Fire Rating Alternatives Compared
Remedial Building Services will be the first to tell you that every building, and every situation is different. Thus there is no universal answer as to what the best solution for your fire rating requirements are. Every situation needs to be analysed to understand the requirements and the likely circumstances and a decision then made with a consideration to safety, design, functionality and price.
Below is a simple summary of the 3 more popular passive fire rating alternatives available in the marketplace.
Vermiculite
- High film build means there is less clearance available (minimum thickness 10mm) affecting aesthetics, construction allowances and access.
- Low coverage & high wastage (20kg bag covers approx. 3m² @15mm thickness allowing for 15-20% wastage).
- High weight factor (see comparison table found below).
- Where longer FRL’s are required, a thicker film – above 15mm – will be applied. However, thicker films may require mechanical reinforcement to ensure integrity of the coating.
- As a result, costs of construction may increase due to increased steel costs
- Lower production rates per lineal metre compared to thin film intumescents. Due to slower application rates and comparatively long drying times film builds above 20mm (Common in higher FRL’s) may take many days to cure depending on site conditions.
- Application process causes significant disruption to other trades working in the vicinity due to excessive material ‘scatter’
Fire Resistant Fireboards
- Minimum board thickness is 13mm, therefore less clearance available (2x13mm boards required for a 1hr FRL).
- Wastage can be extensive depending on steel configuration.
- High weight factor (see comparison table).
- Lower production rates per lineal metre compared to thin film intumescents, due to labour intensive cutting and fixing system process. Difficult to fit over steel connections e.g. cleats, struts, braces etc.
- Susceptible to damage by other trades during fitting and difficult to repair to ensure integrity of the FRL is not compromised.
Thin Film Intumescents - Nullifire S707 Intumescent Basecoat
- Thin film (maximum 5.5mm for light steel).
- Waterborne product, thus less harmful to the environment.
- Minimal wastage (high volume solids, high build).
- Low weight (see comparison table).
- High production rates - Up to 30% faster drying/over coating times compared to solvent based coatings.
- Minimal disruption to other trades on site (application is fast, clean, low odour and minimal space required for materials and equipment).
- Hard finish when dry and easily repaired.
- Allows design criteria to be maintained .
- Nullifire S707 has a VOC content of 13-14gms/litre which would be viewed very favourably for inclusion in Green Star Rated projects. For further information on the Green Building Council of Australia, please visit www.gbca.org.au
Passive Fire Rating Weight Comparisons
1 Hour FRL for a 200 UC 46.2 structural steel column
|
System
|
Thickness
|
Kgs required / Lineal Metre
|
| Vermiculite Spray |
17mm |
26 |
| Fire Resistant Board |
26mm |
17 |
| Nullifire S707 |
0.59mm |
1 |
