Recent changes to window opening restrictions in the National Construction Code (NCC) have been celebrated as a safety commitment in the Building Code of Australia (BCA) for the benefit of all Australians while also lamented by some for the potential detriment to a building’s access to natural ventilation.

The new standard dictates that any unscreened awning window below 1.7 metres must have a restricted opening of 105mm – not excellent news for those who enjoyed the breeze rushing through their fully extended awning window or for those out of favour with the “look” and the translucency of flyscreens.

One option, which is also becoming increasingly popular for other reasons, is to specify bigger awning windows, because a larger operable window means a larger opening and therefore more access to natural ventilation.

From there the question becomes one of capability and until recently, particularly in the residential building sector, the awning window hardware available was insufficient to cater for large, heavy windows.

The latest technology from Doric Products solves the challenge

Doric are not only Australia’s largest privately owned hardware manufacturer, but they are also renowned for their research and development methodology, which ensures new products and upgrades are only brought to the market when they are sure it meets a very specific demand.

Their new DN400 Twin Chainwinder, for example, is designed specifically to cater for those specifying heavy large-scale awning windows for commercial or residential projects. And as is the aim with all new Doric products, it reaches the market right when it’s needed.

The DN400 comes with the secure key lockable configuration and easy to use large fold down lever that are standard to the award-winning Doric Products chainwinder range. The difference between the DN400 and other chainwinders, say the Doric DS177 for example, is of course its dual-chain with single-lever functionality, which offers the same usability of a single chainwinder but with a far greater weight or load rating.

Beyond its easy use and the load bearing capability, the DN400 also comes with a host of features and benefits that would please those specifying large awning windows for their projects:


  • Self-restriction to an opening distance of approx. 105mm in accordance with new testing standards. (NCC)
  • Removable chain from sash plate to aid installation and to assist in cleaning – “ Chain Secure”


  • Suitable for use on both Commercial and Residential applications
  • Supplied with a Stainless Steel chain as standard
  • Available with either “5 pin” or “ 6 disc” cylinder locking mechanism
  • Smooth, effortless operation and control for large awning openings
  • Australian Industry Standard 6 year warranty applies
  • Available in a wide range of standard and non-standard powder-coated colours

Doric understand that the changing capabilities of designers as well as evolving building codes and product compliance standards mean that new products are an absolute necessity for the advancement of the built environment in Australia.

Their DN400 is testament to their push to be at the forefront of hardware design and to stay in touch with designers and specifiers who are also looking to push their boundaries and design capabilities.

Click here to download Doric's free white paper Reducing Falls from Windows and Balconies – Design Requirements & Responsibilities.