VENTILATION | OPEN CEILINGS Increasing the size of the Coanda plate makes little difference to the throw and overall performance Typical swirl diffuser throw pattern with 5C cooling the air to cling to the full circumference of the Coanda plate. As a rule of thumb, a plate that is 300mm larger than the outside flange of a diffuser should provide enough distance for the exiting air to attach to the plate, so achieving the full Coanda effect and horizontal movement of air. Interestingly, our research showed that increasing the size of the Coanda plate makes little difference little difference to the projection of air into the room and provides similar air patterns to standard diffuser data. We carried out research to find out how big the plate had to be to create the Coanda effect and found that the 300mm notional plate size on multiple diffusers could be reduced drastically in size. We have therefore been able to introduce smaller plates for the swirl diffuser series. We even advanced our plate diffusers to have larger run-offs of outer flange frames, and thefore we can remove the need for additional coanda plates with the slightly larger integrated face plate designs. Coanda plates are typically manufactured from the same material (Above, top) Thermal diagram showing how a Coanda plate attached to a diffuser allows the ow of conditioned air to mix with room air to avoid dumping downwards onto occupants as the diffuser flange and can be painted any colour. They can be of almost any material, and can be solid, opaque or even transparent. They can even be backlit with LED lighting. We are looking to develop Coanda plates further for linear and slot diffusers. The required length of Coanda for specific linear products has been initially assessed and will allow the Coanda plates for these to be reduced below the notional 300mm length. Our research and development department also allows us to size Coanda plates for each individual scenario or application. Remember, when designing any open-plan ceiling system, the correct selection of diffuser must have a Coanda plate or Coanda run-off if comfort conditions are to be achieved. CJ ROY JONES is technical director at Gilberts Blackpool A Coanda plate Trusted Technology Partner Ian Stripp, Account Manager www.sav-systems.com 46 May 2019 www.cibsejournal.com CIBSE May19 pp45-46 Opening ceilings.indd 46 26/04/2019 17:26