Scientific Principles PowerPoint 5 PDF

PowerPoint 5 Principles of combustion and heating gases  LESSON INTENT All leaners must be able to know the 3 elements that make up the fire triangle. Be able to discuss the different principles of combustion Learners must be able to distinguish the different types of gass...

PowerPoint 5 Principles of combustion and heating gases  LESSON INTENT All leaners must be able to know the 3 elements that make up the fire triangle. Be able to discuss the different principles of combustion Learners must be able to distinguish the different types of gasses that we use. Find out where we use these different types of gasses in different plumbing situations  PRINCIPLES OF COMBUSTION Fire is one of the most destructive elements that exists. Combustion is a chemical reaction with oxygen: Fuel + Oxygen + Heat = Fire Propane + Oxygen + spark = Flame Various gases are used in plumbing situations: Soldering Heating water Space heating Cooking The three common gases are: Natural gas Propane Butane  Values of gases Natural gas Propane Butane Relative density 0.58 1.78 2.0 Calorific value 39MJ/m3 95.0MJ/m3 121.5MJ/m3 Flame 19500C 19800C 19960C temperature Air/gas ratio 2:1 5:1 6.5:1 (approx) Natural gas: commonly used in domestic properties for boiler and cooker fuel. Ventilation is required in certain applications. Not hot enough for soldering. Propane: commonly used for caravan boiler and cooking. Also used if mains gas is unavailable. Ventilation required. Butane: commonly used in barbecues, due to high calorific value. Too hot for soldering. Ventilation required. CHECK YOUR KNOWLEDGE WITH THESE QUESTIONS 1. What 3 things make up the fire triangle? 2. What are the 3 most common gasses we use? 3. What has a higher flame temperature propane or butane? 4. What is natural gas used for? 5. What is the calorific value of butane? TRAFFIC LIGHT IT: WHERE IS YOUR LEARNING AT? Red = I have not really understood the content we have studied today (write down 2 questions that you need help with) Amber = I have understood the content on Effective Questionning (write down 1 one question you need to clarify) Green = I have understood all the content (write down one example from what we have studied)