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Choosing the Right System

When selecting a stainless steel drainage system, the following issues must be considered:

Corrosion resistance

Ensure the correct grade of stainless steel is chosen for adequate chemical and temperature protection.

Refer to Chemical Resistance Chart. The corrosion resistance information contained within this table is indicative only.

All data is based on reactions noted at an ambient temperature of 20°C. Higher temperatures will generally reduce the corrosion resistance of the materials.

Typical factors that affect material selection:

  • type(s) of chemical(s) and % composition in the liquid
  • concentration percentages
  • contact time with trough system
  • temperatures of liquid flowing into the trough
  • flushing system employed o clear liquids from the system
  • type of cleaning agent (see Care & Maintenance)
  • grate, locking mechnism and trash basket materials
  • sealant for compatibility, if applicable

Test samples should be used for final determination of chemical resistance, contact ACO.

Chemical resistance chart
Yes Recommended
Suitable Suitable, contact ACO for further advice
No Not recommended
No data No data available

Reagent Stainless Steel 304 Stainless Steel 316
Acetic Acid 20% yes yes
Acetic Acid 80% yes yes
Acetone yes yes
Alcohol (Methyl or Ethyl) yes yes
Aluminium Chloride Question Question
Aluminium Sulphate yes yes
Ammonia Gas (Dry) yes yes
Ammonium Chloride Question Question
Ammonium Hydroxide yes yes
Ammonium Nitrate yes yes
Ammonium Phosphate yes yes
Ammonium Sulphate Question yes
Ammonium Sulphide yes yes
Amyl Chloride yes yes
Aniline yes yes
Barium Chloride yes yes
Barium Hydroxide 10% No data No data
Barium Sulphate yes yes
Barium Sulphide No data No data
Beer yes yes
Beet Sugar Liquors yes yes
Benzene yes yes
Benzoic Acid yes yes
Bleach -12.5%Active C1 No data No data
Boric Acid yes yes
Bromic Acid Question Question
Bromine Water No No
Butane yes yes
Calcium Carbonate yes yes
Calcium Chloride No Question
Calcium Hydroxide Question yes
Calcium Hypochlorite No Question
Calcium Sulphate yes yes
Cane Sugar Liquors No data No data
Carbon Acid No data No data
Carbon Bisulphide yes yes
Carbon Dioxide yes yes
Carbon Monoxide yes yes
Carbon Tetrachloride Question Question
Caustic Potash yes yes
Caustic Soda yes yes
Chloride (Dry) Question Question
Chloride (Wet) No No
Chloroacetic Acid No data yes
Chlorobenzene yes yes
Chloroform Question Question
Chrome Acid 50% No No
Chromic Acid 10% yes yes
Citric Acid Question yes
Copper Chloride No No
Copper Cyanide yes yes
Copper Nitrate yes yes
Copper Sulphate yes yes
Cottonseed Oil No data No data
Cresol No data No data
Cyclohexanone Question yes
Cyclorexanol No data No data
Dimethyleanine No data No data
Dionylphalate No data No data
Disodium Phosphate No data No data
Distilled Water yes yes
Ethyl Acetate yes yes
Ethylene Chloride yes yes
Ethylene Glycol yes yes
Ethylene Glycol yes yes
Ferric Sulphate yes yes
Fluorene Gas (Wet) No No
Formaldehyde (37%) yes yes
Formic Acid (90%) No yes
Freon 12 yes yes
Fruit Juices and Pulp Question yes
Furfural yes yes
Gasoline (Refined) yes yes
Glucose yes yes
Glycerine yes yes
Hydrobromic Acid (20%) No No
Hydrochloric Acid (40%) No No
Hydrocyanic Acid yes yes
Hydrogen Peroxide (90%) yes yes
Hydroquinone No data No data
Hypochlorous Acid No data No data
Iodine No Question
Kerosene yes yes
Lactic Acid 25% yes yes
Linseed Oil yes yes
Liqueurs No data No data
Magnesium Chloride Question Question
Magnesium Sulphate yes yes
Maleic Acid Question Question
Methyl Chloride Question Question
Methyl Ethyl Ketone No data No data
Milk yes yes
Minerals Oils No data No data
Muriatic Acid No No
Nickel Chloride Question Question
Nickel Sulphate yes yes
Oils and Fats yes yes
Oleic Acid yes yes
Oleum No data No data
Oxalic Acid Question Question
Palmitic Acid 10% No data No data
Perchloric Acid 10% No No
Perchloric Acid 70% No No
Petroleum Oils (Sour) yes yes
Phenol 5% yes yes
Phosphorous Trichloride yes yes
Photographic Solutions Question Question
Picric Acid yes yes
Plating Solutions No data No data
Potassium Carbonate yes yes
Potassium Chloride yes yes
Potassium Cyanide yes yes
Potassium Dichromate yes yes
Potassium Hydroxide yes yes
Potassium Permanganate yes yes
Potassium Sulphate yes yes
Propane Gas No data No data
Propyl Alcohol No data No data
Sea Water No Question
Sewage Question Question
Silver Nitrate yes yes
Silver Sulphate yes yes
Sodium Bicarbonate yes yes
Sodium Bisulphite yes yes
Sodium Carbonate yes yes
Sodium Cyanide yes yes
Sodium Ferrocyanide No data No data
Sodium Hydroxide yes yes
Sodium Hypochlorite Question yes
Sodium Sulphate yes yes
Sodium Sulphide Question yes
Sodium Sulphite Question yes
Sodium Thiosulphate yes yes
Stannous Chloride Question Question
Stearic Acid yes yes
Sulphite Liquor No data No data
Sulphurous Acid Question Question
Sulphur Question yes
Sulphur Dioxide (Dry) Question yes
Sulphur Dioxide (Wet) Question yes
Sulphuric Acid 50% No No
Sulphuric Acid 70% No No
Sulphuric Acid 93% No No
Tannic Acid yes yes
Tanning Liquors yes yes
Tartaric Acid No data No data
Toluene No data No data
Trichloroethylene yes yes
Triethanolamine No data No data
Trisodium Phosphate No data No data
Turpentine yes yes
Urea yes yes
Urine yes yes
Vinegar yes yes
Water (Fresh) yes yes
Water (Mine) yes yes
Water (Salt) Question Question
Whisky yes yes
Wines yes yes
Xylene No data No data
Zinc Chloride No No
Zinc Sulphate Question yes


Ensure the correct edge profile, grate and installation is selected to suit the load requirements of the project.

ACO recommends that grates are secured for heavy duty applications.

Load classifications

AS 3996 Clause 1.1 Scope
“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…”

ACO believes that EN 1433: Drainage Channels for Vehicular and Pedestrian Areas, also provides a good measure of performance.

The load classes of both codes are shown in the table below.

load class classifications

Typical installation drawings
Description PDF DWG
System channel with standard edge profile in ground slab with concrete finish flooring PDF DWG
System channel with folded edge profile in ground slab with tile flooring – retrofit application PDF DWG
System channel with solid edge profile in ground slab with concrete finish flooring PDF DWG
System channel with solid edge profile in ground slab with resin finish flooring PDF DWG
System channel with vinyl seal edge profile in suspended slab with vinyl finish flooring PDF DWG
System channel with solid edge profile in suspended slab with resin finish flooring PDF DWG
SlotChannel with vinyl seal profile in suspended slab with vinyl flooring PDF DWG
SlotChannel with solid edge profile in ground slab with concrete flooring PDF DWG
SlotChannel with solid edge profile in ground slab with tile flooring PDF DWG


Ensure the widths, invert depths, grate types and any falls within the trough meet the hydraulic and installation requirements of the project

ACO has an established Technical Services Department, with many years experience advising on surface drainage. Services include advice at the initial design stage through to on-site support, where required.

If you’d like assistance with trench and grate hydraulics to help select the correct size drain for your application, please contact us here.

Channel hydraulics

A channel’s hydraulic capacity is calculated by the amount of water the channel is able to collect and drain in a given time period. This determines the size of channel required.

One way to alter a channels capacity is by changing its physical cross sectional size (width x depth). The other is by changing its hydraulic run length. This is defined as the distance water needs to travel before being discharged through an outlet. Changing this can dramatically alter a channel’s run capacity. With all other factors equal, the shorter a hydraulic run length, the higher a channels capacity to drain.

hydraulicsThe volume of liquid a channel system needs to collect and remove in a given time period determines its size. Slab restrictions may limit the depth of the channel leaving its width as the usual variable for correct sizing.

Typical factors that affect the size of a channel:

  • number of, and discharge rate (generally measured in litres per second) of wash down hoses in a room
  • volume of spill containment
  • hydraulic capacity of waste pipe beneath the floor connecting to the channel (for liquid evacuation)
  • quantity, size(s) and location (along its length) of trough outlet(s)
  • desired trough invert fall along the length of the system
  • speed of liquid across the floor during service and/or wash down operations. In this instance the selection of the grate must also be considered
  • for external areas: rainfall intensity,size of catchment, ground falls etc

ACO offers different sized channels and a broad selection of grates to meet most hydraulic requirements and offers technical support to customers to help ensure correct system specification.

Grate hydraulics

A grate fails hydraulically when water bypass occurs. Consideration must also be given to the inlet size of the grate to ensure it adequately removes water, but not at the expense of introducing litter into the drainage system, or compromise the safety of users.

A grate’s hydraulic capacity is calculated by the amount of water it will allow to pass through it in a given time period. Failure to allow passage of water into its underlying channel will result in bypass, regardless of how much capacity the channel has.

There are three factors that affect the hydraulic capacity of a grate, its size, its collective intake area and the design of its inlets.
For instance, a longitudinal bar grate can have a large cumulative intake area. Between the bars, each slot acts as an individual elongated orifice and the grate will only reach its capacity once each orifice has flooded. The bars also have the effect of slowing down the speed of water, ensuring gravity has enough time to maximise the evacuation of the water between the bars.

In comparison, the intake areas (and therefore capacity) of Tile and Brickslot grates are much smaller than a longitudinal bar design. A Tile grate has only two openings along the length of the drain. There are fewer opportunities for water to be evacuated through the design.


Furthermore, Brickslot grate styles are the most compromised design as there is only one slot for water to be interrupted and slowed.



During heavy storms, water bridging is common due to the increased flow rate. This can result in bypass, so longitudinal bar grates are preferred in vulnerableareas.

Outlet type

Ensure the correct size and location of outlet is selected to meet the underground pipework requirements

Legislative requirements

Ensure the correct grate and edge profile meet the aesthetic and safety requirements of the project.

legislative requirementsAS1428.2-1992 Design for access and mobility – Part 2, clause 9(c) states:

If gratings are located in a walking surface, they shall have spaces not more than 13mm wide and not more than 150mm long. If grates have elongated openings, they shall be placed so that the long dimension is transverse to the dominant direction of travel.

ACO offers a range of Heelsafe® grates that have openings of less or equal to 7mm.

A range of rated Heelsafe® Anti-Slip grates are available from ACO and are certified to AS/NZS 4586: Slip Resistance Classification.


ACO Technical Services will give specifiers and installers advice on choosing the correct drainage system for the application.

Choosing The Right System
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