TABLE OF CONTENTS - The Professional Green Building Council

Theme B: Creating a livable, healthy and environmentally viable citiesFFH = H − X1 − X 2 − X 3 − X 4 − Y1− Y2− L(1)Where, FFH is the finished floor height of RFS; H is the height between slab andslab; X1 is the thickness of the slab; X2 is the sectional height of the structuralbeam; X3 is the sectional height of air ducts; X4 is the thickness of the ceilingpanels; Y1 is the interstice height between the structural beam and the air ducts;Y2 is the interstice height between the air ducts and the ceiling panel; and L is thedistance between the ceiling panel and the top surface of raised floor panel.The investment company intends to refurbish the existing building withoutinterfering with the current structure. Accordingly, the thickness of slab (X1) andthe sectional height of the structural beam (X2) are constant. As per the aboveequation, the allowable FFH of RFS is mainly determined by the distance betweenslab and slab (H) and the renovation of the ceiling plenum (X3, X4, Y1, Y2).Brainstorming points out that the use of UAD determines the appropriate FFH,which further decides whether the space volume (H) is sufficient.If the UAD method is used, a deep floor plenum is expected. As per the engineer’sopinions, 300mm is generally perceived as the minimum FFH to allow desirableair distribution in the floor plenum. For a typical multi-level office building, X1 isaround 120mm; X2 is around 500mm; X3 is around 300mm; X4 is around 30mm;Y1 is around 100mm; Y2 is around 150mm; and L is not less than 2400mm as perthe Building Code of Australia. Accordingly, the distance between slab and slabneeds to meet Equation (2).H ≥ ( X1 + X 2 + X 3 + X 4 + Y1+ Y2+ L)+ 300mm(2)• If the clients wish to keep the ceiling air system while applying UAD forthe special reasons such as using a ceiling and under-floor mixed systemand keeping the ceiling air system as a backup, slab to slab height must notbe less than 3900mm.462