Welcome to our Help Center! 👋
Your guide to common enquiries for our trench drains.
Our Help Center provides quick and easy access to information and support about trench drains.
Overview & Design
Covers trench drain purposes, system types, and design benefits including modular and V-profiled channels.Materials & Standards
Details materials, grates, load standards, and specialised solutions for civil and commercial projects.Residential & Maintenance
Explains residential applications, sizing, installation, and ongoing maintenance for long-term performance.
This FAQ section answers common questions about trench drains, including surface water management, design options, materials, installation, and maintenance. Learn about modular systems, polymer concrete, grates, load standards, and specialised solutions for roads, airports, ports, and light rail.
For further assistance, feel free to contact our technical support team.
Q&A:
- Why is surface drainage important?
It is understood that standing water in and around facilities can cause severe structural damage. Potential problems include cracked foundations due to static water pressure buildup on the wall, settling, degradation of adjoining building materials, and freeze–thaw issues. Similarly, ponding (i.e. water collection) and hydroplaning on roads, highways, and bridges are possible safety hazards that can be avoided.
Effectively handling and transporting away rainfall during and after storms is a prime component in facility and road construction planning.
To find out more, click here.
2. What are the different types of surface drainage?
Surface drainage can be accomplished using three different systems - in-line pits, open swales, or grated trench drains. Cost comparisons have shown modular trench drains to have lower total installed costs when labour, excavation, pipework, grading etc., are taken into account.
To find out more, click here.
3. Are modular trench drainage systems expensive?On average, pre-cast modular trench drains cost about 10 percent less to install and maintain than grated pits, and 20 percent less than cast-in-situ trench drain systems.
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4. Why are V profiled drains better than the flat bottom U shaped drains?
The design of V profiled drains is inspired by sewers with egg shaped profiles where liquid velocities need to be maximised during low flows.
During average rainfall, water levels in ACO’s channels will be higher (due to their V shape) and therefore will run cleaner as sediment tends to be washed downstream due to the resulting higher velocities. This means that the trench drain is clear and ready for the peak design storms.
The design of V profiled drains also yields a stronger wall profile.
To find out more, click here.
5. Are modular trench drainage systems expensive?
On average, pre-cast modular trench drains cost about 10 percent less to install and maintain than grated pits, and 20 percent less than cast-in-situ trench drain systems.
To find out more, click here.
6. What are the different types of trench drains?
Trench drain systems employ a simple angled grade on both sides of a linear trench to move runoff into a point along the channel. Liquids are then discharged at the end of the drain into an underground pipe system or culvert. Trench drains need a shallower excavation than in-line pits with extensive underground piping.
Cast-in-situ systems are one type of trench drain design. This method uses extensive formwork and labour required for producing and installing the system. A form is built (usually wood) and concrete is poured around it and the form removed to leave a trench. Most cast-in-place systems are usually 300mm and 400mm in width, and possibly wider. These large widths require oversize grates, which drive up project cost dramatically.
To find out more, click here.
7. What is a modular trench drainage system?
Modular trench drains are another way to produce a trench. Modular trench drain channels are typically factory manufactured and offered in metre or half-metre lengths to enable easy transport to the jobsite, on-site handling, and versatile configurations.
Modular channels usually start at 100mm wide. These narrower widths use smaller grates, significantly reducing overall project costs. Wider systems are available if required by hydraulics or application.
Channels are aligned onsite via male/female interconnecting ends to form a continuous sloped run. Systems offer up to 40 interconnecting sloped channel depths (sizes) to create continuously sloped trenches up to 40 metres long. Neutral channels with no slope that can be inserted along runs to extend length.
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8. What is Polycrete®?
'POLYCRETE®' is ACO's trademark for products made from polymer concrete produced in Australia. It encompasses ACO's extensive portfolio of polymer concrete pits, channels, ducts, lids, risers and containment sumps.
To find out more, click here.
9. What is polymer concrete?
Polymer concrete is a durable material which is resistant to road salts and common chemicals. It is made from polyester resin reinforced with mineral aggregates and fillers.
Polymer concrete is a versatile, durable, composite material produced by mixing a variety of mineral fillers with a synthetic or natural resin binding agent. This advanced engineering material is used in many industries but is most common in the building and construction industries where its long life and material properties make it ideal for many products.
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10. Can modular trench drains be used with harsh chemicals?
While polymer concrete provides effective durability in general applications where stormwater or dilute detergents are used, certain industrial applications require drainage of liquids that are corrosive, at extreme temperatures or both. Stainless steel is recommend for these applications.
To find out more, click here.
11. Are polymer trench drain systems weather resistant?
Polymer concrete has a coefficient of expansion and contraction similar to portland cement, and so they will expand and contract at the same rate as the encasement, minimising buckling or pulling away from the concrete surround. They have a low rate of water absorption and will not fail structurally during freeze-thaw cycles.
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12. Why are there so many different grates?
Except for the visible grate, most of the trench drain system is underground and virtually invisible. So the grate must work together with the channel to provide the right load classification performance (AS 3996) and visual qualities.
Grates come in a variety of different materials such as ductile iron, galvanised steel, stainless steel, non-ferrous metals and plastics.
Grates that comply with the requirements for pedestrian & cycle areas (AS 3996 & AS 4586) and disability access are available (AS 1428.2).
To find out more, click here.
13. What are the different load standards for grates?
AS 3996
"This standard specifies requirements for access covers and grates for use in vehicular and pedestrian areas. It applies to access covers & grates having a clear opening of up to 1300mm...." Clause 1.1 Scope.As part of ACO's continuous product development and commitment to quality, ACO has NATA certified testing equipment (Licence number 15193), operated by fully trained and certified technicians.
EN 1433
The only standard written specifically for grated trench drains, and internationally recognised, is DIN 19580. EN 1433 is superseding DIN 19580. It accounts for different widths of grates, with different size test blocks for different size channels. EN 1433 tests products in exactly the same method as DIN 19580 with the same load categories, up to 900kN.As with DIN 19580, EN 1433 offers test methods for both the grate and channel body. It accounts for both proof loading and catastrophic failure.
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14. Does ACO only make trench drain products?
ACO in Australasia offers an extensive portfolio of stormwater, building drainage systems; electrical pit and ducting systems; access covers and other products for niche applications.
To find out more, click here.
15. What trench drains are used for Civil Infrastructure projects?For civil infrastructure projects, a wide range of trench drain systems can be used depending on the project requirements.
These trench drains are either monolithic with non-removable grates or can be accessible with removable lockable grates.
ACO offers a dedicated range of trench drains for roads & highways; rail, bus, truck stops, bridges & tunnels, seaports and container terminals.
Find out more, click here
16. Why are trench drains in roads used?
Trench drains in roads and motorways are used to remove surface water quickly to eliminate aquaplaning and reduce splashing. Trench drains are often used in lieu of conventional kerb inlet pits to offer continuous linear drainage in limited construction depth areas.
ACO offers a dedicate range of trench drains for road, highways and motorways.
Find out more, click here
17. How far do you space pits in a road?
Pit spacing depends on the catchment hydraulics and topography of the road being drained. Pits are integrated in trench drains so that as a system, they can provide continuous drainage.
ACO offers a free service to assist engineers with their design.
Find out more, click here
18. What are the best trench drains for airports?ACO offers dedicated ranges of trench drains for airside or landside of the terminal buildings These innovative solutions are proven systems that can meet the extreme demands of airports.
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19. What drains are used in light rail environments?
Wharves and docks provide the most challenging environments for any pavement elements and trench drains must be integrated carefully into the slab.
ACO offers a dedicated range of trench drains for sea port pavements.
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20. What trench drains are used in a sea port pavement?
Highly specialised drains are needed for the water management of track infrastructure. These drains are developed to suit grooved rails and track slabs.
ACO offers a dedicated range of trench drains for light rail projects.
Find out more, click here
21. What trench drains are used in a sea port pavement?
Highly specialised drains are needed for the water management of track infrastructure. These drains are developed to suit grooved rails and track slabs.ACO offers a dedicated range of trench drains for light rail projects.
Find out more, click here
22. Which drainage channel material should I select?
For residential projects, both plastic and polymer concrete bodies are both acceptable for use. However polymer concrete is far more durable over the long term and provides stronger and stiffer channels suitable for constant car traffic. Additionally, plastic bodies are flexible and can bend inwards squeezing the grate as a result of compacted earth fill/concrete. This can make grate removal/replacement difficult.Polymer concrete is best suited for concrete pavements. For building applications e.g. balconies, door tracks, showers, stainless steel is the best material as it can be cleaned easily and is aesthetically more pleasing.
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23. What types of drains are used in residential applications?
There are a number of drainage options for both inside and outside of the building for bathrooms driveways, gardens, thresholds, balconies etc. Materials vary from, plastic, polymer concrete to steel depending on the application.
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24. What's the difference between a residential and a commercial stormwater trench drain?
A residential drain is generally designed and manufactured for homes, small offices and gardens. Commercial drains are built for urban, commercial or industrial applications. Consequently, they are load rated, lockable and grates need to meet key public criteria for pedestrian safety e.g. heel safety.
Unlike residential drains, commercial drains generally need to be sloped and satisfy key hydraulic criteria.
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25. How big (wide, deep) does my trench drain need to be?
Trench drains need to be sized according to the rainfall intensity of the local region and the catchment area. ACO can help you size a trench drain.
Send us your details or use our DIY software, click here
26. How often do I need to maintain my trench drain?
This depends on local factors – Is it a leafy area? Is it close to a garden bed? What are the consequences of blockage – is it protecting a garage entry?A blocked trench drain serves no one. Drains must be cleaned if they are to work. ACO offers drainage baskets with its commercial trench drains.
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27. How do I install my DIY drain?
Depending on the pavement type and anticipated traffic, drains need to be encased in the ground.ACO installation instructions are found here