Sanitary appliances form a critical part of building services in Kenya, ensuring hygiene and comfort in diverse environments such as hospitals, schools, hotels, and commercial offices. Accurate drawings of these appliances are essential for effective installation, maintenance, and inspection, enabling technicians and engineers to communicate design intent clearly. This chapter introduces various types of working drawings and sketching methods used to represent sanitary appliances, equipping students with skills to produce and interpret technical illustrations relevant across professional sectors.

2.1 Working drawings

Working drawings are technical illustrations that convey detailed information about sanitary appliances, including their dimensions, layout, and connections. In Kenya’s multidisciplinary professional settings, these drawings facilitate coordination among architects, plumbers, and facility managers. Understanding different types of working drawings allows students to produce clear documentation tailored to specific project requirements.

2.1.1 Pictorial

Pictorial drawings provide a three-dimensional representation of sanitary appliances, helping visualize the final installation in a realistic manner.

Purpose of Pictorial Drawings

• Visual Clarity: They present the appliance in a near-real form, making it easier for non-technical stakeholders to understand the design.
• Installation Guidance: Assist technicians by showing how components fit together spatially, reducing installation errors.
• Client Communication: Useful for presentations to clients or facility managers who may not interpret line drawings well.
• Design Validation: Help verify that the appliance fits within the available space without clashes.
• Maintenance Planning: Visualize access points for repairs and routine checks.

Types of Pictorial Drawings

• Isometric Drawings: Show the appliance from an angle where all three dimensions are visible, maintaining scale equally along axes.
• Oblique Drawings: Present the front face in true scale, with depth drawn at an angle for clarity.
• Perspective Drawings: Mimic human eye perception with vanishing points, providing realistic depth but not to scale.
• Exploded Views: Illustrate components separated but aligned to show assembly order.
• Cutaway Views: Reveal internal parts by removing sections of the appliance.

Architectural symbols for various sinks and showers (Source: INSTALLATION_OF_ABOVE_AND_UNDER_GROUND_DRAINAGE_SYSTEM (2))

Construction Procedure for an Isometric Drawing of a Wash Basin

1. Draw the Isometric Axes: Begin with three lines intersecting at a point, each 120 degrees apart.
2. Mark Key Dimensions: Transfer the length, width, and height of the basin along the respective axes using the scale.
3. Sketch the Outline: Connect dimension points to form the basin’s outer shape.
4. Add Internal Details: Draw inner bowl contours and rim thickness.
5. Include Fixtures: Sketch tap holes and overflow slots.
6. Label Components: Mark parts clearly using standard notation.

Standards and Conventions

• Follow BS EN ISO 128 for line types and drawing layout.
• Use continuous thick lines for visible edges and dashed lines for hidden features.
• Apply appropriate scales, often 1:10 or 1:20 for pictorials.
• Include a title block with drawing name-scale, date, and drafter’s name as per Kenya Bureau of Standards (KEBS) guidelines.

2.1.2 Line drawing

Line drawings are two-dimensional representations using lines to convey the shape, size, and details of sanitary appliances. They are essential for fabrication and installation documentation.

Characteristics of Line Drawings

• Simplicity: Focuses on outlines and essential features without shading or textures.
• Precision: Dimensions and proportions are exact, suitable for manufacturing.
• Clarity: Uses varied line types to distinguish visible, hidden, and centre lines.
• Standardization: Employs uniform symbols and conventions for easy interpretation.
• Reproducibility: Easily copied and modified for revisions.

Types of Line Drawings Used in Sanitary Appliance Installation

• Plan View: Shows the appliance from above, detailing footprint and connections.

Common plumbing fixture symbols used in construction drawings (Source: PLUMB 5 LEARNING GUIDE-1 (1))

• Elevation View: Side or front view illustrating height and vertical arrangements.

Various types of sanitary fixtures used in construction (Source: INSTALLATION_OF_ABOVE_AND_UNDER_GROUND_DRAINAGE_SYSTEM (2))

• Sectional View: Cut through the appliance to reveal internal components.

• Detail View: Enlarged part of the drawing focusing on complex features.

• Assembly Drawing: Shows how different components fit together.

Construction Procedure for a Line Drawing of a Toilet Suite Plan

1. Set Drawing Scale: Choose an appropriate scale, typically 1:20 or 1:25.
2. Draw Outline: Sketch the base footprint of the toilet pan and cistern.
3. Add Internal Details: Mark the seat, flushing mechanism, and water inlet.
4. Include Pipe Connections: Indicate waste outlet and water supply lines with correct symbols.
5. Dimension the Drawing: Add all necessary measurements, including distances to walls and floor levels.
6. Annotate: Label parts and include notes on materials or installation requirements.

Line Types and Symbols Standards

• Use BS 8888 and KEBS standards for line types: continuous thick for visible edges, dashed thin for hidden edges.
• Employ standardized sanitary symbols such as circles for taps, rectangles for basins.
• Dimension lines should have arrowheads and be placed outside the drawing.
• Text fonts must be legible and consistent, usually sans-serif.

2.1.3 Freehand sketching

Freehand sketching is a quick, informal drawing method used on-site or in meetings to capture ideas and details without precise instruments.

Importance of Freehand Sketching in Sanitary Installation

• Speed: Enables rapid recording of observations or modifications.
• Communication: Facilitates discussion between installers, clients, and supervisors.
• Problem Solving: Visualizes potential solutions or adjustments on the spot.
• Flexibility: Can be done anywhere without special tools.
• Documentation: Provides a preliminary record before formal drawings.

Techniques for Effective Freehand Sketching

• Use Light Guidelines: Start with faint lines to establish proportions.
• Simplify Shapes: Break complex appliances into basic geometric forms.
• Include Key Details: Focus on dimensions, connection points, and orientation.
• Annotate Liberally: Add notes and measurements directly on the sketch.
• Practice Regularly: Develop hand-eye coordination for accuracy.

Common Tools for Freehand Sketching

• Use pencils for initial sketches to allow corrections.
• Maintain a clean and organized sketchbook for future reference.
• Use pens only after confirming accuracy of the sketch.

Practice Procedure for a Freehand Sketch of a Washroom Layout

1. Observe the Site: Note the positions of sanitary appliances and walls.
2. Draw Perimeter Walls: Sketch the room outline lightly.
3. Add Appliance Shapes: Represent toilets, sinks, and showers with simple symbols.
4. Mark Connection Points: Indicate water supply and drainage locations.
5. Include Dimensions: Approximate key measurements.
6. Review and Correct: Adjust proportions and add annotations.

2.1.4 Scale drawings

Scale drawings represent sanitary appliances proportionally reduced or enlarged to fit on paper, essential for accurate planning and construction.

Definition and Importance of Scale Drawings

• Definition: A drawing where all dimensions are proportionally scaled down or up from actual size.
• Accuracy: Ensures precise communication of size and spatial relationships.
• Space Planning: Helps in allocating room for appliances in confined spaces.
• Cost Estimation: Facilitates accurate material quantity calculations.
• Compliance: Meets regulatory requirements for building plans.

Common Scales Used in Sanitary Appliance Drawings

• Full Scale (1:1): Used for small components or detailed parts.
• Reduced Scales (1:10, 1:20, 1:50): Suitable for room layouts and plumbing plans.
• Enlarged Scales (2:1, 5:1): Used for intricate parts requiring clarity.
• Selection Criteria: Depends on drawing size, detail level, and purpose.

Procedure for Preparing a Scale Drawing of a Kitchen Sink Installation

1. Choose Scale: Select 1:20 for room layout clarity.
2. Measure Actual Dimensions: Record sink size, counter space, and pipe positions.
3. Convert Dimensions: Multiply actual measurements by scale factor (e.g., divide by 20).
4. Draw Room Outline: Use scaled dimensions for walls and counters.
5. Sketch Sink and Fixtures: Position appliances according to scaled measurements.
6. Add Notes and Dimensions: Indicate water supply and drainage points.

Tools and Standards for Scale Drawing

• Follow BS EN ISO 128 for dimensioning and line conventions.
• Use scale rulers to avoid calculation errors.
• Maintain neatness and clarity for professional presentation.

Chapter Summary

This chapter introduced various types of working drawings essential for sanitary appliances installation, including pictorial, line, freehand sketching, and scale drawings, each serving distinct purposes in visualizing and planning installations. The importance of accurately interpreting working sanitary drawings was emphasized to ensure that installation tasks align with design requirements and site conditions. Students learned how to decode measurements on these drawings to facilitate precise placement and fitting of sanitary appliances. The chapter also covered the standard symbols used in sanitary drawings, enabling clear communication and understanding among professionals involved in plumbing and construction projects. Mastery of these drawing types and symbols is crucial for effective planning, execution, and troubleshooting in sanitary installations. Overall, the chapter laid a foundation for creating and interpreting simple sanitary appliance sketches that meet technical and practical work requirements.