Piping Fabrication Procedure

Piping Fabrication Procedure:

1. Marking shall be done according to drawing requirement and the same shall be checked by concerned supervisor prior to cutting.
2. The cutting shall be generally done as follows:

                                          i.    Carbon Steel pipes          -          By gas cutting & grinding.

                                        ii.    Alloy Steel pipes              -          By grinding or flammable cutting.

                                       iii.    Stainless Steel Pipes       -          By grinding or plasma cutting.

3. Before cutting the pipe Heat Number will be transferred to the cut pieces by low stress dye stamping, Paint marking or Tagging.
4. End preparation and fit-up shall be done at shop as per the approved Specification and WPS.
5. Care shall be taken to make sure that longitudinal seams on the joining pipes will not come in one line in a butt joint. Seams will be staggered at least 100mm apart and also will clear the branch connections. Care shall be taken to make sure that longitudinal seams are not resting on the steel structure.
6. Pipes and Fittings for fit-up will be placed on temporary pipe bed and will make sure that supports are secured properly.
7. Welding of the joint will be done after getting QC fit-up Inspection clearance and the same shall be offered for Client inspection randomly.
8. All flange connected to equipment shall be tack welded only.
9. Line No, Component Heat No., Joint No., Fit-up inspection signature, Welder No., Visual inspection signature and date of welding will be marked near to the joint with metal paint marker.
10. Spool No. will be marked with paint marker and aluminum tag will be tied to the spool. Fabrication completed spools will be shifted from shop to lay down area.
11. NDT shall be performed as required by Project specification. After NDT clearance, spools shall be released for erection / painting with release notice.
12. NDT rejected spools will be identified with yellow I black tag and the repair will be done immediately and NDT will be executed on repaired weld areas as required.
13. After painting, field inspection shall be offered for QC and the same shall be QC recorded in the prescribed format.
14. After painting inspection, the spool shall be released for erection.
15. Stainless Steel fabrication will be done in the shop with an isolated area from carbon steel and alloy steel.
16. No tools, tackles, equipment will be used for SS which has been used for CS. All tools and equipment dedicated to SS work shall be clearly marked "For Stainless Steel" only.
17. For Stainless steel materials, stainless steels tools will be used for grinding, brushing and clamping etc.
18. Pre heating and PWHT will be done at shop and field as per specification requirements.
19. All flanged raised faces of completed spools will be fitted with plywood blinds for protection and spool ends shall be fitted with proper caps         

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Fire Protection System in Plants

Fire Protection System in Plants:

Fire protection systems are unique in that the majority of their service life is spent in a static, no-flow condition. However, when required to operate in an emergency, fire protection systems can be critically important to the safety of building occupants, the protection of property, and the continued operation of a facility for these reasons, the piping associated with fire protection system must be designed to minimize service interruptions and be capable of operating reliably over an extended period of time.

To ensure that fire protection systems are reliable, building & insurance authorities require that they be constructed in accordance with nationally recognized standards. Federal regulations or locally adopted requirements may also be applicable.

Fire protection piping deals with the network of distribution piping that delivers fire extinguishing agents. Fire protection piping’s are designed both above ground system piping and underground water supply

TYPES OF FIRE SUPPRESSION SYSTEMS

1.     AUTOMATIC SPRINKLER SYSTEM

2.     GASEOUS FIRE SUPPRESSION SYSTEMS

3.     FOAM FIRE SUPPRESSION SYSTEM

4.     CHEMICAL EXTINGUISHING SYSTEM

5.     WATER MIST SYSTEM

6.     STANDPIPE SYSTEM

7.     HYDRANT SYSTEM AND WATER SUPPLIES

Piping Isometric Drawings

Piping Isometric Drawings:

Piping isometrics are three dimensional representations on a drawing sheet. An isometric drawing covers a complete line as per the line list connecting one piece of equipment to another. It should show all information necessary for the fabrication and erection. ISO are not drawn to scale but should be proportional for easy understanding. Dimensions are given relative to center line of piping.

Should include the following

1.    Plant north

2.    Dimensions & angles

3.    Ref number of P&ID, GA drawings, line numbers, direction of flow, insulation and tracing.

4.    Equipment location and equipment identification.

5.    Nozzle identification on the connected equipment.

6.    Size and type of valve / direction of operation.

7.    Size and number of control valve

8.    Location & orientation and number of each equipment.

9.    Field weld

10. Location of high point vents & low point drains

11. Bill of material

12. Requirements of stress relieving seal welding, pickling, coating, etc.

Pipe Supports

 SUPPORTING ELEMENTS:


ANCHOR:

A special supporting device for restraining  pipes in position and direction to permit the control of pipe movement which occurs due to thermal expansion.


CLEVIS PIPE CLAMP:

A pipe supporting device used only for non-insulated pipes.


CONSTANT LOAD SUPPORT:

A spring loaded support designed to enable the load on the pipe to be constant and balanced regardless of the vertical movement that may take place.


GUIDE:

A device for ensuring a pipe is restrained from moving in a direction (or) plane other than that warranted by ideal design conditions.

HANGER:

                           

A method of supporting pipe work from a structure above, usually maintaining the pipe work at a designed level but allowing limited axial and sometimes, lateral movement.

RESTRAINT:

A (pipe work) supporting device that partially (or) totally restricts movement in one (or) more directions.

ROLLER SUPPORT:

A roller, on which the pipe rests, permitting axial movement in a horizontal plane.

SLIDER SUPPORT:

A special pipe support designed to permit longitudinal movement of the pipe work in a horizontal plane.

SPRING HANGER:

A pipe support designed to counteract differing positions as a result of the varying conditions to which the piping is subjected.

STANCHION:

 

A structural steel member whose main function is to withstand axial compressive stresses.

TRESTLE:

A structural steel frame usually designed to carry a bank of pipes above ground level

TRUNNION:

A tubular piece of steel welded to the side of a pipe to enable the latter to be supported.

TURN BUCKLE:

A device for providing axial adjustment for pipe hanger rods – adjustment is achieved by the turn buckle having right and left handed threads.

SHOE:

A metal piece attached to the under side of a pipe which rests on supporting steel.  Primarily used to reduce wear from sliding for lines subject to movement.  Permits insulation to be applied to pipe.


 

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Base Material chemical Analysis, Electrode and Filler Wire for Various Welding Process

BOLT TORQUE VALUE

Bolt Torque value designed according to AISC Design guide Chapter 4, Section 4.3 (Second Edition 2001)

Note:
Tightening tools shall be calibrated by using Skid more tension calibrator on daily basis for all size bolts.
A Minimum of 3 bolts of each diameter must be tightened at least once each working day in a calibrating device capable of indicating actual bolt pretension.
The average bolt pretension variation is ±10% in general (This variance due to thread conditions, surface conditions under the nut and lubrication).
The impact wrench should be calibrated a minimum of 5% greater than the required bolt pretension.
After torquing, the bolt tip should be marked.

Parts of Weld Joints

Common Pipe fittings

Take off formula for Thread fittings