Plumber Red Seal · Question
According to the National Plumbing Code (NPC), what is the minimum grade for a 4-inch horizontal sanitary drainage pipe?
The NPC generally requires a minimum grade of 1:50 or 2% for horizontal drainage pipes 3 inches or larger to ensure proper scouring action and solids transport.
Start free practice for Plumber Red Seal
177 questions · no signup required · 40 free questions per day
Question: According to the National Plumbing Code (NPC), what is the minimum grade for a 4-inch horizontal sanitary drainage pipe?
Answer options:
- 1:100 (1%) ✅ 1:50 (2%)
- 1:25 (4%)
- 1:200 (0.5%)
Correct answer: 1:50 (2%)
Explanation: The NPC generally requires a minimum grade of 1:50 or 2% for horizontal drainage pipes 3 inches or larger to ensure proper scouring action and solids transport.
Start free practice for Plumber Red Seal
177 questions · no signup required · 40 free questions per day
More about Plumber Red Seal
Related Questions
- Before starting a new plumbing installation in a residential basement, what is the primary reason why a plumbe
- A plumber is installing a new kitchen sink in an existing residential dwelling. The sink drain is connected to
- A plumber is installing drainage for a dishwasher in a residential kitchen. The dishwasher P-trap is located 1
- A plumber is asked to install a backflow prevention assembly on a lawn irrigation system connected to the pota
- A plumber is considering the velocity of water in a 50 mm (2") copper pipe supplying a commercial building. Ex
- A plumber is designing the domestic hot water recirculation system for a multi-story residential building. Wha
More for Plumber Red Seal candidates
Practice tests
Question explanations
- Before starting a new plumbing installation in a residential basement, what is the primary reason why a plumbe
- A plumber is installing a new kitchen sink in an existing residential dwelling. The sink drain is connected to
- A plumber is installing drainage for a dishwasher in a residential kitchen. The dishwasher P-trap is located 1
- A plumber is asked to install a backflow prevention assembly on a lawn irrigation system connected to the pota
Ready to practice?
Free, no signup required. Build a wrong-question list as you go.
Start Free Plumber Red Seal Practice →Related courses
Other Canadian certifications candidates often prepare for alongside this one.