It is not often that the fire protection industry has a day like the one at Exova Warringtonfire Aus Pty Ltd fire testing laboratories in May where five full scale fire tests were witnessed by 70 building officials and practitioners. The aim of the day was to show those with the responsibility to approve or design fire protection in buildings what testing takes place on the elements they are signing off on.
It also demonstrated the rigor behind the testing regime that ensures appropriate certification. The third objective was for the audience to see and feel what intense fire can be like in a controlled environment.
There were five tests on the day and three of them will be discussed:
- Full scale wall/Peno and fire door test.
- Bushfire test.
- Room Burn.
The 70 people witnessing the test knew the theory around the tests but many had not seen a test in their careers. Each of these tests had many take away points but in this short article only one will be mentioned for each of the three tests.
Keeping in mind that many of our readers are not professionals in this area each of the three tests will be described but not so detailed that it turns into a scientific paper, however enough to understand what went on.
The first test is a clear example of why we test at all by comparing a rated fire door with a solid core door, which many people see as an equivalent alternative.
Fire separation is measured in minutes, that is, the time it takes for the elements (a door in this case) to fail within the prescribed fire criteria. There are three ways in which an element can fail:
- Structural adequacy; this is the requirement to maintain a load bearing ability during a fire.
- Integrity; the ability of an element not to let flames and/or hot gasses transfer to the non-fire side, usually via cracks and the door edge.
- Insulation; the ability to not transfer heat to the non-fire side of the element, 140°C average rise across the door and with no point increasing more than 180°C.
These three measurements are displayed in that order in minutes e.g. 120/60/60 as this test has no structural requirement the test was for –/30/30. In many guidelines it is said that that a solid core door is equal or close to that of a 30 minute rated door. The test on the day had the solid core door fail in only six minutes showing clearly that they don’t have the protection many think they have.
The room test is to see how long an empty room will take to achieve flashover, the only fuel being the the walls and ceiling lining. There are four groups of materials which depend on the amount of time during a room burn test that material takes to flashover (FO).
The table above right is a simplistic explanation so you can get an understanding of what the audience was witnessing. For the room burn a lining of plywood was chosen, the test was quite dramatic with flashover occurring at 5.30 minutes; many were surprised at the intensity of the flashover in what is perceived as an empty room.
The bushfire test assesses how the exterior of a building will react to the various aspects of a bushfire attack. This test is for individual elements such as windows, doors, walls, skylights etc.
Bushfire attack is classified by the amount of heat flux imposed on a building, during a bushfire, measured in kW/m² there are five BAL levels 12.5, 19, 29, 40 and flame zone. This test moved a heat source, equivalent to BAL 29, to simulate a bushfire attack on roof elements, in this case specifically a skylight The element tested behaved as expected during the test but what surprised many in the audience was the intensity of the heat when the radiant panel doors were opened forcing those at the front to retreat a considerable distance from the heat. It is worth mentioning that the BAL ratings are for building elements and that even at the lowest level of BAL 12.5 a person would perish within minutes if they were caught in the open during a bushfire of this intensity.
Exova should be congratulated for this initiative, bringing together a large number of building surveyors, engineers and scientists to see what is involved in the testing of those parts of a building that are essential to stop the spread of fire and so allowing occupants to escape or in the case of bushfire, know what protection they needed in relation to the threat the surrounding bush has on the property.
All of those attending had their own takeaways from the experience and it will make them more aware of the consequences of their decisions and/or more confident that the testing regimes ensure that their decisions are the correct ones.
For further information, go to www.exova.com