University of Rizal System
College of Engineering
Mechanical Engineering
Morong, Rizal
GENERAL PIPING SYSTEMS AND
LAYOUTS OF INDUSTRIAL PLANT
INDUSTRIAL PLANT ENGINEERING
Submitted by:
Chris Jericho T. Monterola
Erwin Josh C. Apiado
Vixen P. Bautista
Jan Angelo G. Clemente
Jose Crisologo B. Dalit
John Cedric F. Golla
Eduardo G. Quemuel
Carlo Rae F. Villacampa
4 ME - A
Submitted to:
Engr. Jakki Stacy Wayne A. Serra
Subject Instructor
2nd Semester
S.Y.: 2022-2023
University of Rizal System
College of Engineering - Mechanical Engineering
ME18 Industrial Plant Engineering
GENERAL PIPING SYSTEMS AND LAYOUTS OF INDUSTRIAL PLANT
Introduction to Piping System
A pipe can be defined as a tube made of metal, plastic, wood, concrete or
fiberglass. Pipes are used to carry liquids, gases, slurries, or fine particles. A piping
system is generally considered to include the complete interconnection of pipes, including
in-line components such as pipe fittings and flanges. Pumps, heat exchanges, valves and
tanks are also considered part of piping system. Piping systems are the arteries of our
industrial processes and the contribution of piping systems are essential in an
industrialized society.
Fig. 1 illustrates the magnitude of piping required in a typical chemical process
plant. Piping systems accounts for a significant portion of the total plant cost, at times as
much as one-third of the total investment. Piping systems arranged within a very confined
area can be added challenge to piping and support engineers.
Figure 1
Piping Material
The material to be used for pipe manufacture must be chosen to suit the operating
conditions of the piping system. Guidance of selecting the correct material can be
obtained from standard piping codes. As an example, the ASME Code for Pressure Piping
contains sections on Power Piping, Industrial Gas and Air Piping, Refinery and Oil Piping,
and Refrigeration
Piping Systems. The objective being to ensure that the material used is entirely
safe under the operating conditions of pressure, temperature, corrosion, and erosion
expected. Some of the materials most commonly used for power plant piping are
discussed in the following sections.
➢ Steel – Steel is the most frequently used material for piping. Forged steel is
extensively used for fittings while cast steel is primarily used for special
applications. Pipe is manufactured in two main categories – seamless and welded.
➢ Cast Iron – Cast iron has a high resistance to corrosion and to abrasion and is
used for ash handling systems, sewage lines and underground water lines. It is,
however, very brittle and is not suitable for most power plant services. It is made
in different grades such as gray cast iron, malleable cast iron and ductile cast iron.
➢ Brass and Copper – Non-ferrous material such as copper and copper alloys are
used in power plants in instrumentation and water services where temperature is
not a prime factor.
Commercial Pipe Sizes
Commercial pipe is made in standard sizes each having several different wall
thicknesses or weights. Up to and including 304.8 mm (12 inch) pipe, the size is
expressed as nominal (approximate) inside diameter. Above 304.8 mm, the size is given
as the actual outside diameter. All classes of pipe of a given size have the same outside
diameter, with the extra thickness for different weights on the inside.
There are two systems used to designate the various wall thicknesses of different
sizes of pipe. The older method lists pipe as standard (S), extra strong (XS) and double
extra strong (XXS). The newer method, which is superseding the older method, uses
schedule numbers to designate wall thickness. These numbers are 10, 20, 30, 40, 60, 80,
100, 120, 140 and 160. In most sizes of pipe, schedule 40 corresponds to standard and
schedule 80 corresponds to extra strong.
Dimensions and the mass in kg/m of different sizes of steel pipe with varying wall
thicknesses is shown in Fig. 2.
Figure 2
Pipe Fittings
A fitting is used in pipe systems to connect straight pipe sections, adapt to different
sizes or shapes and for other purposes, such as regulating (or measuring) fluid flow. Pipe
Fittings (especially uncommon types) require money, time, materials and tools to install,
and are an important part of piping and plumbing systems. Valves are technically fittings,
but are usually discussed separately. The purposes of the fittings, shown in Fig. 3 may
be generally stated as follows:
Figure 3
➢ Elbows – for making angle turns in piping.
➢ Nipples – for making close connections. They are threaded on both ends with the
close nipple threaded for its entire length.
➢ Couplings – for connecting two pieces of pipe of the same size in a straight line.
➢ Unions – for providing an easy method for dismantling piping.
➢ Tees and Crosses – for making branch line connections at 90º.
➢ Y-bends – for making branch line connections at 45º.
➢ Return Bends – for reversing direction of a pipe run.
➢ Plugs and Caps – for closing off open pipe ends or fittings.
➢ Bushings – for connecting pipes of different sizes. The male end fits into a coupling
and the smaller pipe is then screwed into the female end. The smaller connection
may be tapped eccentrically to permit free drainage of water.
➢ Reducers – for reducing pipe size. Has two female connections into which the
different sized pipes fit. May also be made with one connection eccentric for free
drainage of water.
Methods of Connecting Pipe
There are three general methods used to join or connect lengths of pressure
piping. These are:
1. Screwed Connections.
2. Flanged Connections.
3. Welded Joints.
Each of these methods has certain advantages and disadvantages and each will
be discussed in the following sections.
Screwed Connections
In this method, threads are cut on each end of the pipe and screwed fittings such
as unions, couplings, and elbows are used to join the lengths. This method is generally
used for pipe sizes less than 101.6 mm (4 inch) for low and moderate pressures. It has
the advantage that the piping can be easily disassembled or assembled. However, the
threaded connections are subject to leakage and the strength of the pipe is reduced when
threads are cut in the pipe wall.
Flanged Connections
This method uses flanges at the pipe ends which are bolted together, face to face,
usually with a gasket between the two faces. Flanged connections have the advantage
over welded connections of permitting disassembly and are more convenient to assemble
and disassemble than the screwed connections. Gaskets are usually used between
flange faces. Gaskets are made of a comparatively soft material which, when the flanged
connection is tightened, will fill in any small depressions in the flange faces and thus
prevent leakage.
Welded Connections
In this method, the pipe lengths are welded directly to one another and directly to
any valves or fittings that may be required. The use of these welded joints for piping has
several advantages over the use of screwed connections or flanged connections. And the
main disadvantage of using welded joints for piping is the necessity of obtaining a skilled
welder whenever a connection is to be made
Piping Supports
Piping must be supported in such a way as to prevent its weight from being carried
by the equipment to which it is attached. Various types of piping support are shown in
Fig. 4.
Figure 4
Piping Drainage
In the case of steam piping, it is necessary to constantly drain any condensate
from the lines. If this is not done then the condensate will be carried along with the steam
and may produce water hammer and possibly rupture pipes or fittings. In addition, the
admission of moisture carrying steam to turbines or engines is most undesirable. Various
devices are used to remove this condensate and moisture from the lines and these are
discussed in the following sections.
Steam Separators
Steam separators, sometimes called steam purifiers are devices which, when
installed in the steam line, will remove moisture droplets and other suspended impurities
from the steam. To do this, the separator either causes the steam to suddenly change its
direction of flow or else it imparts a whirling motion to the steam. Both of these causes
the moisture and other particles to be thrown out of the steam stream.
Steam Traps
The purpose of the steam trap is to discharge the water of condensation from
steam lines, separators and other equipment without permitting steam to escape. In
addition, most traps are designed to discharge any air present in the lines or
equipment. Steam traps should be installed in lines wherever condensate must be
drained as rapidly as it accumulates, and wherever condensate must be recovered for
heating, for hot water needs, or for return to boilers. They are a “must” for steam piping,
separators, and all steam heated or steam operated equipment.
Piping Insulation
Most
piping
systems
are
used
to
convey
substances
that
are
at
temperatures much higher than that of the surrounding air. Examples would include the
main steam piping and feedwater piping. In order to reduce the amount of heat lost to the
surrounding air from the hot substance, the piping is covered with insulation. The
insulation not only retains the heat in the hot lines but also prevents the temperature
inside the process plant building from becoming uncomfortably high. In addition,
insulation of hot pipe lines will prevent injury to personnel due to contact with the bare
surfaces of the pipe.
In the case of piping which carries substances at a lower temperature than that of
the surrounding air, insulating the piping will prevent sweating of the pipe and
consequent dripping and corrosion.
Some of the more common materials used for piping insulating are the following:
➢ Diatomaceous Silica – This material is bonded with clay and asbestos and is used
for temperatures up to 1030ºC.
➢ Asbestos – Pipe covering sections are molded from asbestos fibre and are used
for temperatures up to 650ºC.
➢ Calcium Silicate – This insulation is made from silica and lime and is suitable for
temperatures up to 650ºC.
➢ Cellular Glass – This material is glass which has been melted and foamed and
then molded into pipe covering forms. It can be used for temperatures up to 430ºC.
➢ Magnesia (85%) – This material is composed of magnesium carbonate with
asbestos fibre. It is available in molded form for pipe covering and also is supplied
in powdered form to be mixed with water to form an insulating cement which is
used to cover pipe fittings. Magnesia pipe covering is suitable for service up to
315ºC.
➢ Glass Fibre – This is glass that has been processed into fibres and then formed
into pipe covering sections which are suitable for temperatures up to 190ºC.
➢ Plastic Foams – These are plastics that have been processed into a foam during
manufacture and then formed into pipe covering sections. They are available for
temperatures as low as -170ºC and as high as 120ºC.
Industrial Plant Layout
Plant layout is the most effective physical arrangement, either existing or in plans
of industrial facilities i.e. arrangement of machines, processing equipment and service
departments to achieve greatest co-ordination and efficiency of 4 M’s (Men, Materials,
Machines and Methods) in a plant.
Layout problems are fundamental to every type of organization/enterprise and are
experienced in all kinds of concerns/undertakings. The adequacy of layout affects the
efficiency of subsequent operations.
It is an important pre-requisite for efficient operations and also has a great deal in
common with many problems. Once the site of the plant has been decided, the next
important problem before the management of the enterprise is to plan suitable layout for
the plant.
Following points should be considered in designing a layout:
➢ It should follow minimum material handling and minimum in process inventory.
➢ It should be designed such way that it should utilize space properly.
➢ It should provide employee safety and comfort.
➢ It should be flexible to change according to future product requirement.
➢ Minimize production time.
Types of Plant Layouts
➢ Product Layout
In this layout all machines, equipment and work stations are arranged according
to sequence of operation of products and closer to each other. It is also called as Line
Layout. In Product Layout Raw Material is fed at one end and Finished Product is
Came Out at another end from last workstation.
It is also known as line (type) layout. It implies that various operations on raw
material are performed in a sequence and the machines are placed along the product
flow line, i.e., machines are arranged in the sequence in which the raw material will
be operated upon. This type of layout is preferred for continuous production, i.e.,
involving a continuous flow of in-process material towards the finished product stage.
Figure 5 shows a product type of layout.
Figure 5
➢ Process Layout
In this layout, machines or equipment grouped and installed in one area, according
to their function. For example, lathes are installed in one area and grinding machines
are grouped in one area. It also called as functional Layout. In this layout, machines
are not arranged according to the operation sequence of a product. Product or
products will move in between theses work stations according to their operation
sequence. This will result in zig zag movement of material and higher material
movement compared to product layout.
This functional layout is also characterized by keeping similar machines or similar
operations at one location (place). In other words, all lathes will be at one place, all
milling machines at another and so on, that is machines have been arranged
according to their functions. This type of layout is generally employed for industries
engaged in job order production and non-repetitive kind of maintenance or
manufacturing activities. Figure 6 shows a process layout product movement.
Figure 6
➢ Combination Layout
Combination layout is the combination of process layout and product layout. In this
layout advantages of both product and Process layout are obtained.
In such cases machinery is arranged in a process layout but the process grouping
(a group of number of similar machines) is then arranged in a sequence to
manufacture various types and sizes of products. The point to note is that, no matter
the product varies in size and type, the sequence of operations remains same or
similar. Figure 7 shows a combination type of layout for manufacturing different sized
gears.
Figure 7
➢ Fixed Layout
In fixed Layout the Product is fixed or it remains Stationary at specific location and
all Machines, Men and Material is moved around it to manufacture it. We can follow
this layout when the product is huge. Layout by fixed position of the product is inherent
in ship building, aircraft manufacture (Fig. 8) and big pressure vessels fabrication. In
other types of layouts discussed earlier, the product moves past stationary production
equipment, whereas in this case the reverse applies; men and equipment are moved
to the material, which remains at one place and the product is completed at that place
where the material lies.
Figure 8
Factors Influencing Industrial Plant Layout
➢ Man Factor – Safety & working conditions, skill levels, and number of workers.
➢ Material Factor - It includes the various input materials like raw materials, semifinished parts and materials in process scrap, finished products, packing
materials, tools and other services.
➢ Machinery Factor - The operating machinery is also one of the most important
factors therefore all the information’s regarding equipment and the tools are
necessary for inspection, processing and maintenance etc.
➢ Movement Factor - A good layout should ensure short moves and should
always tend towards completion of product. It also includes interdepartmental
movements and material handling equipment.
➢ Waiting Factor - Whenever material or men is stopped, waiting occurs which
costs money. Waiting includes handling cost in waiting area, money tied up
with idle material etc. Waiting may occur at the receiving point, materials in
process, between the operations etc.
➢ Service Factor - It includes the activities and facilities for personnel such as fire
protection, lighting, heating and ventilation etc. Services for material such as
quality control, production control, services for machinery such as repair and
maintenance and utilities liked power, fuel/gas and water supply etc.
➢ Building Factor - It includes outside and inside building features, shape of
building, type of building (single or multistory) etc.
➢ Flexibility Factor - This includes consideration due to changes in material,
machinery, process, man, supporting activities and installation limitations etc.
It means easy changing to new arrangements or it includes flexibility and
expendability of layouts.