Lesson Notes By Weeks and Term v5 - Grade 12

Lesson Video

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Performance objectives

• Identify and interpret standard symbols for building services.
• Draw schematic diagrams for basic plumbing and electrical circuits.
• Detail the layout of drainage systems on a site plan.
• Describe the purpose of key components like geysers and distribution boards.
• Explain the importance of coordinated planning for building services.

Lesson summary

Building services are the systems within a building that make it habitable and functional. This includes things like plumbing, electrical systems, drainage, and ventilation. In South Africa, understanding these systems and how they're represented in civil drawings is crucial for construction projects, infrastructure development, and even basic home maintenance. Consider the challenges of providing clean water and sanitation in rural areas, or ensuring efficient electricity supply in urban environments – all rely on the proper design and implementation of building services.

Lesson notes

2. 1. Introduction to Building Services Building services are the invisible infrastructure that makes a building livable and functional. They are essential for comfort, safety, and hygiene. In South Africa, building services need to address unique challenges such as water scarcity, load shedding, and diverse climate conditions.

Building services typically include: Plumbing: Water supply (potable and non-potable), drainage (sewerage and stormwater), gas supply (if applicable), and fire protection systems.

Electrical: Power distribution, lighting, communication systems, security systems, and backup power systems (generators or solar). Heating, Ventilation, and Air Conditioning (HVAC): (Covered in more advanced courses, but important to acknowledge its existence).

Drainage: Stormwater and sewerage systems. 2.

2. Plumbing Systems Water Supply: Water enters a building through a mains connection and is distributed to various fixtures (taps, toilets, showers, etc.). Pressure is crucial; pressure-reducing valves (PRVs) might be needed if the mains pressure is too high. Backflow prevention devices are essential to prevent contamination of the mains water supply. Hot water is generated by geysers (electric or solar).

Drainage: Wastewater (sewerage) and stormwater are drained separately. Sewerage flows to a municipal sewer line or a septic tank. Stormwater is directed to a stormwater drainage system or a natural watercourse.

Materials: Common plumbing materials include copper pipes, PVC pipes, and HDPE pipes. The choice of material depends on factors like pressure, temperature, and chemical resistance. SANS standards specify the requirements for plumbing materials and installation.

Symbols: Common plumbing symbols include: Tap: A small circle with a line extending from it.

Geyser: A rectangle with a wavy line inside.

Sewer Pipe: A dashed line.

Water Pipe: A solid line.

Toilet: A stylized representation of a toilet bowl.

Example: Sketch a schematic diagram of a basic plumbing system for a small house. The house has a single bathroom (toilet, sink, shower) and a kitchen sink. Show the cold water supply from the mains, the geyser, and the hot and cold water distribution to the fixtures. Show the drainage from the fixtures to the sewer line. 2.

3. Electrical Systems Power Supply: Electricity enters a building from the municipal grid. A distribution board (DB board) distributes power to various circuits within the building. Circuits are protected by circuit breakers or fuses.

Wiring: Electrical wiring is typically done using copper or aluminum conductors. Wires are insulated to prevent short circuits. Different colors are used to identify different wires (live, neutral, earth). SANS 10142-1 is the standard for electrical installations.

Lighting: Lighting can be incandescent, fluorescent, LED, or other types. Energy-efficient lighting is becoming increasingly important in South Africa.

Outlets and Switches: Outlets (sockets) provide power for appliances. Switches control lighting and other electrical devices.

Symbols: Common electrical symbols include: Light Switch: A circle with a line extending from it.

Outlet (Socket): A rectangle with two or three lines inside.

Light Fitting: A circle with a cross inside.

Distribution Board: A rectangle with a lightning bolt inside.

Wiring: A solid line (typically with annotations indicating the number and size of wires).

Example: Sketch a schematic diagram of a basic electrical circuit for a room. The room has one light fitting, one light switch, and two electrical outlets. Show the wiring from the DB board to the switch, then to the light fitting, and finally to the outlets. Include the earth wire. 2.

4. Drainage Systems Sewerage: Wastewater from toilets, sinks, and showers flows through sewer pipes to a municipal sewer line or a septic tank. Sewer pipes are typically made of PVC or clay.

Stormwater: Rainwater from roofs and paved areas flows through stormwater drains to a stormwater drainage system or a natural watercourse. Stormwater drains are typically made of concrete or PV

C. Manholes and Inspection Chambers: Manholes and inspection chambers provide access to underground drainage pipes for maintenance and inspection. They are typically located at changes in direction or at intervals along the pipe run.

Site Plans: Drainage systems are typically shown on site plans. Site plans show the location of buildings, roads, drains, manholes, and other features.

Symbols: Common drainage symbols include: Sewer Pipe: A dashed line.

Stormwater Drain: A dotted line.

Manhole: A circle with a cross inside.

Inspection Chamber: A square with a small circle inside.

Example: Draw a plan view of a section of a drainage system for a small industrial park. Show two buildings, a road, and a network of sewer pipes connecting the buildings to a main sewer line. Include two manholes at changes in direction of the pipes. 2.5.