Construction period drainage, also referred to as temporary drainage, ensures effective and reliable surface water management throughout the construction phase. When the final road surface has not yet been completed, water can drain through lateral openings in the cover tops.
If needed, these openings can be sealed with closure plates, providing flexible protection depending on site conditions. This solution helps maintain safety and functionality during all stages of construction.
With the exception of SAKU manhole covers, seals, and PEWEPREN inserts, all our manhole covers are manufactured using standardized, non-combustible materials, including:
- Cast iron
- Cast iron combined with concrete
- Steel
- Reinforced concrete
- Stainless steel
These materials are classified as non-combustible building materials according to DIN 4102, Class A1. For detailed information regarding the fire behavior of our products, please refer to DIN 1986 Part 4.
DUROPREN stands for a high-performance combination of covers or gratings with integrated damping inserts and frames equipped with captive, wear-resistant inserts. In everyday use, sand, road debris, and dirt accumulate in the joint between the cover and frame. Over time, this leads to abrasion of the support surface within the frame. Once wear reaches a critical level, the cover may begin to rattle, resulting not only in noise pollution but also in damage to the manhole cover and its substructure. DUROPREN manhole covers are specifically designed to counteract this issue. In addition to the damping insert in the cover, they feature a highly wear-resistant insert in the frame, which significantly reduces wear and extends the service life of the entire system.
Manhole covers with ventilation openings
We classify manhole covers as ventilated only if their ventilation cross-section meets or exceeds the specifications outlined in DIN EN 124, Section 7.2.
Manhole covers without ventilation openings
Non-ventilated manhole covers may feature closed or fully open lift-out openings, but they are neither watertight nor odor-tight. Covers designed to prevent water ingress or backflow are specifically designated as watertight or backflow-resistant, depending on the application requirements.
"Natural" cast iron for tops for road and yard drains and manhole covers.
Not only has it been confirmed through years of practical experience, but it is now also scientifically proven: the surface coating of cast iron serves a purely cosmetic purpose when it comes to manhole covers for standard sewer systems and tops used in traffic area drainage.
Cast iron is inherently resistant to environmental influences—even to salt solutions caused by winter road salting. This is due to its natural ability to form a protective oxide layer upon surface oxidation, which effectively prevents further material degradation.
For this reason, we intentionally do not apply any surface coating to our cast iron drains and manhole covers—especially for environmental and sustainability reasons. Naturally, the absence of a coating fully complies with all relevant standards.
PEWEPREN refers to permanently elastic damping inserts that are securely integrated into covers, gratings, or frames to prevent loss and ensure long-term functionality.
Manhole covers and tops must be designed to maintain a quiet and stable position, especially in heavy-duty applications such as load classes D 400 to F 900. Products equipped with PEWEPREN inserts meet these demanding requirements. The damping insert is firmly embedded in grooves or chambers within the cover, grate, or frame, offering effective protection against mechanical damage. Proven over many years in practical use, PEWEPREN ensures noise reduction, positional stability, and extended product life.
Manhole covers - backflow-proof, water-tight, gas-tight and odor-tight
Backflow-proof manhole covers are designed to be impermeable to water from both above and below. All backflow-proof covers are also watertight, gas-tight, and odor-tight for non-pressurized sewer systems and sewage gases. For other types of gases, please contact us directly for specific guidance. These covers feature a closure system with a seal positioned between the frame and the cover, which is compressed when the cover is locked. This ensures a secure and tight fit. When installing backflow-proof covers, special attention must be paid to the connection between the manhole structure and the cover. The cover must be anchored securely to withstand the expected backwater pressure, ensuring long-term functionality and safety.
These covers are designed without continuous openings. A raised area along the inner edge of the frame causes the joint between the cover and frame to fill with sand shortly after installation, creating a relatively tight seal. As a result, only small amounts of surface water can penetrate. However, the design ensures that no pressure can build up inside the shaft beneath the cover, maintaining safety and functionality under typical operating conditions.
Manhole covers with closure systems feature a seal positioned between the frame and the cover, which is compressed during locking. This design ensures that the cover is not only securely fastened, but also odor-tight. Daytime watertight manhole covers are designed to be impermeable to unpressurized surface water. However, their watertightness can only be guaranteed if the covers are professionally operated and the seal and sealing surfaces are cleaned and inspected prior to installation. If the seal is damaged, it must be replaced immediately. To maintain optimal performance, daytime watertight covers must be installed in such a way that minimal water remains on the surface, reducing the risk of water penetrating the frame-cover joint.
Manhole covers with customizable surfaces are engineered to allow their top layer to be adapted to match the surrounding area as closely as possible, for example by applying surface materials on site. Any on-site filling must comply with applicable traffic and environmental standards. The load-bearing capacity required by DIN EN 124 is ensured in the product’s delivered state.
Cast iron with lamellar graphite (gray cast iron GG) EN-GJL according to DIN EN 1561 or
Cast iron with nodular graphite (nodular graphite cast iron GGG) EN-GJS in accordance with DIN EN 1563.
Both materials offer distinct advantages and have demonstrated excellent performance in duct casting. They are highly corrosion-resistant and allow for virtually unlimited design flexibility.
Gray cast iron is known for its outstanding vibration damping properties due to its lamellar graphite microstructure.
Ductile cast iron, with its nodular graphite structure, provides significantly higher strength and elongation, making it ideal for components that must withstand high mechanical stress while maintaining a low weight.
Rather than asking,
“Which is the better material?”,
the more relevant question is:
“Which material is best suited for the specific application?”
ACO is equipped with state-of-the-art melting facilities in its own foundries, enabling the production and processing of both materials. This ensures that we can offer the optimal solution tailored to each application - independent of the material choice.