sanitation ph23

Where are the statutory requirements for the installation of drainage systems?

• BS 6700

• BS EN 12056

• Building regulations

• WRAS

Answer explanation

The statutory requirements for drainage system installation are detailed in BS EN 12056, which provides guidelines for the design and installation of gravity drainage systems in buildings.

Identify this type of stack system.

• Primary ventilated stack

• Secondary ventilated stack

• Ventilated discharge branch stack

• Stub stack

Answer explanation

A secondary ventilated stack is designed to improve drainage and prevent siphoning by allowing air to enter the system. This distinguishes it from primary stacks, which do not have this ventilation feature.

If a discharge branch has a gradient of 18mm per metre and the branch is 3 metres in length, what will the vertical drop distance be?

• 54mm

• 18mm

• 36mm

• 72mm

Answer explanation

The gradient of 18mm per metre means for every metre, the drop is 18mm. For 3 metres, the drop is 18mm x 3 = 54mm. Therefore, the vertical drop distance is 54mm.

What is the purpose of the component shown below, when installed at the base of the stack?

• To prevent evaporation

• To prevent backflow

• To prevent expansion

• To prevent compression

Answer explanation

The component at the base of the stack is designed to prevent compression. This ensures that the stack maintains its structural integrity and does not collapse under pressure, which is crucial for its proper functioning.

The maximum recommended length of a discharge pipe from a bath connected to a primary ventilated stack is:

• 3 metres

• 4 metres

• 5 metres

• 6 metres

Answer explanation

The maximum recommended length of a discharge pipe from a bath connected to a primary ventilated stack is 3 metres. This ensures proper drainage and ventilation, preventing potential issues with backflow or blockages.

What is the recommended termination, as per building regulations, for a soil stack inside a building?

• Open ended

• Cowl

• Domical cage

• Air admittance valve

Answer explanation

The recommended termination for a soil stack inside a building is an air admittance valve. This device allows air to enter the drainage system, preventing vacuum formation and ensuring proper drainage without the need for external venting.

What is the minimum sized waste that is allowed to be fitted to a wash basin?

• 32mm

• 40mm

• 50mm

• 100mm

Answer explanation

The minimum size of waste that can be fitted to a wash basin is 32mm. This size is standard for ensuring proper drainage and compatibility with typical plumbing systems.

What is the main purpose of a ventilated branch pipe?

• To prevent positive and negative pressure fluctuations

• To prevent odours from the waste of the appliance

• To reduce the velocity of the waste water

• To prevent compression

Answer explanation

The main purpose of a ventilated branch pipe is to prevent positive and negative pressure fluctuations in the drainage system, ensuring smooth flow and reducing the risk of blockages or backflow.

What is recommended to stop cross-flow in a soil stack opposite a WC?

• Boss strap

• No connections for 100mm

• Air admittance valve

• No connections for 200mm

Answer explanation

To prevent cross-flow in a soil stack opposite a WC, it is recommended to have no connections for 200mm. This ensures proper airflow and minimizes the risk of backflow, maintaining the system's efficiency.

If an air admittance valve is located within some boxing, what is required to allow the valve to operate effectively?

• Access from the loft area

• Additional ventilation in the boxing

• The boxing must be sealed

• Only one appliance can be discharged at any one time

Answer explanation

For an air admittance valve to function properly within boxing, it requires additional ventilation. This allows air to enter and exit freely, ensuring the valve can equalize pressure effectively.