Viemärilukko

Viemärilukko, also known as a trap or siphon, is a crucial component of plumbing systems designed to prevent foul-smelling sewer gases from entering a building. It is essentially a U-shaped bend in a pipe that retains a small amount of water, forming a seal. This water barrier effectively blocks the passage of gases from the sewer line into the living space.

There are several common types of viemärilukko, including P-traps, which are typically found under sinks and are named for their shape. S-traps, less common now due to potential siphoning issues, also use a water seal. Drum traps, a more archaic design, use a larger cylindrical chamber. Institutional and industrial settings might utilize more complex grease traps or oil separators, which also function as a type of viemärilukko by physically capturing specific contaminants before they enter the main sewer system.

The proper functioning of a viemärilukko relies on maintaining the water seal. If a fixture is not used for an extended period, the water in the trap can evaporate, allowing sewer gases to escape. This is why it's advisable to run water in seldom-used drains periodically. Blockages in the viemärilukko are a common plumbing problem, often caused by hair, grease, soap scum, or food particles, leading to slow draining or complete stoppage. Cleaning the viemärilukko is a frequent maintenance task for homeowners and building managers.