Backwater Valve
Backwater Valve
Overview
Laminar backwater valves (non-return valves) are designed to protect buildings against flooding caused by backflow of sewage and stormwater. Backflow can occur due to intense rainfall, snowmelt, or rising water levels in the drainage network.
Installing a backwater valve is a mandatory requirement for buildings with lower-level rooms under the technical building codes in many jurisdictions. Laminar offers a comprehensive range of backwater valves for both sanitary and stormwater systems, designed for reliable, automatic operation without external power.
Compliance: All Laminar backwater valves meet the requirements of EN 13564 and are suitable for use in PUB-compliant installations in Singapore.
Features
Self-Operating Mechanism | No external power required – operates automatically during backflow events. |
Durable Polypropylene Construction | Resistant to corrosion, chemicals, and negative temperatures. |
Effective Rodent Protection | Chromium-nickel guard prevents rats and rodents from entering the building. |
Manual Closure Lever | Allows manual shut-off during maintenance or extended system inactivity to prevent odours. |
Smooth Internal Surface | Prevents sediment buildup and ensures 100% flow capacity when open. |
High-Temperature Resistance | Maximum operating temperature of 95°C. |
Pressure Rating | Maximum operating pressure of 0.5 bar. |
Odour Sealing | Prevents unpleasant sewage odours from re-entering the building. |
Type of Backwater Valve
Backwater valve ø 110
ZB 110 – Installed onto sewage pipes ø 110, weight: 0,94 kg
Backwater valve ø 125
ZB 125 – Installed onto sewage pipes ø 125, weight: 1,24 kg
Backwater valve ø 160
ZB 160 – Installed onto sewage pipes ø 160, weight: 2,03 kg
Backwater valve ø 200
ZB 200 – Installed onto sewage pipes ø 200, weight: 3,60 kg
Anti-flood valve without lever ø 110
ZBTPO 110 – Installed onto sewage pipes ø 110, weight: 0,85 kg
Anti-flood valve without lever ø 160
ZBTPO 160 – Installed onto sewage pipes ø 160, weight: 1,80 kg
Technical Specifications
Material | High-quality polypropylene (PP) |
Metal Components | Chromium-nickel stainless steel (flap guard, screws, nuts, washers) |
Maximum Operating Temperature | 95°C |
Maximum Operating Pressure | 0.5 bar (50 kPa) |
Sealing | Rubber gaskets resistant to aging and atmospheric conditions |
Standards | EN 13564 (Harmonized Standard) |
Flow Capacity | 100% flow when fully open |
Applications
Residential | Protection of basements, ground-floor bathrooms, and low-lying areas |
Commercial | Shopping centres, office buildings with basement levels |
Industrial | Factories, warehouses with floor-level drainage |
Municipal | Stormwater and sanitary sewer systems |
Infrastructure | Pumping stations, drainage networks |
effective protection against rodents
guard protecting the flap is made from chromium-nickel
KARMAT backwater valves are equipped with a manual closure lever
all mounting elements (screws, nuts and washers) are made from chromium-nickel
Why Laminar Backwater Valves?
- EN 13564 Compliant – Meets harmonized European standard for backwater valves
- PUB-Ready – Suitable for PUB requirements in Singapore
- Proven Design – Based on Karmat’s decades of experience in anti-flood devices
- Patented Solutions – Multiple patented designs for reliability and performance
- Corrosion-Resistant – All metal components are chromium-nickel stainless steel
- Full Range – Available in sizes from Ø50 to Ø315
An additional chromium-nickel cover C protecting the lever - available on individual client order
the device’s interior with its smooth surface
high quality elastic gasket material
Installation & Operation
Principle of Operation
During normal flow, the flap hangs loosely open, allowing sewage to flow freely. When backflow occurs, the flap is pushed closed by the reverse pressure, sealing securely against the valve body to prevent sewage from entering the building. This process is fully automatic.
Manual Override
A manual closure lever allows the valve to be locked in the closed position, providing protection during prolonged system inactivity or maintenance.
Maintenance
Periodic inspection is recommended (monthly or after heavy rainfall) to verify smooth operation of the flap and lever. The lever should move freely between open and closed positions.
Example of installation
These backwater valves are designed for installation within horizontal wastewater lines. They are typically positioned before the pipe exits the building perimeter, along the external sewage line before it links to the public utility grid, or directly inside plastic and concrete inspection manholes.
Karmat backwater valve ø 160 in a ø 600 collection well
