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A single stack system is commonly used to discharge soil and waste from a domestic dwelling - Leaving Cert Construction Studies - Question 8 - 2006
Question 8
A single stack system is commonly used to discharge soil and waste from a domestic dwelling. (a) Show, with the aid of notes and detailed sketches, a typical layout... show full transcript
Worked Solution & Example Answer:A single stack system is commonly used to discharge soil and waste from a domestic dwelling - Leaving Cert Construction Studies - Question 8 - 2006
Step 1
Show, with the aid of notes and detailed sketches, a typical layout of a single stack system for a bathroom, situated at first floor level of a dwelling house.
Answer
To illustrate a typical layout of a single stack system, begin by sketching the room dimensions with the following considerations:
- Stack Location: The vertical stack pipe should be positioned close to the bathroom fixtures to minimize the length of waste pipes. The stack pipe is usually a 100 mm diameter uPVC pipe.
- Bathroom Fittings: Place the W.C. adjacent to the stack, ensuring it has a branch discharge pipe of 100 mm that does not exceed 1 metre in length. The sink and shower can be positioned to the side, with specific attention to the length of their pipes which should not exceed 3 metres to maintain proper water flow.
- Design Considerations: Ensure adequate ventilation for the W.C. without any obstruction. The wash hand basin should connect with a 32 mm diameter pipe. Additionally, considering the placement of the extract fan near the shower helps reduce condensation.
Step 2
Using notes and freehand sketches, show two design details that ensure the pipework in an underground drainage system is watertight.
Answer
To ensure the pipework is watertight, consider the following design details:
- Rubber Sealing Ring: Confirm that the rubber sealing ring is inserted properly into the socket. This ring must be correctly seated to create a watertight seal and prevent leaks.
- Trench Depth and Bedding: Ensure that the pipes are laid in a sufficiently deep trench that is properly benched. This includes having the pipes square and bevelled where needed. Additionally, the bedding around the pipes should be level and compact, allowing for stable support without stress on the joints.
Step 3
Using notes and freehand sketches, outline one test that may be carried out on an underground drainage system to determine if the pipework is watertight.
Answer
One effective test for checking the watertightness of an underground drainage system is the Water Test:
- Procedure: Fill the pipe run with water and maintain this level for a specified duration, typically 24 hours. During this time, observe for any signs of leaks or drops in water level, which indicates a potential failure in the sealing of pipe joints.
- Conditions: Ensure that this test is conducted when the conditions are dry to avoid interference from external moisture.
- Other Variations: Additionally, using a pressure gauge can heighten the reliability of the test by assessing the retention of water under pressure conditions.