugs are suitable for double-block and bleed applications. The soft-seal-types, however, may have lower temperature/pressure ratings than those given in ASME/ANSI B16.34 for steel valves, because of the lesser physical properties of the soft-seat materials. Soft-seal plug valves are not normally used for throttling service, since the soft seals are subject to erosion or distortion/displacement caused by fluid flow when the valve is not in the fully open or closed position.A plug valve is a good choice as a block valve when used within the limitations noted above, and when bubble-tight shutoff or quick on/off operation is required.

Function:The plug valve utilizes a cylindrical and usually tapered plug to provide quarter-turn operation from fully open to fully closed. A hole is provided through one axis of the plug, connecting the inlet and outlet ports of the valve body for straight-through flow when in the open position, and completely blocking flow when rotated 90 to the closed position. In the closed position, tight shutoff is obtained either by sealant injected into the plug/body cavity interface, or by resilient, seat-to-metal seat-sealing contact (as in a soft-seated ball valve).

There are three basic plug valve-types: the lubricated, non-lubricated, and soft-sealed fire safe.

Lubricated Plug Valve;A lubricated plug valve depends on injection of a sealant to prevent leakage around the plug through the interface between the plug and the body cavity. The sealant is injected through a pressure fitting into the body cavity and distributed across all seating surfaces via grooves in the plug. The sealant material must be compatible with the process fluid, resist breakdown at maximum design temperature, and retain its fluidity and lubricating properties at minimum design temperature.Lubricated plug valves can provide good long-term performance if adequate maintenance attention can be ensured. With its substantial secondary metal-to-metal seating and capacity for restoring tight shutoff by sealant injection, this valve-type is inherently fire safe with respect to through-leakage. However, appropriate high-temperature stem packings, gaskets, and supplementary seals must be provided to ensure fire safe integrity against external leakage.

Soft-Sealed, Fire safe Plug Valve;Fire safe plug valves use a narrow-band primary-seal ring of a soft, resilient material (such as Teflon) in the annulus between the plug and body cavity to prevent leakage. A fire safe soft-sealed plug valve also has a secondary metal-to-metal backup seal. This assures positive shutoff capability if the soft seal is damaged by fire. The maximum temperature limit of the valve is limited by the soft seal material.

Selecting a type of valve suitable for process;

Selecting the appropriate valve depends on the fluid in a piping system, the system's design conditions, the service application, the functions and types of valves, and the applicable SAES and SAMSS requirements.Other considerations for selecting valves are discussed in further detail in this section.SAES-L-008 and the 04-SAMSS-series provide requirements and limitations for valve selection. It is important to understand that selecting valves may simply be a matter of duplicating valves from a system that has provided good performance.

Valve Sizing;In most cases, valve size is identical to pipe size. In some cases, a valve must be larger than the pipe in order to pass the required flow-rate due to pressure drop across the particular valve-type being used. In other cases, it might be advantageous for a valve to be smaller for economic reasons. When fluid is flowing steadily in a long, straight pipe of uniform diameter, the flow pattern assumes a certain characteristic form.Any disruption, such as due to friction, will cause a drop in pressure. Valves also disrupt the flow pattern and, therefore, cause a pressure drop in the piping system. The loss of pressure produced by a valve consists of: The pressure drop within the valve itself. The pressure drop in the upstream and downstream piping that exceeds what would normally occur if there was no valve in the line.Equations are used to calculate the pressure drop across a valve, based on the flow characteristics of the particular valve type. It must be determined whether the pressure drop is acceptable for the process design requirements. Since the pressure drop caused by valves can affect the size of the valve, it can also influence the selection of one valve-type over another, since different valve-types have different pressure-drop characteristics. It is also normally the process design engineer who determines whether the system pressure drop is acceptable. Further discussion of pressure drop across valves is beyond the scope of this course.

Identifying Valve Inspection and Testing Requirements;All valves require a certain degree of inspection and testing before installation and during operation. This is true for both new and reconditioned valves. The engineer generally does not actually perform or witness the tests. He must specify the mandatory tests for vendors to execute. This section reviews the types of inspection and test procedures that are utilized, where they are specified, and when they should be applied.Several different inspections and testing methods are normally applied to valves. The selection of a particular method is governed by valve material, rating, service conditions, and other considerations. Inspection methods vary from the quick and simple visual inspection of a valve casting and components to more sophisticated radiographic examinations. Test methods may include hydrostatic and/or pneumatic testing of the assembled valve and seats. Impact tests may be required based on the temperature conditions, material, and body thickness. Material testing ensures that materials that are used in the valve meet material specifications with respect to chemistry, strength, and hardness. Pressure testing ensures the integrity of the valve body and valve seat tightness when closed.

There are several tests that might be done to new valves as well. It may be from simple physical check up to radiation checks.

Shell Test;The Shell Test is conducted first, to assure that any body distortions that result from this high-pressure test will be reflected in subsequent seat tests at lower pressures. This test confirms the basic structural integrity of the valve. Back Seat Test;The Back Seat Test is conducted after the Shell Test with same test fluid. Test pressure is to be 110% of the pressure rating at 38C (100F). The stem is to be fully open (back seated), and the stem packing is to be loose. No leakage is permitted during this test. This test may be conducted in conjunction with the optional high-pressure Closure Test. The purpose of this test is to confirm that the valve stem packing may be removed and reinstalled while the valve is still under system pressure with the stem fully open.

Fire safe Test;Whenever such a valve is specified as a block valve in a hazardous fluid service, it should be specified as being A type.A type valve is one that is designed with a secondary metal-to metal seat in addition to the primary soft seat. It also incorporates appropriate stem packing, cover gasket, and external bolting materials that can resist the high temperatures of a fire without major external leakage that could aggravate the emergency situation. They are designed such that the valve's primary seat can be destroyed by fire and remain operable, be essentially free of external leakage, and have only a limited amount of leakage past the seat with the valve closed.Summary:Valves are major components of a piping system and require careful attention during the design process. Selecting a valve is based upon the required valve function: to block flow, throttle flow, or prevent flow reversal. There are numerous types of valves. The valve most commonly used (approximately 75% of the time) is the gate valve. SAES-L-008 provides specials service limitations and selection requirements for valves. The 04-SAMSS-series of specifications provides additional valve design requirements. Once a valve is selected, its flange rating class must be specified based on its design pressure/temperature and the MAOP of the class. Finally, the valve must be inspected and tested.

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Resources Used:Lucid Chart.Creo Parametric 3.0.