Lesson Notes By Weeks and Term v4 - SHS 2
HEALTH AND SAFETY IN ENGINEERING PRACTICE
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HEALTH AND SAFETY IN ENGINEERING PRACTICE
Download the Lessonotes Mobile Ghana app for faster lesson access on Android and iPhone.
Subject: Engineering
Class: SHS 2
Term: 1st Term
Week: 15
Grade code: 2.1.2.LI.4
Strand code: 1
Sub-strand code: 2
Content standard code: 2.1.2.CS.1
Indicator code: 2.1.2.LI.4
Theme: ENGINEERING PRACTICE
Subtheme: HEALTH AND SAFETY IN ENGINEERING PRACTICE
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Welcome, future engineers! Today, we are discussing one of the most important topics in your entire career: Health and Safety. In Ghana, we see engineering all around us – from the trotro driver’s mechanic at Abossey Okai, to the welder in Suame Magazine, to the engineers building the new interchange at Pokuase. In all these places, there are dangers (hazards) that can cause injury or even death. Understanding how to control these hazards is not just about following rules; it’s about protecting yourself, your colleagues, and your community. This lesson will equip you with the knowledge to identify and manage these dangers, making your future workplace a safer and more productive environment.
This lesson focuses on how to manage dangers in the workplace. To do this effectively, we must first understand some key terms and a very important principle called the Hierarchy of Controls. A. Basic Definitions Hazard: A hazard is anything with the potential to cause harm. This can be an object, a substance, a source of energy, or even a situation. Ghanaian Example: A frayed electrical cable at a carpenter's shop is a hazard. A pool of spilled engine oil on the floor of a fitter’s workshop is a hazard. Risk: Risk is the *likelihood* or probability that a hazard will actually cause harm, combined with the *severity* of that harm. Ghanaian Example: The *risk* associated with the frayed cable is a high chance of a severe electric shock or fire. The *risk* of the oil spill is a medium chance of someone slipping and suffering a minor or major injury. Control Measure: A control measure is an action or procedure that is put in place to eliminate a hazard or reduce the risk associated with it. B. The Hierarchy of Controls
Engineers and safety professionals don't just pick random solutions. They use a system called the Hierarchy of Controls to choose the most effective ways to make a situation safe. It is often shown as an inverted pyramid because the most effective controls at the top are the ones you should try to use first, while the least effective ones at the bottom are a last resort.
The 5 Levels of the Hierarchy of Controls (from Most Effective to Least Effective): Elimination (Most Effective) Explanation: This means completely removing the hazard from the workplace. If the hazard isn't there, it can't cause harm. This is the best and most effective solution. General Example: If working at a great height is hazardous, design the work so that it can be done on the ground. Ghanaian Example: A construction company needs to join two building components. Instead of having welders work on high scaffolding, they redesign the process to assemble the components on the ground and then lift the entire completed unit into place with a crane. The hazard of working at height has been *eliminated*. Substitution Explanation: This involves replacing a hazardous substance, process, or machine with a less hazardous one. General Example: Replacing a toxic solvent-based paint with a water-based paint. Ghanaian Example: A metal fabrication shop in Tema uses a very strong, toxic acid to clean metal. To reduce the danger to workers, they *substitute* it with a less toxic, biodegradable cleaning agent that does the same job. Engineering Controls Explanation: These are physical changes to the work environment or equipment that isolate people from the hazard. You are not removing the hazard, but you are building a barrier or making a change to the machine itself. General Example: Putting a guard over a moving part of a machine. Ghanaian Example: A local gari processing plant has a machine for grating cassava with a fast-spinning blade. An *engineering control* would be to weld a permanent metal guard over the opening, with slots just big enough for the cassava to go in, but too small for a worker's hand. Another example is installing a ventilation system to remove welding fumes from a workshop. Administrative Controls Explanation: These are changes to the way people work. They include procedures, rules, training, and signs to warn people about hazards. They rely on people following instructions. General Example: Limiting the time a worker is exposed to a noisy environment. Ghanaian Example: At a road construction site on the N1 highway, *administrative controls* would include: Putting up signs: "DANGER: DEEP EXCAVATION" or "WARNING: HEAVY MACHINERY OPERATING". Training workers on how to safely lift heavy cement bags. Having a "Toolbox Talk" or a short safety meeting every morning before work begins. Creating a rule that only certified electricians can work on wiring. Personal Protective Equipment (PPE) (Least Effective) Explanation: This is equipment worn by the worker to protect them from a hazard. It is the last line of defence. It does not remove the hazard; it only creates a final barrier between the worker and the hazard. It is considered least effective because if the PPE fails or is not worn correctly, the worker is fully exposed to the hazard. General Example: Wearing safety glasses, gloves, or a hard hat. Ghanaian Example: A mason chipping a concrete wall must wear safety goggles to protect his eyes. A welder must wear a welding shield, leather gloves, and an apron. A construction worker at a high-rise building site in Accra must wear a hard hat and safety boots.
Why is PPE the last resort? Because it relies entirely on human behaviour. A worker might forget their goggles, the hard hat might fall off, or gloves might have a hole. The other controls (Elimination, Substitution, Engineering, Administrative) are more reliable because they address the hazard at its source.