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PIPING FUNDAMENTALS

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PIPING FUNDAMENTALS

Piping systems are like arteries and veins They carry the lifeblood of modern

civilization In a modern city they transport water from

the sources of water supply to the points of distribution

convey waste from residential and commercial buildings

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PIPING FUNDAMENTALS….

The design, construction, operation, and maintenance of various piping systems involve :

Understanding of piping fundamentals, Materials, generic and specific design

considerations Fabrication and installation Examinations, testing and inspection Requirements, in addition to the local, state

and federal regulations

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PIPING FUNDAMENTALS….

Different types of piping:

Off-shore (Underground / Above ground)

On-shore (Underground / Above ground)

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PIPING FUNDAMENTALS…..

Piping includes pipe, flanges, fittings, bolting, gaskets, and valves

IPS: Initially a system known as iron pipe size was established to designate the pipe size

The size represented the approximate inside diameter of the pipe in inches

An IPS 6 pipe is one whose inside diameter is approximately 6 inches

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PIPING FUNDAMENTALS….

NPS: Nominal pipe size is a dimensionless designator of pipe size

It indicates standard pipe size NPS 2 indicates a pipe whose outside diameter

is 2.375 in The NPS 12 and smaller pipe has outside

diameter greater than the size designator (say, 2, 4, 6, . . .)

the outside diameter of NPS 14 and larger pipe is the same as the size designator in inches

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PIPING FUNDAMENTALS ….

For example, NPS 14 pipe has an outside diameter equal to 14 in

The inside diameter will depend upon the pipe wall thickness specified by the schedule number

DN: Diameter nominal is also a dimensionless designator of pipe size in the metric unit system, developed by the International Standards Organization (ISO).

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PIPING FUNDAMENTALS ….

It indicates standard pipe size when followed by the specific size designation number without a millimeter symbol

For example, DN 50 is the equivalent designation of NPS 2

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Pipe Wall Thickness

Schedule is expressed in numbers (5, 5S, 10, 10S, 20, 20S, 30, 40, 40S, 60, 80, 80S, 100, 120, 140, 160)

A schedule number indicates the approximate value of the expression 1000*P/S

where P is the service pressure and S is the allowable stress, both expressed in pounds per square inch (psi)

The higher the schedule number, the thicker the pipe is.

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Pipe Wall Thickness ….

The outside diameter of each pipe size is standardized

Therefore, a particular nominal pipe size will have a different inside diameter depending upon the schedule number specified.

The schedule numbers followed by the letter S are per ASME B36.19M, and they are primarily intended for use with stainless steel pipe

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PIPING CLASSIFICATION

It is usual industry practice to classify the pipe in accordance with the pressure temperature rating system used for classifying flanges

piping classified as Class 150, 300, 400, 600, 900, 1500, and 2500

Class 150 300 400 600 900 1500

2500

PN bar

20 50 68 110 150 260 420

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PIPE AND TUBE PRODUCTS

Pressure Tubing: Pressure-tube applications commonly

involve external heat applications, as in boilers or superheaters

Pressure tubing is produced to the actual outside diameter and minimum or average wall thickness specified by the purchaser

Pressure tubing is usually made from steel produced by the open-hearth, basic oxygen, or electric furnace processes.

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PIPE AND TUBE PRODUCTS

Dimensions of Typical Commercial Cast-Steel Flanged Fittings (from ASME B16.5-1996) Page 8 of piping standard.

Pipe: applications commonly involve all piping systems where you are not limited to apply Tube.

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TRAPS (Steam Traps)

The function of a steam trap is to discharge condensate from steam piping or steam heating equipment without permitting live steam to escape.

Some principal types of steam traps are: ● Float ● Thermostatic ● Thermodynamic ● Inverted bucket

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STRAINERS …

Strainers are used in piping systems to protect equipment sensitive to dirt and other particles that may be carried by the fluid

During system start-up and flushing, strainers may be placed upstream of pumps to protect them from construction debris that may have been left in the pipe

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STRAINERS …

The “Y” strainer is generally used upstream of traps, control valves, and instruments

Basket strainers are generally used where high flow capacity is required

Basket strainers are also available in a duplex style which consists of two parallel basket strainers and diverting valves,

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STRAINERS

Permanent strainers may be installed upstream of control valves, traps, and instruments to protect them from corrosion products that may become dislodged and carried throughout the piping system

Strainers are available in a variety of styles, including “Y” and basket

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Flange Types

Flanges differ in method of attachment to the pipe, i.e., whether they are screwed, welded, or lapped

Contact surface facings may be plain serrated, grooved for ring joints, seal-welded, or ground and lapped for metal-to-metal contact

Unfired Pressure Vessels, of the ASME Boiler and Pressure Vessel Code, three types of circular flanges are defined, and these are designated as loose-type, integral-type and optional-type flanges

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Flange Types ….

Loose-Type Flanges. This (slip-on) type covers those designs in which the flange has no direct connection to the nozzle neck or the vessel or pipe wall

and those designs where the method of attachment is not considered to give the mechanical strength equivalent of integral attachment

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Flange Types … Integral-Type Flanges. This type covers

designs in which the flange is cast or forged integrally with the nozzle neck or the vessel or pipe wall, butt-welded thereto, or attached by other forms of arc or gas welding of such a nature that the flange .

Typical loose flanges (threaded and slip-on) and nozzle neck or vessel or pipe wall is considered to be the equivalent of an integral structure.

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Flange Types … Optional-Type Flanges : This type covers

designs where the attachment of the flange to the nozzle neck or the vessel or pipe wall is such that the assembly is considered to act as a unit, which shall be calculated as an integral flange, except that for simplicity the designer may calculate the construction as a loose-type flange, provided that stipulated load values are not exceeded.

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Flange Facing Selection of the type of facing depends to a

considerable extent on the nature of the service:

plain face: the simplest of which is the plain face provided with a ‘‘smooth tool finish.’’ Class 125 cast-iron flanged fittings are provided with this type of facing.

Plain-face joints with red rubber gaskets have been found satisfactory for temperatures up to 220F (105C)

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Flange Facing … The Raised face, the lapped, and the large male-

and-female facings have the same dimensions, which provide a relatively large contact area. Where metal gaskets are used with these facings, the gasket area should be reduced to increase the gasket compression

serrated raised-face joints with graphite-steel-composition gaskets are commonly used for temperatures up to 750F (400C).

For high temperatures and pressures, faces giving a high contact pressure for a given bolt load are customary, such as the tongue-and-groove and ring joints

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VALVES

Valve types: Ball, gate, plug, butterfly, globe, diaphragm, needle, and check valves have all been used in platform production facilities

Ball valves are suitable for most manual on-off hydrocarbon or utilities service when operating temperatures are between -20 ْ F and 180 ْ F, above 180 ْ F should be carefully considered due to the temperature limitations of the soft sealing material

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VALVES….

Ball valves are available in both floating ball and trunnion mounted designs. Valves of the floating ball design, develop high operating torques in high pressure services or large diameters but tend to provide a better seal, Trunnion mounted ball valves turn more easily but may not seal as well. Thus, a trade-off decision is required to select the proper type for each application

Ball valves are not suitable for throttling because in the partially open position, sealing surfaces on the exterior of the ball are exposed to abrasion by process fluids.

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VALVES….

Gate valves are suitable for most on-off, non-vibrating hydrocarbon of utilities service for all temperature ranges.

In vibrating service, gate valves may move open or closed from their normal positions unless the stem packing is carefully adjusted.

Gate valves have better torque characteristics than ball or plug valves but do not have the easy operability of quarter turn action

In sizes 2 inch and larger, manually operated gate valves should be equipped with flexible discs or expanding gates

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Gate valves with unprotected rising stems are not recommended since the marine environment can corrode exposed stems and threads, making the valves hard to operated and damaging stem packing.

Gate valves should not be used for throttling service. Throttling, especially with fluids containing sand, can damage the sealing surfaces.

VALVES….

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VALVES….

Plug valves are suitable for the same applications as ball valves and are also subject to similar temperature limitations.

Plug valves are available with quarter turn action in either lubricated or non-lubricated designs.

Plug valves are typically utilized in chemical processing applications

In contrasts to the ball valve, the plug valve typically requires higher operating torques, meaning larger and more expensive automation packages.

They do not require frequent maintenance lubrication but may be more difficult to free after prolonged setting in one position. The application circumstance will generally dictate a selection preference based on these characteristics.

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VALVES….

Butterfly valves are suitable for coarse throttling and other applications where a tight shutoff is not required.

It is difficult to accomplish a leak-tight seal with a regular butterfly valve.

Butterfly valves are typically utilized in large line sizes in chemical services, waste and water treatment applications and fire protection systems.

They are not suitable as primary block valves for vessels, tanks, etc. where a tight seal is required, use a high performance valve or limit the valve to low differential pressure and low temperature ( 150 2 ْ F ) service.

Because low torque requirements permit butterfly valves to vibrate open, handles with detents should be specified.

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VALVES….

Globe valves: When good throttling control is required ( e.g., in bypass service around control valves) , globe valves are the most suitable.

Diaphragm ( bladder valves). In this valve design, a diaphragm made of an Elastomer is connected to the valve stem. Closure is accomplished by pressing the diaphragm against a metal weir which is a part of the valve body.

Diaphragm valves are used primarily for low pressure water ( 200 psig or less ) service. They are especially suitable for systems containing appreciable sand or other solids.

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PIPING MATERIALS

The selection of materials for piping applications is a process that requires consideration of material characteristics appropriate for the required service.

Material selected must be suitable for the flow medium and the given operating conditions of temperature and pressure safely during the intended design life of the product.

Welding type bend, and the operating environment surrounding the pipe or piping component must be considered

The selection process should lead to the most economical material that meets the requirements of the service conditions and codes and standards that apply