Approved Document H Flashcards
What is Requirement H1?
H1 ensures that buildings have adequate foul water drainage systems to remove waste safely and hygienically.
What is foul water?
Wastewater from toilets, sinks, showers, and other sanitary appliances.
What are the main types of foul water drainage systems?
Separate systems, combined systems, and pumped drainage systems.
What is a separate drainage system?
A system where foul water and rainwater are collected separately and discharged into different drainage networks.
What is a combined drainage system?
A system where both foul water and surface water are collected in the same drainage network.
What are the minimum pipe gradients for foul drainage systems?
1:40 for 100mm pipes, 1:80 for 150mm pipes, to ensure proper flow.
What is the purpose of a trap in foul drainage systems?
Traps prevent foul air from escaping by maintaining a water seal in drainage pipes.
What materials are used for foul drainage pipes?
PVC, clay, cast iron, and concrete, depending on application and regulations.
What are the minimum pipe diameters for foul water drainage?
100mm for most domestic applications; larger diameters for commercial use.
What is an inspection chamber?
A covered access point in a drainage system that allows maintenance and unblocking of pipes.
What is the purpose of vent pipes in foul drainage systems?
They allow the escape of gases and prevent water trap siphonage.
What are the key regulations for drainage connection to public sewers?
Drains must be connected at the correct level and require approval from the sewerage authority.
What is a discharge stack?
A vertical pipe that collects waste from multiple floors and directs it to the sewer system.
What is the minimum height for a vent pipe termination above a roof?
At least 900mm above any opening window or ventilation intake.
How are underground foul water drains protected?
By ensuring adequate depth, correct bedding material, and access points for maintenance.
What is a backflow prevention device?
A valve that prevents sewage from flowing back into a property due to sewer surcharges.
What is the recommended distance between access chambers in a drainage system?
Maximum 30m between chambers or at major pipe bends and junctions.
How should foul water drainage be designed in flood-prone areas?
Using non-return valves and raising discharge points above flood levels.
What is a pumped drainage system?
A system that uses pumps to move wastewater where gravity drainage is not possible.
What special requirements apply to foul drainage in basements?
Pumped systems, backflow prevention, and properly vented discharge stacks must be used.
What is the importance of adequate ventilation in foul drainage systems?
It prevents the build-up of gases, maintains trap seals, and ensures proper system function.
How should drainage be installed to avoid blockages?
Using correct gradients, adequate pipe diameters, and avoiding sharp bends.
What are the requirements for shared foul drainage systems?
Proper access for maintenance, approval from local authorities, and correct sizing for all connected properties.
How should foul drainage pipes be laid beneath buildings?
Pipes should be encased in granular material, adequately ventilated, and accessible for repairs.