Prepared Khalil

Prepared By : Eng- Khalil-Ur-Rehman

Piping Coordination Systems - Symbols for Isometrics

Image Fittings Butt weld

Symbol

Socket Weld

Symbol

Threaded

Symbol Fittings Image

Elbow 90°

Elbow 90°

Elbow 45°

Elbow 45°

Tee equal

Tee equal

Tee reducing

Tee reducing

Cap

Cap

Reducer

concentric

... ... Reducer

concentric ...

Reducer

eccentic

... ... Reducer

eccentic ...

Image Fittings Butt weld

Symbol

Socket Weld

Symbol

Threaded

Symbol Fittings Image

Flanges Weld Neck Socket Weld Threaded Slip-On Lap-Joint Blind Flanges

Symbol

Symbol

Image

Image

Flanges Weld Neck Socket Weld Threaded Slip-On Lap-Joint Blind Flanges

Image Valves Butt weld

Symbol

Flanged

Symbol

Socket or

Threaded

Symbol

Valves Image

Gate

Gate

Globe

Globe

Ball

Ball

Plug

Plug


Butterfly

... Butterfly

Needle

Needle

Diaph ...

Diaph

Y-type

Y-type

Three

way

Three

way

Check

Check

Bottom ...

... Bottom

Relief ...

... Relief

Control

straight ...

... Control

straight

Control

angle ...

... Control

angle

Image Valves Butt weld

Symbol

Flanged

Symbol

Socket or

Threaded

Symbol

Valves Image

Miscellaneous Symbol Image Miscellaneous

Branch outlet

Weldolet®

Branch outlet

Weldolet®

Branch outlet

Nipolet®

Branch outlet

Nipolet®

Flanged branch

outlet

Flangolet

Flanged branch

outlet

Flangolet


Spade

Spade

Spectacle

blind

Spectacle

blind

Hammer

blind

Hammer

blind

Spacer

Spacer

Restriction

orifice

Restriction

orifice

Field Weld

Field Weld

Butt weld Butt weld

Pipe to pipe

connection

Pipe to pipe

connection

Pipe bend

with

special radius

Pipe bend

with

special radius

Sight glass

Sight glass

Direction of

hand wheel

wrench

Hand wheel

Y-type

strainer

Y-type

strainer

Conical

strainer

Conical

strainer Conical

strainer

built-in


Orifice

assembly (typical)

showing

position of taps

Orifice

assembly

Meter run

orifice assembly

(typical)

flanged / butt weld

Meter run

Miscellaneous Symbol Image Miscellaneous

Note: Symbols are shown in black lines. Lighter lines show connected pipe, and are not parts of

the symbols.

Piping Coordination Systems - Piping Isometrics

Piping Isometric

Unlike orthographic, piping isometrics allow the pipe to be drawn in a manner by which the

length, width and depth are shown in a single view. Isometrics are usually drawn from

information found on a plan and elevation views. The symbols that represent fittings, Valves and

flanges are modified to adapt to the isometric grid. Usually, piping isometrics are drawn on

preprinted paper, with lines of equilateral triangles form of 60°.

The Iso, as isometric are commonly referred, is oriented on the grid relative to the north arrow

found on plan drawings. Because iso's are not drawn to scale, dimensions are required to

specify exact lengths of piping runs.

Pipe lengths are determined through calculations using coordinates and elevations. Vertical

lengths of pipe are calculated using elevations, while horizontal lengths are caculated using

north-south and east-west coordinates.

Piping isometrics are generally produced from orthographic drawings and are important pieces of

information to engineers. In very complex or large piping systems, piping isometrics are

essential to the design and manufacturing phases of a project.

Piping isometrics are often used by designers prior to a stress analysis and are also used by

draftsmen to produce shop fabrication spool drawings. Isometrics are the most important

drawings for installation contractors during the field portion of the project.

Large image of a Hand-Drawn Isometric


How to read a Piping Isometric?

A pipe into a isometric view, is always drawn by a single line. This single line is the centerline of

the pipe, and from that line, the dimensions measured. So, not from the outside of a pipe or

fitting.

The image below shows a orthographic view of a butt welded pipe with three sizes (A, B, C).

The A size is measured from the front to the center line of the elbow / pipe.

The B size is measured from centerline to centerline.

The C size is like the A size, measured from the front to the center line of the elbow /

pipe.

Orthographic view

(double line presentation)

Isometric view

The image here on the right shows a

isometric view of the same pipe as on the

left.

As you can see, this drawing is very simple

and quick to implement. The red lines show

the pipe, the black dots are the butt welds

and A, B & C are the dimensions of front to

center line and center line to center line.

The simplicity with which a pipe isometric

can be drawn is one reason to made iso's.

A second reason to made isometrics; if a

pipe should be drawn in several planes

(north to south, then down and then to the

west, etc.), orthographic views really not an

option. In a orthographic view it is not a

problem if the pipe runs in one plane, but


when a pipe in two or three planes to be

drawn, a orthographic view can be unclear.

Another reason why isos are preferred, is

the number of drawings that for

orthographic views should be made.

For example: for a complex pipeline

system, 15 isometrics must be drawn. I've

never tried, but I think for orthographic

views maybe 50 drawings are needed to

show the same as the Iso's.

Isometric, Plan and Elevation Presentations

of a Piping System

The image below show the presentation used in drafting. The isometric view clearly show the

piping arrangement, but the plan view fails to show the bypass loop and valve, and the

supplementary elevation view is needed.


Isometric views in more than one plane

Below are some examples of isometric drawings. The auxiliary lines in the shape of a cube,

ensure better visualization of the pipeline routing.

The drawing on the left shows a pipeline which runs through three planes. The pipe line begins

and ends with a flange.

Routing starting point X

• pipe runs to the east

• pipe runs up

• pipe runs to the north

• pipe runs to the west

• pipe runs down


The drawing on the left is almost identical to the drawing above. A different perspective is

shown, and the pipe that comes from above is longer.

Because this pipe in isometric view, runs behind the other pipe, this must be indicated by a break

in the line.


• pipe runs to the south

• pipe runs up



• pipe runs down

The drawing on the left shows a pipe that runs through three planes and in two planes it make a

bow.



• pipe runs up

• pipe runs up and to the west

• pipe runs up


• pipe runs to the north-west



The drawing on the left shows a pipe that runs through three planes, from one plane to a opposite

plane.



• pipe runs up

• pipe runs up and to the north-west



Hatches on a Isometric Drawing

Hatches on isometric drawings being applied, to indicate that a pipe runs at a certain angle and in

which direction the pipe runs.

Sometimes, small changes in the hatch, the routing of a pipe is no longer the east, but for

example suddenly to the north.

The drawing on the left shows a pipe, where the hatch indicates that the middle leg runs to the

east.


• pipe runs up

• pipe runs up and to the east

• pipe runs up


The drawing on the left shows a pipe, where the hatch indicates that the middle leg runs to the

north.


• pipe runs up

• pipe runs up and to the north

• pipe runs up

The two drawings above show, that changing from only the hatch, a pipeline receives a different

direction. Hatches are particularly important in isometric views.


The drawing on the left shows a pipe, where the hatches indicates that the middle leg runs up and

to the north-west.


• pipe runs up

• pipe runs up and to the north-west


PART GENERAL

1. REFERENCES

1.3.1 American Petroleum Institute (API)

1. API 594 Wafer Check Valves 2. API 600 Steel Gate Valves, Flanged or Buttwelding Ends 3. API 602 Compact Carbon Steel Gate Valves 4. API 607 Fire Test for Soft-Seated Quarter Turn Valves 5. API 608 Metal Ball Valves 6. API 609 Butterfly Valves, Lug Type and Wafer Type

1.3.2 American Society of Mechanical Engineers (ASME)

1. ASME B31.3 Process Piping 2. ASME B1.20.1 Pipe Threads, General Purpose (inch) 3. ASME B16.5 Steel Pipe Flanges and Pipe Fittings 4. ASME B16.9 Wrought Steel Buttweld Fittings 5. ASME B16.10 Face-to-Face and End-to-End Dimensions Ferrous Valves 6. ASME B16.11 Forged Steel Fittings Socketwelding and Threaded 7. ASME B16.21 Nonmetallic Flat Gaskets for Pipe Flanges 8. ASME B16.25 Buttwelding Ends 9. ASME B16.34 Steel Valves - Flanged and Buttwelding Ends 10. ASME B16.36 Orifice Flanges 11. ASME B16.48 Steel Line Blanks 12. ASME B31.1 Power Piping 13. ASME B31.3 Chemical Plant and Petroleum Refinery Piping 14. ASME B36.10 Welded and Seamless Wrought Steel Pipe

1.3.3 Manufacturer Standard Society Practice (MSS)

1. MSS SP-25 MSS Standard Marking System for Valves, Fittings, Flanges and Unions 2. MSS SP-79 Socket-Welding Reducer Inserts 3. MSS SP-83 Class 3000 Steel Pipe Unions, Socket Welding and Threaded 4. MSS SP-95 Swage(d) Nipples and Bull Plugs 5. MSS SP-97 Integrally Reinforced Forged Branch Outlet Fittings - Socket Welding, Threaded and

Buttwelding Ends


1.3.4 Process Industry Practice (PIP)

1. PIP PNSM0001 Piping Line Class Designator System

PART 2 PRODUCTS

NPS DESCRIPTION NOTE CODE

PIPE:

1/2 - 2 ASTM A106-B CS SMLS PE XS/80

201322

2.1/2 -10 ASTM A53-B TYPE-E CS ERW BE STD/40 203270

12 - 24 ASTM A53-B TYPE-E CS ERW BE STD/0.375 203270

FITTINGS:

1/2 - 2 CAP ASTM A105 CS 3000 SW ASME B16.11 206799

1/2 - 2 COUPLING ASTM A105 CS 3000 SW ASME B16.11 207497

1/2 - 2 COUPLING RED ASTM A105 CS 3000 SW ASME B16.11 203384

1/2 - 2 ELL 45 ASTM A105 CS 3000 SW ASME B16.11 203385

1/2 - 2 ELL 90 ASTM A105 CS 3000 SW ASME B16.11 207091

1/2 - 2 INSERT SW RED ASTM A105 CS 3000 MSS SP-79 203383

1/2 - 2 TEE ASTM A105 CS 3000 SW ASME B16.11 207008

1/2 - 2 RED TEE ASTM A105 CS 3000 SW ASME B16.11 203386

1/2 - 2 UNION ASTM A105 CS 3000 SW MSS SP-83 207007

2.1/2 - 24 CAP ASTM A234-WPB CS BW STD ASME B16.9 203343

2.1/2 - 24 ELL 45 ASTM A234-WPB CS BW STD ASME B16.9 203344

2.1/2 - 24 ELL 90 LR ASTM A234-WPB CS BW STD ASME B16.9 203345

2.1/2 - 24 ELL 90 SR ASTM A234-WPB CS BW STD ASME B16.28 203346


2.1/2 - 24 RED CONC ASTM A234-WPB CS BW STD ASME B16.9 203347

2.1/2 - 24 RED ECC ASTM A234-WPB CS BW STD ASME B16.9 203348

2.1/2 - 24 TEE ASTM A234-WPB CS BW STD ASME B16.9 203349

2.1/2 - 24 TEE RED ASTM A234-WPB CS BW STD ASME B16.9 205300

O'LETS:

1/2 - 2 ELBOLET ASTM A105 CS 3000 SW MSS SP-97 205512

1/2 - 2 LATROLET ASTM A105 CS 3000 SW MSS SP-97 ...

1/2 - 2 SOCKOLET ASTM A105 CS 3000 SW MSS SP-97 203425

2.1/2 -6 WELDOLET ASTM A105 CS BW STD MSS SP-97 203405

SWAGES, NIPPLES, THREADED ITEMS:

1/2 - 1 NIPPLE PIPE TBE NPT ASTM A106-B CS XS 200151

1/2 - 1 NIPPLE PIPE POE-TOE NPT ASTM A106-B CS XS 05 203433

1/2 - 4 SWAGE NIPPLE CONC ASTM A234 WPB CS XS BLE-PSE MSS SP-95 207151

1/2 - 3 SWAGE NIPPLE CONC ASTM A234-WPB CS BBE XS MSS SP-95 203435

1/2 - 2 SWAGE NIPPLE ECC ASTM A234-WPB CS BBE XS MSS SP-95 205515

FITTINGS - THREADED:

1/2 - 2 BUSHING ASTM A105 CS NPT HEX ASME B16.11 05 203362

1/2 - 2 CAP ASTM A105 CS 3000 NPT ASME B16.11 05 200147

1/2 - 1 COUPLET (VOGT) ASTM A105 CS 6000 NPT 05 206998

1/2 - 2 COUPLING ASTM A105 CS 3000 NPT ASME B16.11 05 203363

1/2 - 2 COUPLING RED ASTM A105 CS 3000 NPT ASME B16.11 05 203364

1/2 - 2 CROSS ASTM A105 CS 2000 NPT ASME B16.11 05, 06 ...


1/2 - 2 ELL 45 ASTM A105 CS 2000 NPT ASME B16.11 05, 06 203366

1/2 - 2 ELL 90 ASTM A105 CS 2000 NPT ASME B16.11 05, 06 203367

1/2 - 2 PLUG ASTM A105 CS 3000 NPT HEX HD ASME B16.11 05 203371

1/2 - 2 TEE ASTM A105 CS 2000 NPT ASME B16.11 05, 06 203370

1/2 - 2 TEE RED ASTM A105 CS 3000 NPT ASME B16.11 05 203431

1/2 - 2 THREDOLET ASTM A105 CS 3000 NPT MSS SP-97 05 203422

1/2 - 2 UNION ASTM A105 CS 3000 NPT MSS SP-83 05 203372

FLANGES:

1/2 - 24 BLIND ASTM A105 CS ASME B16.5-150 RF 200153

1/2 - 24 FLANGE SO ASTM A105 CS ASME B16.5-150 RF 200158

1 - 2 FLANGE ORIFICE WN ASTM A105 CS ASME B16.36-300 RF XS 206424

2.1/2 - 6 FLANGE ORIFICE WN ASTM A105 CS ASME B16.36-300 RF STD 206425

FLANGES, ALTERNATES:

1/2 - 2 FLANGE THREAD NPT ASTM A105 CS ASME B16.5-150 RF 05 200155

1/2 - 2 FLANGE SW ASTM A105 CS ASME B16.5-150 RF ...

2.1/2 - 24 FLANGE WN ASTM A105 CS ASME B16.5-150 RF STD 03 205382

GASKETS:

1/2 - 24 FLAT RING ASME B16.5-150 F-PTFE 1/16 THK, ASME B16.21 TABLE 4 205867

1 - 6 FLAT RING ASME B16.5-300 F-PTFE 1/16 THK, ASME B16.21 TABLE 5 205815

BOLTING:

... STUD ASTM A193-B7 STL 200021

... NUT HEAVY HEX ASTM A194-2H STL 200029


MISCELLANEOUS:

1/2 - 24 SPACER LINE ASTM A516-70 CS 150 RF 14 205415

2 - 24 STRAINER TEMPORARY CONICAL CS 150 RF 18 205516

1/2 - 2 Y-STRAINER ASTM A105 CS 600 NPT SS SCREEN 05 ...

1 - 12 Y-STRAINER ASTM A216-WCB CS ASME B16.5-150 RF 205892

ITEM, NPS DESCRIPTION NOTE INDEX CODE

VALVES:

1/2 - 2 BALL ASTM A216-WCB CS 1000 SW 316 SS BALL FULL PORT

3-PC R-PTFE SEATS

23, 32,

34 206 206157

1/2 - 6 BALL ASTM A216 STL 150 RF PTFE SEATS, GRAPH PKG, Grounded

268 205020

3 - 14 BUTTERFLY LUG ASTM A216-WCB CS 150 RF, NPS 10 & >GEAR

PTFE SEATS & SEALS 31 204L 206257

1/2 - 2 CHECK H-LIFT ASTM A105 CS 800 SW GRAPH

228 200201

2.1/2 - 12 CHECK SWING ASTM A216-WCB CS 150 RF 34 215 205010

6 - 14 CHECK WAFER ASTM A216-WCB CS 150 W/ SPRING 22, 34 236 205553

1/2 - 2 GATE ASTM A105 CS 800 SW CR TR GRAPH

261 200206

3 - 14 GATE ASTM A216-WCB CS 150 BW STD HF NPS 14 & >GEAR GRAPH 24 240 200203

1/2 - 14 GATE ASTM A216-WCB CS 150 RF HF NPS 14 & >GEAR GRAPH

239 200202

1/2 - 2 GLOBE ASTM A105 CS 800 SW HF GRAPH

283 200210

3 - 12 GLOBE ASTM A216-WCB CS 150 RF HF GRAPH

272 205191

3 - 6 GLOBE ASTM A216-WCB CS 300 BW STD GRAPH 24 272C 205726

1 - 6 GLOBE 3-PORT ASTM A216-WCB CS 150 RF GRAPH 36 270K 208503

3 - 10 PLUG CI 150 RUBBER LINED ECCENTRIC PLUG LIMIT TO 180°F 33 195 205562


1/2 - 6 PLUG DUCTILE IRON 150 RF PTFE SLEEVE 34 180K 205062

1/2 - 8 PLUG (LOW EMISSION) D-IRON PTFE SLEEVE 150 RF 35 180 208521

Notes:

02 - Pipe Bending shall be used ONLY where specified on the drawings or where approved in writing by the EWP project engineer.

03 - Specify WN flanges adjacent to welded fittings and/or Butterfly Valves as alternates only. 05 - Threaded joints are permitted only at terminal of vent, drain, and hydrostatic test

connections, and at instrument take-off points, and to match equipment. 06 - EWP's TED site preference, class 2000 threaded FS fittings are made only in 45° and 90°

elbows, tees, and crosses. The class 2000 fittings are rated same as sch XS/80 (max) threaded pipe. Class 3000 fittings found in existing lines may be replaced by class 2000.

14 - Line blinds, spacers, restricting orifices, and spectacle blinds shall be per Standard Details Doc. No...01 thru 04.

18 - Conical Strainer to be used as temporary start-up strainer at pumps. 20 - Thread sealant to be used on all thread joints except if seal welding is used. Refer to

Specification Doc. No.... 22 - These Valves have no flanges but are installed between line flanges with extra length bolts. 23 - Cast Valves used in "critical service" or "very critical" service should be considered for

radiographic inspection. 24 - BW gate or globe is for alternate use. 25 - Reducing fittings that have ends of different thickness must show thickness (e.g., Conc. Red

- SCH XS x SCH STD). 31 - Butterfly Valves NPS 6 & smaller w/ handle; NPS 8 & larger w/ gear operator. Do not use

above 177°C service. 32 - Intended for orifice taps only.

33 - Doc. No... for slurry service.

34 - Valves with PTFE may be chosen for use in the OXO reactor loop piping. 35 - Valve Index 180 is alternate for 180K. 36 - May be used for Relief Valve changeover.

FABRICATION

A. See Specification Doc. No..., "Piping, General Fabrication," Specification Doc. No..., "Piping,

General Welding,"

Specification Doc. No..., "Piping, Carbon Steel Welding," and Specification Doc. No..., "Pipe

Weld Inspection & Testing."

INSTALLATION

A. See Specification Doc. No..., "Piping, General Installation"


TESTING

A. See Specification Doc. No..., "Piping, General Testing"

B. Vacuum Piping System: Apply Pneumatic Leak Test with internal pressure at 1.5 times the

maximum operating external pressure, or minimum 15 psig (103 kPag, 1.03 bar-g, 1.06 kgf/cm2)

C. Category D Piping System: Apply Initial Service Leak Test

D. Normal Service Piping System: Apply standard Hydrostatic Leak Test.

E. Category M Piping System: Apply both a standard Hydrostatic Leak Test & a Sensitive Leak

Test with helium tracer gas.

F. Maximum Hydrostatic Test Pressure: 413 psig (2848 kPag, 28.4 bar-g, 29.0 kgf/cm2)

CLEANING

A. See Specification Doc. No..., "Piping, General Cleaning"


90 DEGREE BRANCH TABLE

H

E

A

D

E

R

S

I

Z

E

N

P

S

1/2 T

3/4 V T

CONNECTION TYPE

1 V V T

1.1/2 V V V T

2 V V V V T

3 S S S S S T

4 S S S S S D T

6 S S S S S D D T

8 S S S S S U D D T

10 S S S S S U U D D T

12 S S S S S U U U D D T

14 S S S S S W W W P D D T

16 S S S S S W W W P P D D T

18 S S S S S W W W P P P D D T

20 S S S S S W W W P P P P D D T

24 S S S S S W W W P P P P P D D T

1/2 3/4 1 1.1/2 2 3 4 6 8 10 12 14 16 18 20 24

B R A N C H S I Z E S NPS

D = TEE & REDUCER

S = SOCKOLET

V = SW TEE W/ INSERT


E = REDUCING TEE

T = TEE

W = WELDOLET

P = REINFORCING PAD

U = UNREINF. STUB-IN

D or V may be substituted by E. S or W may be substituted by P (minimum pad width = 1"). P = Reinforcing pad with minimum thickness equal to header thickness, and width equal to 1/2

of the branch nominal pipe size. Drill 1/8" (3mm) diameter hole in each pad section for venting (a weld gap is acceptable as a means of venting).

END OF PIPE SPECIFICATION

Weld End Preparation at Unequal Wall Thicknesses

Acceptable Design in Piping components

In most piping systems there are components such as valves, castings, heavier header sections,

and equipment nozzles which are welded to the pipe.

In such instances the heavier sections are machined to match the lighter pipe wall and the excess

thickness tapered both internally and externally to form a transition zone.

Limits imposed by the various codes for this transition zone are fairly uniform.

The external surface of the heavier component is tapered at an angle of 30° maximum for a

minimum length equal to 1.1/2 times the pipe minimum wall thickness and then at 45° for a

minimum of 1.1/2 times the pipe minimum wall.

Internally, either a straight bore followed by a 30° slope or a taper bore at a maximum slope of 1

to 4 for a minimum distance of 2 times the pipe minimum wall are required.

The surface of the weld can also be tapered to accommodate differing thickness. This taper

should not exceed 30°. It may be necessary to deposit weld metal to assure that these limits are

not violated.

Below some tables with acceptable design for unequal wall thicknesses acc to ASME B31.8

Internal Offset


A

B

C

D

External Offset


E

F

Combination Offset

G

NOTE:

(1) No minimum when materials joined have equal specified minimum yield strengths.



Definition and Details of Flanges - Types of Flanges

Flange types

As already described before, the most used flange types acc. to ASME B16.5 are: Welding Neck,

Slip On, Socket Weld, Lap Joint, Threaded and Blind flange. Below you will find a short

description and definition of each type, completed with an detailed image.

Most common flange types

Welding Neck flange

Welding Neck Flanges are easy to recognize at the long tapered hub, that goes gradually over to

the wall thickness from a pipe or fitting.

The long tapered hub provides an important reinforcement for use in several applications

involving high pressure, sub-zero and / or elevated temperatures. The smooth transition from

flange thickness to pipe or fitting wall thickness effected by the taper is extremely beneficial,

under conditions of repeated bending, caused by line expansion or other variable forces.

These flanges are bored to match the inside diameter of the mating pipe or fitting so there will be

no restriction of product flow. This prevents turbulence at the joint and reduces erosion. They

also provide excellent stress distribution through the tapered hub and are easily radiographed for

flaw detection.

This flange type will be welded to a pipe or fitting with a single full penetration, V weld

(Buttweld).

Details of Welding Neck flange


1. Weld Neck flange 2. Butt Weld

3. Pipe or Fitting

Slip On flange

The calculated strength from a Slip On flange under internal pressure is of the order of two-thirds

that of Welding Neck flanges, and their life under fatigue is about one-third that of the latter.

The connection with the pipe is done with 2 fillet welds, as well at the outside as also at the

inside of the flange.

The X measure on the image, are approximately:

Wall thickness of pipe + 3 mm.

This space is necessary, to do not damage the flange face, during the welding process.

A disadvantage of the flange is, that principle always firstly a pipe must be welded and then just

a fitting. A combination of flange and elbow or flange and tee is not possible, because named

fittings have not a straight end, that complete slid in the Slip On flange.

Details of Slip On flange


1. Slip On flange 2. Filled weld outside

3. Filled weld inside 4. Pipe

Socket Weld flange

Socket Weld flanges were initially developed for use on small-size high pressure piping. Their

static strength is equal to Slip On flanges, but their fatigue strength 50% greater than double-

welded Slip On flanges.

The connection with the pipe is done with 1 fillet weld, at the outside of the flange. But before

welding, a space must be created between flange or fitting and pipe.

ASME B31.1 1998 127.3 Preparation for Welding (E) Socket Weld Assembly says:

In assembly of the joint before welding, the pipe or tube shall be inserted into the socket to the

maximum depth and then withdrawn approximately 1/16" (1.6 mm) away from contact between

the end of the pipe and the shoulder of the socket.

The purpose for the bottoming clearance in a Socket Weld is usually to reduce the residual stress

at the root of the weld that could occur during solidification of the weld metal. The image shows

you the X measure for the expansion gap.

The disadvantage of this flange is right the gap, that must be made. By corrosive products, and

mainly in stainless steel pipe systems, the crack between pipe and flange can give corrosion

problems. In some processes this flange is also not allowed. I am not an expert in this matter, but

on the internet, you will find a lot of information about forms of corrosion.

Also for this flange counts, that principle always firstly a pipe must be welded and then just a

fitting.


Details of Socket Weld Flange

1. Socket Weld flange 2. Filled weld 3. Pipe

X = Expansion gap

Lap Joint flange

Lap Joint Flanges have all the same common dimensions as any other flange named on this page

however it does not have a raised face, they used in conjunction with a "Lap Joint Stub End".

These flanges are nearly identical to a Slip On flange with the exception of a radius at the

intersection of the flange face and the bore to accommodate the flanged portion of the Stub End.

Their pressure-holding ability is little, if any, better than that of Slip On flanges and the fatigue

life for the assembly is only one tenth that of Welding Neck flanges.

They may be used at all pressures and are available in a full size range. These flanges slip over

the pipe, and are not welded or otherwise fastened to it. Bolting pressure is transmitted to the

gasket by the pressure of the flange against the back of the pipe lap (Stub End).

Lap Joint flanges have certain special advantages:

Freedom to swivel around the pipe facilitates the lining up of opposing flange bolt holes. Lack of contact with the fluid in the pipe often permits the use of inexpensive carbon steel

flanges with corrosion resistant pipe. In systems which erode or corrode quickly, the flanges may be salvaged for re-use.


Details of Lap Joint Flange

1. Lap Joint flange 2. Stub End

3. Butt weld 4. Pipe or Fitting

Stub End

A Stub End always will be used with a Lap Joint flange, as a backing flange.

This flange connections are applied, in low-pressure and non critical applications, and is a cheap

method of flanging.

In a stainless steel pipe system, for example, a carbon steel flange can be applied, because they

are not come in contact with the product in the pipe.

Stub Ends are available in almost all pipe diameters. Dimensions and dimensional tolerances are

defined in the ASME B.16.9 standard. Light-weight corrosion resistant Stub Ends (fittings) are

defined in MSS SP43.

Lap Joint Flange with a Stub End


Threaded flange

Threaded Flanges are used for special circumstances with their main advantage being that they

can be attached to the pipe without welding. Sometimes a seal weld is also used in conjunction

with the threaded connection.

Although still available in most sizes and pressure ratings, screwed fittings today are used almost

exclusively in smaller pipe sizes.

A threaded flange or fitting is not suitable for a pipe system with thin wall thickness, because

cutting thread on a pipe is not possible. Thus, thicker wall thickness must be chosen...what is

thicker ?

ASME B31.3 Piping Guide says:

Where steel pipe is threaded and used for steam service above 250 psi or for water service above

100 psi with water temperatures above 220° F, the pipe shall be seamless and have a thickness

at least equal to schedule 80 of ASME B36.10.

Details of Threaded flange

1. Threaded flange 2. Thread 3. Pipe or Fitting

Blind flange

Blind Flanges are manufactured without a bore and used to blank off the ends of piping, Valves

and pressure vessel openings.

From the standpoint of internal pressure and bolt loading, blind flanges, particularly in the larger

sizes, are the most highly stressed flange types.

However, most of these stresses are bending types near the center, and since there is no standard

inside diameter, these flanges are suitable for higher pressure temperature applications.


Details of Blind flange

1. Blind flange 2. Stud Bolt 3. Gasket 4. Other flange

Remark(s) of the Author...

A simple manner to make a 1/16" Gap...

Have you ever seen a Socket Weld contraction ring ?. It is a split ring that is engineered and designed to give a pre-measured 1/16" minimum gap for socket welds. Made from a certified stainless steel, and resists corrosion from chemicals, radioactive materials and water. Once inserted into the fitting the ring becomes a permanent part of the joint. It will not rattle or vibrate even under extreme pressure. Another manner is the applying of in water-soluble board. Make rings with a hole punch with outside and inside diameter of the pipe. Insert the ring into the flange or fitting and after hydrotesting there is no ring anymore. For both solutions, ask your customer for permission.

Hold them on its place...

If a Lap Joint flanged connection must be disassembled, for example to replace a gasket, it is not always possible to do that on the conventional manner. The conventional manner is the use of a flange spreader or crowbar that pushed off the two flanges. By Lap Joint flanges that is not possible, because these slide back over the pipe, while the Stub Ends stay together. To prevent that, often are on 3 places, single millimeters behind the flange, on the Stub End, short pieces flat steel, will be welded.


There is no general rule how a Lap Joint flange must be hold on its place, and therefore it can deviate per customer specification.

You knew that...?

At the smallest sizes, the amount of wall lost during threading actually equals approximately 55% of the original pipe wall.

Butt welds vs Fillet welds

In systems with relatively high pressures and temperatures, we need to avoid the use of fillet welds. Butt welds, in such systems must be used. The strength of a butt weld is at least the strength of the base material. The strength of fillet welds related to the strength of the butt weld, is about one third. At higher pressures and temperatures, the expansion and contraction caused fast for serious cracks in fillet welds and therefore the use of butt welds is essential. For conduits to critical machinery such as pumps, compressors and turbines, which are exposed to vibration (in addition to the expansion and contraction), we should avoid the use of fillet welds or threaded connections. Fillet welds have a higher sensitivity to cracks due to stress concentration, while butt welds are characterized by smooth exchange of tensions. So, for critical situations, we have to use flanges connected by butt welding like as weld neck and ring type joint, and avoid using flanges connected by fillet welds like slip-on or Socket Weld.

All Flange Bolt Holes Straddle the Centerlines

That means: For a vertical flange face (the flange face in the vertical and the line is horizontal) the bolt

holes want to be orientated to straddle the vertical and horizontal centerlines.


Correct vertical flange position...


Incorrect vertical flange position...DO NOT !

For a horizontal flange face (the flange face is horizontal and the line is vertical above or

vertical down) the bolt holes want to be orientated to straddle the Plant North centerlines.

See below on this page, a image of a plant north situation.


Correct horizontal flange position...

Incorrect horizontal flange position...DO NOT !

It is very important, that is not deviated from the standard bolt hole orientation. Only on

explicit request, e.g. of the customer, may be a different orientation be applied. In 99

percent of all cases, where you will see a different orientation, you can assume that it is a

mistake. This centerline rule for flanges, understood and followed by all responsible

equipment manufacturers and piping fabricators.


Plant North A plant north, is a horizontal reference point, and is derived from an official geographical

reference point. A plant north is applied...see more about plant coordinates in the main

Menu "Docs" Dimensioning from Reference Points.

1 = Official reference point

2 = South West angle of new plant

X = East West distance from new plant to reference point

Y = North South distance from new plant to reference point Definition and details of O'let Branch Connections

Branch Connection Fittings general Branch Connection fittings (also known as O'lets) are fittings which provide an outlet

from a larger pipe to a smaller one (or one of the same size). The main pipe onto which

the branch connection is welded is usually called the Run or Header size. The pipe to

which the branch connection provides a channel is usually called the Branch or Outlet

size. Branch connections are in all sizes, types, bores, and classes, in a wide range of

stainless steel, chrome-moly, and other alloys.

Perhaps you know, Bonney Forge has been supplying quality branch fittings (O'lets) for

many years. In 1943 when Bonney Forge pioneered the "Shape of Reinforcement" for

branch connections, who would have thought it would fast become a recognized industry

standard. Today, Bonney Forge Branch Connections offer complete run pipe

reinforcement while avoiding cracks, fillet welds, and sharp re-entrant corner

reinforcement tapering at the sides, thus preventing abrupt changes in thickness where the

fitting joins the header pipe.

Bonney Forge fittings meeting the 100% reinforcement requirement of applicable piping

codes i.e. ASME B31.1, B31.3, B31.4 and B31.8. They also meet the 2001 edition of

MSS-SP-97 Standard- "Integrally Reinforced Forged Branch Outlet Fittings".


Types of Branch Connection Fittings

Weldolet® is the most common of all branch connections, and is welded onto the

outlet pipe. The ends are bevelled to facilitate this process, and therefore the weldolet

is considered a butt-weld fitting. Weldolet's are designed to minimize stress

concentrations and provide integral reinforcement.

Sockolet® utilizes the basic Weldolet® however the branch affixes by way of a socket

inside the olet. The bore matches the outlet bore, and the existence of a counter bore

roughly the size of the OD of the outlet provides a socket where the pipe can sit,

facilitating installation and welding. The Sockolet® is considered a socket fitting, and

manufactured in 3000#, 6000# and 9000# classes.

Thredolet® utilizes the basic Weldolet® however the branch affixes by way of a thread

just inside the top of the olet. The bore matches the outlet bore, and the existence of

this threading facilitates installation, as no welding is necessary. The Thredolet® is

considered a threaded fitting, andmanufactured in 3000# and 6000# classes.

Latrolet®, used for 45° lateral connections, is available butt-weld to meet specific

reinforcement requirements, and 3000# or 6000# classes for Socket Weld and

threaded applications.

Elbolet® is used on 90° Long Radius Elbows (can be manufactured for Short Radius

Elbows) for thermowell and instrumentation connections. Available butt-weld to meet

specific reinforcement requirements, and 3000# and 6000# classes for Socket Weld

and threaded applications.

Nipolet® is a one piece fitting for valve take-offs, drains and vents. Manufactured for

Extra Strong and Double Extra Strong applications in 3.1/2in to 6.1/2in lengths.

Available with male-socket-weld or male threaded outlets.


Sweepolet® is a contoured, integrally reinforced, butt-weld branch connection with a

low stress intensification factor for low stresses and long fatigue life. The attachment

weld is easily examined by radiography, ultrasound and other standard non-

destructive techniques. Manufactured to meet your specific reinforcement

requirements.

Specifying the Schedule of both the Run

and Branch Generally the schedules of the run pipe and branch pipe are identical and thus

specification of the equivalent schedule Weldolet assures the proper fitting being used.

Example: 16" Standard weight x 6" Standard weight is specified as a 6" standard weight fitting.

Where the schedule of the run is greater or less than the schedule of the branch, it is

essential that both schedules be specified since (a) The Weldolet's reinforcing

characteristics are a function of the run pipe wall thickness, which in turn designates the

schedule of the basic Weldolet® fitting to be used;(b) The wall thickness of the outlet or

branch end must match the wall thickness of the branch pipe.

Example: 16" Extra strong x 6" Standard weight

16" Standard weight x 6" Extra strong

Special care is suggested to avoid confusing schedule 40 and standard weight as being

identical (above 10" schedule 40 is heavier) and schedule 80 and extra strong (above 8"

schedule 80 is heavier).

Example: 8" Schedule 80 x 4" Schedule 80 fitting or extra strong fitting.18" Schedule 80 x 4"

Schedule 80 is a considerably heavier fitting, because the reinforcement is for 18"

schedule 80 pipe with a wall thickness of approximately 1".

The Weldolet® is available in standard code designs for all combinations of run wall

thicknesses up through 3.1/2" thickness and branch wall thicknesses up through double

extra strong. Designs for thicknesses greater than these can be developed on request.

Remark(s) of the Author... Make sure that the supplier has a design approval for the fitting (there are many small

outfits out there making their own fittings without any documentation)

Try the site of Bonney Forge. They have all the dimensions and you'll be sure the fittings

have a design approval. It seems that the dimensions specified in MSS SP-97, based on

Bonney Forge.

Weldolet, Sockolet, Thredolet, Latrolet, Elbolet, Nipolet, Sweepolet are trademarks

registered ® for the exclusive use of Bonney Forge.

Bolts & Nuts for flanged connections

http://www.bonneyforge.com/


Types of Bolts

In Petro and chemical industry for flange connections Stud Bolts and Hex Bolts are used. The

Stud Bolt is a threaded rod with 2 heavy hexagon nuts, while the Hex Bolt has a head with one

nut. Nuts and head are both six sided.

Stud Bolts general

The quantity of bolts for a flange connection will be given by the number of bolt holes in a

flange, diameter and length of bolts is dependent of flange type and Pressure Class of flange.

Stud Bolt length are defined in ASME B16.5 standard. The length in inches is equal to the

effective thread length measured parallel to the axis, from the first to the first thread without the

chamfers (points). First thread is defined as the intersection of the major diameter of the thread

with the base of the point.


Notes:

The length of metric Stud Bolts measured parallel to axis, is the distance from each Stud Bolt, including the point.

To allow the use of hydraulic tensioning equipment, larger dimension studs shall be often one diameter longer than "standard". That bolts to have plastic end cap protection.

Threads of Stud Bolts

Bolts threading are defined in ASME B1.1 Unified Inch Screw Threads, (UN and UNR Thread

Form). The most common thread is a symmetrical form with a V-profile. The included angle is

60°. This form is widely used in the Unified thread (UN, UNC, UNF, UNRC, UNRF) form as

the ISO / metric threads.

The advantage of a symmetrical threads is that they are easier to produce and inspect compared

with non-symmetrical threads. These are typically used in general-purpose fasteners.

Thread series cover designations of diameter/pitch combinations that are measured by the

number of threads per inch (TPI) applied to a single diameter.

Standard Thread Pitches

Coarse thread series (UNC/UNRC) is the most widely used thread system and applied in most of the screws, bolts and nuts. Coarse threads are used for threads in low strength materials such as iron, mild steel, copper and softer alloy, aluminium, etc.. The coarse thread is also more tolerant in adverse conditions and facilitate quick assembly.

Fine thread series (UNF/UNRF) is commonly used in precision applications and in there where require a higher tensile strength than the coarse thread series.

8 - Thread series (8UN) is the specified thread forming method for several ASTM standards including A193 B7, A193 B8/B8M, and A320. This series is mostly used for diameters one inch and above.


Hex Nuts

Hex nuts (dimensional data) are defined in ASME B18.2.2, and even as bolts the threading in

ASME B1.1. Depending on a customer specification, nuts must be both sites chamfered or with

on one side a washer-face.

Dimensions of above mentioned nuts, can be found on page Heavy Hex Nuts of this website.

Note: the height of a nut for Stud Bolts are the same as the diameter of the thread rod.

Materials for Stud Bolts

Dimensions from Stud Bolts are defined in the ASME B16.5 standard. The material qualities for

studs are defined in the different ASTM standards, and are indicated by Grade. Frequently used

grades are A193 for thread rods and A194 for the nuts.

ASTM A193 covers alloy and stainless steel bolting material for pressure vessels, Valves,

flanges, and fittings for high temperature or high pressure service, or other special purpose

applications.

ASTM A194 covers a variety of carbon, alloy, and martensitic and austenitic stainless steel nuts.

These nuts are intended for high-pressure or high-temperature service, or both.

Below you will find as an example a table with materials and grades for flanges, thread rods

(bolts) and nuts, arranged on design temperature, flanges, thread rods and recommended nuts.

DESIGN

TEMPERATURE FLANGES

GRADE

THREAD RODS

GRADE

NUTS

-195° to 102°C

ASTM A 182

Gr. F304, F304L, F316,

F316L, F321, F347

A320 Gr. B8 Class 2 A194 Gr. 8A

http://www.wermac.org/bolts/dimensions_heavy-hex-nuts_asme-B18-2-2_used-with-stud-bolts-asme-B16-5.html


-101° to -47°C ASTM A 350

Gr. LF3 A 320 Gr. L7 A 194 Gr. 7

-46° to -30°C ASTM A 350

Gr. LF2 A 320 Gr. L7 A 194 Gr. 7

-29° to 427°C ASTM A 105 A 193 Gr. B7 A 194 Gr. 2H

428° to 537°C ASTM A 182

Gr. F11, F22 A 193 Gr. B16 A 194 Gr. 2H

538° to 648°C ASTM A182

Gr. F11, F22 A 193 Gr. B8 Class 1 A 194 Gr. 8A

649° to 815°C ASTM A182

Gr. F304 H, F316 H A 193 Gr. B8 Class 1 A 194 Gr. 8A

DESIGN

TEMPERATURE FLANGES

GRADE

THREAD RODS

GRADE

NUTS

Note: Materials in the table above are being provided for guidance purposes

Marking of Stud Bolts

Thread rods and nuts must be marked by the manufacturer with a unique identifier to identify the

manufacturer or private label distributor, as appropriate. Below a number of ASTM examples.

Remark(s) of the Author...

Improper Flange Connections - the Bolts are too short!

What can you do?


The picture show a improperly bolted flange, because two bolts are too short, and the nuts are not completely on the bolts. This means that the joint may not be as strong as it should be. Flanges are designed so that the entire nut-bolt combination holds the forces on the flange. If the nut is only partially screwed onto the bolt, the connection may not be strong enough.

If your job includes putting equipment together, assembling flanged pipe, bolting manhole covers or other bolted connections on equipment, or other equipment assembly, remember that the job is not complete until all of the bolts are properly installed and tightened.

Some equipment requires special bolt tightening procedures. For example, you may have to use a torque wrench to correctly tighten the bolts to the specification, or tighten the bolts in a special order. Make sure that you follow the correct procedure, use the correct tools, and that you are properly trained in the equipment assembly procedure.

Check pipes and equipment for properly bolted flanges as part of your plant safety inspections. As simple guidance, bolts that do not extend beyond the nuts should be reviewed by a plant piping craftsman or engineer.

If you observe improperly bolted flanges in your plant, report them so they can be repaired, and make sure the required repairs are completed.

Inspect new equipment, or equipment which has been re-assembled after maintenance, to make sure it is correctly assembled and properly bolted before starting up.


What is the proper length of a Stud Bolt? As a rule, you can use:

The free threads of the bolt above the top of the nut is equals to 1/3 times the bolt diameter.

Expansion Joints (Bellows) in Piping Systems

www.maxflexindustrial.com


What are Expansion Joints?

Expansion joints are used in piping systems to absorb thermal expansion or terminal movement

where the use of expansion loops is undesirable or impractical. Expansion joints are available in

many different shapes and materials.

Bellow you will find a short description of Metallic, Rubber and Teflon® joints.

Metallic Expansion Joints

Metallic Expansion Joints are installed in pipe work and duct systems to prevent damage caused

by thermal growth, vibration, pressure thrust and other mechanical forces.

There is a wide range of metallic bellows designs in a variety of materials. Options range from

the simplest convoluted bellows used in petroleum refineries.

Materials include all types of stainless steels and high grade nickel alloy steels.

Any pipe connecting two points is subjected to numerous types of action which result in stresses

on the pipe. Some of the causes of these stresses are:

internal or external pressure at working temperature

weight of the pipe it self and the parts supported on it

movement imposed on pipe sections by external restraints

thermal expansion

Rubber Expansion Joints

Rubber Expansion Joints are a flexible connector fabricated from natural or synthetic elastomers

and fabrics with metallic reinforcements designed to provide stress relief in piping systems due

to thermal changes.

When flexibility for this movement cannot be designed into the piping system itself, an

expansion joint is the ideal solution. Rubber expansion joints compensate for lateral, torsional

and angular movements preventing damage and undue downtime of plant operations.

The special construction of the rubber joints can solve problems like:

Vibration, Noise, Shock, Corrosion, Abrasion

Stresses, Load Stress, Equipment Movement

Vibration, Pressure Pulsation and Movement in a Piping System


Teflon® Expansion Joints

Teflon® Expansion Joints corrosion proof, non-aging with extraordinary flex life and unmatched

reliability.

The Teflon® expansion joint has a widespread acceptance in the chemical processing industry,

piping applications where acids and highly corrosive chemicals are being handled and

commercial heating and air conditioning systems as pump connectors and a strategic point

throughout a system.

They can be used to compensate for:

• Movement, Misalignment, Axial Travel

• Angular Deflection, and or Vibration in Piping Systems

The Expansion Joint Manufacturers

Association, Inc.

The Expansion Joint Manufacturers Association, Inc. is an organization of established

manufacturers of metal bellows type expansion joints.

EJMA was founded in 1955 to establish and maintain quality design and manufacturing

standards. These Standards combine the knowledge and experience of the association's Technical

Committee and are available to assist users, designers, and others in the selection and application

of expansion joints for safe and reliable piping and vessel installation.

EJMA members are experienced and knowledgeable manufacturers that have demonstrated

many years of reliable service to industry. As reputable manufacturers, EJMA members are the

best source for product value, design, and service.

EJMA carries out extensive technical research and testing on many important aspects of

expansion joint design and manufacturing.


Rubber Expansion Joint in practice

Introduction to Hot Tapping & Line Stopping



What is a Hot Tap and why it is made?

Hot Taps or Hot Tapping is the ability to safely tie into a pressurized system, by drilling or

cutting, while it is on stream and under pressure.

Typical connections consist:

Tapping fittings like Weldolet®, Reinforced Branch or Split Tee.

Split Tees often to be used as branch and main pipe has the same diameters.

Isolation Valve like gate or Ball Valve.

Hot tapping machine which includes the cutter, and housing.

Mechanical fittings may be used for making hot taps on pipelines and mains provided they are

designed for the operating pressure of the pipeline or main, and are suitable for the purpose.

Design: ANSI B31.1, B31.3, ANSI B31.4 & B31.8, ASME Sec. VIII Div.1 & 2

Fabrication: ASME Sec. VIII Div.1

Welding: ASME Sec. IX

NDT: ASME Sec. V

There are many reasons to made a Hot Tap. While is preferred to install nozzles during a

turnaround, installing a nozzle with equipment in operation is sometimes advantageous,

especially if it averts a costly shut down.

Remarks before made a Hot Tap

A hot tap shall not be considered a routine procedure, but shall be used only when there is

no practical alternative.

Hot Taps shall be installed by trained and experienced crews.

It should be noted that hot tapping of sour gas lines presents special health and

metallurgical concerns and shall be done only to written operating company approved

plans.

For each hottap shall be ensured that the pipe that is drilled or sawed has sufficient wall

thickness, which can be measured with ultrasonic thickness gauges. The existing pipe

wall thickness (actual) needs to be at least equal to the required thickness for pressure

plus a reasonable thickness allowance for welding. If the actual thickness is barely more

than that required for pressure, then loss of containment at the weld pool is a risk.

Welding on in-service pipelines requires weld procedure development and qualification,

as well as a highly trained workforce to ensure integrity of welds when pipelines are

operating at full pressure and under full flow conditions.


Hot Tap setup

For a hot tap, there are three key components necessary to safely drill into a pipe; the fitting, the

Valve, and the hot tap machine. The fitting is attached to the pipe, mostly by welding.

In many cases, the fitting is a Weldolet® where a flange is welded, or a split tee with a flanged

outlet (see image above).

Onto this fitting, a Valve is attached, and the hot tap machine is attached to the Valve (see

images on the right). For hot taps, new Stud Bolts, gaskets and a new Valve should always be

used when that components will become part of the permanent facilities and equipment.

The fitting/Valve combination, is attached to the pipe, and is normally pressure tested. The

pressure test is very important, so as to make sure that there are no structural problems with the

fitting, and so that there are no leaks in the welds.

The hot tap cutter, is a specialized type of hole saw, with a pilot bit in the middle, mounted inside

of a hot tap adapter housing.

The hot tap cutter is attached to a cutter holder, with the pilot bit, and is attached to the working

end of the hot tap machine, so that it fits into the inside of the tapping adapter.

The tapping adapter will contain the pressure of the pipe system, while the pipe is being cut, it

houses the cutter, and cutter holder, and bolts to the Valve.


Hot Tap operation

Split Tee (www.armorplateonline.com)

The Hot Tap is made in one continuous process, the machine is started, and the cut continues,

until the cutter passes through the pipe wall, resulting in the removal of a section of pipe, known

as the "coupon".

The coupon is normally retained on one or more u-wires, which are attached to the pilot bit.

Once the cutter has cut through the pipe, the hot tap machine is stopped, the cutter is retracted

into the hot tap adapter, and the Valve is closed.

Pressure is bled off from the inside of the Tapping Adapter, so that the hot tap machine can be

removed from the line. The machine is removed from the line, and the new service is established.

Hot Tap Coupon

The Coupon, is the section of pipe that is removed, to establish service. It is very highly desirable

to "retain" the coupon, and remove it from the pipe, and in the vast majority of hot taps, this is

the case.

Please note, short of not performing the hot tap, there is no way to absolutely guarantee that the

coupon will not be "dropped".

Coupon retention is mostly the "job" of the u-wires. These are wires which run through the pilot

bit, and are cut and bent, so that they can fold back against the bit, into a relief area milled into

the bit, and then fold out, when the pilot bit has cut through the pipe.

In almost all cases, multiple u-wires are used, to act as insurance against losing the coupon.


Line Stopping

Line Stops, sometimes called Stopples (Stopple® is a trademark of TD Williamson Company)

start with a hot tap, but are intended to stop the flow in the pipe.

Line Stops are of necessity, somewhat more complicated than normal hot taps, but they start out

in much the same way. A fitting is attached to the pipe, a hot tap is performed as previously

detailed. Once the hot tap has been completed, the Valve is closed, then another machine, known

as a line stop actuator is installed on the pipe.

The line stop actuator is used to insert a plugging head into the pipe, the most common type

being a pivot head mechanism. Line stops are used to replace Valves, fittings and other

equipment. Once the job is done, pressure is equalized, and the line stop head is removed.

The Line Stop Fitting has a specially modified flange, which includes a special plug, that allows

for removal of the Valve. There are several different designs for these flanges, but they all work

pretty much the same, the plug is inserted into the flange through the Valve, it is securely locked

in place, with the result that the pressure can be bled off of the housing and Valve, the Valve can

then be removed, and the flange blinded off.

Line Stop setup

The Line Stop Setup includes the hot tap machine, plus an additional piece of equipment, a line

stop actuator. The Line Stop Actuator can be either mechanical (screw type), or hydraulic, it is

used, to place the line stop head into the line, therefore stopping the flow in the line.

The Line Stop Actuator is bolted to a Line Stop Housing, which has to be long enough to include

the line stop head (pivot head, or folding head), so that the Line Stop Actuator, and Housing, can

be bolted to the line stop Valve.

Line stops often utilize special Valves, called Sandwich Valves.

Line Stops are normally performed through rental Valves, owned by the service company who

performs the work, once the work is completed, the fitting will remain on the pipe, but the Valve

and all other equipment is removed.

Line Stop operation

A Line Stop starts out the same way as does a Hot Tap, but a larger cutter is used,.

The larger hole in the pipe, allows the line stop head to fit into the pipe.

Once the cut is made, the Valve is closed the hot tap machine is removed from the line, and a

line stop actuator is bolted into place.

New gaskets are always to be used for every setup, but "used" studs and nuts are often used,

because this operation is a temporary operation, the Valve, machine, and actuator are removed at

the end of the job.

New studs, nuts, and gaskets should be used on the final completion, when a blind flange is

installed outside of the completion plug.

The line stop actuator is operated, to push the plugging head (line stop head), down, into the


pipe, the common pivot head, will pivot in the direction of the flow, and form a stop, thus

stopping the flow in the pipe.

Completion Plug

In order to remove the Valve used for line stop operations, a completion plug is set into the line

stop fitting flange (Completion Flange).

There are several different types of completion flange/plug sets, but they all operate in basically

the same manner, the completion plug and flange are manufactured, so as to allow the flange, to

accept and lock into place, a completion plug.

This completion plug is set below the Valve, once set, pressure above the plug can be bled off,

and the Valve can then be removed.

Once the plug has been properly positioned, it is locked into place with the lock ring segments,

this prevents plug movement, with the o-ring becoming the primary seal.

Several different types of completion plugs have been developed with metal to metal seals, in

addition to the o-ring seal.

Line Stopping

Procedure

All following images are from

Furmanite.

They are a little matched to the

style

of this website requirements.




Source: partially from CEEJ Publishing's and Furmanite.

Documents

Prepared Khalil