Commercial projects often see more traffic, specifically heavy-duty traffic such as delivery vehicles. To ensure that a drainage system is adequately designed for heavy vehicles, load class ratings (AS3996) should be referenced. Concrete encasement and different grate designs will have varying load class ratings dependant on the material they're constructed from and the level of engineering that has gone into design and manufacturing.

General load class ratings go from Class A to Class E. Typical light vehicles such as cars and utes in a residential situation will be Class B (2,670kg wheel loads). A commercial situation can require load ratings from Class C (5,000kg wheel loads) right up to Class E (13,700kg wheel loads). Channel drains also gain their strength from the concrete surround, therefore while the grate load class is imperative so is the concrete encasement. Allproof channels are designed to have a minimum of 100mm concrete surround for load Class A up to a minimum of 200mm for Class E. This encasement is often checked off by an engineer as the trench created by the channel and its encasement can have an effect on structural slabs.

To help identify how this can impact product selections I have outlined the below hypothetical scenarios.

Scenario A: Communal area catering to pedestrian traffic outside an office complex.

In this situation, Allproof’s Commercial Channel with Wedge Wire grate would be an excellent choice. The Wedge Wire grate is load Class B allowing for any light maintenance or service vehicles to access the area, is slip resistant rated to R11 (AS4586), heelproof (openings less than 8mm) and resistant to bicycle tyre penetration (AS3996). The use of grate lockdowns will prevent any slight movement and reduce the risk of theft. Auckland’s CBD is next to the harbour; 316 stainless steel grating is recommended in marine environments and spray zones. Install details are available for alternative embedment for asphalt and paver finishes.

Scenario B: Loading dock of a commercial complex such as a mall (e.g. Westfield Newmarket).

A 200mm clear opening Polymer Concrete (PC) channel with a cast iron grate would be prudent in this situation. PC channels utilise polymers to supplement cement as the binder material, this creates a durable product that is highly resistant to a wide variety of chemicals and has extremely low permeability. Cast iron grates have excellent physical properties and are load rated up to Class E with a minimum 200mm concrete surround. Cast iron is resistant to dynamic wheel loads such as trucks manoeuvring or forklifts turning on them as well as good vibration dampening which helps protect surrounding concrete. Grate lockdowns are imperative in this situation to prevent the small movement of grates knocking against the channel edges under heavy wheel loads.

Scenario C: A residential garage with internal access to the dwelling.

Allproof’s NZ made Domestic Channel made from 100% recycled plastic has been designed for residential applications making it a durable and economic choice for areas subjected to light vehicle access. Alternatively for garages expecting heavy vehicle access or looking for a premium product specification, 100mm clear opening PC would make an excellent selection. A plastic or stainless grate would be advisable as these maintain their finish, and suit modern building aesthetics. A minimum of 100mm concrete surround is required, therefore it would need to be pulled off the building slab by at least 100mm to achieve full encasement. According to E2/AS2 clause 9.1.3.4, garage door openings in this scenario will have a “50mm minimum total level change between the interior and the exterior paving”, the 100mm distance from the garage entrance allows room to create a small ramp to direct water away from the opening and towards the channel drain.

In the selection of a channel drain solution, reviewing the expected loadings, the application, and the local environment will ensure a durable and functional solution.