Lesson Notes By Weeks and Term v4 - SHS 3

Lesson Video

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Performance objectives

• Define substructure and superstructure.
• Identify the main components of each.
• Explain the importance of each component.
• Distinguish between materials used for each.
• Analyze a simple building plan to identify these elements.

Lesson summary

This lesson introduces the fundamental concepts of substructure and superstructure in building construction. While the substructure provides support from the ground, the superstructure is the visible part of the building we live and work in. For the superstructure to be functional and habitable, it requires essential systems known as "building services." Today, we will focus on three critical services that make a house a home in Ghana: getting clean water in (Cold-Water Installation), having power for our lights and appliances (Electricity Supply), and safely getting rid of waste (Waste Disposal).

Lesson notes

A. Defining Substructure and Superstructure

Before we discuss the services, let's understand where they fit. A building is divided into two main parts: Substructure: This is the part of the building that is below the ground level. Its main job is to transfer the entire load of the building safely to the soil. In Ghana, this primarily consists of the foundation (e.g., strip foundation, pad foundation) and the foundation walls up to the ground floor level. Superstructure: This is the part of the building that is above the ground level. It is the visible part of the house we occupy. This includes the walls, columns, beams, floors, stairs, roof, doors, and windows.

The services we are studying today are the systems integrated *within the superstructure* to make it liveable. Think of the superstructure as the body and the services as the circulatory, nervous, and digestive systems that make the body function. B. Introduction to Building Services

Building services are the engineering systems that provide comfort, functionality, and safety for the occupants of a building. They are the "lifelines" of a modern house. Today, we focus on the three most basic and essential ones. C. Detailed Breakdown of the Three Major Services Cold-Water Installation (Supply System) Purpose: To provide a reliable supply of clean, cold, and potable (drinkable) water from the source to various points of use (fixtures and fittings) within the building. Source: Typically, the Ghana Water Company Limited (GWCL) mains pipe that runs along the street. In many homes, this water is first stored in a reservoir, often a polyethylene tank ("polytank"), to ensure a constant supply, especially in areas with intermittent flow. Medium of Transport: Water is transported through a network of pipes. Common materials include: uPVC (unplasticized Polyvinyl Chloride): Rigid, common for main supply lines. PPR (Polypropylene Random Copolymer): Greenish or whitish pipes, joined by heat fusion, very durable. Galvanised Iron (GI): Older material, prone to rust over time. Key Components: Main Stopcock: A valve located at the boundary of the property to shut off the entire water supply from the GWCL mains. Storage Tank (Polytank): Stores water to provide consistent pressure and supply. Usually elevated on a stand for gravity feed. Distribution Pipes: A network of smaller diameter pipes that carry water from the tank to different rooms. Valves (Gate Valve/Ball Valve): Used to isolate specific sections of the plumbing (e.g., a bathroom) for repairs without shutting off the whole house. Fixtures & Fittings: The points of use, such as taps (in kitchens, bathrooms), showerheads, and toilet cisterns. Core Principle: The system must be watertight to prevent leakage and designed with appropriate pipe sizes to maintain adequate pressure at all taps. Electricity Supply (Electrical System) Purpose: To safely conduct electrical energy from the national grid to power fixtures (lights), fittings (sockets), and appliances (fridges, air-conditioners, TVs, etc.) in the building. Source: The national grid, supplied by the Electricity Company of Ghana (ECG) or the Northern Electricity Distribution Company (NEDCo). Medium of Transport: Electricity is transported through insulated cables and wires. The insulation (usually a plastic or rubber coating) is crucial for safety. Key Components: Service Cable: The main cable from the ECG pole to the house. Meter: The device that measures the amount of electricity consumed. It can be a prepaid or postpaid meter. Consumer Unit (or Fuse Box/Breaker Box): The "brain" of the electrical system. It receives the main supply and distributes it to different circuits in the house. It contains circuit breakers or fuses that automatically cut power in case of an overload or short circuit, preventing fires and damage. Circuits: Separate wiring paths for different parts of the house (e.g., lighting circuit, socket circuit, air-conditioner circuit). Fixtures & Fittings: The points of use, such as light bulbs, ceiling fans, socket outlets, and switches. Earthing System (Earth Wire): A critical safety feature that provides a path for fault current to flow to the ground, preventing electric shocks from metal-cased appliances. Core Principle: The system must be perfectly insulated to prevent leakage of current and designed with appropriate safety devices to prevent electric shocks and fires. Waste Disposal System (Sanitary System) Purpose: To safely and hygienically collect and dispose of liquid and solid waste from the building, protecting the health of occupants and the environment. Source: Waste is generated at fixtures within the building, such as water closets (WCs), sinks, and floor drains. Types of Waste: Soil Waste (or Blackwater): Waste from WCs containing human excreta. Wastewater (or Greywater): Waste from kitchens, bathrooms (showers, sinks), and laundry. Medium of Transport: Waste is transported through a network of larger diameter pipes, typically made of uPVC. The system relies mainly on gravity. Key Components: Traps (e.g., P-trap, S-trap): A U-shaped bend in the pipe under a sink or behind a WC. It holds a small amount of water to create a seal that prevents foul-smelling sewer gases from entering the building. Waste Pipes: Pipes that carry waste from fixtures to a central drainage pipe. Soil Stack/Vent Pipe: A vertical pipe that carries waste downwards and also extends upwards to the roof. The vent allows sewer gases to escape and prevents a vacuum from forming, ensuring smooth flow. Inspection Chamber / Manhole: A covered chamber providing access to the underground drains for inspection and cleaning. Septic Tank: An underground watertight container where solid waste settles and is decomposed by bacteria. The liquid effluent flows out for further treatment. This is common in areas without a central sewer system. Soak-away (or Soak Pit): A pit filled with coarse stones into which liquid effluent from the septic tank flows and gradually soaks into the surrounding ground. Connection to Public Drain: In well-planned urban areas, the building's drainage system connects directly to the main public sewer line. Core Principle: The system must be designed to ensure sanitation by completely removing waste and preventing contamination of water sources or the living environment. D. Distinguishing Between the Three Services: A Comparison Table

Evaluation guide

• Distinguish Electricity Supply, Cold -Water Installation and Waste Disposal as
• different forms of Services.
• Collaboration: Ask learners in mixed ability groups to distinguish between the major
• basic Services in the building as