SIPHONIC SYSTEM COMPONENTS

Critical components of siphonic systems: rainwater filters, pipe lines, fittings and mounting elements

SIPHONIC RAINWATER FILTERS (ROOF DRAINAGE FILTERS)

The most critical component of the siphonic system is the special rainwater filters on the roof. These siphonic filters are designed to cut off air at the entry point of rainwater into the system.

  • Vortex-Breaking Plates:

    The vortex-breaking plates on the filter prevent water from entering in a rotating manner; when water reaches a certain level, only water is allowed to enter the pipe and air entry is blocked.

  • Completely Full Flow Mode:

    Thus, the system can quickly transition to completely full flow mode and create a vacuum effect.

  • Leaf Retaining Grilles:

    Most filters also have leaf retaining grilles to catch objects such as leaves and mud. These grilles are designed to prevent large debris from entering the system and causing clogging while allowing water to flow freely.

MATERIAL OPTIONS
  • Pilsan
    High Strength Plastic:

    ABS, polyethylene etc. filters are preferred for their lightweight and corrosion-resistant structures.

  • Pilsan
    Stainless Steel:

    Can be used in projects where long life and fire resistance are desired.

PIPE LINE AND FITTINGS (ACCESSORIES)

As siphonic system pipe material, high density polyethylene (HDPE) pipes are generally used. HDPE pipes are ideal for rainwater drainage due to their light weight, corrosion resistance and smooth inner surfaces.
  • Standard and Diameter Range:

    In Turkey, HDPE siphonic pipes are produced in accordance with TS EN 1519 standard. Typically, downpipes from the roof and horizontal lines are selected in diameters ranging from Ø50 mm to Ø300 mm according to the project.

  • Segment-by-Segment Diameter Change:

    In siphonic systems, pipe diameters can be changed segment by segment through calculations. Different diameter sections may need to be used along the line to balance flow velocity and pressure differences.

  • Fittings and Transition Parts:

    Transition parts (reductions) and fittings such as elbows and tees must be designed appropriately for the system.

PIPE JOINING METHODS

As a pipe joining method, gasketless and completely leak-tight joining is of great importance. Since siphonic pipe lines will operate under vacuum, even the slightest air leakage disrupts the system's efficiency.

  • Pilsan
    Butt-Weld:

    Butt-weld or electrofusion sleeve joining methods are generally used in joining HDPE pipes.

  • Pilsan
    Gasketed Joining Not Preferred:

    Unlike gasketed or fittinged classical wastewater pipes, O-ring gasket push-fit joining is not preferred in siphonic systems, as gaskets age over time and risk air leakage under vacuum.

Welded HDPE lines are more integrated and safe against sudden pressure changes. The smoothness of the inner surface of pipes is also a critical issue in terms of flow efficiency. HDPE has a low friction coefficient in this respect and also makes it difficult for accumulations to form inside the pipe. The smoothness of the inner surfaces of accessories and the absence of sharp edges reduce turbulence and pressure losses in flow. Wide-angle elbows and gradual transitions are preferred as much as possible to maintain the flow regime.

SUSPENSION AND MOUNTING ELEMENTS

Special suspension systems are used to enable siphonic pipe lines to be installed near the ceiling, slope-free and over long distances. To control vibrations and movements that may occur in pipes during high-flow flow, and to tolerate thermal expansion, carriers specific to this system are designed in addition to standard installation hangers.

  • Rail System:

    Generally, special rail profiles are mounted to the ceiling and pipes are suspended with special pipe clamps that can move on these rails.

  • Sliding Clamps:

    The rail system contains sliding clamps that allow pipes to expand linearly; thus, longitudinal movements that may occur in pipes due to temperature changes or sudden vacuum effect are absorbed without disrupting system integrity.

  • 0% Slope Support:

    Suspension elements fix pipes so that they remain without sagging even at 0% slope and contribute to the safe operation of the pipe line at high flow velocities.

  • Regular Support:

    Especially when horizontal lines are long, these special clamps placed at certain intervals firmly grip the pipe but also allow controlled flexibility.

During installation, regular support of pipes and solid anchoring to the ceiling or roof is essential. The strength of the suspension system is calculated taking into account the weight of full pipes and dynamic loads of flow. As a result, with a properly designed suspension method, siphonic system pipes are safely hung on building carriers and a robust installation is created that can operate for many years without requiring maintenance.

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