Types of Drawings used in a Project

Types of Drawings used in a Project 

The use of drawings as a means of communication is as old as the existence of mankind. It is a well-known fact that drawing is a universal language allowing communication between people regardless of language barriers. This exchange of ideas and shape description is normally referred to as the graphic language.

A drawing is a two-dimensional representation of three-dimensional objects. It is a graphic representation of an object, or a part of it, and is the result of creative thought by an engineer or a technician. Graphics is a visual communication language which include images, text, and numeric information. When one person sketches a rough map in giving direction to another, it is graphic communication.

It is through the use of the graphic language that people transfer their ideas from their minds and verbal discussions to visual conceptions recognizable by others. Within the realm of the graphic language, there exist several types of drawings, which can range from the simple free-hand idea sketches to the technical set of working drawings needed for the construction of a large project.

Drawings play an important role in the construction field to convey the ideologies and perspective of the designer to the layman at the construction site. The drawings can be used to indicate the overall appearance, inside or outside the structure, or they can be used to indicate precise measurements and other details for the construction of the project. Drawings are used in the design process of the project for visualization, communication, and documentation.

Drawings can be made free-hand, by mechanical tools, or by computer methods. Working drawings are the set of technical drawings used for the production of the products. They contain all the necessary information needed to produce and assemble a product. They are means of clearly and concisely communicating all of the information necessary to transform an idea or a concept in to reality. Hence, a technical drawing frequently contains more than just a graphic representation of its subject. It also contains dimensions, notes, and specifications.

Different types of drawings are is used during the construction of a project. These drawings provide layout plans and details for construction of each and every area of the project. Important types of drawings are described below in an alphabetical manner.

Architectural drawing – It is the technical representation of a building which is made prior to the beginning of the construction process. It is made with lines, projections and is based on a scale.

Architectural site plan – It is an aerial view of the construction site which includes the primary building and its adjoining constructions.  Among its wide applications, one can include construction drawings for building improvement and understanding the scope of construction activities. Along with it, it helps to identify the topography of the building including roads, and pavements etc.

Artistic drawing – It is a form of free-hand representation which makes use of pictures to provide a general impression of the object being drawn. There are no hard rules or standards in the preparation of artistic drawings. These are simply drawn by the artists, based more or less on their talent and skills. Although these drawings are frequently very attractive, they find very limited use in the world of science.

As-built drawing – It is also known as record drawing. On construction projects, it is normal for changes to be made during construction because of circumstances which emerge on site. As a result, it is normal that as-built drawings is prepared, either during the construction process or when construction is complete, to reflect what has actually been built.

The as-built drawings provide a comparison between what has been built and the original plan. This can happen because of the incidental conditions the site engineer is to make changes in the construction pattern and design. The site engineer normally mark-up changes are made to the ‘final construction issue’ drawings onsite using red ink, and these can then be used by the consultant team to create record drawings showing the completed project.

Assembly drawing – It is a drawing which shows the different parts of an equipment in their correct working locations. Assembly drawings demonstrate how a number of separate sub-assemblies, parts, standard components, and specifications come together in a unified assembly. Normally speaking, an assembly drawing is used to show fit and function, and to verify how a product is put together. In order to fulfill its purpose, assembly drawing is to provide sufficient information to enable the assembly of a component.

Assembly drawing provides precise, detailed information as to the construction of buildings or equipments, including matters such as the fixing of materials, components, and elements. It is used to represent items which consist of more than one component. These drawings show how the components fit together and can include, orthogonal plans, sections and elevations, or three-dimensional (3-D) views, showing the assembled components, or an exploded view showing the relationship between the components and how they fit together. In some cases, it is not necessary to produce assembly drawing, since the assembly information can be given on the location drawing, particularly when it is drawn to a scale of 1:50.

In case of structures, this type of drawing is made to depict the connection between two components of a structure. It shows how the different parts of this structure fit together. It has all kinds of designs and patterns including 3D, sectional, and elevation views.

The purpose of an assembly drawing is to (i) show the construction of individual elements of structure (foundations, walls, floors and roofs) / equipment, (ii) show the arrangement where two elements meet each other, e.g., the junction between a wall and a roof, and between a column and a wall, and (iii) provide a reference as to where more detailed information about a particular part of the construction is provided.

The important features of assembly drawings include (i) they have a number of views to show how parts fit together, (ii) they have normally section views to show how parts fit and to eliminate hidden details, (iii) they typically have dimensions to indicate range of motions and / or overall size of assembly for reference purposes, (iv) they have leader lines and balloons to identify individual components, (v) they have parts list (bill of materials, BOM) which is related to balloon numbers on drawing, and (vi) they can need multiple 3-D views (in different orientations) on a separate page for very large assemblies. There are several types of assembly drawings. Fig 1 shows example of an assembly drawing.

Fig 1 Example of assembly drawing

Block flow diagram – It is a drawing of the process used to simplify and understand the basic structure of the process. It is the simplest form of the flow diagram used in the industry. Blocks in this diagram can represent anything from a single piece of equipment to an entire plant. For a complex process, this diagram can be used to break up a complicated system into more reasonable principal stages / sectors.

Block flow diagram (BFD) is made for a process unit. It reflects (i) functional requirements of the unit, (ii) depicts the different processes carried out within the process unit and their sequence, and (iii) shows the inputs (feed) and outputs (products). The diagram is used to explain the normal material flows throughout the entire plant. It is generalized to certain plant sectors or stages. The diagram helps orient operators to the products and important operation zones of a process facility. Fig 2 shows an example of a simple BFD.

Fig 2 A simple block flow diagram

Block plan – A block plan is the representation of a wider area which is in proximity to the main building under construction. A block plan can include the adjoining buildings, the roads, boundaries, and other such components. More importantly, a block plan is represented in scales, which also means that they cover a wide area.

Block plans normally show the siting of a project in relation to survey maps. Conventions are used to depict boundaries, roads, and other details. Depending on the size of the project, the desired scales are 1:2,500, 1:1,250, and 1:500.

Civil drawing – A civil drawing is a type of technical drawing which shows information about grading, landscaping, or other site details.

Column layout – Column layout reinforces the design and pattern of the columns of the whole structure. This plan is divided floor-wise and demarcates the exact size and distance between every column of the building. Column layout drawings further make it easier for the site engineers to make sense of the whole building layout.

Completion drawing – This drawing is also known as record drawing or as-built drawing. There are bound to be certain variations, additions, or alterations as project progresses, because of unseen site conditions and advancement in technology. Howsoever small the variations, additions, or alterations can be, these are to be recorded on the completion drawings. Completion drawings are to be prepared simultaneously as the work proceeds.

Component drawing – A component drawing is mostly referred to as the drawing supplied by the manufacturer of the equipment. This kind of the drawing is complete with all the details of the component hence providing a detailed insight into its markings and different sub-parts.

Component drawing is a detailed drawing of a component to facilitate its production. All the principles of orthographic projection and the technique of graphic representation are followed to communicate the details in this drawing.

A component drawing provides detailed information about the nature and manufacture of a specific item incorporated on an assembly / layout drawing. This is in contrast to an assembly drawing which shows several parts, or a location drawing which provides general information. The purpose of a component drawing is to (i) show the nature, shape, assembly method and further details of components, needed by the manufacturer and others, and (ii) provide additional information which cannot be conveniently given on location or assembly drawings.

Normally, components are ‘self-contained’ and sourced from a single supplier, typically the complete unit provided by the supplier rather than its constituent parts. Component drawings provide detailed information about the individual units. They can be drawn at large scales suchas; 1:10, 1:5, 1:2, 1:1, and so on. They can include information such as component dimensions, construction, tolerances, and so on.

Concept drawing or sketch – Concept drawing or sketch is a drawing, frequently freehand, which is used as a quick and simple way of exploring initial ideas for designs. This drawing /sketch is not intended to be accurate or definitive, merely a way of investigating and communicating design principles and aesthetic concepts.

Concept drawings are more like the first draft of a construction project which is made in the first instance. They are not very detailed or distinguished. The concept drawings are like rough sketches. They are more prominently used to describe an overview of the object.

Sketches are always made as the first step in the preparation of engineering drawings. The work-piece (object) is carefully studied and all the necessary dimensions are measured. The views which are necessary to completely describe the object are very roughly drawn (free hand). All dimensions are indicated on the sketch as deemed necessary. In majority of the situations, axonometric views of the object are drawn.

Sketches are never submitted anywhere. They are just drawn to assist the person at a later time during the preparation of the standard drawings. That is, the only purpose of preparing sketches is to enable the person to transfer useful information from the spot to a convenient place where the person can actually prepare acceptable engineering drawing. For this reason, there are no hard rules or general guidelines with respect to sketches. However, sketches are to be drawn accurately so that they can prove useful at a later stage.

Construction drawing – This drawing is also known as the working drawing. It provides dimensioned, graphical information which can be used at the construction site for the construction work, or by suppliers to fabricate components of the works or to assemble or install components. Along with specifications and bills of quantities or schedules of work, it forms a part of the ‘production information’, which is prepared by designers and passed to the construction team to enable a project to be constructed.

Construction drawing provides an insight into the development of a construction site. These drawings are made in different stages. Some plans are necessary to be made before the construction begins while others are made while the construction is under progress. Construction drawing provides an outlet for the engineers to convey their ideas and concepts regarding a project.

Construction drawing is a means of showing in a graphical form the shape, size and position of a building or equipment on a site, together with the composition of the materials used and the way the building or equipment is to be constructed or put together. The information on construction drawings has to be presented in a precise, unambiguous manner so that it can be understood by anyone with a knowledge of draughtsmanship and construction.

Contract drawings – The engineer can carry on with detailed design only after the completion of tender drawings. If tendering has been straight forward and without any alternative proposals, the contract drawings are the same as tender drawings. If alternate proposals have been accepted, new or additional drawings are to be prepared as per the accepted tender proposals and alternatives.

Cross section drawing – Cross-section drawing allows the engineer look at the different components of an object vertically. This 2-dimensional (2-D) drawing is helpful to provide an overview of both the visible and hidden components of the object.

Design drawing – Design drawing is made during the initial stages of the project and used for all initial activities including contract bidding. Design drawings are subject to revision with the progress of the project.

Design drawing is used to develop and communicate ideas about a developing design. In the early stages of design, the design drawing simply demonstrates to the people the ability of a particular design team to undertake the design. This drawing is then be used to develop and communicate the brief, investigate potential sites and assess options, develop the approved idea into a coherent and coordinated design, and so on.

Design drawing is somewhat similar to concept drawing. It means that this drawing is also useful in case of fetching new conversions for a particular project.  It is also useful in proposing of the designs and providing a rough idea to the designing teams for their reference. This drawing can also become a benchmark or can be used as a comparison.

Detail drawing – Detail drawing is the drawings of any kind of geometric structure which is to be constructed. The drawing is more detailed and pay attention to the intricate designs and details of any construction project

Detail drawing is an engineering drawing presenting single item (object / equipment component / work-piece etc.). The drawing is meant for enabling a person in a workshop to produce (by machining / casting / forging / fabricating etc.) the desired item. Such details as dimensional tolerances, surface finish, special treatments, material to be used for the component etc. are specified. The number of views to be presented depends on the complexity of the item. In several situations, sectional views are included to show hidden details which cannot conveniently and explicitly appear in any external view.

The scale used for the detail drawing is to allow a clear understanding of the drawing (i.e., use enlargements and / or reductions as one finds it appropriate). Sometimes just a small portion of the drawing is enlarged to show all the details. Such partial enlargements are normally included in the same drawing. When the item is drawn much enlarged, it is desired to add a picture (drawing) to true size for more information.

Detail drawing provide a detailed description of the geometric form of a part of an object such as a machine, and a plant etc. It tends to be large-scale drawing which shows in detail parts which can be included in less detail on general arrangement drawing.

Electrical drawing – Electrical drawing, also known as a wiring diagram, is a type of technical drawing which provides visual representation and information relating to an electrical system or circuit. It provides information about the electrical circuits and other systems. It is used to guide and convey the engineering design to the electricians or any other person who uses it to help in installing the electrical system.

The electrical drawing represents an in-depth account of all the electrical connections, outlets, fixtures, switches, lighting, fans, and everything else. This drawing provides pillar support to the electricians allowing them to understand the wiring layout on the site floor. It also indicates the load capacity and information about all the electrical equipments and systems.

Elevation drawing – An elevation is a view people get if they look in a horizontal direction at the vertical side, or face, of an object. When drawing an elevation, one is required to take the horizontal dimensions from the plans and the vertical dimensions from the sections.

The term ‘elevation’ refers to an orthographic projection of the exterior (or sometimes the interior) faces of the object, i.e., a two-dimensional (2-D) drawing of the object. Since the object is rarely of a simple rectangular shape in plan, an elevation drawing is a first angle projection which shows all parts of the object as seen from a particular direction with the perspective flattened. Normally, elevation drawing is made for four directional views, for example, north, south, east, west.

Engineering drawing – An engineering drawing is a type of technical drawing used to define the requirements for engineering products or components. Typically, the purpose of an engineering drawing is to clearly and accurately capture all geometric features of a product or component so that a manufacturer or engineer can produce the required item.

A plant facility can need the installation of some structure or equipment. The engineering drawing is targeted toward the convenient placement of such structure or equipment. The engineering drawing is more of a guide to help the installation engineer for getting the desired results. Engineering drawings of real-life objects are normally prepared in three stages namely (i) sketches, (ii) hand drafts, and (iii) detail drawings. This sequence is not very binding but majority of the people find it very useful to work in that order.

Environment plan drawing – Some projects are built around rivers or streams. In that case, the environmental plan drawing provides insights into how erosion and sedimentation is to be managed. These drawings also talk about plant effluent removal procedures and chemical disposal mechanisms. Moreover, it also has the procedures and plans to reduce the harmful effects.

Equipment drawing – It is pertaining to equipment parts or components. It is presented through a number of orthographic views, so that the size and shape of the component is fully understood. Part drawings and assembly drawings belong to this classification. Fig 3a shows example of equipment drawing.

Fig 3 Examples of equipment and production drawings

Erection drawing – It is a drawing for the erection of steel structures / equipments election. This drawing is a graphical representation and contains the information regarding connections of the assemblies. The erection drawings are designed at the final stage of the development of workshop drawings.

The information which is normally provided in the erection drawing is (i) floor plans and sections of the steel structures / equipments are arranged towards each other and inter-connected in space, (ii)   local sections, views, connections of assemblies and other images to show how the assemblies are connected with each other, (iii) markings (names) of assemblies, specifying the profile (section) of the main part of the assembly, (iv) connection type of assemblies (using mounting bolts, including strength grade, standard and sizes of bolts, nuts and washers, or applying site welding, and showing the type of the weld and its dimensions), (v) all necessary dimensions (snapping of assemblies to coordinate axes, distances between assemblies etc.), (vi) technical instructions to be followed during the erection of assemblies, (vii) title block, (viii) lists (list of erection drawings, list of assembly drawings, material list, metal goods list, list of site welds), and (vii) layout plan of the steel frame of the building. Erection drawings are the basis for assembly , erection of the steel structure / equipment.

Excavation drawing – Excavation drawing is needed for knowing the length, depth, and width of the excavation needed for foundation work. It tells about the extent of excavation, removal of soil, and the process of excavation as well as the different processes used for excavation like trenching, wall shafts, tunnelling, and others.

Finishing drawing – The finishing drawing has a close relationship with the elevation drawings as it also talks about the smaller details of a facility. This drawing is important for maintaining the aesthetic value of the structure.

Fire-fighting drawing – This drawing is drawn before the construction of a facility. The drawing shows the pattern of the placement of the fire hoses, points, water outlets, and everything connected with fire-fighting. The drawing also lays out the fire protection plan and safety systems which are to be set in place.

Floor plan drawing – This drawing is in-depth version of the floor layout. Civil floor plans are made irrespective of the fact that they are to be utilized during the construction of a building, or production shop. Applications include an understanding of the dimensions and different kinds of installment. This helps in getting an idea about the usage of the limited room space.

Floor plans are normally very useful, and they are the most used location drawings. They are really the sectional plans since they show the view obtained by cutting horizontally through a building at some point above the floor level. It is assumed that one move away the top part of the building and look down at the plan of the remaining bottom part. This plan view not only shows the arrangement of the rooms and spaces and their shapes, but also shows the thickness of all the external and internal walls.

The level at which one cuts horizontally through a building is normally assumed to be 1 metre above the floor level. This has the advantage of passing through most of the windows and doors, which means that dimensions giving the positions of all openings can be given. The purpose of a location floor plan is to (i) indicate the shape and the layout of the building, (ii) provide the setting out dimensions for the building, (iii) locate spaces such as rooms, and parts such as doors, and (iv) provide references stating where more detailed information can be found.

Floor plans are a form of orthographic projection which can be used to show the layout of floors within buildings. They can be prepared as part of the design process, or to provide instructions for construction, frequently associated with other drawings, schedules, and specifications.

Flow chart – A flowchart is a type of diagram that represents a workflow or process. A flowchart can also be defined as a diagrammatic representation of an algorithm, a step-by-step approach to solving a task. The flowchart shows the steps as boxes of various kinds, and their order by connecting the boxes with arrows.

A flowchart shows separate steps of a process in sequential order. It is a generic tool which can be adapted for a wide variety of purposes, and can be used to describe different processes, such as a manufacturing process, an administrative or service process, or a project plan.

Framing plan drawing – Framing plan drawing is similar to the beam layout. It offers information about the framework, sizes, and positions of the beams. It is helpful since to the site engineers as they can easily understand and layout the plans for the roof, floor, and other such structures which are a necessary part of a building.

Foundation plan drawing – A foundation plan drawing shows the top view of the footings or foundation walls, and shows their area and their location by distances between centre-lines and by distances from reference lines or boundary lines. Actually, it is a horizontal section view cut through the walls for the foundation showing beams, girders, piers or columns, and openings, along with dimensions and internal composition. The foundation plan is used primarily by the people who construct the foundation of   the   proposed   structure

A foundation plan drawing can be made for any floor of a plant facility. The purpose of making this drawing is to convey the dimensions, sizes, shapes, and every single configuration of a floor. Footings are also a necessary part of a foundation plan drawing.

General arrangement drawing – General arrangement drawing, normally known as GA drawing, forms the backbone of precision engineering and project planning. It is a comprehensive visual representation which provides a holistic view of a layout of a project, ensuring smooth execution and minimal errors. GA drawing acts as a blueprint for architects, engineers, and contracting agencies, facilitating seamless collaboration and communication throughout the project life-cycle.

GA drawing plays an important role in precision engineering by offering a clear and concise overview of the design and layout of the project. This drawing includes necessary details such as dimensions, scales, and positioning of major components, providing a foundation for accurate construction. With precise measurements and explanations, GA drawing minimizes uncertainties and discrepancies, leading to a higher level of accuracy and efficiency during the implementation phase.

A well-made general arrangement drawing comprises several key elements which adds to its effectiveness. These elements include (i) title block which contains project information like title, author, date, and revision details, (ii) orthographic views containing multiple views of the project from different angles for a comprehensive understanding, (iii) explanations such as dimensional labels, notes, and symbols for clear communication, (iv) sectional views such as cross-sections to showcase internal details of complex structures, (v) bill of materials (BOM) which is a detailed list of materials needed for construction, (vi) legend which explains symbols and abbreviations used throughout the drawing, and (vii) scaling and units which clearly defines the scale and units for accurate measurements.

General arrangement drawing presents the overall composition of an object. Depending on the complexity of the facility, there is likely need of a number of different projections, such as plans, sections and elevations, and they can be spread across several different drawings.

General note – The general note does not have any drawings. It contains detailed information about the project which includes the by-laws, codes, length, mapping forms, construction type, legends, abbreviations, and everything else which is necessary.

HVAC drawing – HVAC (heating ventilation and air conditioning) drawing provides information about the heating and ventilation systems. It also includes the air conditioning patterns and layout which are to be constructed inside the building. The HVAC drawing provides an insight into these complex systems and helps in planning the construction process accordingly.

The HVAC plan is a schematic diagram which visually represents the structure and components of mechanical systems installed for thermal comfort, air-conditioning, and better air quality. HVAC symbols are used to depict the layout of devices, ventilation network, and other components of a HVAC system. The purpose of using HVAC symbols is to design an accurate HVAC plan which satisfies the environmental requirements of comfort by adjusting the outdoor air conditions. There are two common types of HVAC plans. The central HVAC plan is used when the need is to locate the system away from the building. It uses delivery ductwork to deliver the conditioned air. The local HVAC systems are normally positioned near or inside the conditioned zone with ductwork requirements.

Installation drawing – Installation drawing is the drawing which is based on the detailed design or coordination drawing with the primary purpose of defining that information needed for the installation of plant and equipment. This drawing is particularly important for complex installations. The drawing comprises plan, section and elevation.

Installation drawing includes information about (i) precise positioning, (ii) supports and fixings, (iii) information from manufacturers shop drawings, (iv) space allowances for installation, (v) installation work in connection, such as cutting, and, sealing holes, chasing block and brickwork for conduits or pipes, lifting and replacing floors, constructing plinths and so on, (vi) plant and equipment requirement, (vii) requirements  for service connections, (viii) requirement to leave access space for operation and maintenance, and (ix) other maintenance access requirements such as access panels, decking, platforms, ladders and handrails. It is important that the information presented is carefully co-ordinated so that clashes are avoided.

Isometric drawing – This drawing is used for piping. Isometric drawing is 3-D representation of piping on two dimensions of the drawing sheet. Isometric drawing covers a complete line as per the line list connecting one piece of equipment to another. It shows all information necessary for the fabrication and erection. It is not drawn to scale but is to be proportional for easy understanding. Dimensions are given relative to centre-line of piping.

Isometric drawing also includes (i) plant North with the direction so selected as to facilitate easy checking of GA drawing with isometric drawing, (ii) dimensions and angles, (iii) reference number of P&IDs (piping and instrument diagram), GA drawings, line numbers, direction of flow, insulation and tracing, (iv) equipment location and equipment identification, (v) nozzle identification on the connected equipment, (vi) details of flange on the equipment if the specification is different from the connecting piping, (vii) size and type of every valve and direction of operation, (viii) size and number of control valve, (ix) location, orientation and number of each equipment, (x) field weld, preferred in all directions to take care of site variations (it can also be covered with a general note), (xi) location of high point vents and low point drains, which is preferably covered with a standard arrangement note, (xii) any special requirement such as line to be tested prior to installation etc., (xiii) BOMs, and (xiv) requirements of stress relieving, seal welding, pickling, and coating etc. Fig 4 shows isometric pipeline drawings.

Fig 4 Isometric pipeline drawings

Landscape drawing – The landscape drawing is the aerial view of the whole area in which the building is built. It includes the areas designated for trees, street lights, parks, pools, and everything else. Landscape plan is more frequently used to depict the external aesthetics of the building. One can also include in them the paths, roads, pavements, parking areas, and several other things.

Lintel beam layout – Lintel beam is another form of support structure which is made above the doors and windows. It is reinforced structures which is made to provide strength to the part of the building that is made above the windows and doors. In this kind of drawings, one finds the correct positions, dimensions, and the number of lintel beams on every floor.

Location drawing – It is also referred to as general arrangement drawings. It is made to showcase the composition of the entire project. If the project has several parts and buildings to be constructed, then the location drawing is required to include details for all of them. Under it, one can consider adding elevations, projections, different plans, and sections.

Location plan – A location plan is a supporting document which is needed to be included as part of the detailed project report. The location plan provides an illustration of the proposed development in the surrounding area of the project.

The location plan covers a wide area. This kind of drawing needs the engineer to check out the whole area where the project is to be constructed. The location plan represents the objects and more importantly, it shows the relationship between the different stages of project development.

Manufacturing drawing – Manufacturing drawing shows all the detailed dimensions and specifications of a single part so that it can be made with precision. Manufacturing drawing includes complete dimensions, the surface finish, welding information, plating, and any other requirements such as the deburring of the part. The quantities and complexity of the part influences how the manufacturer decides which method is the most cost effective to produce it.

Material flow diagram – It is also known as material flow chart. It is used to visualize the use of materials. e.g. along a supply chain. It is used to show material and mass flows in a visually appealing way. Hence, It can show e.g., the distribution of goods or the consumption of resources within a production system. Also, it is applicable for holistic material flow analyses. It can cover a large number of areas such as (i) material flow analysis and management, (ii) supply chain management, (iii) plant planning, (iv) process engineering, and (v) logistics.

Several times, it is visualized by so called Sankey diagram where flow widths proportional to the flow quantity. Material flow diagram provides a lot of benefits for the visualization of material usages.

Model – Model comes after the drawings. It is made for the project and it personify how the project is going to look when it is complete. The benefit of making model is that it helps the engineers in identifying the difficulties. Everything is clear in a model, the design, elevation, as well as internal and external detailing.

Part drawing – It is a detailed drawing of a component to facilitate its production. All the principles of orthographic projection and the technique of graphic representation are followed to communicate the details in a part drawing. A part drawing with production details is also called as a production drawing or working drawing.

Penetration drawing – It is designed for structural, mechanical, electrical, plumbing, and fire protection systems. This drawing is dimensionally locating all sleeve / cores and shaft penetration through floors and walls including the size of the actual opening and rough-in dimensions.

Perspective drawing – A perspective drawing highlights the spatial aspects of a building along with showing its three-dimensional volumes. It is the realistic image of the project which is under construction. In addition to this, there are different types of perspectives based on vanishing points.

Perspective drawing is a technique for depicting three-dimensional volumes and spatial relationships based on the eye level and vanishing point (or points) of the viewer. It can give a realistic impression of what a volume or space is going to look like in reality. Constructing perspective drawings of projects is extremely complicated, but has been much simplified recently ecause of the development of computer aided design (CAD), building information modelling (BIM), and other forms of computer-generated imagery (CGI).

Piping and instrument diagram (P&ID) – P&ID is sometimes called process and instrument diagram. It is more technical, describing mechanical details for piping designers, electrical engineers, instrument engineers, and other technical experts who need this detail more than they need process details. P&IDs take the conceptual aspects of a process flow diagram (PFD) and add detail about the equipment, process sequence, process and utility piping, bypass lines, instruments, valves, vents, drains and other items.

P&IDs are the drawings showing piping and communications as schematic (unscaled) lines and control features as symbols. P&IDs show the functional relationship of piping, instrumentation, equipment, and controllers. They are normally a part of the instrumentation drawings in a project drawing set. P&IDs are normally made by process engineers, controls engineers, and electrical engineers. The main purpose of a P&ID is to indicate if the equipments are automatically controlled, and if so, how they are inter-locked with instruments. P&IDs convey the inter-connectivity of automated equipments.

P&ID is based on the PFD and depicts the technical realization of a process by means of graphical symbols representing equipment and piping, together with graphical symbols for process measurement and control functions. All equipment, valves, and fittings are represented as per ISO 10628-2. The process measuring and control tasks are represented as per IEC 62424. Auxiliary systems can be represented by rectangular frames with references to separate flow diagrams.

The P&ID contains at least the basic information consisting of (i) function and type of equipment and machinery, including drives, conveyors, and installed back-up / reserve equipment, (ii) designation of apparatus and machinery, including drives, (iii) characteristic data of equipment and machinery, given in separate lists, if necessary, (iv) indication of nominal sizes, pressure ratings, material, and type of piping, e.g., by stating the pipeline number, piping class, or designations, (v) details of equipment, machinery, piping, valves, and fittings e.g., pipe reducers given in separate list if necessary, (vi) symbols for  process measurement, and control functions including letter codes for process variables, control functions, and  designation of the process, measurement, and control function, and (vii) characteristic data of drives, given in separate lists if necessary. Fig 5 shows piping and instrumentation diagram with basic information.

Fig 5 Piping and instrumentation diagram with basic information

Piping drawing – Piping engineers derive basics from the BFD, PFD, and P&ID drawings to represent the pipeline routing on the drawing. There are two types of views used in the piping drawings (i) orthographic views representing plans and elevations, and (ii) perspective views which are isometric views. Fig 6 shows single-line and double-line orthographic pipeline drawings.

Fig 6 Types of pipeline drawings

Piping drawings are scaled graphic representations of piping systems and devices. They include plans (top views), elevations (frontal or profile views) and sections (internal frontal or profile views). Piping drawings can be very complex sometimes as they show all equipment, fittings, instrumentations, dimensions and notes. Data for piping drawings are derived from PFDs, structural, mechanical, instrumentation drawings, and catalogues / manuals of the suppliers. Piping drawings include (i) plot or site plan, (ii) unit plan, (iii) zone plan, (iv) equipment drawings, (v) equipment layout drawings, (vi) piping plans and elevations, and (vii) 3-D (three dimensional) plant model.

Piping layout is developed in both plan view and elevation view and section / details are added for clarity wherever necessary. These drawings are called the ‘general arrangement’ (GA) of piping. For representing a three-plane piping in two dimensions of the paper, certain symbols as given in the national and international standards are followed.  Orthographic symbols are available in templates which are used for speeding up the manual drafting and also in the symbol library for computer aided design (CAD).

Plant layout drawing – Plant layout drawing refers to the arrangement of physical facilities such as machines, equipment, tools, utilities, furnaces, and control rooms etc. in such a manner so as to have quickest flow of material at the lowest cost and with the least quantity of handling in the production of the product from the receipt of the input materials to the dispatch of the finished products. The word ‘plant’ in the plant layout can refer to a production unit of a plant or a complete plant consisting of several production units. Fig 7 shows a simple typical plant layout.

Fig 7 A simple typical plant layout

Plant layout refers to arrangement of equipments and facilities or plant design. It is a blue print of internal structure and arrangement in a plant. It is a plan for proper and effective utilization of equipments and facilities for the production of the products. It provides smooth flow of materials, and facilitates smooth running of the technological processes in the plant.

Layout design normally involves getting a suitable arrangement of equipments or units and their connections within a pre-defined area based on pre-specified criteria. These items can be process-equipment, furnaces, electric control rooms, instruments and control rooms, product inspection area, and quality control laboratory, stores, workshops, offices, canteen and change rooms, and fire station etc.  with connections by pipes, conveyors, vehicular transport or any other suitable material handling equipment. Plant layout includes plant roads and rail tracks.

Plant site drawing – Plant site drawing is prepared during the detailed engineering of the project. Plant site drawings take into account on-site issues and are detailed drawings used for ordering the pipeline components and installation of the equipments of the project.

Plinth beam layout drawing – Plinth beam is another form of beam structure which reinforces the support system of a building. The plinth beam layout drawing showcases the position, length, and sectional design of the plinth beams. Here too, the plinth beams drawing is also made floor-wise.

Plumbing drawing – Plumbing drawing is similar to the electrical drawings and they showcase the water outlets and the piping system of a plant facility. The plumbing construction plan drawing shows the markings and the location of the plumbing components. This includes the sanitary pipes, water pipes, water drainage systems, and everything else which is related to the plumbing of the plant facility. It also includes the position of the taps and other water outlets on every floor. Also, one can check out here how Revit software can improvise the creation of plumbing designs.

Presentation drawing – Presentation drawings is prepared as a part of proposals, for exhibitions, or even for publications. This type of drawing includes any kind of drawings.

Process flow diagram – A PFD is a type of flow-chart which demonstrates the relationships between major components of a plant unit. It is very frequently used in process engineering, though its concepts are sometimes applied to other processes as well. It is used to document a process, improve a process, or model a new process. Depending on its use and content, it can also be called a process flow chart, flow-sheet, schematic flow diagram, macro flow-chart, top-down flow-chart, system flow diagram, or system diagram.

PFD primarily defines (i) a schematic representation of the sequence of all relevant operations occurring during a process and includes information considered desirable for analysis, (ii) the process presenting events which occur to the material(s) to convert the feed-stock(s) to the specified products, and (iii) an operation occurring when an object (or material) is intentionally changed in any of its physical or chemical characteristics, is assembled or dis-assembled from another object or is arranged or prepared for another operation, transportation, inspection or storage.

PFD normally includes (i) plant design basis indicating feed-stock, product and main streams flow rates and operating conditions, (ii) identification of the scope of the process, (iii) graphically the arrangement of major equipment, process lines, and main control loops, and (iv) needed utilities which are used continuously in the process.

PFD has multiple purposes which include (i) documenting a process for better understanding, quality control, and training of employees., (ii) standardizing a process for optimal efficiency and repeatability, (iii) studying a process for efficiency and improvement, hence helping to show unnecessary steps, and other inefficiencies, (iv) modelling a better process or creating a brand-new process, and (v) communicating and collaborate with diagrams which speak to different roles in the organization or outside of it. Diagramming is quick and easy.

PFD uses a series of symbols and notations to depict a process. The symbols vary in different places, and the diagrams can range from simple, hand drawn scrawls, or sticky notes to professional-looking diagrams with expandable detail, produced with software. Fig 8 shows process flow diagram with basic information. In the diagram alternative designations for devices and equipment with back-up redundancy can be assigned using suffix letters (e.g., P1 A/B).

Fig 8 Process flow diagram with basic information

Production drawing – It also referred to as working drawing. A component or part drawing is termed as a production drawing, if it facilitates its manufacture. It is an authorized document to produce the component on the shop floor. It furnishes all the dimensions, limits, and special finishing processes such as heat treatment, honing, griding, lapping, and surface finish etc., to guide the technician on the shop floor in producing the component. The title also mentions the material used for the product, and number of parts needed for the assembled unit etc. Since a technician normally makes one component at a time, it is advisable to prepare the production drawing of each component on a separate sheet. However, in some cases the drawings of related components can be given on the same sheet. Fig 3b shows an example of production drawing.

Record drawing – It is the as-built drawing which provide a comparison between what has been built and the original plan. It is the ‘final construction issue’ drawing by the consultant team to create record of the completed project.

Reinforced concrete structures drawing – The two main groups of drawings for showing reinforced concrete structures are general arrangement drawings, and reinforcement drawings. General arrangement drawings are floor plans, roof plans, sections and elevations, drawn to a small scale and provide overall view of the work. They supply the setting out dimensions, the positions and sometimes the sizes of all the members. A reference grid is provided similar to that for a structural steel buildi

Reinforcement drawings of structural elements are drawn to a larger scale and give detailed information about the reinforcement. There is no justification for ambiguity, and it is necessary that all drawings are easy to read, and cannot be misunderstood.

Roof beam and shuttering layout drawing – A roof beam is made to strengthen the overall structure of a building. A roof beam is a triangular structure which is normally made on the top of the building.

Roof slab layout drawing – The roof slab layout drawing is more prominently made in the AutoCAD architectural software. The main purpose of the roof slabs is to provide a detailed account of the floors, roof faces, and other such surfaces which need precise edge information.

Sankey diagram – It is a data visualization technique or flow diagram which emphasizes flow / movement / change from one state to another or one time to another, in which the width of the arrows is proportional to the flow rate of the depicted extensive property. It can also visualize the energy accounts, material flow accounts, and cost breakdowns.2 The diagram is frequently used in the visualization of material flow analysis. It emphasizes the major transfers or flows within a system. It helps to locate the most important contributions to a flow. It frequently shows conserved quantities within defined system boundaries.

Scale drawing – Scale drawing is a generic term used to describe any drawing which shows items at less than (or more than) their actual size. This is normally necessary where the item is so large or small that it is not useful or convenient to draw it at its actual size.

Scale drawing demonstrates the larger objects as it is not possible to draw them in the original size. So, this means that every drawing of a project facility is a type of scale drawing. For example, a location plan has a scale of 1:1,000, a site plan has a scale of 1:200, scale of a floor plan is 1:100, and so on. The larger the size of the object under construction, the higher is the tendency of the scale.

Section drawing – As the name suggests, the section drawing shows the structure / equipment in a sliced form. This kind of drawing helps identify the primary structure / equipment in relation to other surrounding structures / equipments in a building. Further, section drawings also provide information on the types of materials to be used in the assembly / erection of the structure / equipment.

Section drawing shows a view of a structure as though it had been sliced in half or cut along another imaginary plane. This can be useful as it gives a view through the spaces and surrounding structures / equipment (typically across a vertical plane) which can reveal the relationships between the different parts of the buildings that might not be apparent on plan drawings.

A section is a view of an equipment or a building obtained by making an imaginary cut through it. The term section is mainly used where the cut is made in a vertical direction, and this is so in the case of location sections.

The purpose of a location section is to (i) give a vertical view of the building or equipment, and (ii) provide overall vertical dimensions and levels. The purpose of a location elevation is also to (i) show the external faces of the building, and (ii) locate the door and window openings and other features of the building.

A vertical section through a building shows details of the construction of the foundations, walls, floors, roof and other parts. The number of sections needed of a building depends on its size and complexity. Normally, there are at least two sections. One of these is a cross section, across the width of the building. The second is a longitudinal section, along the length of the building. Sections are intended to help the site engineer construct the building, so the exact position of the section is to be chosen to show as much construction as possible.

Shop drawing – Shop drawing can be prepared by contractors, sub-contractors, suppliers, manufacturers, or fabricators. The shop drawing normally relates to pre-fabricated components, showing how they are to be manufactured or installed. It takes design intent drawings and specifications prepared by the project design team and develop them to show in detail how the component is actually to be manufactured, fabricated, assembled, or installed.

Shop drawings are also a sort of construction guide which personifies how the object is to be installed, fitted, or manufactured. Shop drawings ensure compliance with the original design and specifications of the object.

Single line diagram – A single-line diagram (SLD), also sometimes called one-line diagram, is a simplest symbolic representation of an electric power system. A single line in the diagram typically corresponds to more than one physical conductor. In a direct current system, the line includes the supply and return paths, in a three-phase system, the line represents all three phases (the conductors are both supply and return because of the nature of the alternating current circuits).

The single-line diagram has its largest application in power flow studies. Electrical elements such as circuit breakers, transformers, capacitors, bus bars, and conductors are shown by standardized schematic symbols. Instead of representing each of three phases with a separate line or terminal, only one conductor is represented.

The single-line diagram is a form of block diagram graphically depicting the paths for power flow between entities of the system. Elements on the diagram do not represent the physical size or location of the electrical equipment, but it is a common convention to organize the diagram with the same left-to-right, top-to-bottom sequence as the switchgear or other apparatus represented. A single-line diagram can also be used to show a high-level view of conduit runs for a PLC control system.

Site plan drawing – A site plan is a location drawing, and like most plans is a view looking downwards. It supplies a bird’s eye view of the shape, size and layout of the entire site.

The site plan is a large-scale map of the plant site and reveals boundaries, roads, railroad, pavement, building outlines, large structures, production shop area, major pipe racks, storage areas, waste effluent ponds, large underground pipes, and disposal, shipping and loading areas. True north and assumed plant north is shown on the site plan. The plant personnel use this plan to decide where the production shops are to be located. The site plan is frequently divided into smaller units which are numbered. These are sometimes called key or index plans and are defined by match (boundary) lines. The unit plot plan is developed from the site plan. It reveals the equipment foundation outlines, structural foundation outlines, and structural members in a unit. Coordinates for centre-lines of equipment are indicated, except for pumps where the pump shaft centre-line is used as reference.

The purpose of a site plan is to (i) provide a general picture of the site, including its shape and extent, (ii) locate the buildings and other elements of the project, e.g., roads, garden, walls and landscaping- both horizontally and vertically, (iii) indicate the levels and surface features of the finished site, and (iv) sometimes provide information on external services, especially underground drainage.

A site plan is a large-scale drawing that shows the full extent of the site for an existing or proposed development. Site plans, along with location plans, can be necessary for planning applications. In majority of the cases, site plans are to be drawn up following a series of desk studies and site investigations.

Structural drawing – Structural drawing focuses on the structural aspect of the building. Structural drawing helps those, whose job it is to fabricate, erect, supervise and integrate the structural engineering work. The different needs and priorities of these people influence the method of providing, the information, which sometimes vary from architectural drawing techniques.

Structural working drawing – The process of preparing working drawings for structural engineering work is normally referred to as structural detailing. The general principle followed is to break down the total structure into individual elements such as columns, beams, and floor slabs etc., and then to detail each element in turn.

The three main groups of drawings for illustrating steelwork structures are general arrangement drawings, fixing details, and details of individual members. General arrangement drawings include steel framing plans, elevations and sections. Steel framing plans indicate the positions and sizes of beams at a specific floor or roof level, together with the positions and sizes of columns. Elevations and sections show columns and beams as well as additional members such as wind bracing.

It is necessary to identify each steel member by a distinctive mark reference whenever it appears on a drawing. The same mark is painted on the actual member before it leaves the workshop for dispatch to the site. A common system is to mark the horizontal grid lines on the steel framing plans with numbers-1, 2, 3 etc. -and the vertical grid lines with letters- A, B, C etc.

Submission drawings – Submission drawings are prepared with reference to the by-laws drafted and implemented by an authority. These are sent to the authorities for their approval and include index plans, detailed drawings, elevation drawings, and other sectional plans.

Technical drawing – The term ‘technical drawing’ has a very broad meaning, referring to any drawing which conveys the way that something functions or how it is manufactured / erected. Technical drawings are intended to convey one specific meaning, as opposed to artistic drawings which are expressive and can be interpreted in a number of ways. Majority of the drawings prepared during the design and construction of a project can be considered to be technical drawings.

Technical drawings also convey a broad meaning with regard to a construction project. The basic purpose of technical drawings is to indicate how an object function. Almost every drawing made before, during, and post-construction can be referred to as a technical drawing.

Unit plot plan – Unit plot plan shows the coordinates of steel column centre-lines and extremities of buildings. The equipment arrangement drawing is an updated unit plot plan where equipment outlines are added to the unit plan drawing. It shows the positions of equipment with outlines drawn to scale. Several viable drawings are normally made in order to optimize and meet process needs.

Utility flow diagram – Utility flow diagram (UFD) is a special type of process flow diagram. It is a schematic graphic means needed for the representation of transport, distribution, and collection of forms of energy. In a UFD, process equipment can be represented by boxes with inscriptions and with utility connections. The graphical symbols represent equipment and the lines represent flows of mass, energy, or energy carriers. Fig 9 shows process flow diagram as utility flow diagram.

Fig 9 Process flow diagram as utility flow diagram

Wiring diagram – It is a diagram that shows how a circuit works logically and electrically. It uses symbols to identify components and interconnecting lines to display the electrical continuity of a circuit. It is frequently being used for trouble-shooting purposes. It is also known as a ladder diagram.

Working drawing – Working drawing is a complete set of drawings such that the object represented can be built from it alone without additional information. Working drawing also includes a legend which provides information about the different components.

Working plan – The designers create working plans or construction plans for the contraction engineers to help them understand the scope of the project. The benefits of such a plan include the convenience to fabricate the construction material according to the overall design.

Wrapping up, it can be said that there are a lot of benefits to have the above types of drawings since these drawings act as the guiding principles for every person working at the construction site.

Leave a Comment