Let's analyze the question: --- **Question 8:** What is the maximum permissible gas leak rate for a low-pressure installation during a tightness test? **Options:** - a) 15 L/h - b) 10 L/h - c) 5 L/h - d) 2.5 L/h --- ### Step-by-Step Solution 1. **Understanding the Question:** - The question asks about the maximum permissible gas leak rate (in liters per hour, L/h) for a low-pressure gas installation during a tightness test. 2. **Standard Reference:** - According to most gas safety standards (such as those followed in the UK, e.g., IGEM/UP/1B and Gas Safety (Installation and Use) Regulations), the maximum permissible leak rate for low-pressure gas systems during a tightness test is **no more than 0.0005 m³/h per appliance** or **no more than 4 L/h for the whole installation**. However, many standards round this up to **5 L/h** for simplicity. 3. **Selecting the Best Answer:** - From the given options, the closest and most commonly accepted value is: - **c) 5 L/h** --- ### **Final Answer** **The maximum permissible gas leak rate for a low-pressure installation during a tightness test is:** > **c) 5 L/h**