Siphonic Drainage System for Flat Roofs

Siphonic Drainage System for Flat Roofs
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What is Siphonic Drainage?

epams how does it work

Siphonic drainage uses the principle of negative pressure to accelerate the flow of rainwater.

With fewer air pockets in the pipes, the system reaches full-pipe flow faster, enabling rapid evacuation of water and reducing the number and size of vertical downpipes needed.

Pam Building’s epams® system offers an advanced siphonic roof drainage solution engineered to evacuate large volumes of rainwater quickly and efficiently. Unlike traditional gravity systems, the siphonic principle creates a full-bore flow within the pipes, enabling higher discharge rates with fewer downpipes. This system is ideal for large flat roofs on structures like airports, shopping centers, warehouses, and gymnasiums.

Siphonic Drainage vs Traditional Gravity Systems

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Criteria Siphonic Drainage (epams®) Traditional Gravity Systems
Pipe Diameter Smaller Larger
Number of Downpipes Reduced High
Flow Efficiency High (full-bore) Lower (partially filled)
Space Saving Yes No
Installation Cost Lower (fewer components) Higher (more piping & civil work)

epams® allows designers to simplify layouts and optimize space use while delivering outstanding drainage performance.

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Key Benefits of epams® Siphonic Drainage System

Reduced Downpipes
Fewer outlets and verticals needed due to high flow rate
Architectural Flexibility
Low-profile piping enables more design freedom
Faster Installation
Reduced pipework and trenching requirements
Integrated Protection
Grating and anti-vortex mechanisms ensure clog-free performance

Explore Our Siphonic Outlet Options

stainless steel outlet
Stainless Steel Outlet
Ideal for green roofs, coastal or corrosive environments. Designed to resist chemical exposure and weather conditions.
cast iron outlet
Cast Iron Outlet
Suitable for most flat roofs and car parks. Robust, durable, and perfectly suited for concrete or metal roof installations.

Applications & Use Cases

use cases epams   The epams® system is suited to a variety of large-scale projects:

  •     • Commercial buildings with large flat rooftops

  •     Industrial facilities where rainwater load is significant

  •     Airports and hangars requiring fast drainage

  •     Shopping malls and gymnasiums with extensive roofing areas

    With options adapted for both synthetic membrane roofs and green roofs, epams® can be tailored to suit any building envelope.

Discover all our case studies

Easy Installation & Low Maintenance

epams® is designed for efficient installation:

  • Reduced pipe length and trenching

  • Push-fit assembly for faster setup

  • Integrated grating and anti-vortex devices prevent clogging

Its low-maintenance design and long service life make it an ideal choice for modern building design and retrofits.

Optimizing usage with epams® accessories

Outlet with Steel Plate
WITH STEEL PLATE
For all flat roof configurations, offering stability and secure anchoring.
Green Roof Kit
GREEN ROOFS
Efficient drainage and seamless integration with vegetated surfaces.
PVC Membrane Kit
FOR FLEXIBLE PVC MEMBRANE
For non-accessible roofs or zones waterproofed by PVC-P membranes.
To Be Welded
TO BE WELDED
Gutters or metal roof valleys with welded connection requirements.
With Flange
WITH FLANGE
Extra-thick metal gutters or synthetic membrane roofs with high compression needs.

Our Technical Support Service for epams®

A siphonic roof drainage system like epams® requires expert design to ensure performance and safety. At Pam Building, our trained sales and technical teams assess your project feasibility and carry out a tailored hydraulic study using dedicated epams® sizing software.

We ensure proper system balance and maintain dynamic pressure under 5 bar to maximize system lifespan. A dedicated specialist supports your project from design to installation.

Any change to the pipework layout triggers a new hydraulic calculation to guarantee performance. Before final acceptance, Pam Building or an approved third party verifies that the installation matches the latest isometric drawings.

This complete technical support—feasibility analysis, project follow-up, and post-installation validation—delivers efficiency and peace of mind on every epams® project.

👉 Contact our technical team for a custom study.
👉 Learn more about epams®

Our Technical Support Service for epams®

A siphonic roof drainage system like epams® requires expert design to ensure performance and safety. At Pam Building, our trained sales and technical teams assess your project feasibility and carry out a tailored hydraulic study using dedicated epams® sizing software.

We ensure proper system balance and maintain dynamic pressure under 5 bar to maximize system lifespan. A dedicated specialist supports your project from design to installation.

Any change to the pipework layout triggers a new hydraulic calculation to guarantee performance. Before final acceptance, Pam Building or an approved third party verifies that the installation matches the latest isometric drawings.

This complete technical support—feasibility analysis, project follow-up, and post-installation validation—delivers efficiency and peace of mind on every epams® project.

👉 Contact our technical team for a custom study.
👉 Learn more about epams®

TECHNICAL SUPPORT

Tel. +33 (0) 3 66 74 00 89

tc@pambuilding.com

Frequently Asked Questions (FAQ)

1. How does a siphonic drainage system work?

It uses negative pressure to fill the pipes entirely, creating a vacuum effect that accelerates the evacuation of rainwater.

2. Is siphonic drainage suitable for small buildings?

While designed for large flat roofs, small buildings with limited downpipe space can also benefit from EPAMS.

3. What maintenance does EPAMS require?

Minimal. Integrated gratings and anti-vortex protection reduce the risk of clogging. Annual inspection is recommended.

4. Can EPAMS be integrated into green roofs?

Yes, especially with the stainless steel outlet designed for corrosion-prone environments.

5. How does EPAMS contribute to environmental certifications?

By minimizing pipework and maximizing efficiency, it reduces material usage and supports green building criteria.

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