These are for use indoors in shopping centres, airports and hotels. To suits tiles they have a decorative edge and are limited to light occasional traffic.

Raised Ductile Edges are perfect for pavers up to 40mm in slow moving, heavy trafficable areas they are robust and have a Class "C" loading.

Concrete Infill Covers are used to match surrounding concrete areas. They are a much more solid product than solid top covers thus allowing fast moving, continuous heavy traffic and have a long life expectancy in roads.

These are good for use where access covers will be opened regularly. These are limited to slow moving occasional heavy traffic.

Applies to public areas and domains when there are all types of public trans versing across grating. There is a 10mm gap between bars for good water flows and comply to AS1428.1 Access and Mobility Code.

This gives our products very early strength for manufacturing and handling. It also allows our products to be stronger, lighter and faster. 50mpa Concrete also has sulphur resistant benefits in aggressive soils and sewerage applications.

You can order coloured concrete to match surroundings. For example Black/Grey to match tar or paved areas.

This is very effective when doing maintenance jobs on existing roads. The product comes with the concrete already cured for traffic.

Only if the zinc coating has been compromised. If the galvaning coating is damaged, then if moisture gets to the mild steel, then the mild steel will start to rust. If this occurs, then the integrity of the product is compromised & will continue to deteriorate.

Precast concrete is preformed concrete using moulds to create a finished product.

There are two main types. Wetcast Concrete & dry cast concrete.

Wetcast concrete generally regarded as the superior process in the drainage industry, as it is typically stronger, less pouress or actually sealed, so no general liquids permiate through the walls.

Drycast is typically formed under pressure and usually has voids throughout, that will let water penertrate through if continually exposed to it.

This allows for quicker installation time no need to form up and waiting for concrete to cure.

A cover is a solid lid designed to restrict water from passing through it.

A grate is a grid type design which allows water to pass through it.

Durham's have over 50 years' experience in providing long life products with a proven performance.

Stainless steel is a steel alloy with a minimum of 10.5% chromium content by mass. There are two common grades of stainless steel used in the drainage industry. Grade 304 & 316. Grade 316 is the higher (more resistant) grade.

Stainless steel does not readily corrode, rust or stain with water as ordinary steel does. However it is not fully stain-proof in low oxygen, high-salinity or poor air-ciculation environments.

There are 2 common termonoligies for load ratings: Class Rating & "Duty"

Class Load Ratings are specific load classifications under standards, such as AS3996-2006 & BS/EN: 124 - 1994. "Duties" (Light, Medium, Heavy & Extra Heavy) are more ambiguous and are open to interpretation. These usually do not have "specific" load ratings.

Australian Standards has 7 load classes. A (lightest) to G (Heaviest)

From AS3996-2006 (Please reference the full standard for more details)

Class A: Areas (including footways) accessible only to pedestrians and pedal cyclists and closed to other traffic). Nominal Wheel load of 330kg's - Ultimate Limit State Design Load 10kN.

Class B: Areas (including footways anf light tractor paths) accerssible to vehicles (excluding commercial vehicles) or livestock. Nominal Wheel Load of 2670kg's - Ultimate Limit State Design Load 80kN.

Class C: Malls and areas open to slow moving commercial vehicles. Nominal Wheel Load of 5000kg's - Ultimate Limit State Design Load 150kN.

Class D: Carriageways of raods and areas open to commercial vehicles. Nominal Wheel Load 8000kg's - Ultimate Limit State Design Load 210kN.

Class E: General docks and aircraft pavements. Nominal Wheel Load of 13700kg's - Ultimate Limit State Design Load 400kN.

Class F: Docks and aircraft pavements subject to high wheel loads. Nominal Wheel Load of 20000kg's - Ultimate Limit State Design Load 600kN.

Class G: Docks and aircraft pavements subject to very hight wheel loads. Nominal Wheel Load of 30000kg's - Ultimate Limit State Design Load 900kN.

*NB: A force of 10kn approximtely equal to the weight of 1 tonne.

"Duties" are commonly refered to the following loadings (but not by all suppliers):

Light Duty: Pedestrian Areas only

Medium Duty: Light vehicles (cars)

Heavy Duty: Commercial Vehicles (cars & light trucks)

Extra Heavy Duty: Heavy Vehicles (Trucks & commercial vehicles)

DURHAM precast concrete products can be a quicker, easier and cheaper option than cast on site items. Durham precast products are of a high quality and continuous consistancy.

On our website there is a quote request form ("Quote Sheet"). It is located in the top right corner of the menu bar. Simply click on this & fill out the form.

Alternitively, as you navigate through the site, you can click on a product and "Add" it to your quote sheet.

A cover and frame that provide a gas tight seal to AS3996-2006.

Refer to AS3996-2006 - Appendix F for more detail.

A cover and frame that provide a water tight seal to AS3996-2006.

Refer to AS3996-2006 - Appendix E for more detail.

A sealed cover and frame provides both a gas-tight and water-tight seal. It is a lid designed to restrict the access of surface water and restrict the escape of gas.

*Refer to AS3996-2006 Appexdix E & F for more details.

If you clicked on the question then the answer will be revealed.

It is a hop dipped, zinc coated mild steel. The mild steel products are a fabricated (welded) product. The galvaning is applied after the fabrication to give the mild steel a protective coating. It is typically silver in colour.

No, during the production of cast ductile iron products a fine layer of iron dust is deposited on the cast item, which can form red-brown marks when it comes into contact with moisture. These red-brown marks are regarded as a patina, and do not have a negative effect on the cast ductile functionality.

Ductile Iron is Super Grade Cast Iron made through the casting process. Ductile Iron is a Long Life Product with superior performance to galvanised mild steel products.

AS3996-2006 Australian Standards for: Access Covers & Grates

BS EN124 : 1994 Gully tops and manhole tops for vehicular and pedestrian areas

BS 750 : 1984 Underground fire hydrants and surface box frames and covers

AS 3600-2009 Australian Standards for: Concrete Structures

AS 3735-2001 Australian Standard for: Concrete Structures for retaining liquids

AS 1428.2-1992 Design for access and mobility