View Full Version : (A)Piping Materials and Piping Code and Standards

05-10-2009, 06:55 PM
AIA American Insurance Association
ANSI American National Standards Institute
API American Petroleum Institute
ASME American Society of Mechanical Engineers
ASTM American Society for Testing and Materials
AWS American Welding Society
AWWA American Waterworks Association
FCI Fluid Controls Institute
GSA General Service Administration
ISA Instrument Society of America
MSS Manufacturers' Standardization Society of the Valve and Fittings Industry
NFPA National Fire Protection Association
PFI Pipe Fabrication Institute
USDC United States Department of Commerce
Regulation, Code

Design of the piping system shall obey the regulation firstly and two or more regulations may be applied on the piping system.
At the time, the design shall obey each regulation because each one has each difference objective. Almost all regulations provide only minimum requirements. Therefore, the code or standard is required for supplement to the regulation. However, the designer is cautioned that the code or standard is not a design handbook. The code or standard does not do away with the need for the designer or competent engineering judgment.

Pressure piping codes in USA are as follows:

(1) ANSI/ASME B31.1- Power Piping
This code shall be applied to the piping systems for electric generation stations, industrial and institutional plants, control and district heating plants.

(2)ANSI/ASME B31.2- Fuel Gas Piping
This code shall be applied to the piping systems for fuel gases such as natural gas, manufactured gas, liquified petroleum gas(LPG)-air mixtures above the upper combustible limit, liquified petroleum gas(LPG) in the gaseous phase, or mixtures of these gases.

(3)ANSI/ASME B31.3- Chemical Plant and Petroleum Refinery Piping
This code shall be applied to the piping systems handling all fluids, including fluidized solids, and to all types of service including raw, intermediate, and finished chemicals. This code covers all piping within the property limits of facilities engaged in the processing or handling of chemical, petroleum, or related products such as a chemical plant, petroleum refinery, loading terminal, natural gas processing plant (including liquified natural gas facilities), bulk plant, compound plant and tank farm.

(4)ANSI/ASME B31.4- Liquid Petroleum Transportation Piping Systems
This code shall be applied to the piping systems transporting liquids such as crude oil, condensate, natural gasoline, natural gas liquids, liquified petroleum gas, liquid anhydrous ammonia and liquid petroleum products between producer's lease facilities, tankfarms, natural gas processing plants, refineries, stations,ammonia plants, terminals (marine, rail and track), and other delivery and receiving plants.

(5)ANSI/ASME B31.5- Refrigeration Piping
This code shall be applied to refrigerant and brine piping for temperature as low as -320'F.

(6)ANSI/ASME B31.8- Gas Transmission and Distribution Piping Systems
This code shall be applied to gas transmission and distribution systems including gas pipelines, gas compressor stations, gas metering and regulating stations, gas mains and service lines up to the outlet of the customer's meter set assembly.
Piping Components ေတြကေတာ့

1.Pipe ပို္က္
2.Flange Joints ပိုက္ဆက္တဲ့ေနရာမွာ သုံးတဲ့ပစၥည္း
2.1 Gaskets
2.2 Bolting

3.Fittings ပိုက္လမ္းေၾကာင္းအတြက္ ပစၥည္း
3.1 Elbows
3.2 Bends
3.3 Tees
3.4 Reducers

4.Valves အရည္ကိုထိန္းခ်ဳပ္တဲ့ပစၥည္း
4.1 Gate
4.2 Globe
4.3 Angle
4.4 Needle
4.5 Check
4.6 Cock/Plug
4.7 Ball
4.8 Butterfly

5.Special components အရည္အတြက္ အျခားလုိအပ္တဲ့ပစၥည္း
5.1 Steam Traps

5.2 Strainers
5.3 Expansion Joints
5.4 Universal Joints
5.5 Flexible Hose
ဘယ္လုိ material ေတြနဲ႔ထုတ္လုိ႔ရသလဲ

Pipe are classified mainly by MATERIAL and SIZE.
Cast Iron Iron Pipe
Ductile Iron
Carbon Steel Steel Pipe
Low-alloy steel Ferrous Pipe
Stainless steel
Aluminium/ Al Alloy Non-ferrous Pipe
Copper/Cu Alloy
Rubber tubing Non-metallic pipe
Hume (Concrete)

Pipe are also availabe with a variety of linings, such as polyethylene, cement-mortar, glass, etc.

Most countries have a standard regulating for the pipe outer diameter, wall thickness and their tolerances, in which a Nominal Pipe Size(NPS) is adopted. So, as long as the pipes and pipe fittings have an identical nominal pipe size, they can be joined together regardless of their inner diameters.

There are two measurement systems used for the nominal pipe size: the inch system used in the USA and UK,etc. and the metric system used in most other countries. Both of these systems are employed in Japan.
ပိုက္ေတြကိုဘယ္လုပ္ထုတ္လုပ္မွာလဲ (Pipe Manufacturing Methods)
Steel pipes are further classified by the fabrication method employed.
There are two main processes.
1. Seamless steel pipe, fabricated from a solid billet of steel
2. Welded steel pipe, fabricated from steel plates shaped by a press or rollers.
There are two types of pipe in manufacturing service: Seamless pipe and Welded pipe.
Welded pipe ကိုထုတ္လုပ္တဲ့ေနရာမွာ ႏွစ္နည္းရွိပါတယ္။ EFW: Electric Fusion Weld နဲ႔ ERW: Electric Resistance Weld ဆိုၿပီးေတာ့ပါ
(၁)Spiral Pipe (၂)ERW Pipe (၃)Furnace Butt Weld Pipe (၄)EFW Pipe တို႔ဟာ welded pipe ေတြပါ။

ေ႐ြးခ်ယ္တာကိုေတာ့ Project specification (Client requirement) ေပၚမူူတည္ၿပီးေ႐ြးခ်ယ္ပါတယ္.
ဒါေပ့မယ္ if there is no requirement by Client, the Contractor shall decide as follows (General)
Seamless Pipe Carbon Steel (General Process) 1/2"-24"
Carbon Steel (Utility Service) 1/2"-2"
Low Alloy Steel 1/2"-24"
Stainless Steel 1/2"-6"(8")
Welded Pipe Carbon Steel (GP) 26" and larger
C S (U P) 2-1/2" and larger
Low Alloy steel 26" and larger
Stainless 8"(10") and larger
ပိုက္ေတြကို ဘယ္ေတြေပၚမွာမူတည္ၿပီးေ႐ြးခ်ယ္မွာလဲ?

When selecting the type of pipe to be utilized for a specific operation, various factors must be taken into consideration, as follows:
(1) Operating conditions: These include the kind of fluid, operating temperature and pressure.
(2) Material strength: This includes the loading type and aging.
(3) Material resistance to corrosion.
(4) Restrictionns imposed by process requirements.
(5) The requirements given in the applicable codes and standards, such as ANSI,BS,etc. ဒီအခ်က္ကေတာ့ ထူးျခားေနပါတယ္။ဘာလုိဒီကုဒ္ေတြကုိသုံးၾကတာလဲ။

Many other factors must be taken into account, such as economic efficiency, which includes marketability and interchangeability, and workability, such as weldability and machinablility. Thus the selection of the pipe must be made with care and forethought.

The material most widely used for process piping is CARBON STEEL, because of its favorable characteristics, as follows:
(1) Strength and ductility
(2) Machinability and weldability
(3) Adjustable characteristics through composition changes and heat treatment
(4) High availability and low cost production
2.FLANGE JOINTS (ပိုက္ေတြဆက္တဲ့ေနရာမွာ အေရးႀကီးဆုံးပစၥည္းျဖစ္တဲ့ အရာ)

2.1 General
A flange joint consists of two flanges, with a gasket between them, tightly secured together by bolting.

Flange joint ေတြကိုဘာလုိ႔သုံးလဲ?

Flange joints are used where a quick and easy assembly and disassembly of piping is required, as in the following cases
(1)With equipments
(2)With instruments
(3)With valves
(4)With piping of different materials
(5)with other piping components, such as strainers and steam traps,
(6)Where frequent piping assembly and disassembly are required.
(7)with headers.

*Recently, however, flange joints are used only when absolutely necessary, as they tend to cause leakages. ဒါအဓိက အားနည္းခ်က္ပဲ။

2.2 Classification
ဒီ Flange joint ေတြကို အမ်ိဳးအစားေတြခြဲထားသလားလုိ႔ ေမးရင္ေတာ့ ခြဲထားတယ္လုိ႔ပဲ ေျဖရမွာပဲ။
Flange joints are classified by the type of flange connection to the pipe, and by the type of flange facing.
Connection အရ ခြဲထားေတြကေတာ့ (Classification by connection type are) 1.welding-neck
4.lap (Van stone)
5.Screwed တို႔ျဖစ္ပါတယ္။

Facing ေတြအရေတာ့ အမ်ားႀကီးရွိပါတယ္ ၿပီးေတာ့ သုံးတဲ့ service အလုိက္ေ႐ြးခ်ယ္ပါတယ္ (Figure facings come in various types and are selected in accordance with the kind of service in which they are to be used)
An important factor in selecting the type of facing is the shape of the gasket seat; this must ensure the optimum gasket flow when the faces are bolted together. bolt ညႇပ္လုိက္ရင္ ေဘးကိုကားထြက္လာတာကို gasket flow လို႔ေခၚတယ္။
Facing ေတြအရ ခြဲထားတဲ့ Flange ေတြကေတာ့ 1.Flat face
2.Raised face
3.Male-female face
4.Tongue-groove face
5.Ring joint face

A gasket is inserted between the contact facings of the flange to seal or plug any irregularities in those facings and prevent leaks.
အသုံးျပဳတဲ့ gasket type သုံးမ်ိဳးပဲရွိပါတယ္ (There are three types of gaskets used: non-metallic, semimetallic and metallic.)
(1)Nonmetallic Gaskets
A feature of nonmetallic gasket is their softness, when compared with metallic gaskets. (ေပ်ာ့တယ္)
These gaskets are used over a wide range of services, as they possess a reasonable elasticity and strength. (Elasticity and strength ႀကိဳက္လုိ႔)
Nonmetallic gaskets are fabricated of a combination of several of the following materials: ဒီလုိပစၥည္းေတြကေန ထုတ္ပါတယ္တဲ့
(a) Asbestos
(b) Synthetic resin (tetrafluoroethylene, polyester, nylon, etc)
(c) Rubber (natural rubber, nitrile rubber (NBR),neoprene rubber (CR), isobutylene-isoprene rubber (IIR), styrene rubber (SBR), fluoro-rubber (Viton), and silicone rubber, etch.)
(d)Organic materials (leather, cotton, hemp, jute, cork, etc.)

(2)Semimetallic Gaskets

Semimetallic gaskets are fabricated of a combination of metallic and nonmetallic materials, and are applicable over a wide temperature and pressure range. The advantages of metallic gaskets are utilized by compensating for the inferior elasticity of metal with preshaped profiles and by the use of metallic in combination with nonmetallic materials.
ွSemimetallic gaskets are of mainly three types: wire-mesh compressed asbestos sheeting, vortex type gaskets, and various kinds of metallic-coated gaskets. သုံးမ်ိဳးေတာင္ရွိတယ္

(3)Metallic Gasket

Metallic gaskets are used where the temperature or pressure, or both, cannot be withstood by nonmetallic or semimetallic gaskets.

Metallic gasket ေတြက ခုနနွစ္ခု မရတဲ့ အရာမ်ိဳးမွာသုံးတယ္။
ဘယ္ႏွစ္မ်ိဳးရွိလဲဆိုေတာ့ ၄ မ်ိဳးေတာင္ရွိတယ္

Corrugated Soft aluminum
Iron or Soft Steel
Serrated Soft copper or Brass (4 to 6 % Cr)
Flat Stainless Steel
Ring Joint(Oval) Iron or Soft Steel (4 to 6% Cr)
(Octa) Stainless Steel

Post တစ္ခု အေနနဲ႔ ခဏတင္ထားျခင္းျဖစ္သျဖင့္ စာမ်ားမွာ ပုံစံမက်ေသးပါ..ေခတၱခဏ သည္းခံေပးပါရန္...

05-10-2009, 07:31 PM
Flanges are fastened together with bolts and nuts. Two types of bolts are used: machine and stud. (Stud ကနွစ္ဘက္ရစ္)

Machine (head) bolts are used mainly for carbon steel piping in moderate and atmospheric temperature and low pressure service, and
Stud bolts for carbon steel in other services, and for stainless steel and alloy steel piping.

The screw thread is either Metric or Unified (inch). The Metric thread is becoming more widely used internationally, although the Unified thread is still used (mainly in USA and UK)

Bolt ေတြကေတာ့ 1. Machine(Head) Bolt
2. Continuous-thread stud
3. Double-end stud (thick)
4. Double-end stud (thin)
5. Double-end stud (Flange) flange အတြက္ပါ

Pipe Fittings are used to connect straight lengths of piping, make bends and branches, and for reducing the size of the piping. They are also used for various other functions.
ၤFittings come in several different connection types: e.g, butt-welding, sock-welding, screw and flanges.

In general, pipe fittings are of the same material as that of the pipes: except where special fittings are used, such as castings.

The main types of pipe fittings used in the piping system are as follows:
such as caps, couplings, nipples,etc.
90' Elbox Long Radius, 90' Elbow Short Radius, 45' Elbow Long Radius, 180' Return Long Radius Short Radius, Straight Tee, Reducing outlet tee,straight tee, Reducing outlet tee, concentric reducer, ecentric reducer, Lap Joint stub ends(ASA length(Mss Length), Cap

စာမ်က္နွာ၁၉ ကို ခဏေက်ာ္ထားပါတယ္ (ဓာတ္ပုံေတြ၇ိုက္ထားပါတယ္)
3.2 Elbows

Elbows are formed pipe fittings used to make 90 or 45 degree changes in direction of the run of the piping. Elbows are either seamless, manufactured by casting,forging, or bending from thick-wall pipe, or fabricated by pressing and welding steel plate. The elbows normally used are "long radius" with a curvature equal to 1.5 times the Nominal Pipe Size, and "short raudius" (SR) with a curvature radius equal to one diameter Nominal Pipe Size. Forged and malleable cast iron elbows, however, are usually fabricated to individual standards.
Miter bends are fabricated by welding appropriately trimmed pipe stubs, and are used mainly for large diameter piping. Eg. 3-pieces miter bend, 5-pieces miter bend
3.3 Bends

Bends are fabricated by the hot or cold forming of straight pipe. Bends are similar to elbows in shape, but the curvature radius of a bend is normally 3 to 5 times the NPS. Elbows က 1.5 အထိပဲေနာ္

The use of bends for normal equipment piping is limited as they require more exclusive space, thus they are used mainly for slurry and powder transporation.
3.4 Tees

Tees are employed to provide branches at a right angle to the straight run of the piping. Tees are classified into two types, full branch and reducing. In a full branch tee the bore diameters are all the same, in a reducing tee the diameter of the branch bore is smaller than the diameters of the other two bores.
Where a branch is needed in smaller diameter piping, the main pipe is bored out and a branch pipe fitted to it, by welding either directly or with a boss.
3.5 Reducers

Reducers are mainly butt-welding fittings used to connect two straight pipes of different diameters. Reducers come in tow types; concentric or eccentric, depending on whether the pipe center lines coincides or not. Eccentric reducers are used to facilitate multi-pipe supporting, as on a pickrack, and to avoid trapping air or liquid in the horizonal suction line of a pump.

other fittings used for joining straight pipes of different diameters, listed as follows.
(1)Reducting sockets
(2)Reducing nipples
(3)Swaged nipples (Small bore reducers)
3.6 Other fittings

Various other types of fittings are used in the piping system, depending upon the circumstances involved. Some of these fittings, listed as follows.
(1) Sockets
(2) Couplings
(3) Nipples
(10)Bosses- common use
(11)Weldolets - Not used in Japan
(12)Half coupling - Special purpose
4. Valves

A valve is a device used to control the fluid flow in the piping by closing or opening the piping passages.

A great variety of valves are used in a process plant, and the valve type, material and structure are selected in accordance with the service in which it will be used.

Valves can be classified in many ways. The main types of valves are as follows:
(1) Gate Valves
(2) Globe valves
(3) Angle valves
(4) Needle valves
(5) Check valves
(6) Cock/plug valves
(7) Ball valves
(8) Butterfly valves

The classifications base on material are as follows:

(1) Forged steel valves
(2) Cast iron valves
(3) Cast steel valves
(4) Bronze valves
(5) Others

The valves come in several different connection types; e.g, Flange, butt-welding, sock-welding and screw.

(1) Gate valves:
In the operation of a gate valve, the fluid flow is interrupted by placing a disc at a right angle to the flow direction. Gate valves are most commonly used at the inlets and outlets of rotating machinery and other equipment, and as block valves where a fully open or fully clossed status is required.

Gate valves have the following features:

(1) Little or no pressure loss across the valve is felt,as the valve does not cause turbulence, since there is no change in the direction of the fluid flow or in the flow line sectional area.

(2) The movement of the stem and disc is vertical, thus the face-to-face dimension is relatively small. However, the valve height and the lift are necessarily large, since the valve stroke must be equal to the diameter of the disk.

(3) Because it interrupts the flow at a right angle, vibration and erosion will occur at the disk, when the valve is in a throuttling (disc halfway) position. Thus gate valves should be used only at a fully open or fully closed position, and should not be used for flow control.

(4)As the valve tightening force required is less than that for a globe valve, the gate valve is more suitable for large sized valves and for high pressure services.

(2) Globe valve
The Globe valve gets its name from the globular shape of the valve body. In the operation of a globe valve, a conical or cylindrical disk is placed in contact with a seat which is perpendicular to the valve stem axis, necessitating the use of a larger body size than that of a gate valve. The structure causes sudden changes in the flow direction, giving rise to turbulence in, and considerable resistance to, the flow; making the valve suitable for flow regulation. Globe valves are used mainly for throttling; eg as bypass valves for a control valve and reciprocating machinery, in the cooling water and centrifugal pump discharge lines, and as flushing or reducing valves in a refrigeration system.

(3) Angle valve
The angle valve has the same structure as the globe valve except that the end faces are at a right angle to each other, enabling the flow direction to be changed without the use of elbow.

(4) Needle valves
The needle valve is similar to the globe or angle valve except that the disk has a more acute angle, to secure a wider range of flow control.

(5)Check valves
The check valve is designed to permit flow in only one direction and to prevent backflow, and is used mostly in the delivery lines at pumps and compressors. The three principal types of check valves are the swing check, the lift check and the ball check.

(1)Swing check valve
The swing check valve is used generally for 2 inch and larger NPS piping. The disc is hinged and opens in one direction only, and the valve can be installed in both vertical and horizonatal piping.
The slightly tilted valve seat allows the disk to remain in contact with the seat under its own weight only in a horizontal installation, with the result that only a small amount of back-pressure is needed to prevent backflow. This type of structure permits slamming, which will cause wear at the disk and seat. To counteract this,a counter-weight may be furnished at the hinge-pin to control the disk movement, or a shock absorber may be needed in the case of a large size valve.

(2)Lift check valve
The structure of th lift check valve is very simple, and resembles that of the globe valve, except that it has no stem. The vertical action of the plug disc permits flow in only one direction. Because of the large resistance effect, the lift check valve is used for 1-1/2 inch and smaller NPS piping. The structure allows only a horizontal installation.

(3)Ball check valve
Like the lift check valve, the ball check valve is used mainly for 1-1/2 inch and smaller NPS piping. In the ball check valve, the ball replaces the plug disk used in the lift check valve. Both vertical and horizontal type ball check valves are available. The ball sealing is achieved by gravity or backpressure, or both, and is free to rotate; which distributes wear and assists in keeping the contacting surfaces clean. Maintaining complete roundness of the ball is impracticable, and leakage will occur.. The pressure loss is fairly small when compared with that of a lift check valve.

(6)Cock/Plug valves
Cock or plug valves are used for high viscosity fluid service, where the fluid will coagulate easily, or where rapid opening and closing of the valve is required.
The main structure of a cock valve consists of a conical plug with the body tapered to fit the plug.
The valve functions by turning the plug through a 90 degree rotation.
The structure is simple and flow resistance is small. However, operation is difficult due to the large surface contact area between the plug and seat, and it is difficult to obtain complete airtightness. Thus this type of plug valve is used in small NPS piping in low pressure service.
To counteract these defects, plug valves are available with lubrication. The lubricant is forced through conduits between the plug and the seat face, forming a film that not only makes handling easier but also has the added advantage of acting as a seal. The lubricant used must have no adverse affect on the fluid handled.
Another advantage of the cock and plug valves is that they may be used as multiport valves. ပုံမွန္းၾကည့္ၾကည့္ေပါ့။

(7)Ball valves
The ball valve operations on the same principle as the plug valve, except that a ball is used instead of a plug, and that the ball has a round bore instead of the rectangular bore used in the plug.

The advantages of the ball valve are as follows:
(1)Small pressure loss as the ball bore has the same diameter as the piping.
(2)Easier handling
(3)Compact, light weight and few working parts.
However, the use of Teflon and rubber seats has restricted the use of the ball valve, due to their temperature limitations.

(8)Butterfly valves
One of the oldest types of valve, butterfly valves were used mostly for low-pressure services requiring less strict closure, such as air or water service, and for services where turbulence or resistance must be avoided. However, since the addition of a rubber or composition seating, which allows a complete sealing, the butterfly valve now enjoys a far wider usage, due to its simple and lightweight structure and superior flow characteristics.

KINDS OF VALVES MAIN PURPOSES 1(Stop) 2(Adj) 3(Rev) 4(Q) 5(Dir) 6(P Drp) 7(HP) 8(HT) 9(HV) 10(Slur) 11(Large)
GATE VALVE ON-OFF FLOW 3 0 0 1 1 3 3 3 1 1 3
GLOBE VALVE 1 3 0 0 1 1 3 3 0 1 0
CHECK VALVE 0 0 3 0 3 1 3 3 3 1 3
BALL VALVE 3 1 0 3 1 3 3 1 3 1 0
BUTTER VALVE(Concentric) 3 1 0 3 1 3 0 0 3 1 3
BUTTER VALVE(Eccentric) 3 1 0 3 1 3 1 1 3 1 3
PLUG VALVE 3 1 0 3 1 3 3 1 3 3 3

5.Special components

5.1 Steam Traps
Steam is a convenient and easily handled medium for heating, for driving machinery( turbines, etc.), for cleaning, and for creating vaccum. Thus the control and effective utilization of steam is an important part of the plant operation. An essential element in this control and utilization is the steam trap.
A steam trap is an automatic valve device able to discharge condensate from a steam line without also discharging steam.Condensate will cause considerable trouble in piping and equipment, and will have a detrimental effect on the plant operation; thus it must be removed to ensure the safety and effienciency of the steam facilities.
Some of the problems caused by condensate in the piping and equipment are as follows;
(a) Nonuniform temperature distribution in piping and equipment, leading to damage and corrosion from stress.
(b) Deterioration in the heating efficiency.
(c)Corrosion accelerated by air and soluble gases carried by steam
(d)Excessive pressure lossess
(e)Water hammer
(f)Ruptures in the piping from expansion or blockages casued by freezing.
(g)Damage to the blades in a turbine

Steam traps are classified into three categories by operating principles; as follows
(a)Mechanical trap (density sensitive)
(1)Open Bucket
(2)Inverted bucket
(b)Thermostatic traps (Temperature sensitive)
(c)Thermodynamic traps (Thermodynamic differential)
(2)Controlled disc

The various types of steam traps are rarely interchangeable, and the selection of an unsuitable type of trap will cause problems. Careful consideration must be given to the operating principle, mechanical structure and features of the traps, as well as the service conditions involved.Water hammer and steam-locking must also be taken into account.

The types of traps used should be kept to a minimum in one plant to alleviate maintenance problems. Selecting the traps should be based on the following considerations.
(1)Connection type and size
(2)Steam pressure
(1) Maximum and minimum inlet pressure
(2) Maximum and minimum outlet pressure
(3) Activation pressure difference between inlet and outlet
(1)Maximum steam temperature
(2)Condensate temperature
(4)Steam quality

(5)Condensate discharge rate

(6)Condensate recovery

(7)Process for which trap will be used

(8)Process operating conditions
5.2 Strainers
Strainers are installed to prevent the entry of, and to ensure the removal of, dirt, scale and foreign substances in the piping, and are installed at various locations, as follows;
(1)On the suction side of pumps and turbines
(2)In the feed piping supplying raw materials to equipment.
(3)At the inlets of flowmeter and steam traps

Strainers are constructed so that the filter element may be periodically removed and cleaned, to prevent blockages. Some strainers are self-cleaning. The following types of strainers are available, as listed below.
(1) Y-type
(2) T-type
(3) Bucket type
(4) Cone type

5.3 Expansion Joints

Expansion Joints are installed to absorb expansion in the piping system caused by temperature changes in the fluid in the pipe and in the ambient temp;, to absorb vibration caused by fluid surge or pulsation and to prevent damage to piping due to ground settlement or to earthquake.

Three basic types
(1)Sleeve type
(2)Bellow type
(3)Victaulic type

5.4 Universal Joints

This type of joint is fitted where the flow direction of the pipe must be allowed to change freely and is used in loading arms, tank drain piping,etc.
(1)Swivel joint
(2)swing joint
(3)Universal joint

5.5 Flexible Hose

Flexible hose is used to absorb mechanical vibration and differential settlement and as loading hose.