General Piping and Valves

GENERAL PIPING &

VALVES•ME 514 – INDUSTRIAL PLANT

DESIGN

1.0DEFINITIONS 1.1 Pipe and Tube The fundamental difference between pipe and

tube is the dimensional standard to which each is manufactured. A pipe is a tube with a round cross section conforming to the dimensional requirements for nominal pipe size as tabulated in table for Pipe Schedules.

A tube is a hollow product of round or any other cross section having a continuous periphery. Round tube size maybe specified with respect to any two, but not all three of the following: outside diameter or internal diameter or nominal diameter.

1.0DEFINITIONS (CONT..) 1.2 Black pipe – steel pipe that has not

been galvanized. 1.3 Bell and Spigot Joint – the commonly

used joint in cast-iron pipe. Each piece is made with an enlarged diameter or bell at one end into which the plain or spigot end of another piece is inserted when laying. The joint is then made tight by cement, oakum, or rubber caulked into the bell around the spigot.

1.4 Bull Head Tee – a tee the branch of which is larger than the run.

1.0DEFINITIONS (CONT..) 1.5 Butt Weld Joint – a welded pipe joint

made with the ends of the two pipes butting each other, the weld being around the periphery.

1.6 Carbon Steel Pipe – steel pipe which owes its properties chiefly to the carbon which it contains.

1.7 Check Valve – a valve designed to allow a fluid to pass through in one direction only. A common type has a plate so suspended that the reverse flow aids gravity in forcing the plate against a seat, shutting off reverse flow.

1.0DEFINITIONS (CONT..) 1.8 Compression Joint – a multi-piece joint

with cup shaped threaded nuts which, when tightened compress tapered sleeves so that they form joint on the periphery of the tubing they connect.

1.9 Cross-Over – a small fitting with a double offset, or shaped like the letter U with the ends turned out. It is only made in small sizes and used to pass the flow of one pipe past another when the pipes are in the same plane.

1.10 Expansion Loop – a large radius bend in a pipe line to absorb longitudinal expansion in the pipe line due to heat.

1.0DEFINITIONS (CONT..) 1.11 Galvanized Pipe – steel pipe coated with zinc

to resist corrosion. 1.12 Gate Valve – a valve employing a gate, often

wedge-shaped, allowing fluid to flow when the gate is lifted from the seat. Such valves have less resistance to flow than globe valves.

1.13 Globe Valve – one with a somewhat globe shaped body with a manually raised or lowered disc which when closed rests on a seat so as to prevent passage of a fluid.

1.14 Header – a large pipe or drum into which each of a group of boilers is connected. Also used for a large pipe from which a number of smaller ones are connected in line and from the side of the large pipe.

1.0DEFINITIONS (CONT..) 1.15 Malleable Iron – cast iron heat-treated

to reduce its brittleness. The process enables the materials to stretch to some extent and to stand greater shock.

1.16 Manifold – a fitting with a number of branches in line connecting to smaller pipes. Used largely as an interchangeable term with header.

1.17 Medium Pressure – when applied to valves and fittings, implies they are suitable for a working pressure of from 862 to 1207 kPa (125 to 175 psi).

1.0DEFINITIONS (CONT..) 1.18 Mill Length – also known as random

length. Run-of-mill pipe is 4880 mm to 6000 mm (16 ft to 20 ft) in length. Some pipe are made in double lengths of 9150 mm to 10,675 mm (30 ft to 35 ft).

1.19 Relief Valve – one designed to open automatically to relieve excess pressure.

1.20 Run – a length of pipe made of more than one piece of pipe; a portion of a fitting having its ends in line or nearly so, in contradistinction to the branch or side opening, as of a tee.

1.0DEFINITIONS (CONT..) 1.21 Saddle Flange – a flange curved to fit a

boiler or tank and to be attached to a threaded pipe. The flange is riveted or welded to an adjoining pipe.

1.22 Socket Weld – a joint made by use of a socket weld fitting which has a prepared female end or socket for insertion of the pipe to which it is welded.

1.23 Standard Pressure – formerly used to designate cast-iron flanges, fittings, valves, etc., suitable for a maximum working steam pressure of 862 kPa.

1.24 Street Elbow – an elbow with male thread on one end , and female thread on the other end.

1.0DEFINITIONS (CONT..) 1.25 Stress-Relieving – uniform heating

of a structure or portion thereof to a sufficient temperature to relieve the major portion of the residual stresses, followed by uniform cooling.

1.26 Wrought Iron – iron refined to a plastic state in a puddling furnace. It is characterized by the presence of about 3 percent of slag irregularly mixed with pure iron and about 0.5 percent carbon.

1.0DEFINITIONS (CONT..) 1.27 Wrought Pipe – this term refers to

both wrought steel and wrought iron. Wrought in this sense means worked, as in the process of forming furnace-welded pipe from skelp, or seamless pipe from plates or billets. The expression wrought pipe is thus used as a distinction from cast pipe. When wrought-iron pipe is referred to, it should be designated by its complete name.

2.0GENERAL REQUIREMENTS 2.1 All piping shall be run parallel to

building walls. 2.2 Grouped piping shall be supported on

racks either on horizontal or vertical planes. 2.3 All piping to headers shall come from

below rack. 2.4 All piping from headers shall go up

above rack. 2.5 All piping above or below racks shall

be supported on separate racks. 2.6 All piping should run with slight

inclination for drainage of main headers.

2.0 GENERAL REQUIREMENTS (CONT..)

2.7 All piping on racks shall have a sufficient spacing for pipe or chain wrenches so that any single line can be altered without disturbing the rest of the piping on rack.

2.8 All piping 63.5 mm (2 ½ in) and above shall be flanged while smaller sizes can be screwed.

2.9 On long headers a pair of flanges shall be provided for every three lengths of 6000 mm (20 ft) of pipes 63.5 mm (2 ½ in ) and above.

2.10 On long headers a pair of unions shall be provided for every three lengths of 6000 mm (20 ft) of pipes smaller than 63.5 mm (2 ½ in).


2.11 All piping subject to varying temperature shall be provided with expansion joints or expansion loops to take care of expansion.

2.12 No galvanized piping shall be used of steam.

2.13 No piping material shall be used that is easily corroded by material passing thru.

2.14 All piping shall be clamped by “U” bolts or clamps to supporting racks except steam piping.

2.15 Piping supports shall be placed on a 3000 mm (10 ft) intervals or less.


2.16 All steam piping shall be supported on rollers or sliding support for expansion.

2.17 All piping carrying pressure shall be of sufficient bursting strength for the pressure applied. A minimum factor of safety of 4 for working pressure applied shall be used.

2.18 A minimum factor of safety of 4 for working applied shall be used.

2.19 For conveying liquids subject to water hammer additional safety factor of a minimum of 100% of working pressure shall be used.

2.20 Piping supports shall be placed on a 3000 mm (10 ft) intervals or less.


2.21 All piping carrying steam, hot water or hot liquids shall be insulated to prevent accidental contact and loss of heat.

2.22 Drains for steam piping shall be provided with steam traps.

2.23 On all screwed joints the threaded portion shall enter fittings with three threads by hand before a pipe wrench is applied.

2.24 Pipe threads shall be lubricated by white lead, red lead graphite and oil or other approved thread lubricants before tightening.


2.25 No rubber or rubberized gasket shall be used for steam or hot liquids.

2.26 A shut-off valve shall be installed to every branch from headers.

2.27 All piping shall be reasonable cleaned before installation.

2.28 All piping shall be free from burns or protruding metals inside.

2.29 No piping carrying steam or hot liquids shall be imbedded in concrete walls or floors.

2.30 Where piping has to be located in trenches the pipes shall be supported on steel benches on floor of trench.


2.31 Where piping has to be located in trenches a suitable drainage or sump for removal of liquid accumulations shall be provided for trench.

2.32 Where piping carrying steam or hot liquids have to pass walls of concrete suitable sleeves made of pipes one size bigger shall be imbedded in concrete before piping is laid.

2.33 Piping to all equipments shall not impose any stress on equipment being connected.

2.34 Pipe carrying liquids with solids shall use long radius elbows or tees with plugs in the direction of flow.

3.0 IDENTIFICATION COLORS FOR PIPES

Identification of piping by color, or color bands at convenient locations shall be as follows:

3.0 IDENTIFICATION COLORS FOR PIPES (CONT..)


In addition to color coding, the specific contents of piping must be identified by sticker, stencil, tag, etc.

Color bands and pipe flow identifications shall be as specified and installed as shown.



4.0FLUID FLOW VELOCITIES In practice, the average fluid flow velocities

may be as follows:

a. Water - - - - - - - - - - 1.5 – 3.0 meters/sec. b. High Pressure Saturated Steam ----- 25 –

50 meters/sec. c. High Pressure Superheated Steam --- 50 –

77 meters/sec. d. Atmospheric Exhaust Steam ---- 40 – 60

meters/sec. e. Low Pressure Exhaust Steam --- 100 – 120

meters/sec.

5.0 POWER PIPING SYSTEMS AND DESIGN 5.1 Scope. Power piping systems include all steam,

water and oil piping and the component parts such as the pipe, flanges, bolting, gaskets, valves, and fittings for steam generating plants, central heating plants and industrial plants.

5.0 POWER PIPING SYSTEMS AND DESIGN (CONT..) 5.2 Materials. Materials used shall conform to Table

11.6.2 (PSME Code 2008). Any material other than those specified should meet the physical & chemical requirements & test of the latest revision of the respective specifications in Table 11.6.2.

5.0 POWER PIPING SYSTEMS AND DESIGN(CONT..)






5.0 POWER PIPING SYSTEMS AND DESIGN (CONT..)

5.3 Valves It is mandatory that valves be (a) of the

design or equal to the design which the manufacturer thereof recommends for the service, and (b) of materials allowed by the code for the pressure & temperature.

All valves in nominal sizes:

80 mm (3 in) and smaller for pressure above 1724 kPa (250 psig) but not above 2758 kPa (400 psig).


50 mm (2 in) smaller for pressures above 25787 kPa (400 psig) not above 4137 kPa (600 psig).

40 mm ( 1 ½ in) and smaller for pressures above 4137 kPa (600 psig) may have screwed, flanged, or welding ends.

For all valves, larger than sizes specified in the preceding paragraph, flanged or welding ends shall be used.


5.4 Wall Thickness. The following formula shall be used to

determine pipe wall thickness:

Where tm = minimum pipe wall thickness in mm P = maximum internal service pressure in kPa t = nominal pipe wall thickness in mm D = outside diameter of pipe in mm S = allowable stress in materials in kPa C = allowance for threading, mechanical

strength of corrosion in mm, see Table 11.6.4a Y = co-efficient for values, Table 11.6.4b

CYPS

PDtm

2


• Since all pipe furnished by the mill is subject to 12 ½ % variation in wall thickness, the thickness tm should be multiplied by 8/7 to obtain the nominal wall thickness.



5.5 Variations in presure and temperature. Either pressure or temperature, or both, may

exceed the nominal design values if the computed stress in the pipe wall calculated for the pressure does not exceed the allowable S value in Table 11.6.5 and 11.6.5a for the expected temperature by more than the following allowances for the period of duration indicated:

a. Up to 15 percent increase above the S value during 10 percent of the operating period.

b. Up to 20 percent increase above the S value during one percent of the operating period.






5.6 Pressure reducing and relief valves.

a. Where pressure reducing valves are used, one or more relief or safety valves shall be provided on the low pressure side of the reducing valve in case the piping or equipment on the low pressure side does not meet the requirements for the full initial pressure. The relief or safety valve shall be located adjoining or as close as possible to the reducing valve. Proper protection shall be provided to prevent injury or damage caused by escaping fluid from relief or safety valves if vented to the atmosphere. The vents shall be of ample size and as short and direct as possible. The combined discharge capacity of the relief valves shall be such that the pressure rating of the lower pressure piping and equipment will not be exceeded if the reducing valves sticks open.


b. It is mandatory that a pressure gage is installed on the low pressure side of a reducing valve.


5.7 Pipe a. For pressure above 4,137 kPa (600

psig) , the pipe shall be: 1. Seamless steel meeting ASTM

specification A-106, A-312, A-335 or A-376; or

2. Forged and bored steel meeting A-369 or

3. Automatic welded steel meeting A-312 or

4. Electric-fusion welded steel pipe meeting with ASTM specification A-155


b. For pressure above 1724 kPa (250 psig), but not above 4137 kPa (600 psig) , pipe shall be:

1. Electric-fusion welded steel of ASTM specification A-134 or A-139

2. Electric-resistance welded steel pipe of ASTM specification A-135

3. Forged or bored steel meeting A-380; or 4. Automatic welded steel meeting A-312 5. Electric-fusion welded steel pipe meeting with

ASTM specifications A-155 6. Seamless steel in accordance with ASTM

specification A-106 7. Seamless or electric-resistance welded steel

pipe of ASTM specification of A-53


c. For service up to 400 C (750 F) and pressure of not over 1724 kPa (250 psig), any of the following classes of pipe may be used:

1. Electric-fusion welded steel of ASTM specification A-134 or A-139

2. Electric-resistance welded steel pipe of ASTM specification A-135

3. Wrought-iron pipe of ASTM specification A-72


d. Grade A seamless steel pipe of ASTM specification A-106, wrought-iron pipe of ASTM A-72, Grade A seamless steel pipe of ASTM A-53, or grade A electric welded pipe of ASTM A-53, A-135 or A-139 shall be used for close coiling, cold bending or other uses.


5.8 Boltings a. The following standards shall apply to

bolting: For steam service pressure in excess of

1724 kPa (250 psig) or for steam or water service temperature exceeding 232 C (450 F), the bolting material shall conform to ASTM specifications A-193. For temperature exceeding 400 C (750 F), only bolts studs are recommended. When cast iron flanges are used, bolting material shall be of carbon steel conforming to ASTM specification A-307, Grade B, or A-107, Grade 1120.


b. Flange bolts or bolt-studs shall be of the dimensions and material specified for the purpose in the corresponding American flange standards. Bolts or bolt-studs shall extend completely through the nuts and if desired may have reduced shank of a diameter not less than the diameter at root of threads.

c. Nuts shall conform to ASTM specification A-194.


5.9 Flanges a. Flanges shall conform to the American

Standard B 16.5 for respective pressures and temperature or to the specifications set by the manufacturer.

b. 1724 kPa (250 psig) and class 862 kPa (125 psig) cast-iron integral or screwed companion flanges may be used with a full dace gasket or with a ring gasket extending to the inner edge of the bolt holes. When using a full face gasket, the bolting maybe of heat-treated carbon steel (ASTM-A261), or alloy steel (ASTM A-193). When using a ring gasket, the bolting shall be of carbon steel equivalent to ASTM A-307, Grade B, without heat-treatment other than stress relief.


c. When bolting together two Class 1724 kPa (250 psig) integral or screwed companions cast-iron flanges, having 1.6 mm (1/16 in) raised faces, the bolting shall be of carbon steel equivalent to ASTM A-307, Grade B. Without heat-treatment other than the stress relief.


d. 1034 kPa (150 psig) steel flanges may be bolted to cast-iron valves, fittings or other parts having either integral Class 862 kPa (125 psig) cast-iron flanges or screwed Class 862 kPa (125 psig) companion flanges. When such construction is used, the 1.6 mm (1/16 in) raised face on the steel flange shall be removed. When bolting such flanges together using a ring gasket extending to the inner edge of the bolt holes, the bolting shall be of carbon steel equivalent to ASTM A-307 Grade B, without heat-treatment other than stress relief. When bolting such flanges together using full face gasket, the bolting may be heat treated carbon steel (ASTM A-261) or alloy steel (ASTM A-193).


e. 2069 kPa (300 psig) steel flanges may be bolted to cast-iron valves, fittings, or other parts having either integral Class 1724 kPa (250 psig) cast iron flanges or screwed Class 1724 kPa (250 psig) cast-iron companion flanges without any changes in the raised faces on either flange. Where such construction is used, the bolting shall be of carbon steel equivalent to ASTM A-307 Grade B, without heat treatment other than stress relief.


5.10 Fittings a. The minimum mill thickness of all flange

or screwed fittings and the strength of factory-made welding fittings shall not be less than that specified for the pressure and temperatures in the respective American Standards.

b. All fittings in nominal sized above; 80 mm for pressures above 1724 kPa (250 psig) but not above 2758 kPa (400 psig); 50 mm for pressures above 2758 kPa (400 psig) but not above 4137 kPa (600 psig), and 40 mm for pressures above 4137 kPa (600 psig) but not above 17238 kPa (2500 psig) shall have flanged ends or welding ends.


5.11 Gaskets a. Gaskets where required, shall be of

material that resists attack by the fluid carried in the pipe line, shall be strong enough to hold the pressure, and perform the purpose intended throughout the temperature range encountered. Gaskets shall be as thin as the finish of the surface that will permit to reduce possibility of blowing out.

b. Paper, vegetable fiber, rubber or rubber inserted gaskets shall not be used for temperatures in excess of 121 C (250 F).


5.12 Hangers, supports,anchors a. Piping and equipment shall be supported

in a thoroughly substantial and workman like manner, rigid enough to prevent excessive vibration and anchored sufficiently to prevent undue strains on boilers and the equipment served. Hangers, supports, and anchors shall be made of durable materials in tunnels and buildings of permanent fire proof construction, piping may be supported on or hung from wood structures if all piping used for conveying fluid at temperatures above 121 C (250 F) is spaced or insulated from such wooden members to prevent dangerous heating.


b. Hangers and supports shall permit free expansion and contraction of the piping between anchors. All piping shall be carried on adjustable hangers properly levelled supports, and suitable springs, sway bracing, vibration dampeners, etc. shall be provided where necessary.


5.13 Pipe sleeves a. Where steam pipe pass through walls,

partitions, floors, beams, etc., construction of combustible material, protecting metal sleeves or thimbles shall be provided to give a clearance of not less than 6.35 mm (1/4 in) under hot and cold conditions all around the pipe, or pipe and covering. When steam pipes pass through metal partitions, etc., a clearance of at least 6.35 mm (1/4 in) under hot and cold conditions shall be left all around the pipe, or pipe covering. In any cases, if the fluid temperature exceeds 121 C (250 F), the pipe shall be insulated inside the sleeve with a covering of at least standard thickness.


b. Walls, floors, partitions, beams, etc., shall not be cast solidly to or built up around and in contact with a steam, hot water, or hot oil pipe. Where such pipe must be installed in a concrete floor or other building member, it shall be protected for the entire buried length with a suitable protecting pipe sleeve of steel, cast iron, wrought iron, or tile; exception maybe taken to the preceding rules where pipes pass through walls, floors, partitions, etc., that must be kept water tight.


5.14 Drains,drips, and steam traps a. Suitable drains or drips shall be

provided wherever necessary to drain the condensate from all sections of the piping and equipment whenever it may collect. Suitable drains shall also be provided to empty water lines, water storage tanks, equipment containing water, etc., when such piping and equipment is out of service. At least one valve shall be placed in each drip or drain line.


b. Drip lines from steam headers, mains, separators, and other equipment shall be properly drained by traps installed in accessible locations and below the level of the apparatus drained. Drip pumps, drip (preferably with orifice control) maybe used in lieu of traps, if they are safely installed protected and operated under regular supervision. All drain lines shall have drip valves for free blow to the atmosphere.


c. Drip lines from steam headers, mains, separators, and other equipment operating at different pressures shall not be connected to discharge through the same trap. Where several traps discharge into one header which is or maybe under pressure, a stop valve and a check valve shall be placed in the discharge line from each trap.


d. Trap discharge piping shall have the same thickness as the inlet piping unless it is vented to atmosphere or operated under low pressure and has no stop valves. The trap discharge piping shall have at least the pressure rating of the maximum discharge pressure to which it maybe subjected against freezing where necessary. Drainage from steam traps, if open to atmosphere, shall be safeguarded to prevent accidents from hot discharge.


5.15 Hydrostatic tests a. Before Erection All valves, fittings, etc., shall be capable of

withstanding a hydrostatic shell test made before erection equal to twice the primary steam service pressure, except that steel fittings and valves shall be capable of withstanding the test pressure as given in the American Standard for Steel Pipe Flanges and Flanged Fittings for the specific material, pressure standard and facing involved (ring joint facing for welding ends.) Pipe shall be capable of meeting the hydrostatic test requirements contained in the respective specification in Table 11.6.2, under which it is purchased.


If a hydrostatic mill test pressure for pipe is not stated in any of the specifications enumerated in Table 11.6.2, the pipe shall be capable of meeting a minimum internal hydrostatic test pressure determined from the formula.

Where: P = test pressure in kPa t = nominal pipe wall thickness in mm. D = pipe outside diameter in mm, and

DStP 2


S = allowable stress in material in kilopascal and which shall be taken as not less than 50 percent of the specified yield point of the material except that hydrostatic tests shall not exceed 17,238 kPa (2500 psig) for sized 80 mm (3 in) and below, or 19,306 kPa (2800 psig) for size over 80 mm (3 in) nor shall the stress produced exceed 80 percent of the specified yield point.


b. After Erection All piping systems shall be capable of withstanding

a hydrostatic test pressure of one and one-half times the design pressure, except that the test pressure shall in no case exceed the adjusted pressure-temperature rating for 38 C (100 F) as given in the American Standard for Steel Pipe Flanges and Flange Fittings for the material and pressure standard involved. For systems joined wholly with welded joints the adjusted pressure rating shall be that for ring joint facing for systems joined wholly or partly with flanged joints adjusted pressure rating shall be that for ring joint facing. For systems joined wholly or partly with flanged joints the adjusted pressure rating shall be that for the type of facing used. .


5.16 Expansion and flexibility. a. Piping systems are subject to a

diversity of loadings creating stresses of different types and patterns, of which only the following more significant ones need generally be considered in piping stress analysis:

1. Pressure, internal or external 2. Weight of pipe, fittings and valves,

containing fluid and insulation, and other external loadings such as wind.

3 Thermal expansion of the line.


The first two loadings produce sustained stresses which are evaluated by conventional methods. The stresses due to thermal expansion on the other hand, if of sufficient initial magnitude will be relaxed as a result of local flow in the form of yielding or in the form of creep. The stress reduction which has taken place will appear as a stress or reversed sign in the cold condition.


b. Materials The thermal expansion range shall be determined

from the Table 11.6.16.2 as the difference between the unit expansion shown for the maximum normal-operating metal temperature and that for the minimum normal-operating metal temperature (for hot lines this may usually be taken as the erection temperature). For materials not included in this table, reference shall be made to authority source data, such as publication of the National Bureau of Standards. The cold and hot moduli of elasticity, Ec and Eh, and the moduli of torsional rigidity, Gc and Gh, respectively, may be taken as the values shown for the minimum and maximum normal operating metal temperatures in Table 11.6.16.2a for ferrous and Table 11.6.16.2b for non-ferrous materials.


c. For flexibility calculations, Poisson’s ratio may be taken as 0.3 at all temperatures for all ferrous materials.

d. The S values, Sc and Sh at the minimum and maximum operating metal temperatures, respectively, to be used for determining the allowable expansion stress range SA shall be taken for the type of piping system involved from the applicable tables in the respective sections of the code. In the case of welded pipe, the longitudinal joint efficiency maybe disregarded in calculating expansion





5.17 General. a. Piping systems shall be designed

to have sufficient flexibility to prevent thermal expansion from causing:

1. Failure from over-stress of the piping material or anchors

2. Leakage at joints 3. Detrimental distortion of

connected equipment resulting from excessive thrusts and moments.


b. Flexibility shall be provided by changes of direction in the piping through the use of bends, loops, and off-sets; or provision shall be made to absorb thermal strains by expansion joints of the slip joints or bellows type. If desirable, flexibility may be provided by increasing or corrugating portions or all of the pipe. In this case, anchors or ties of sufficient strength and rigidity shall be installed to provide for end force due to fluid pressure and other causes..


c. Basic Assumptions and Requirements

1. Formal calculations or model tests shall be required when reasonable doubt exists as to the adequate flexibility of a system. Each problem shall be analyzed by a method appropriate to the conditions.


No hard and fast rule can be given as to when as analysis should be made. However, in the absence of better information the need for a formal stress analysis for a two-anchor system of uniform pipe size is indicated when the following approximate criterion is not satisfied:

Where: D = nominal pipe size, mm Y = resultant of movements to be absorbed by

pipe line, mm U = anchor distance (length of straight line

joining anchors), meter. L = developed length of line axis, meter.

03.02

ULDY


2. In calculating the flexibility of a piping system between anchor points, the system shall be treated as a whole. The significance of all parts of the line and of all restraints such as solid hangers or guides including intermediate restraints introduced for the purpose of reducing moments and forces on equipment or small branch lines shall be recognized.


3. Calculations shall take into account stress-intensification factors found to exist in components other than plain straight pipe. Credit may be taken for the extra flexibility of such components. In the absence of more directly applicable data, the flexibility factors shown in Fig. 11.6.17.3(c) may be used.


4. Dimensional properties of pipe and fittings as used in flexibility calculations, shall be based on nominal dimensions. The pressure stresses for services subject to severe condition shall be based on the reduced thickness of the pipe.


5. The total expansion range from the minimum of the maximum normal-operating temperature shall be used in all calculations, whether piping is cold sprung or not. Not only the expansion of the line itself, but also linear and angular movements of the equipment to which it is attached, shall be considered.


6. Calculations for the expansion stresses SE shall be based on the modulus of elasticity Ec at room temperature.

5.0

POW

ER P

IPIN

G S

YSTE

MS

AND

D

ESIG

N (

CON

T..)

5.0 POWER PIPING SYSTEMS AND DESIGN (CONT..) 5.18 Stresses and reactions. a. Using the foregoing assumptions, the stresses,

and reactions due to the expansion shall be investigated at all significant points.

The expansion stresses shall be combined in accordance with the following formula.

Where: Sb = iMb/Z = resultant bending stress kPa St = Mt/2Z = torsiional stress kPa Mb = resultant bending moment,n Newton-meter. Mt = torsional moment, Newton-meter. Z = section modulus of pipe (m3), i = stress intensification factor

22 4 tbE SSS

5.0 POWER PIPING SYSTEMS AND DESIGN (CONT..) b. The maximum computed expansion stress,

SE based on 100 per cent of the expansion and Ec for the cold condition shall not exceed the allowable stress range, SA:

Where:

In the above formula SC = allowable stress (S value) in the cold

condition Sh = allowable stress (S value) in the hot

condition SC and Sh are to be taken from the table in the

applicable date, the values of f shall be taken from the following table:

Attach Fig. 11.6.1.7.3(c) and Fig. For graph for k and i.

hCA SSfS 25.025.1




Expected life is meant the total number of years during which system is expected to be in active operation.

The sum of the longitudinal stresses due to pressure, weight and other sustained external loadings shall not exceed Sh.

Where the sum of these stresses is less than Sh the difference between Sh and this sum may be added to the term 0.25 Sh in the above formula.

5.0 POWER PIPING SYSTEMS AND DESIGN (CONT..) The longitudinal pressure stress Sep shall be

determined by dividing the end force due to internal pressure:

By the cross-sectional area of the pipe wall

Or

In which Sep = longitudinal pressure stress, kPa p = internal pressure, kPa d = nominal outside diameter of the pipe m inus two

times the normal wall thickness in mm D = nominal outside diameter of pipe, mm

2

2dpF

22

4dDA

22

2

dDpd

SFSep

5.0 POWER PIPING SYSTEMS AND DESIGN (CONT..) The reactions (forces and moments) Rh

and Rc in the hot and cold conditions, respectively, shall be obtained as follows from the reactions R derived from the flexibility calculations based on the modulus of elasticity at room temperature Ec.

or

Whichever is greater, and with the further condition that:

cc

hh R

EE

CR

321

CRRc

REE

SSR

h

c

c

hc

1

5.0 POWER PIPING SYSTEMS AND DESIGN (CONT..) Where: C = cold spring factor varying from zero for

no cold spring to one for 100 percent cold spring

Se = maximum computed expansion stress Ec = modulus of elasticity in the cold

condition Eh = modulus of elasticity in hot condition R = range of reactions corresponding to the

full expansion range based on EC.

Rc and Rh represent the maximum reactions estimated to occur in the cold and hot conditions, respectively.

5.0 POWER PIPING SYSTEMS AND DESIGN (CONT..) c. The design and spacing of support

shall be checked to assure that the sum of the longitudinal stress due to the weight, pressure, and other sustained external loading does not exceed Sh.

6.0INDUSTRIAL GAS AND AIR PIPING SYSTEMS 6.1 This is industrial air and gas in

mines, power plants, industrial and gas manufacturing plants.

a. Piping with metal temperature above 232 C (450 F) or below -2.9 C (27 F).

b. Air piping systems operating at pressures of 207 kPa (30 psig) or less.

c. Piping lines with firebrick or other refractory material used for conveying hot gases.

6.0INDUSTRIAL GAS AND AIR PIPING SYSTEMS (CONT..) 6.2 Wall thickness of Pipe The minimum thickness of pipe wall

required shall be determined by the following formula for the designated pressure and for temperature not exceeding 232 C (450 F).

C

PSPDtm

8.02

6.0INDUSTRIAL GAS AND AIR PIPING SYSTEMS (CONT..) Where: P = maximum allowable, operating pressure in

kPa. The value obtained maybe rounded to the next higher unit of 10. The maximum allowable operating pressure computed with S values permitted under this paragraph, shall not exceed two-thirds of the mill test pressure for a service temperature of 38 C (100 F) or less and five-ninths of the mill test pressure for a service temperature of 232 C (450 F).

S = maximum allowable hoop stress in kPa, see Table 11.7.2.

6.0INDUSTRIAL GAS AND AIR PIPING SYSTEMS (CONT..)


6.0INDUSTRIAL GAS AND AIR PIPING SYSTEMS (CONT..) For steel or wrought-iron pipe (except butt

welded-manufactured under a specification not listed in Table 11.7.2) the value of S shall be 0.6K for a service temperature of 38 C (100 F) or less or 0.52K for a service temperature of 232 C (450 F) where K is the stipulated minimum effective yield strength calculated in the manner described in Section 11.7.3.

tm = minimum pipe wall thickness in mm, i.e., nominal wall thickness less the manufacturing tolerance for the thickness. Where available from on hand or in stock, the actual measured wall thickness maybe used to calculate the maximum allowable operating pressure.

6.0INDUSTRIAL GAS AND AIR PIPING SYSTEMS (CONT..) C = corrosion in millimetre obtained from the following:

D = outside diameter of pipe in inches (mm).

6.0INDUSTRIAL GAS AND AIR PIPING SYSTEMS (CONT..) 6.3 Effective Yield Strength (K)

The effective yield strength K of steel or wrought-iron pipe maybe determined by taking the product of Y, the stipulated minimum yield strength, and E, efficiency of the longitudinal joint. The value of E shall be taken from the following:


6.0INDUSTRIAL GAS AND AIR PIPING SYSTEMS (CONT..) Alternatively, the effective yield strength

maybe determined by internal hydrostatic pressure tests on finished lengths of pipe or on cylindrical samples cut from the results of such tests in accordance with the following formula:

Where: K = effective yield strength in kPa. Py = pressure at the yield strength of the

pipe in kPa.

tDP

K y

2

6.0INDUSTRIAL GAS AND AIR PIPING SYSTEMS (CONT..) This maybe taken as the pressure

required to cause a volumetric offset of 0.2 per cent of as the pressure required to cause a permanent increase in circumference of 0.1 per cent at any point, but other suitable methods of determining that the stress in the steel has reached the yield strength may be used, provided such methods conform in all respects to recognized engineering practices. t = stipulated nominal pipe wall thickness in mm. D = stipulated outside diameter of pipe in mm.

7.0REFRIGERATOR PIPING SYSTEM 7.1 Refrigeration piping shall be

understood to comprise all refrigerant and brine piping, whenever used and whether erected on the premise or factory assembled.

7.2 Minimum Design Pressures for Refrigerant Piping

a. Piping Systems for refrigerants shall be designed for not less than the pressures given in Table 11.8.2.1.

7.0REFRIGERATOR PIPING SYSTEM (CONT..)

7.0REFRIGERATOR PIPING SYSTEM (CONT..) b. For refrigerants not listed in Table 11.8.2.1

the design pressure for the high-pressure side shall be not less than the saturated vapour pressure of the refrigerant at 54 C (130 F). The design pressure for the low-pressure side shall be not less than the saturated vapour pressure of the refrigerant at 32 C (90 F). For refrigerant not listed in Table 11.8.2.1 and having a critical temperature below 54 C (130 F), the design pressure for the high pressure side shall be not less than 1.5 times the critical pressure and the design pressure for the low-pressure side shall be not less than the critical pressure. In no case shall be design pressure be less than 270 kPa (39 psig).

7.0REFRIGERATOR PIPING SYSTEM (CONT..) c. Piping systems for brine shall be

designed for the maximum pressure which can be imposed on the system in normal operation, but not less than 689.5 kPa (100 psig) including for cast-iron pipe, the water hammer allowance as shown in Table 11.8.2.3.


7.0REFRIGERATOR PIPING SYSTEM (CONT..) d. For working temperatures below 18 C

(65 F), an allowance for brittleness of castings, forgings, bolting, and pipe shall be made as follows:

Cast Iron, Wrought-Iron, and Carbon Steel ferrous materials shall have the design pressure including allowance for water hammer increased 2 percent for each degree below 18 C (65 F) and shall not be used below -73 C (-100 F).

Copper, brass, bronze. No adjustment.

7.0REFRIGERATOR PIPING SYSTEM (CONT..) 7.3 Thickness of Pipe

The minimum thickness of pipe wall required shall be determined by the following formula:

Where: tm = minimum pipe wall thickness in mm

CPS

PDtm

8.02

7.0REFRIGERATOR PIPING SYSTEM (CONT..) P = maximum internal service pressure in kPa

(plus allowance for temperatures as provide in Sec. 11.8.2.4 (7.2.d) and water hammer allowance for cast-iron pipe as provided in Sec. 11.8.2.3 (7.2.c)). The value of P shall not be taken at less than 689.5 kPa (100 psig) for any condition of service or material.

D = outside diameter of pipe in mm S = allowable stress in material due to internal

pressure, kPa, Table 11.8.3. C = allowance for threading, mechanical

strength, and/or corrosion, in mm obtained from the following list.



7.0REFRIGERATOR PIPING SYSTEM (CONT..) 7.4 Piping of Pressure Relieving Devices

The most important design factor about pressure relieving devices is the underlying principle of intrinsic safety. They must “fail safe” or not at all. Therefore, the solution to problems in pressure relied piping must be based on sound design practices. Because failure is intolerable, simplicity and directness of design should be encouraged as a mass to reliability.

7.0REFRIGERATOR PIPING SYSTEM (CONT..) There are at least four good reasons why the

installation of pressure safety valves and disc should be engineered with care:

a. The inlet and outlet piping can reduce the capacity of the device below a safe value.

b. The operation of the device maybe adversely affected to the point where the opening or closing pressure is altered. In the case of safety valves, premature leaking or “simmering” may occur at pressures less than the set pressure or chattering may occur after the valve opens.

c. The reaction thrust at the same time the device starts to discharge can cause mechanical failure of the piping.

d. Good design saves maintenance pesos.

7.0REFRIGERATOR PIPING SYSTEM (CONT..) 7.5 Safety Valve Inlet Piping In order to operate satisfactorily, a safety

valve must be mounted vertically. It should be directly on the vessel nozzle or on a short connection fitting that provides direct and unobstructed flow between the vessel and the valve. Safety valves protecting piping systems should of course be mounted in a similar manner. The device may never be installed on a fitting having a smaller inside diameter than the safety valve inlet connection.

7.0REFRIGERATOR PIPING SYSTEM (CONT..) 7.6 Pressure Drop The pressure drop between the vessel

and safety valve inlet flange should not be so large that the valve is “starved” or chattering will result. The following limitations are suggested:

a. The pressure drop due to friction should not exceed 1 percent of the accumulated relieving pressure.

b. The pressure drop due to velocity head loss should not exceed 2 percent of the accumulated relieving pressure.

7.0REFRIGERATOR PIPING SYSTEM (CONT..) Some safety valve manufacturer

suggested a maximum total pressure drop of 2 percent of set pressure. In the absence of test data, it is recommended that this more conservative limit be used.

7.0REFRIGERATOR PIPING SYSTEM (CONT..) These recommendations are based on a

blowdown of a 4 percent. Within this limits, if the blowdown setting is increased, the pressure drop maybe increased proportionately. Remember however, that pressure lost in the inlet piping must be taken into consideration when sizing the safety valve. Pressure loss in the discharge piping should be minimized by running the line as directly as possible. Use long-radius bends and avoid close-up fittings. In no case may the cross-sectioned area of the discharge pipe be less than that of the valve outlet.

7.0REFRIGERATOR PIPING SYSTEM (CONT..) 7.7 Piping Supports

Safety valves, although they may not be included under heading of “delicate instruments”, nonetheless instruments. They are required to measure within three percent and to perform a specific control function. Excessive strain on the valve body adversely affects its ability to measure and control.

7.0REFRIGERATOR PIPING SYSTEM (CONT..) Supports for discharge piping should be designed

to keep the load on the valve to a minimum. In high temperature service, high loads will cause permanent distortion of the valve because of creep in the metal. Even at low temperature, valve distortion will cause the valve to leak at pressures lower than the set pressure and result in faulty operation. The discharge piping should be supported free of the valve and carefully aligned so that the forces acting on the valve will be at minimum when the equipment is under normal operating conditions. Expansion joints or long radius bends of proper design and cold spring should be provided to prevent excessive strain.

7.0REFRIGERATOR PIPING SYSTEM (CONT..) The major stresses to which the

discharge pipe is subjected are usually due to thermal expansion and discharge reaction forces. The sudden release of compressible fluid into a multi-directional discharge pipe produces an impact load and bourdon effect at each charge of direction. The piping must be adequately anchored to prevent sway or vibration while the valve is discharging.


7.0REFRIGERATOR PIPING SYSTEM (CONT..) NOTES: A. The maximum weight per span is based on

bigger steel pipe size weight full of water fittings and insulated.

1. The copper tubing and fittings (for instrument air lines) shall be supported not more than 5 feet on centers or as shown on the drawings.

2. Vertical risers shall be supported from the building construction by means of approved pipe clamps of U-bolts at every floor. Provide slide guides for pipes subject to thermal expansion. Supports shall be of adequate size structural steel shapes or sections where pipe clamps are too short to connect to the building.

7.0REFRIGERATOR PIPING SYSTEM (CONT..) 2. Piping restraints shall be provided

to prevent unnecessary pipe movements due to vibration and seismic forces and damage to pipe joints such as cast iron pipe soldered copper pipes and others as required.

7.0REFRIGERATOR PIPING SYSTEM (CONT..) 7.8 Reaction Forces

The total stress imposed on a safety valve or its piping is caused by the sum of these forces:

a. Internal pressure b. Dead weight of piping c. Thermal expansion or contraction of either

the discharge line of the equipment upon which the valve is mounted and

d. The bending moment cause by the reaction thrust of the discharge.

All of these stresses except the latter are common to practically every problem in piping stress analysis.

7.0REFRIGERATOR PIPING SYSTEM (CONT..) The magnitude of the reaction force resulting from the

instantaneous release of a compressible fluid maybe calculated from the two simple formulas given below.

For safety valve: For safety disc: Where: F1 = Reaction force, kg A = Area of valve orifice or disc., sq. Mm. P1 = inlet pressure at time of opening, kPa (set

pressure plus 14.7) K = ratio of specific heats, Cp/Cv Note: Psi x 6.895 = kPa

11 2.0 APKF

11 2.063.0 APKF

7.0REFRIGERATOR PIPING SYSTEM (CONT..) If it is possible for air to be relieved from

the system under special conditions, use a minimum value of K = 1.4 for design.

Calculation of the reaction force for liquid service demonstrates that this force is negligible. However, since it is usually possible to trap air or gas in any pressure system, it is recommended that K = 104 be used in the above formulas as a basis design for liquid service.


7.0REFRIGERATOR PIPING SYSTEM (CONT..) 7.9 Compressor Piping

Piping in a compressor circuit should connect directly point to point; bends instead of elbows give less friction loss and less vibration; angular branch connections eliminate hard tees and give a smoother flow; double offsets for directional change should be avoided;

7.0REFRIGERATOR PIPING SYSTEM (CONT..) closely integrated intercoolers with the

machine minimizes piping; pulsation dampeners should be located on the cylinders without any interconnecting pipe; knockout drums should be adjacent to the machine; several aftercoolers or exchangers in the circuit should be stacked as much as possible for a direct gas flow; and equipment in the circuit should be in process flow sequence.

7.0REFRIGERATOR PIPING SYSTEM (CONT..) Because of the ever present vibration

problems of reciprocating compressors, pipe supports have a very important role in piping design. Supports independent of any other foundation or structure is almost mandatory. Pipe systems “nailed down” close to grade is a much preferred arrangement. If badly designed compressor piping has to be corrected after start-up of the plant, it can become very expensive.

8.0 VALVES

8.0 VALVES INTRODUCTION

Valves are mechanical devices designed to direct, start, stop, mix or regulate the flow, pressure or temperature of a process fluid. The common types of valves available are gate valves, globe valves, butterfly valves etc. the materials commonly used for construction are iron, steel, plastic, brass or a mixture of special alloys.

8.0 VALVES (CONT..) According to their function valves may be

classified as on-off valves, non-return valves, and control valves. The on-off valves are used to start or stop the flow through the process. Gate valves and pressure relief valves are examples of on-off type of valves to mention a few. The non-return valves allow the fluid to flow in one particular direction only. The control valves are used to regulate flow, temperature or pressure through a system.

8.0 VALVES (CONT..) ON-OFF VALVES: GATE VALVES Gate valves are linear motion valves having

a closure element perpendicular to the process flow that slides into the main stream to provide shut off. These are used in low-pressure systems. The problem with these valves is that they cannot handle throttling operations, are easily fouled and cannot be used in systems having high-pressure drops. It is difficult to obtain tight shut off with these valves and they take longer to open or close than any other manual valves. The different types of gate valves are parallel gate valves knife edged gate valves and through conduit gate valves.

8.0 VALVES (CONT..)

8.0 VALVES (CONT..) BUTTERFLY VALVES These valves are mainly used as an on–off

valve. It is mainly a rotary motion valve that uses a rotating round disk as a regulating element. There are two types of butterfly valves –concentric and eccentric butterfly valves. These valves can be directly installed in between two flanges without any special end connections owing to their very narrow face-to-face dimensions.

8.0 VALVES (CONT..) It has a large flow coefficient and due to

rotary motion of shaft the friction forces generated are far less than a linear motion valve. They have a high pressure recovery factor. These valves are used in low pressure applications. Cavitation and choked flow can occur easily with these valves when installed in an application with high pressure drop.

8.0 VALVES (CONT..)

8.0 VALVES (CONT..) PLUG COCKS AND BALL VALVES For temperature below 250 C, metallic plug

cocks are useful in chemical process lines. As in laboratory stopcock, a quarter turn of the stem takes the valve from fully open to fully closed, and when fully open, the channel through the plug may be as large as the inside of the pipe itself, and the pressure drop is minimal. In a ball valve the sealing element is spherical, and the problems of alignment and “freezing” of the element are less than with a plug cock.

8.0 VALVES (CONT..) In both plug cocks and ball valves the area

of contact between moving element and the seat is large, and both can therefore be used in throttling service. Ball valves find occasional application in flow control.

8.0 VALVES (CONT..)

8.0 VALVES (CONT..) NON RETURN (CHECK) VALVES Non-return valves allow the fluid to flow

only in the desired direction. The design is such that any flow or pressure in the opposite direction is mechanically restricted from occurring. All check valves are non return valves.

Non return valves are used to prevent back flow of fluids, which could damage equipment or upset the process. Such valves are especially useful in protecting a pump in a liquid application or compressed gas applications from back flow when pump or compressor is shut down . Non return valves are also used in process systems that have varying pressure which must be kept separate.

8.0 VALVES (CONT..) There are two types of check(non-return)

valves, swing types and spring types. In the swing type, the pressure of the water

forces the valve gate to 'swing' open, but once the flow stops, gravity causes the gate to fall closed , preventing a reversal of the flow. This type of valve must be mounted vertically or horizontally to work properly.

In contrast, the gate in a spring check valve is spring loaded. Water pressure forces the gate open just as in the swing type, but when the flow stops, the spring, not gravity, forces the gate closed. This enables the valve to be mounted in any position and at any angle..

8.0 VALVES (CONT..)

8.0 VALVES (CONT..) GLOBE VALVES A globe valve is a linear motion valve

characterized by a globe style body with a long face to face dimension that accommodates smooth, rounded flow passages sufficiently long enough to ensure smooth flow through the valve without any sharp turns. These valves can be used in both gas as well as liquid applications and can handle severe conditions of temperature and pressure.

8.0 VALVES (CONT..) The majority of the globe valves have a top

entry design thus permitting a easier servicing of the internal parts and allowing the valves to remain in line when maintenance is taking place. But these valves have certain disadvantages also. They have a high cost and a large size factor and cannot be used for unclean liquids. They are mainly used for flow control and in cases involving vacuum or high temperature extremes.

8.0 VALVES (CONT..)

8.0 VALVES (CONT..) SOLENOID VALVE: Solenoid valves are best suited for small,

short-stroke on-off operations requiring very high speed of response. These valves can open or close in 8 to 12 milliseconds. However, they are limited to pressure drops below 20.7 bars although when pivoted with pilot levers or double seats, they can handle higher pressure drops. A solenoid valve contains a valve body, a magnetic core attached to the stem and disc, and a solenoid coil. A small spring assists the release and initial closing of the valve. The valve is electrically energized to open.

8.0 VALVES (CONT..) When an electrical signal is input to a

solenoid valve (magnetic changeover valve), the drawing force of the solenoid moves the spool, changing the direction of flow. Because the electrical signal is switched at the valve, remote control and automatic control are simple. Stronger springs are used to overcome the friction of the packing when it is required. Reversing the valve plug causes reverse action (open when de-energized). These valves are quite expensive.

8.0 VALVES (CONT..)

8.0 VALVES (CONT..) Bellow Seal Valve Bellow seal valves are a special type of

globe valves which are used for fine control of flow. The main difference between the ordinary globe valves and the bellow seal valve is that in the globe valve there is gland packing along the stem but in the bellow seal valve, a bellow is used to prevent leakage instead of the packing. Bellow seal valves are totally leak-proof. They are used to handle corrosive liquids. This type of valve has been used in the butadiene extraction unit.

8.0 VALVES (CONT..)

8.0 VALVES (CONT..) MATERIAL OF CONSTRUCTION OF VALVES The selection of the valve body material is

usually based on pressure, temperature, corrosive properties and erosive properties of the flow media. Also the choice of the materials depends on economic factors. Majority of control valves involve non corrosive fluids at reasonable temperatures and pressure. Therefore cast iron and cast carbon steel are most commonly used valve body materials.

8.0 VALVES (CONT..)

8.0 VALVES (CONT..)

9.0PIPE SCHEDULE

9.0PIPE SCHEDULE The purpose of the pipe schedule

standards is for all industries that use pipes to use the same standards. Pipe schedules are a means of categorizing pipe and identifying the strengths and characteristics of its capabilities. For all pipe sizes and outside diameter (O.D.) remains relatively constant. The variations in wall thickness affects only the inside diameter (I.D.).

9.0PIPE SCHEDULE (CONT..) Pipe schedule is an American definition

to define pipe thickness and how much pressure can the pipe stand. The most commonly used schedules today are 40, 80, and 160. There is a commonly held belief that the schedule number is an indicator of the service pressure that the pipe can take.

9.0PIPE SCHEDULE (CONT..) The Iron pipe size (IPS) is an older system

still used by some manufacturers and legacy drawings and equipment. The IPS number is the same as the NPS, 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 0.375” wall thickness for NPS 12 and larger. SX is identical to SCH 80 for NPS 1/8 to NPS 8, inclusive, and indicates 0.500” wall thickness for NPS 8 and larger. Different definitions exist for XXS, but it is generally thicker than schedule 160.

9.0PIPE SCHEDULE (CONT..) Industrial pipe thickness follow a set

formula, expressed as the “schedule number” as established by the American Standard Association (ASA) now re-organized as ANI – the American National Standard Institute. Eleven schedule number are available for use: 5, 10, 20, 30, 40, 60, 80, 100, 120, 140, & 160.

9.0PIPE SCHEDULE (CONT..) A schedule number indicate the

approximate value of Sch. No. = 1000P/S Where P = service pressure (psi) S = allowable stress (psi)

9.0PIPE SCHEDULE (CONT..) The higher the schedule number is, the

thicker the pipe is. Since the outside diameter of each pipe size is standardized, a particular nominal pipe size will have different inside pipe diameter depending on the schedule specified.

9.0PIPE SCHEDULE (CONT..) Welded and Seamless Wrought Steel

Pipe

To distinguish different weights of pipe. It is common to use the Schedule terminology from ANSI/ASME B36.10 Welded and Seamless Wrought Steel Pipe:

• Light Wall • Schedule 10 (Sch/10, S/10) • Schedule 20 (Sch/20, S/20) • Schedule 30 (Sch/30, S/30) • Schedule 40 (Sch/40, S/40)

9.0PIPE SCHEDULE (CONT..) • Standard Weight (ST, Std, STD) • Schedule 60 (Sch/60, S/60) • Extra Strong (Extra Heavy, EH, XH, XS) • Schedule 80 (Sch/80, S/80) • Schedule 100 (Sch/100, S/100) • Schedule 120 (Sch/120, S/120) • Schedule 140 (Sch/140, S/140) • Schedule 160 (Sch/160, S/160) • Double Extra Strong (Double extra

heavy, XXH, XXS) Note that many of the schedules are

identical in certain sizes.

9.0PIPE SCHEDULE (CONT..) Stainless Steel Pipe

For stainless steel pipe thru 12-inch, schedule numbers from Schedule 5S to schedule 80S are used as published in ANSI/ASME 36.19M Stainless Steel Pipe.

• Schedule 5S (Sch/5S, S/5S) • Schedule 10S (Sch/10S, S/10S) • Schedule 40S (Sch/40S, S/40S) • Schedule 80S (Sch/80S, S/80S)

10.TYPES OF COPPER PIPE AND TUBES

10. TYPES OF COPPER PIPE AND TUBES Copper pipe and tube comes in a variety

of types, with different wall thicknesses, ductility and intended used. The difference between copper pipe and copper tube is the the way the diameter of the pipe is measured. Copper tube is measured by outside diameter (OD) whereas copper pipe is measured by inside diameter (ID). Depending on the plumbing job you are doing, local and national plumbing codes will dictate which type of copper pipe is acceptable.

10. TYPES OF COPPER PIPE AND TUBES Type L copper pipe

Type L copper pipe and tube has a thicker wall than type M and DWV pipes making it the preferred choice for longevity. There are two kinds of type L; Hard, and soft temper. Type L will be marked with blue along the pipe or tubing.

10. TYPES OF COPPER PIPE AND TUBES Hard temper type L plumbing applications

include: Above ground water distribution Above and below ground drainage and

venting systems Building sewer

Soft temper type L plumbing applications include:

Water service pipe Water distribution above and below ground

10. TYPES OF COPPER PIPE AND TUBES Type M copper pipe

Type M copper pipe and tubing is commonly used in residential plumbing because it has thin walls and can be produced and sold at a much lower cost. For water distribution longevity type M is not recommended. Type M copper is also better for heating applications because of the thin wall thickness. Type M is identified with RED markings along the pipe.

10. TYPES OF COPPER PIPE AND TUBES Hard temper type M plumbing

applications include:

Above ground water distribution Above ground drainage systems

Soft temper type M shall not be used in plumbing systems.

10. TYPES OF COPPER PIPE AND TUBES Type K copper pipe

Type K copper pipe and tube is the most robust of the four types because it has the largest wall thickness. Type K comes in hard and soft temper and will be identified by green markings. Type K copper can be used for many other applications such as: Fuel, gasses, HVAC, fire protection systems and vacuum systems to name a few.

10. TYPES OF COPPER PIPE AND TUBES Hard temper type K plumbing applications

include:

Above ground water distribution Above and below ground drainage and

venting systems Building sewer

Soft temper type K plumbing applications include:

Water service pipe Water distribution above and below ground

10. TYPES OF COPPER PIPE AND TUBES DWV copper pipe

DWV copper pipe is used for drainage waste and vent (DWV), above ground only and is identified by yellow markings.

11.PROBLEMS

11. PROBLEMS 1. Determine the specifications of

material and wall thickness for a 12 in pipe to carry steam at a state selected from the following: (a) 425 psig, 600 F; (b) 400 psig, saturated; (c) 1275 psig, 950 F(d) 850 psig, 850 F.

11. PROBLEMS (CONT..) 2. Would Schedule 120, 8 in pipe

made to A53-SA Specification be acceptable on a line operating at 250 psig, 750 F?

11. PROBLEMS (CONT..) 3. Specify the pipe required to carry

600,000 lb steam per hr at 1255 psig, 1000 F, with velocity approximating 10,000 fpm.

11. PROBLEMS (CONT..) 4. What maximum working pressure

is advisable in an 18 in OD, Schedule 40 pipe A53-SA, operations not to exceed 450 F?

END

Documents

General Piping and Valves