Lesson Notes By Weeks and Term v5 - Grade 12

Lesson Video

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Performance objectives

• Identify and draw standard symbols for building services.
• Detail the layout of water and drainage systems.
• Detail the layout of basic electrical services.
• Understand the need for coordinated planning.
• Interpret and explain key components in each system.

Lesson summary

Building services are the systems within a building that make it habitable, functional, and safe. In South Africa, understanding these systems is crucial for addressing challenges related to housing, infrastructure development, and sustainable living.

Think about it: reliable water supply is essential in drought-prone areas; efficient electrical systems are vital to combat load shedding; and proper drainage is necessary to prevent flooding during heavy rains. This week, we will focus on detailing these building services within civil drawings, which are crucial for effective communication between architects, engineers, and construction workers.

Lesson notes

2. 1. Water Supply Systems A water supply system delivers potable (drinkable) water to a building. In South Africa, this system typically involves a connection to the municipal water supply, although borehole water is also used in some areas.

Components: Water Meter: Measures the amount of water consumed by the building. Crucial for billing purposes.

Main Stopcock (Valve): Allows the water supply to be shut off to the entire building, essential for repairs or emergencies.

Pipes: Typically made of copper, PVC, or HDPE (High-Density Polyethylene). Copper is more durable but more expensive. PVC is common for cold water lines and drainage, while HDPE is often used for underground pipes.

Fixtures: Taps, showers, toilets, sinks, etc., that utilize the water supply.

Geyser (Water Heater): Heats water for domestic use. Solar water heaters are becoming increasingly common in South Africa due to energy efficiency benefits and government incentives.

Detailing in Civil Drawings: Use standard symbols to represent pipes, valves, and fixtures. Refer to SANS 10140-1 for standardized symbols. Indicate pipe sizes and materials. Show the location of the water meter and main stopcock. Indicate the layout of hot and cold water pipes. Show the location of the geyser and any solar water heating systems.

Example: Consider a small, single-story house in a township. The water supply comes from the municipal line. The drawing must show the water meter located outside the house, near the property boundary. A 20mm copper pipe runs from the water meter to the main stopcock inside the house, typically near the kitchen. From there, PVC pipes (15mm diameter) distribute cold water to the kitchen sink, bathroom sink, toilet, and shower. A geyser is located in the bathroom or kitchen and supplies hot water (15mm copper pipe) to the kitchen and bathroom sinks, and shower. Show all pipes clearly with hidden lines where appropriate. 2.

2. Drainage Systems A drainage system removes wastewater from a building. This includes sewage (water from toilets), greywater (water from sinks, showers, and washing machines), and stormwater (rainwater).

Components: Pipes: Typically made of PV

C. Traps: U-shaped bends in pipes that hold water and prevent sewer gases from entering the building. Located under sinks, showers, and toilets.

Inspection Chambers (Manholes): Allow access to the drainage system for cleaning and maintenance.

Vent Pipes: Allow air to enter the drainage system, preventing siphoning of water from traps.

Septic Tank (if applicable): Used in areas without access to a municipal sewage system. Separates solids from liquids.

Soak Away (if applicable): Drains the effluent from the septic tank into the ground.

Detailing in Civil Drawings: Use standard symbols to represent pipes, traps, inspection chambers, and vent pipes. Indicate pipe sizes and gradients (slope). Drainage pipes must have a slight slope to allow gravity to carry the wastewater. Show the location of inspection chambers. Indicate the layout of the septic tank and soak away (if applicable). Show the connection to the municipal sewer line or the location of the septic tank.

Example: For the same small house, the drainage system will collect wastewater from the kitchen sink, bathroom sink, toilet, and shower. Each fixture must have a trap (50mm diameter PVC). The waste pipes (typically 110mm PVC for toilet waste, 50mm for other fixtures) connect to a main drain pipe that slopes towards an inspection chamber located outside the house. From the inspection chamber, the drain pipe connects to the municipal sewer line. A vent pipe extends from the highest point of the drainage system to the roof to allow air to enter. Indicate the slope of the main drain (e.g., 1:50). 2.

3. Electrical Services Electrical services provide power to a building for lighting, appliances, and other electrical equipment.

Components: Electrical Meter: Measures the amount of electricity consumed by the building.

Distribution Board (DB): Contains circuit breakers that protect individual circuits from overloads and short circuits.

Circuit Breakers: Automatically trip (switch off) when a circuit is overloaded.

Wiring: Carries electricity throughout the building.

Socket Outlets: Provide power for appliances.

Light Fittings: Provide illumination.

Switches: Control lighting and other electrical devices.

Earthing System: Protects against electric shock.

Detailing in Civil Drawings: Use standard symbols to represent socket outlets, light fittings, switches, and the distribution board. Indicate the location of the electrical meter. Show the layout of wiring runs. Indicate the positions of light fittings and switches. Indicate the positions of socket outlets (e.g., single or double socket, height above the floor). Show the location of the distribution board. Specify the type and size of wiring.