History of piping technology..• 3000 BC mesopotamia use baked clay to water distribution• 1000 BC blacksmith weld metal by heating and hammering hot metals• 400 BC rome use cylindrical and triangular pipe• Nowadays, pipe used everywhere..
International codes and standard guide..• United States ASME B 31.X for piping system ASME B 16.X for for pipe flanges and fitting• North america and europe “NPS” Nominal Pipe Size used in north america “DN” Diametre Nominal used in europe
Detailed codes..• For pipe sizes less than NPS 14 inch (DN 350), both methods give a nominal value for the OD that is rounded off and is not the same as the actual OD. For example, NPS 2 inch and DN 50 are the same pipe, but the actual OD is 2.375 inches or 60.33 millimetres. The only way to obtain the actual OD is to look it up in a reference table.• For pipe sizes of NPS 14 inch (DN 350) and greater the NPS size is the actual diameter in inches and the DN size is equal to NPS times 25 (not 25.4) rounded to a convenient multiple of 50. For example, NPS 14 has an OD of 14 inches or 355.60 millimetres, and is equivalent to DN 350.
IPS,sch number,• Schedule number : an old agreement to express pipe wall thickness. Till today,origin of number 20,40,60 etc,remain unanswered.. 1955 wall thickness Gathered from :
IPS The Iron pipe size• Still used today• The IPS number is the same as the NPS number• but the schedules were limited to Standard Wall (STD), Extra Strong (XS), and Double Extra Strong (XXS)• STD is identical to SCH 40 for NPS 1/8 to NPS 10, inclusive, and indicates .375" wall thickness for NPS 12 and larger.• XS is identical to SCH 80 for NPS 1/8 to NPS 8, inclusive, and indicates .500" wall thickness for NPS 8 and larger• XXS is in fact thicker than SCH 160 for NPS 1/8" to 6" inclusive, whereas SCH 160 is thicker than XXS for NPS 8" and larger
Type of pipe..• Seamless Pipe• Seam Welded Pipe
Mechanical properties..• Yield stress, ultimate strength and elongation at rupture are fundamental mechanical properties of pipe and fitting materials.• They reflect the ability of the material to be fabricated and to resist applied loads in service.• All three properties are essential for piping systems
Hardness..• Hardness is the resistance of a material to indentation by a hard object of standard shape pushed with a predefined force against the surface.• Hardness is an interesting property because it is, indirectly, a reflection of tensile strength and ductility
toughness..• Toughness is the ability of a material to absorb impact energy prior to rup- ture. It is also defined as the materials ability to absorb plastic energy, dynamic or static
Fatigue..• Fatigue strength is the ability of a material to sustain cyclic stresses without developing a propagating crack. Fatigue strength of base metals and the unique aspects of the fatigue strength of pipefittings
Physical properties..• Physical properties include density or specific gravity, Youngs modulus and coefficient of thermal expansion.
Internal pressure..• Consider a straight section of pipe filled with a pressurized liquid or gas. The internal pressure generates three principal stresses in the pipe wall,• a hoop stress (also referred to as circumferential or tangen- tial stress), longitudinal stress (also referred to as axial stress), and a radial stress.
External pressure..• If the external pressure is steadily increased, there will come a point where the cylinder will suddenly buckle.• If the cylinder is long and thin, this buckling will occur while the cylinder wall is still elastic.• The external pressure at which elastic buckling occurs is called the critical elastic pressure
Explosion..• Deflagration and detonation are the propagation of a combustion zone at subsonic and supersonic velocity, respectively.• Explosion is generally defined as the resulting burst of the containing tank, vessel or pipe.• The pressure wave that accompanies a deflagration progresses relatively slowly, for example at about 3 ft/sec (for hydrocarbon-air mixtures) and lasts from milliseconds to seconds.• The pressure wave that accompanies detonation travels at supersonic velocities, near Mach 5, in the order of 5000 to 9,000 ft/sec [Lees] and even 2700 ft/sec for high explosives
Defining allowable op pressure..• Pressure limits
Subsea pipelines..• Pipelines assembly – S-curve: The pipeline is assembled horizontally on the lay vessel and lowered with a smooth S shape. – Tow: The pipeline is assembled on shore then towed on buoys to its final location and sunk in place – J-curve: The pipeline is assembled vertically on the lay vessel and lowered with a smooth J shape.
Repair technique..• Bolted Pipe Clamps• Flange Insert Clamps (Insert Ring or Tongue Clamps)• Simple Pipe Clamps with Single Plane Lug Plates• Clamp Bolts• Elbow Clamps• Sealants• Lap Patches• Welding Caps• Welded-on Nozzle• Full Encirclement Welded Sleeve Without End Plates