Saudi American Glass Technical Services will be happy to recommend the required glass specification for any practical glass floor. Glass dimensions along with uniformly distributed and concentrated design loads for floors and stair treads should be determined from BS 6399: part 1:1996 and forwarded to the Technical Services Department.
Calculations for glass in floors are generally stress limited, but the supporting structure for any glass floor must be limited in its deflection or the stiff glass panes may effectively have their backs broken. Saudi American Glass calculation results therefore detail the deflection limits for glass edges and the required I value for the supporting beams.
Fig 1 illustrates the principles to be adopted when installing four edge supported internal glass floor panels, for pedestrian traffic only. The detail shows that the edges of the glass must be fully supported on 3mm thick shore A 60 hardness (approx) neoprene rubber at least as wide as the glass is thick. The minimum recommended dimension for glass to glass joints is 3mm. Surface jointing sealants should be flexible and durable enough to prevent the ingress of grit or sand toward glass edges.
The preferred general glass specification is SAGF Safe T Lam Glass incorporating thick annealed float suitably supported along all four edges. In certain circumstances annealed glass may not be suitably strong and tempered glass must therefore be used.
Tempered glass is stronger than annealed glass but when broken it instantaneously shatters into many tiny fragments of glass. Such breakage in tempered glass in a floor would therefore result in an instantaneous loss of support to anyone or anything that happened to be stood on the tempered glass floor at the time.
Wherever tempered glass is considered for installation into a floor the load bearing pane of tempered glass must be laminated to an additional and at least equal non load bearing pane to provide continued structural integrity of the floor in the event of glass breakage.
The minimum thickness for tempered glass is 12mm as thinner specifications are not considered to be robust for floors.
Glass floor panels should be checked regularly as damage to glass edges or surfaces will serve to reduce the design strength of the glass.
Glass floor panels should be cleaned regularly with a mild detergent and a soft cloth or mop. Excess water should be removed immediately and the glass surface dried to reduce the risk of slippage. Scraping or cleaning with metal implements is not recommended.
Where laminated glasses comprise different glass thicknesses they should be installed with the thicker glass ply uppermost. It is common practice to laminate a thin tempered wearing pane to walking surfaces, with a suitable anti slip fritted finish. Such wearing panes are not considered in the design strength of the finished glass product.
Approximately 1m2 is usually considered to be a practical maximum area for each pane of glass due to handling considerations.