Foreword - Location is RelativeAn object's location is always given relative to another reference object.For example, the location of a HeatExchanger may be described as five blocks from the GeneralServiceBuilding. To be more specific, the HeatExchanger is four blocks east and three blocks south of the GeneralServiceBuilding. With this illustration, a direction and a distance from the GeneralServiceBuilding has been established.Several things are assumed to be known, the place to begin (GeneralServiceBuilding), and understanding of east and south (reference directions), and the length of a block (unitofdisplacement). Without consensus on these things, communication of the location of a ProcessPlant becomes unclear.

Reference PointsBefore beginning with making drawings for a new process plant or building, there must be determine where the new building in the area will take his place. A coordination system, which refers to an officially recognized point therefore is necessary.In the Netherlands, for example, are thousands of official reference points, distributed across the country ...search on the Internet on geographic coordinate conversion, triangulation stations, benchmarks, geography or topography. You'll find a lot of information about how reference points are measured and identified.Horizontal ReferenceDefining a starting point of the site related to the North / South direction, is one of the first steps in setting up a coordination system.In principle, with a simple reliable compass the direction of the magnetic north can to be determined. In the image below the true north is at 18. As a draftsman would work with the true north coordinates, he will immediately find out that each line from west to east and from north to south at an angle of 18 must be drawn.To avoid this, a Plant North will be determined. In the example below, the true north, 18 is reversed, draftsmen and construction contractors will be grateful for it.General there will be tried, to approach the true north-south coordinates as close as possible.A rule is, that the angle between true north and Plant North can not exceed 45. At 50, for example, the Plant North would be on the right side, so on the Eastern side of the image.

1= Official reference point2= South West angle of new plantX= East West distance from new plant to reference pointY= North South distance from new plant to reference pointVertical ReferenceBefore starting with any building, the site is leveled (graded), what means that the ground is made as flat as practically possible. After leveling we talking about "finished grade", where the highest graded point is termed "highpointoffinishedgrade".This highest point of finished grade refers to an official reference point on which all vertical measurements are related. In the Netherlands, for example, many vertical measurement are in relation to the "NormaalAmsterdamsPeil" (NAP). If the field compared to the NAP is 1 meter higher, usually the reference point will not become a zero start of 1000 mm, but in this case a zero start at zero(0).On a isometric view of a pipe line elevations are indicated by EL.109665 or EL.99450 etc..What is meant by this vertical dimensions ? The first EL.109665 you can read as: centerline of pipe is 9665 mm above zero point The second EL.99450 you can read as: centerline of pipe is 550 mm below zero pointWell, the vertical zero point in this case is 100 meters (100000 mm), and this has the advantage that no negative (minus) values on drawings need to be appliedPiping Coordination Systems - Plot Plan&Equipment ArrangementForewordFor clarity, as on this website the word Plant is used, then it refers to a Process plant such as a Chemicalplant, Petroleumrefinery, GasProcessingplant, Petrochemical, Pharmaceutical, Textile, Paper, Semiconductor&Cryogenic plants and related processing plants and terminals. Al these plants fall under the scope of ASME B31.3 Process Piping.Drawings, which are shown on this page, are fictitious, but they have been drawn a functional Plot Plan of a Process Plant.Over the years, I've seen a lot of Plot Plans of several engineering companies. All these companies show a certain standard in their plans, but the layout and dimensioning is often quite different. Also sometimes customers or authorities wants to have additional information on a Plot Plan. For this reason there is no general rule, for a "final" Plot Plan.Plot Plan

A Plot Plan is a scale drawing that gives an overview (top view) of the entire plant. All roads, buildings, units, tank farms, employee entrance etc. will be given on a PlotPlan. It also listed the true north and Plantnorth, portaddress, sometimes prevailingwinds, referencepoint(s), horizontalreferences etc..You will understand that a whole process plant, usually can not be given on a readable drawing. Therefore, a distinction is made between a OverallPlotPlan and a DetailedPlotPlan.Overall Plot PlanA Overall Plot Plan, sometimes this plan called a Site Plan or a Site Master Plan, you can compare with a city road map. Important buildings, parks and street names are given, but not the house numbers or the number of rooms in a building.With the drawing in your hands, you should find a certain process tank farm and a specific tank, but not a pump or a plate cooler, or heights of buildings, tanks and so on. That kind of equipment and dimensions are not shown on a OverallPlotPlan.IMAGINARY OVERALL PLOT PLAN

Larger image of a imaginaryOverall Plot Plan.Right down on the drawing you can see the starting point of this imaginary Overall Plot Plan.North starting with N - 000.000 coordinate and East with E - 400.000 coordinate.Both related to an officially recognized reference point, but in practice, the east coordinates refer often to another reference object, and do not start with the coordinates E - 000.000.Right on the top under "Notes" you can see the plant north coordinates and (important !) starting reference elevation of this plant is EL.100000. (see Reference points)There are no pipe-bridges, pipelines, pumps or other equipment shown on that drawing, but the plan gives a good impression of a overall process plant.Detailed Plot PlanIn contrast with a Overall Plot Plan, a Detailed Plot Plan gives a overview (top view) of a part of a process plant. Generally it shows a part of a certain area, floor or unit.As you might have seen on the overall Plot Plan, the process building is largely equipped with a roof, and only some equipment parts are visible from above.TOP VIEW 4th FLOOR DETAILED PLOT PLAN at EL.129200

The plan shows the whole 4th floor on a elevation of EL.129200. These elevation are related to the upper part, Top of Concrete (T.O.C.) of the 4th floor of the FM-AREA, and indicates a elevation of 29200 millimeters from the starting point (EL.100000) of the process plant. Furthermore, it shows some equipment, alarge pipeline and some smaller, astaircase and the columns of the steel structure of the building.Watch out, that all East and North dimensions, starting at the center lines of the columns.A major advantage of a proper detailed Plot Plan is that you can determine from your office, or a new piece of equipment in a certain area, floor or unit, can be placed. That however only applies to the horizontal dimensions, because you cannot see possibly obstructions in the verticallevel.What you also cannot see on a Plot Plan, are the elevations of the equipment. That means that you do not know, or a device on the 4th floor or may be already on the third floor begins...for this reason, EquipmentArrangements have been considered.What is a Equipment Arrangement?Equipment Arrangements are drawings, which show the top and side-view of a part of a process plant. The top-view is similar to a detailed Plot Plan, except that only equipment is shown.Both equipment arrangements shows the equipment in aparticular area, and sometimes afew details around aspecific device. With a drawing of a site-view you can see the elevations of a certain device, and if the device is going through one, or more floors.TOP VIEW 4th FLOOR EQUIPMENT ARRANGEMENT at EL.129200

LOOKING SOUTH 3th and 4th FLOOR EQUIPMENT ARRANGEMENT at EL.121900 and EL.129200

SummaryPlot Plans and equipment arrangements are resources to help determine relative and specific positioning of equipment on a process plant, related to the plant north, that on the drawings must be shown.Both help the development of support facilities and are used to determine the most cost-effective construction sequence and methods. They are also used for operational needs, such as training and emergency access, and are essential for obtaining permits and determining environmental and personnel safety. They are the main documents used in assessing fire protection and if necessary, to obtain government permits..Plot Plans and equipment arrangements are dynamic documents and evolve further during the construction phase and the lifetime of a process plant.Piping Coordination Systems -Piping ArrangementViews in Piping DrawingsThere are two types of views in hand-drawn piping drawings: Orthographic - Plans and Elevations Pictorial - Isometric ViewsOrthographic drawings are views (front, side, top etc.) of an piping system, and in Piping they are called "PipingArrangements".An orthographic view shows only one side, and therefore multiple drawings (views) are necessary to show a complete PipingArrangement.In complex systems, where orthographic views do not illustrate the details of the design, pictorial view in isometric presentation is made for clarity.Priorities on a Piping ArrangementProcess equipment and piping have priority on the Piping Arrangement. The major primary beams and secondary beams are also shown, even as Utility stations so that the most efficient route for utilities can be determined.Order of importance of pipe lines in a Piping Arrangement: Alloy steel and other special materials Large bore piping High temperature/high pressure piping Lined piping Carbon Steel Process Piping Utility pipingFurther (if possible) all equipment, instrument connections, with the tag numbers will be shown on a Piping Arrangement. Important details are often in a larger scale in the same drawing shown.Even as a Plot Plan, a whole process plant usually can not be given on a readable drawing. Therefore the Piping Arrangement show parts of a process plant.Types of Piping Arrangement DrawingsPipelines on a Piping Arrangement are shown by single lines and double lines.In single line representation only the center line of the pipeline is drawn using a solid line. In double line representation the actual size to scale is drawn with center line marked in chain-dotted lines.Single lines representation Flanges are shown as thick lines drawn to the scaled outsite diameter of the flange. For flanged joints a small gap between dimension lines will be shown to indicate a gasket. Valves are shown with identification number and a handwheel is drawn with stem fully extended. If a valve is lever operated, then the movement of handle position is given. Dimensions for flanged valves are given to the flange faces, while non flanged valves are dimensioned to the center lines of their stems.

Example of a single line Piping ArrangementThe drawing shows 2 pumps, 4 valves (all Handwheel operated and flanged), a pipe line and a column.

The line number CD - PL - 101 - 12 - C300 - T2 - I2tells something about the pipe line.CDIndicator for plant or system, where the pipeline is located.

PLIndicator for a service designation.

101Indicator for the serial number of the pipe line.

12Indicator NPS, in this case the main pipeline is NPS 12.

C300Indicator for Pipe Line Class or "PipeSpec".C tells that the material is Carbon Steel, and 300 indicates the Pressure Class.

T2Indicator for E-tracing type.

I2Indicator for Insulation type.

Above description of the line number is only an example. For line numbers are no standard definitions, and therefore a customer specification can be different from what is here defined.The indication 12-314 (Typ) on the valve told that the valve is 12 inches and 314 indicates the type of valve. The same applies also to the valve near the pump, where DR indicates a Drain Valve.Typ stands for Typical and means that there is another ore more valves in that drawing with the same specification. The advantage of this indicator is, that items with the same specification only once need to be defined.Furthermore, the red arrow indicates the flow direction, which perhaps is unnecessary, because the pipe line is connected to the Suction side of the pump. Dis. = Discharge, pressure side of a pump Suc. = Suction, suction side of a pumpAn important item is designationTF(Top Flat) which is shown to the eccentric reducer at the pump. That means that the flat side of the reducer is on the top of de pipe line. If it was vice versaBF(Bottom Flat), also the elevation to the suction side of the pump must be given.Example for the pump suction side:A eccentric reducer 12 to 8 inch has a center-line difference from 52.4 millimeters.(12" = O.D. 323.9 mm / 8" = O.D. 219.1 mm / Length = 203 mm / Center-line difference = 52.4 mm).If the reducer bottom flat, an elevation round off upwards EL. 100548 must be shown.

Note: The connection to the column is Class 600. This change in Pressure Class is indicatedby a so-called "Specbreak" (change of Piping Class Specification). In this case it means, that the flange that connect to nozzle C1 also must be have a Pressure Class of 600, and that the material probably not changed.Another important item is the elevation (given in red) of nozzle C1 from the column. The elevation EL. 104966 is shown, because the pipe line ends with an eccentric reducer Bottom Flat (BF). In this case it means, that the vertical centerline from nozzle C1 is 15.88 mm above the center line of the pipeline.A eccentric reducer 14 x 12 (355.6 mm x 323.9 mm) has a length of 330 mm and a center-line difference from 15.88 mm.Symbols on a Piping Arragement DrawingOn the drawing can be seen that the pipe line(s) from the pumps run up to the column. The pipeline starts with elevation EL. 100600 at the pump suction site and ends at elevation EL. 104950 at nozzle "C1" from the column. But without the elevations, the upward routing is also visible.For single line representation there are a lot of symbols, which illustrate a directional change.The three partly open blue circles in the drawing, indicate three Elbows which are bending down.The two blue half-moons around the pipelines/valves indicate that the valves are at the bottom of the pipeline are located. The two valves are needed to drain the pipeline. By applying eccentric reducers (Top Flat) in the lowest part of the pipeline, the two valves make it possible to fully empty the system.In the main Menu "Docs" the most used drawing symbols can be found.3-Dimensional ViewMore and more engineering companies show Plot Plans, equipment and piping arrangements in a 3D view. Better 3D software has made this possible, and generally has this way of drawing many advantages.There are many programs that can be made 3D views, but they are all very expensive. Large engineering companies often have developed their own software. Some of these programs make it possible "to walking through a whole plant" in order to find a particular item. It is very impressive, what is possible with that type of software.SummaryA standard Piping Arrangement does not exist.Like a Plot Plan or Equipment Arrangement, in the development phase of a new plant, the requirements for the drawings will be made by customer and/or engineering company.Remark(s) of the Author...My own experience with 3-Dimensional Views...Since 1999, I draw many topics in 3D views.The reason is, that I have noted that a pipefitter or construction worker knows immediately what he must build. Another reason is, that people who are not able to read a drawing, also know what I am trying to explain.For myself, I discovered that it cost me less time, to make different views, because with acceptable 3D software, each view (what ever you want) in seconds can be displayed and printed.My first 3-D drawing

In recent years I have found a combination of both, Orthographic and 3D view. If it is a simple drawing I show only two or three orthographic views. In complex drawings I show the necessary orthographicthis views with in the right corner of the drawing, a 3D view. It works perfectly for those who must carry out the job.Simple drawing of a 3-Dimensional view from the Piping Arrangement above mentioned.

The 3D view from the Piping Arrangement is simple but it probably shows, for most users, a direct understandable drawing.At the end of 2008 I had a job for the design of a new 14 inch pipeline from and between two storage tanks. Normally I had made isometric views from the new pipe line and orthographic views of the supports. But in that case, for the first time, I made only 3d views to scale from the pipeline, valves, supports etc.. I gave the pipefitters and construction workers all possible views...the job is performed without any problems.With respect to our "grandfathers", they builded without our current techniques, the largest plants on earth.Piping Coordination Systems - Piping&Instrumentation DiagramThe piping and Instrument Diagram(P&ID)provides a schematic representation of the piping, process control, and instrumentation which shows the functional relationships among the system components. The P&ID also provides important information needed by the constructor and manufacturer to develop the other construction input documents (the isometric drawings or orthographic physical layout drawings).

Very large image of a simplePiping&Instrument Diagram(Dim 3000x2146 / 220kb)The P&ID provides direct input to the field for the physical design and installation of field-run piping. For clarity, it is usual practice to use the same general layout of flow paths on the P&ID as used on the system flow diagram.The P&ID ties together the system description, the system flow diagram, the electric control schematic, and the control logic diagram. It accomplishes this by showing all the piping, equipment, principal instruments, instrument loops, and control interlocks.The P&ID contains a minimum amount of text in the form of notes (the system descriptions minimize the need for text on the P&ID). The first P&ID in the set for the job should contain a legend defining all symbols used; if certain symbols are defined elsewhere, it may be appropriate to only reference their source. The P&IDs are also used by the start-up organizations for preparing flushing, testing, and blowout procedures for the piping system and by the plant operators to operate the system. The correctness and completeness of the SD, SFD, and P&ID drawings are crucial to the success of the start-up program.The P&ID should show the following:Instruments significant to the process piping,including: Mechanical equipment All Valves associated with the process piping Process pipes Vents and drains Special fittings Sampling lines Permanent start-up and flushing linesAll size transitions in line: Reducers and increasers, swages, etc Direction of flow Interfaces for class changes Seismic category Quality level Interconnection references Annunciation inputs Plant computer inputs Vendor and contractor interfaces Identification of components and subsystems by others Reference to a vendor drawing for details not shown Intended physical sequence of equipment: Including branch lines, reducers, etc.

Specific information as applicable to job: Instrument designations Equipment names and numbers Pipeline identification Valve identification

Remark(s) of the Author...The P&ID for a defined system should be limited to coverage of that system to the maximum practical extent. Other systems that interface with the subject system are shown in phantom if such portions are detailed elsewhere.Whenever a line is broken off as a matter of drafting convenience, both the break and the continuation are labeled so that one can readily trace the line from both sides of the break. This applies whether the break and continuation are on the same sheet or on different sheets of the drawing.Except for very simple P&ID, the drawing should have the horizontal and vertical borders marked to permit reference to any small area of the drawing, such as by "Continued at PG-12".Piping IsometricUnlike orthographics, piping isometrics allow the pipe to be drawn in a manner by which the length, width and depth are shown in a single view. Isometrics are usually drawn from information found on a plan and elevation views. The symbols that represent fittings, Valves and flanges are modified to adapt to the isometric grid. Usually, piping isometrics are drawn on preprinted paper, with lines of equilateral triangles form of 60.Image of a isometric grid.

The Iso, as isometric are commonly referred, is oriented on the grid relative to the north arrow found on plan drawings. Becauseiso's are not drawn to scale, dimensions are required to specify exact lengths of piping runs.Pipe lengths are determined through calculations using coordinates and elevations. Vertical lengths of pipe are calculated using elevations, while horizontal lengths are caculated using north-south and east-west coordinates.Piping isometrics are generally produced from orthographic drawings and are important pieces of information to engineers. In very complex or large piping systems, piping isometrics are essential to the design and manufacturing phases of a project.Piping isometrics are often used by designers prior to a stress analysis and are also used by draftsmen to produce shop fabrication spool drawings. Isometrics are the most important drawings for installation contractors during the field portion of the project.Large image of a Hand-Drawn Isometric

How to read a Piping Isometric?A pipe into a isometric view, is always drawn by a single line. This single line is the centerline of the pipe, and from that line, the dimensions measured. So, not from the outside of a pipe or fitting.The image below shows a orthographic view of a butt welded pipe with three sizes (A, B, C). The A size is measured from the front to the center line of the elbow / pipe. The B size is measured from centerline to centerline. The C size is like the A size, measured from the front to the center line of the elbow / pipe.Orthographic view(double line presentation)

Isometric viewThe image here on the right shows a isometric view of the same pipe as on the left.As you can see, this drawing is very simple and quick to implement. The red lines show the pipe, the black dots are the butt welds and A, B & C are the dimensions of front to center line and center line to center line.The simplicity with which a pipe isometric can be drawn is one reason to made iso's.A second reason to made isometrics; if a pipe should be drawn in several planes (north to south, then down and then to the west, etc.), orthographic views really not an option. In a orthographic view it is not a problem if the pipe runs in one plane, but when a pipe in two or three planes to be drawn, a orthographic view can be unclear.Another reason why isos are preferred, is the number of drawings that for orthographic views should be made.For example: for a complex pipeline system, 15 isometrics must be drawn. I've never tried, but I think for orthographic views maybe 50 drawings are needed to show the same as the Iso's.

Isometric, Plan and Elevation Presentations of a Piping SystemThe image below show the presentation used in drafting. The isometric view clearly show the piping arrangement, but the plan view fails to show the bypass loop and valve, and the supplementary elevation view is needed.

Isometric views in more than one planeBelow are some examples of isometric drawings. The auxiliary lines in the shape of a cube, ensure better visualization of the pipeline routing.

The drawing on the left shows a pipeline which runs through three planes. The pipe line begins and ends with a flange.Routing starting pointXpipe runs to the eastpipe runs uppipe runs to the northpipe runs to the westpipe runs down

The drawing on the left is almost identical to the drawing above. A different perspective is shown, and the pipe that comes from above is longer.Because this pipe in isometric view, runs behind the other pipe, this must be indicated by a break in the line.Routing starting pointXpipe runs to the southpipe runs uppipe runs to the westpipe runs to the northpipe runs down

The drawing on the left shows a pipe that runs through three planes and in two planes it make a bow.Routing starting pointXpipe runs to the southpipe runs uppipe runs up and to the westpipe runs uppipe runs to the westpipe runs to the north-westpipe runs to the north

The drawing on the left shows a pipe that runs through three planes, from one plane to a opposite plane.Routing starting pointXpipe runs to the southpipe runs uppipe runs up and to the north-westpipe runs to the northHatches on a Isometric DrawingHatches on isometric drawings being applied, to indicate that a pipe runs at a certain angle and in which direction the pipe runs.Sometimes, small changes in the hatch, the routing of a pipe is no longer the east, but for example suddenly to the north.

The drawing on the left shows a pipe, where the hatch indicates that the middle leg runs to the east.Routing starting pointXpipe runs uppipe runs up and to the eastpipe runs up

The drawing on the left shows a pipe, where the hatch indicates that the middle leg runs to the north.Routing starting pointXpipe runs uppipe runs up and to the northpipe runs upThe two drawings above show, that changing from only the hatch, a pipeline receives a different direction. Hatches are particularly important in isometric views.

The drawing on the left shows a pipe, where the hatches indicates that the middle leg runs up and to the north-west.Routing starting pointXpipe runs uppipe runs up and to the north-westpipe runs to the north