1. PIPING

TECHNICAL TRAINING (PIPING)

TABLE OF CONTENTS

1.

INTRODUCTION TO PIPING.........................................................................................1

2.

PIPE................................................................................................................................1

3. PIPE FITTINGS.................................................................................................................3 4.

PIPING MAINTENANCE..............................................................................................12

5. SAFETY FOR PIPING MAINTENANCE………………………………………………….

TECHNICAL TRAINING (PIPING )

1.

INTRODUCTION TO PIPING Piping includes pipe, flanges, fittings, bolting, gaskets, valves, and the pressurecontaining portions of other piping components..

2.

PIPE Pipe is a Tubular item made of metal, plastic, glass etc.meant for conveying Liquid, Gas or any thing that flows. Pipe is customarily identified by Nominal Pipe Size (NPS) with wall thickness defined by schedule number, and conforming to the dimensional requirement of

2.1

•ASME B36.10M

Welded and Seamless Wrought Steel Pipe

•ASME B36.19M

Stainless Steel Pipe

Pipe Size Nominal pipe size (NPS) is a dimensionless designator of pipe size. It indicates standard pipe size when followed by the specific size designation number without an inch symbol. For example, 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, …). However, the outside diameter of NPS 14 and larger pipe is the same as the size designator in inches. 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. Refer to ASME B36.10M or ASME B36.19M.

2.2

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. 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. Note that the original pipe wall thickness designations of STD, XS, and XXS have been retained; however, they correspond to a certain schedule number depending upon the


nominal pipe size. The nominal wall thickness of NPS 10 and smaller schedule 40 pipe is same as that of STD. WT. pipe. Also, NPS 8 and smaller schedule 80 pipe has the same wall thickness as XS pipe. The schedule numbers followed by the letter S are per ASME B36.19M, and they are primarily intended for use with stainless steel pipe. The pipe wall thickness specified by a schedule number followed by the letter S may or may not be the same as that specified by a schedule number without the letter S. Refer to ASME B36.19M and ASME B36.10M.10,11 ASME B36.19M does not cover all pipe sizes. Therefore, the dimensional requirements of ASME B36.10M apply to stainless steel pipe of the sizes and schedules not covered by ASME B36.19M.


3.

PIPE FITTINGS Fittings permit a change in direction of piping, a change in diameter of pipe or a branch to made from the main run of pipe. They are formed from plate or pipe, machined from forged blanks, cast, or molded from plastics End connection can be classified in common as follows, • Socket Weld : for size up to 1½’’ • Butt Weld : for size greater than 1½’’ • Threaded : for size up to 1½’’

Dimensional Standard • For Socket Weld & Threaded end: ANSI/ASME B16.11 • For Bevelled end: ANSI/ASME B 16.9 • Thickness for Beveled end fittings = Thickness of pipe 3.1

Elbows Used for change in direction of pipe routing. They are of 2 types.

Fig.3.1a 45 Elbow

Short Radius Elbow, R = 1D

Fig.3.1b 90 Elbow

Short Radius Elbow, R = 1D


Long Radius Elbow, R = 1.5D 3.2

Long Radius Elbow, R = 1.5D

Tee Used for taking a branch. 1) Equal/Straight tee – All 3 sizes are equal 2) Unequal/Reduced tee – Branch size is always smaller

Fig.3.2 Reduce Tee and Tee

3.3

Reducer Used when change in pipe size. They are of 2 types. 1) Concentric Reducer 2) Eccentric Reducer In case of Eccentric Reducer one side is tapered while the other side is straight. Here the difference in elevation of the axis exists leading to eccentricity. Its construction is like a trapezoid. In case of Concentric Reducer both sides are tapered and the axis is also the same. Its construction is like a cone. Thumb Rule for Reduction: Maximum Lower Size ---> higher size / 2 For example if the Header Size is 6’’, then 6"/2 = 3" and hence the next lower size possible is 2½’’. Hence it can be seen that reduction from 6’’ to 2½’’ is possible. Further reduction beyond 2 ½’’ is not possible.


Concentric

Eccentric Fig.3.3 Reducer

3.4

Fittings for small line

3.4.1

Weldolet Used to take Butt Weld branch for which Reducing tee is not possible. Used in high pressure, high temperature pipe class from 900 rating.

Fig.3.4.1 Weldolet

3.4.2

Sockolets Same as Weldolet except there is a Socket weld end at Branch side. Caps are used at the end of the line for the termination of the line.

Fig.3.4.2 Sockolet


3.4.3

Coupling

Full Coupling

Half Coupling

Used to take a branch upto 1½’’ size. End connections are Socket Weld or Threaded 3.5

FLANGES Flanges are used to make a joint that is required to be dismantled. Various attributes of Flanges are described below.

3.5.1

Pressure Class (Rating) Rating is maximum allowable non-shock working gauge pressure. There are 150, 300, 600, 900, 1500, 2500 ratings. To select a pressure class the following two steps are followed. Decide the group of material from Table 1A of ASME 16.5. Refer Table 2 of ASME 16.5 for design condition.

3.5.2

End Type There are five end types of Flanges. 1) Weld neck flange Regular welding-neck flanges are used with but-welding fittings. Suitable where extreme temperature, shear, impact and vibratory stresses apply. Regularity of the bore is maintained.


Fig. 3.5.2 1) Welding-neck flange

2) Socket weld flange The socket welding flange is similar to a slip-on flange except it has a bore and a counter bore dimension. The counter bore is slightly larger than the O.D. of the matching pipe, allowing the pipe to be inserted into the flange similar to a slip-on flange. The diameter of the smaller bore is the same as the I.D. of the matching pipe a restriction is built into the bottom of the bore which sets as a shoulder for the pipe to rest on. This eliminates any restriction in flow when using a socket welding flange.

.

Fig.3.5.2. 2) Socket weld flange

3) Slip-on flange The internal weld is slightly more subject to corrosion than the butt weld. The flange has poor resistance to shock and vibration. It introduces irregularily in the bore. It is cheaper to buy than the welding-neck flange, but is is costlier to assemble. It is easier to align than the welding-neck flange. Calculated strengths under internal pressure are about one third that of the corresponding welding-neck flanges.


Fig.3.5.2. 3) Slip-on flange

4) Threaded flange The threaded flange is similar to the slip-on flange, but the bore is threaded. Its chief merit is that It can be assembled without welding, explaining its use in low pressure services at ordinary atmospheric temperatures, and in highly explosive areas where welding create a hazard. It is mainly used in Galvanized pipes.

Fig.3.5.2. 4) Threaded flange

5) Blind flange The blind flange is a flange without a bore, It is used to close off the end of a piping system and/or pressure vessel opening. It also permits easy access to the interior of a line or vessel once it has been sealed and must be reopened. It is used for ending a line.


Fig.3.5.2. 5) Blind flange

3.5.3

FLANGE FACE 1) Flat-Face

Fig.3.5.3. 1) Flat-face type

Most commonly used for mating with non-steel flanges on the bodies of pumps, valves, etc. The gaskets used (see Gaskets below) have an outside diameter equal to that of the flange itself. This ensures an even pressure distribution across the flange and reduces the risk of cracking of cast-iron or bronze flange on tightening or from plant vibration. 2) Raised Face The raised face is the most common type of flange, in which the gasket covers only the raised faces.

Fig.3.5.3. 2) Raised-face type


3) Ring-Type Joint

Fig.3.5.3 3) Ring- type joint

Ring-joint flange is a more expensive facing, and considered the most efficient for hightemperature and high-pressure service. Both flanges of a pair are alike. The ring-joint facing is not prone to damage in handling as the surfaces in contact with the gasket are recessed. Use of facings of this type may increase as hollow metal O-rings gain acceptance for process chemical seals.

4) Lap Joint

Fig.3.5.3 4) Lap joint type

Lap-joint flange is shaped to accommodate to the stub end. The combination of flange and stub end presents similar geometry to the raised-face flange and can be used where severe bending stresses will not occur.

3.5.4

Design and Dimension Standard


The dimensional standards generally used are ANSI/ASME B16.5 for size upto 24’ ANSI/ASME B16.47 series A & B for size above 24’’. 3.6

GASKETS Gaskets are used to avoid Static leakage and metal to metal contact. There are two types of gaskets from material point of view. Design & Dimension Standard: ANSI/ASME B 16.20 For Metallic Gaskets ANSI/ASME B 16.21 For Non-metallic Gaskets

3.6.1

Metallic Gasket Metal is used in the construction of Gasket either as main material or as reinforcing material. e.g. Spiral wound gasket.

3.6.2

Non-metallic Gasket Metal is not used in the construction of gaskets. e.g. Flat Gasket


4.

PIPING MAINTENANCE. Refer to STANDARD MAINTENANCE PROCEDURE FOR PIPING SYSTEM and WORK STEP FOR DISMANTLE AND INSTALL PIPING

4.1.

Preparation work - Prepare tool & equipment required : Hand tool (non- sparking tool for Hydrocarbon service), crane, chain block, sling,… - Install scaffolding, ladder, platform, remove insulation if required. - Prepare material : gasket, bolt/nut, piping components spare parts… - Prepare PTW (Permit to work)

4.2

Check condition for maintenance work Check safety condition for work : isolating,de-pressurizing,cooling down, venting, draining, Purging( check Hydricarbon/poisonous gas content before work)

4.3

Start maintenance work Confirm with General Foreman to start maintenance work ( remove piping components for Cleaning/repair, clean flange faces, re-install with new gasket, leak test…)

5.

SAFETY REGULATION Remember that: SAFETY FIRST ! Every body must be trained, understand well and Strictly follows the Safety Regulations during working at site, for example : wear PPE, strictly follows the working at high procedure, confined space procedure, chemical safety, Safety for welding and cutting procedurs etc…


1. PIPING

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