A drainage grate’s primary function is to let water enter the trench system efficiently. Grates must remove the quantity of water specified and be strong enough to withstand traffic without collapsing. Aesthetics are often secondary to function, but still important to grate selection.
ACO Freestyle iron grates
ACO offers grates in a variety of sizes, patterns, and materials, from tried and true slotted stainless steel to discreet drainage concepts such as Brickslot and EcoPanel.
Another innovative option is Freestyle, a cost-effective way to design your own iron grate pattern for KlassikDrain or SlabDrain.
Below you will find each standard Stormwater Grate ACO offers, along with standards and specifications. The ACO Stormwater Grate Visualizer—an online grate + surface selector tool—presents these grates within common surrounds for additional visual assistance.
The internationally recognized standard for trench drains is EN 1433: 2002 Drainage Channels for Vehicular and Pedestrian Areas, which uses test block load tests to evaluate and classify grates. The full force of the test load is directed onto the grate.
EN 1433 load test example
EN 1433 Load Classes
Load Class A – 3,372 lbs – 15 kN (46–70 psi)
Residential and light pedestrian traffic
Load Class B – 28,101 lbs – 125 kN (387–580 psi)
Sidewalks and small private parking lots
Load Class C – 56,202 lbs – 250 kN (774–1,160 psi)
Parking lots and general commercial areas
Load Class D – 89,924 lbs – 400 kN (1,238–1,856 psi)
Trafficked sections of roads and highways
Load Class E – 134,885 lbs – 600 kN (1,856–2,785 psi)
Aircraft hangars, industrial areas, gas stations and light commercial forklifts
Load Class F – 202,328 lbs – 900 kN (2,785–4,177 psi)
Aircraft runways, military establishments, docks, heavy industrial, heavy fork trucks and very heavy wheel loads
FAA 200,000 lb Proof Load
This measure is specific to airport extra heavy duty wheel loads up to 100,000 lbs with an engineering safety factor of 2 applied. Although no independent standard refers to this measure, it has become widely accepted as a line of measurement for airside loading requirements at US international airports.
Stainless Steel
16 gauge
Grade 304
Brushed finish
EN-1433 Load Class A–E
Galvanized Steel
13 gauge
Cost-effective stainless alternative
EN-1433 Load Class A–E
Ductile Iron
ASTM A536 Grade 65-45-12 & 80-55-06
EN-1433 Load Class A–F
Support for FAA 200K Load Standard available
Polypropylene Plastic
Unique to Type 494D/495D/496D
Black, gray, tan options
UV stable
EN-1433 Load Class B
Polyethylene Plastic
Unique to Type 200D/201D/202D
High-density (HDPE)
Black, gray, tan options
EN-1433 Load Class A
Resin Composite
Unique to Type 454D/492D/492Q
Microgrip anti-slip
UV stable
EN-1433 Load Class C
Aggregate
Unique to EcoPanel
8 colors available
UV-stable resin-bonded
EN-1433 Load Class B
ADA Requirements
ADA Requirements are set out in The Americans with Disabilities Act of 2010, Section 302.3
Where grates are used within walking surfaces, the open slots should be ≤ 0.5” (12.7 mm) wide in one direction. Where the length of the slot is > 0.5”, the opening should run perpendicular to the main direction of traffic.
A grate designed to resist entry of heeled shoes, in which the maximum grate hole size in least dimension shall be 0.31” (8 mm).
Heel-Safe
For applications where high stiletto heels are commonplace, ACO recommends grates with openings of ≤ 0.25” (6.5 mm) or less to prevent heels from becoming trapped, causing injury or falls.
Bicycle-Safe
AS 3996 – 2006 Clause 3.3.6
No US Standard exists detailing slot sizes to avoid bicycle tires from becoming trapped. ACO rates grates based on Australian Standard AS 3996 – 2006 Clause 3.3.6 which specifies maximum slot length dependent on slot width for grates that are deemed Bicycle Tire Penetration Resistant.
Anti-Slip
ACO has tested grate patterns for slip resistance using the widely accepted pendulum test. A result of > 24 BPN is considered Anti-Slip.
ACO recommends selecting a grate with similar BPN values as the surrounding pavement finish. Pavement slope, water, presence of surface contaminants, etc. can also negatively affect slip and skid resistance. Ask ACO for BPN reports if needed.
LEED-Compliant
Many ACO grates are made out of materials considered Leadership in Energy and Environmental Design (LEED) compliant due to their high recycled content and high recyclability %.
Stainless Steel
Galvanized Steel
Ductile Iron
Non-Metallic
Non-metallic ACO grates provide high insulation from electric currents.
These grates can be coupled with SlabDrain H100 polymer concrete channels to form a completely non-metallic system.
Polypropylene Plastic
Polyethylene Plastic (HDPE)
Resin Composite
DrainLok
Factory-fitted locking device removes need for bolts and bars and improves channel hydraulic capacity by snapping directly into the edge rail. DrainLok grates are fit with an anti-shunt mechanism that restricts unwanted grate movement when installed, improving durability and longevity of the system.
QuickLok®
Patented, boltless locking system providing a stud and locking bar for additional security. The locking bar is set into recesses within the channel, while the grate clips into the secured locking bar via the stud.
PowerLok®
Patented, boltless locking system consisting of rails with lugs fitted to grates, and a simple clipping device, providing both a secure fit and easy installation/removal.
Bolted
Bolted grates provide the highest amount of stability and security. PowerDrain and SlabDrain include 4-bolt grate options, while FlowDrain includes 2-bolt grate options.
KlassikDrain Freestyle
Custom Decorative Tops
Architectural features such as entrances, promenades, courtyards and landscaped areas, whether public or private, can all have their appearance significantly enhanced through the creative use of ACO Freestyle grates.
Flexible production tools with ACO’s own foundries make it possible to create unique ductile iron grate designs for projects with a custom surface design on a standard KlassikDrain DrainLok grate.
The two-part tool consists of a standard lower part to provide the structural support of the grate and a customizable top section where the designers unique patterns can be created. A minimum order of 400 half-meter length grates is required for this option.
Custom top and standard structural sub-frame
Grate Design
Any design can be submitted to ACO, who will advise on any necessary edits to convert the design into a physical product.
