A modern, attractive student accommodation building on campus at Sheffield Hallam University, Pearl Works is Managed by Omnia Space. The site has room for 57 student apartments and a Tesco retail unit across four stories. In accordance with Building Regulations Approved Document B, the building required an appropriate smoke control system to reduce the risk to residents in the case of a fire, enabling safer escape routes by directing smoke away.
Initial designs specified the use of a natural smoke shaft, a system which exploits the natural buoyancy of hot air and smoke to keep escape routes clear in the case of a fire. Smoke is vented into a builder’s work shaft via dampers in the lobbies of each floor. However, it was discovered that means of escape travel distances were excessive for such a system. This means that the furthest distance an occupant would have to travel to the stairwell was too great – 24m – for the natural shaft to effectively clear.
The CFD Model
Computational Fluid Dynamics (CFD) showed a required 4.5m3/s flow rate was required to keep the area smoke-free; a mechanical smoke shaft system was needed to provide the extra pulling power. This 4.5m3/s flow rate is well within the range of the Fläkt Woods Smoke Shaft Vent system, and in line with the pre-prepared standard CFD guidance docs that accompany the system. Fläkt Woods utilise Group SCS components, including control panels, switches and actuators to deliver the complete system.
This unique approach from Group SCS and Fläkt Woods is based on years of experience and a large database of previous CFD models showing that the same equipment and installation is appropriate for the vast majority of ‘standard’ smoke shaft systems (below 20 storeys). It removes the need for new CFD models and fire-engineered solutions to be created in each instance, so long as the building in question meets the criteria set out by Fläkt Woods. To simplify things further, Fläkt Woods empowers contractors by giving access to its selection tool, which specifies the appropriate system based on the responses to 12 simple questions – even producing equipment specifications and design approval documents that have been accepted by regulators across the country.
The Smoke Shaft Vent system specified is fully in accordance with European Standard 12101 (parts 6, 7, 9 and 10, relating to fans, ducts, control equipment and power supplies). PD 7974-6:2004 is used to identify acceptable conditions for the escape of occupants in buildings.
The installation of the mechanical smoke shaft system was simple due to the pre-assembled fan skid and control unit that Fläkt Woods supplied, with each element of the system addressable for simple control set up after installation.