 |
 |
 |
|---|
As stated previously, compliance with fire rating requirements is based on design procedures detailed in HERA Document R4-82. This document uses the inclusion of Fire Emergency Reinforcement to provide sufficient structural strength under ultimate fire loading.
To comply with fire rating requirements the floor must meet specific provision with regard to stability, integrity and insulation. The point at which the slab fails to meet any of these requirements determines the fire resistance rating of the slab.
In the fire condition, it is assumed that the deck makes no contribution to overall strength. The deck does play an important role however, in terms of the integrity provisions, as it acts as a diaphragm preventing the passage of flame and hot gasses.
Fulfilment of insulation requirements is achieved with the calculation of an equivalent slab thickness in the HERA document (which is based on ECC, 1984 provisions), and comparing the calculated equivalent thickness to acceptance provisions incorporated within NZS 3101 “New Zealand Concrete Standard”.
It is the stability provisions which result in the most work with regard to tray flooring. Strength in fire is ensured by the inclusion of reinforcement (FER). This can be the reinforcement present in ordinary room temperature design and it may not be necessary to add reinforcement solely for the fire condition.
Three different cases of fire rated slab systems occur:
(a) 30 minute fire rated slabs.
(b) Positive reinforced fire rated slabs.
(c) Negative reinforced fire rated slabs.
With the exceptions of the 30 minute fire rated slab, the amount of reinforcement required is dependant on both the fire rating required and the live loading which the slab is required to sustain.
11.2 scope of manual - fire resistance calculation of tray flooring
11.6 mezzanines as intermediate floors (model type 4)
11.7 compliance with fire resistance requirements
11.8 - 30 minute fire rated composite floor
11.9 positive reinforced fire rated slabs
11.10 negatively reinforced fire rated slabs
11.11 negative reinforcement calculation
11.12 “slab specification” with regard to negative reinforcement calculation
11.13 loadings used in negative reinforcement tables
11.14 live loadings / fire ratings used
11.15 negative reinforcement tables
 |
|---|
 |
 |
 |
 |
 |
 |
 |
 |
 |
 |
 |
|---|