Fire Rated Glass Blocks

There are a couple of common misconceptions regarding fire ratings and glass blocks. One is that all glass blocks are fire rated. Another is that blocks advertised as fire rated can be installed in any manner. Both are incorrect.

To clarify, there are several different FRLs, or Fire Rating Levels and only certain blocks can be used to meet them. However, it must also be emphasised that the rating is given to the entire panel, including a specific type of frame and other fire rated materials installed in a manner tested and approved by the building authorities. Blocks on their own have no inherent fire rating so if they are not installed correctly, they will not comply. And, just as "fire rated" glass blocks installed in a non-approved manner will not achieve any kind of rating, likewise no matter how you install non fire rated blocks, they cannot be turned into fire rated ones.

Glass Blocks Queensland is able to supply and install glass blocks to meet a wide range of fire ratings. Because of the way they have to be installed, we cannot provide fire rated panels prefabricated, nor can we supply DIY kits. It is specialised work and needs to be carried out by a licensee of the manufacturer to ensure full compliance with regulations.

If you have been advised by your architect/builder/certifier/council that your panels require a fire rating, they will have to confirm the exact FRL that needs to be achieved. Prices vary enormously, and before we can provide any indication of costs, we need to establish which blocks we are able to use. An explanation of the fire rating system follows below. If you have any questions, please don't hesitate to contact us.

Fire Rating Technical Data

The Building Code of Australia (BCA) addresses fire ratings in the same way for all building materials. Similar systems are used elsewhere in the world as well. The Fire Resistance Level (FRL) is a set of three numbers. Each number represents the number of minutes that an element can withstand a 'standard' fire while still delivering appropriate performance for the fire situation. The objective is to provide a building in which the fire can be contained in one fire compartment separated from others by fire rated partitions. The fire authorities must be able to access the burning building after the fire has taken hold to evacuate occupants and to fight the fire. They must be able to do this for a given period of time in relative safety.

To establish the FRL, standard furnace tests are carried out on building systems. The systems are loaded, and thermocouples measure temperature on all of the surfaces. Timers measure the time it takes for the system to cease to perform satisfactorily.

The three numbers represent : Structural / Integrity / Insulation

The first number is the number of minutes that the system can carry the appropriate fire load without collapsing.

The second number is the number of minutes before fire breaks through the cladding of the system. This represents a breach of the fire compartment.

The third number is the number of minutes before the temperature on the non- fire side of the system reaches an unacceptable level.

Glass always has a dash instead of a number for the structural category as glass is not a structural element - i.e. it is not load bearing. It should be noted, however, that a fire rated glass block panel is being installed into a wall that does meet the structural requirement and, provided the surrounding structure does not collapse, the glass block panel will be structurally sound for the requisite period.

Fire Ratings - BAL

A separate set of ratings covers bushfire zones - Bushfire Attack Level or BAL. Whereas installations covered by the FRL system are designed to contain fire inside buildings, the focus of the BAL system is on keeping airborne burning materials out and protection against radiant heat. There are six levels of risk, determined by factors such as density and type of vegetation and the slope of the land.

For most BAL ratings, no special conditions have to be met by glass block panels, and they can be installed using the Ezylay Silicone or Mortar systems. Only for the highest category BAL-FZ - 'Flame Zone' where it is deemed there is a significant risk of direct flame contact, is a panel required to be fire rated. Even then, the equivalent of FRL -/60/- is all that is required.