2. Definitions of Terminologies Related to Building Plan and Working Drawings

Definitions Of Terminologies Related to Building Plan and Working Drawings

Introduction In civil engineering and architecture, drawing is the primary language used to communicate ideas, designs, and construction details. To effectively read, interpret, and prepare building plans and working drawings, one must thoroughly understand the standard terminologies used in the industry.

1. Types of Architectural Drawings

Before constructing a building, various graphical representations are prepared to understand its dimensions, aesthetics, and structural details:

• Plan: A drawing of an object in two dimensions as if viewed directly from the top. A plan provides the length, breadth, thickness of walls, column positions, door/window openings, and furniture layouts.
• Site Plan: A plan drawn to a scale (usually 1:500 or more) that shows the orientation of the building, property boundaries, and adjacent roads or landmarks.
• Foundation Plan: A drawing showing the layout, dimensions, and details of the building's foundation and footings.
• Elevation: The external face of the building used for presentation and aesthetic purposes. It shows the total height of the building, heights of doors/windows, and the levels of projections like chajjas (weather shades), but it does not display internal dimensions.
• Section: A drawing representing a vertical cut through the building, showing internal details from the foundation to the terrace. Sections are crucial for reading structural heights, such as sill level, lintel height, ceiling height, and floor thickness.
• Perspective: A three-dimensional visual representation of an object as seen by an observer, drawn on a two-dimensional paper. It provides a realistic pictorial view of how the finished structure will look.
• Working Drawing: The detailed, finalized set of drawings used for actual site construction, which typically includes the developed plan, elevation, section, foundation plan, and a schedule of openings.

2. Area and Boundary Terminologies

When planning a building, statutory authorities mandate specific land and area calculations to control urban density and ensure safety:

• Plot Area: A specific piece of land demarcated by definite property boundaries.
• Built-up Area: The total area of the plot minus the area of open spaces. It is the area covered by the building immediately above the plinth level.
• Plinth Area: The built-up covered area of the building measured at the ground floor level, including the thickness of the external walls.
• Floor Area Ratio (FAR) / Floor Space Index (FSI): A vital urban planning metric defined as the total built-up area on all floors of a building divided by the total plot area.
• Building Line: The designated line of building frontage up to which the plinth of a building adjoining a street or road may lawfully extend.
• Control Line: A line set further back from the building line to account for extra margins needed for future developments, such as the widening of roads or the creation of business centers.
• Setback Distance: The open space distance measured from the centre line of the road to the plinth of the building, left empty for future road expansion, parking, and natural air circulation.

3. Building Planning Principles Terminologies

These terms describe the scientific and artistic rules used to design functional and comfortable spaces:

• Orientation: Setting out the plan of the building with respect to the North-South and East-West directions to maximize natural benefits like sunlight and breeze based on local climate.
• Aspect: The specific direction through which a room receives natural light and ventilation. For instance, a kitchen should ideally have an eastern aspect to capture morning UV rays.
• Prospect: The selection and placement of doors and windows to reveal pleasant external views from the inside, while concealing undesirable surroundings.
• Grouping: The disposition and arrangement of various rooms based on their functional relationships and the convenience of users (e.g., placing the dining room close to the kitchen).
• Circulation: The space dedicated to movement from one place to another within the building. This includes horizontal circulation (passages, corridors) and vertical circulation (stairs, lifts, ramps).
• Privacy: Segregating functions to avoid disturbances. It includes internal privacy (screening views between rooms) and external privacy (shielding the building from street noise or neighbors).
• Elegance: The general aesthetic effect produced for a viewer looking at the building from the outside, achieved through attractive elevations, symmetry, and proper proportions.
• Flexibility: Designing a room so it can serve multiple functional purposes if required, such as using folding doors to combine a living and dining room for large gatherings.

4. Scale and Perspective Terminologies

• Scale: The fixed proportion by which all true distances are mathematically reduced to fit on a drawing paper.
• Representative Factor (RF): A way to express a scale independent of measurement units, defined as the ratio of one unit on paper to the actual number of units it represents on the ground (e.g., an RF of 1:100 means 1 unit on paper equals 100 units on the ground).
• Picture Plane: In perspective drawing, it is the imaginary, transparent two-dimensional vertical plane erected between the observer and the object, upon which the 3D building is drawn.
• Station Point / Eye Point: The fixed position of the observer in the plan from which the object is viewed.
• Horizon Line: A straight horizontal line representing the observer's eye level, upon which the imaginary vanishing points are located.