Fire testing is a crucial step in the safeguarding of buildings.
Whether you manage a home, high-rise apartment building or industrial factory, fire safety is of the utmost importance. There are numerous products required in the construction of buildings, and each element is required to go through an extensive fire testing process.
Recent building fires have brought the issue of fire safety testing for building products into the spotlight. In both the Grenfell (2017) and the Spencer Street (Melbourne) apartment building fire in February 2019, combustible cladding was blamed for fuelling the rapid spread and devastating effects of each fire. In light of these events, we thought we would take the time to highlight the reasons why fire testing is such an important process when designing and specifying products for use in construction.
Research has shown that in the event of a house fire, humans have around 3-4 minutes to escape before the fire starts to engulf much of the building. It is important to note that building fires now spread at a much faster rate than they did 20 years ago, and this is due to the trend towards open plan living which increases the amount of air to fuel the rapid spread of flames. This issue is further compounded by increased use of highly flammable synthetic furnishings. To maximise occupant safety, thorough testing must be carried out on typical building products such as steel and timber supports, flooring products, engineered lumber and more.
Whilst it is not possible to prevent building fires altogether, testing aims to ensure that each building product is somewhat resistant to flame and will not contribute to rapid growth of the fire once ignited. Products are also tested for smoke development, as excessive smoke production is another risk factor for injury and death from asphyxiation.
The National Construction Code (NCC) fire safety requirements have two primary goals:
- To facilitate occupant safety
- To minimise fire spread and damage to other property, in the event of a fire in a building
Meeting these goals requires a combination of passive and active fire protection systems, as well as prevention strategies such as education programs and community safety initiatives. Active protection involves systems such as sprinklers, fire extinguishers and fire/smoke alarms which help to minimise the effects of fire and slow its growth. Passive protection includes good design principles, such as compartmentalising buildings by installing fire resistant walls/flooring and doors which will help to contain the fire/smoke and give building occupants more time and opportunity to escape. When both systems are employed effectively, a building is considered to have total fire protection.
In carrying out extensive product testing, building certifiers and future occupants can be assured that the elements which make up their building do not have significant fire hazard properties. Whilst the building elements may still be combustible, they should have some resistance against ignition and have as little impact as possible on the growth of the fire and spread of flames and smoke.
Fire Testing Process
Fire testing for construction materials can be carried out by a range of independent testing facilities, with the CSIRO being one of the largest providers of fire testing services in Australia. The testing process varies based on the type of material being tested (e.g. flooring, external wall cladding etc).
Australian Standards (AS) 1530.4 ‘Methods for fire tests on building materials, components and structures – Fire-resistance test of elements of construction’ outlines the process and requirements for standard fire tests. The critical categories tested are:
- Structural Adequacy – testing all load-bearing elements of a building. Failure occurs when the element collapses, or the rate of deflection exceeds prescribed limits.
- Integrity – products are tested to determine their level of resistance against the passage of flames/hot gases between different spaces. If any cracks or openings occur within the test specimen, it will be failed. Failure can also occur if continuous flaming is present on the non-exposed side.
- Insulation – when exposed to the furnace, the non-exposed side of a test specimen needs to maintain an even temperature within specified limits. Failure occurs when the temperature exceeds predetermined thresholds.
- The fire rating of a building element is referred to as a Fire Resistance Level (FRL), and it takes the above 3 factors into account. For example, a figure of 60/60/60 indicates that a building element could be expected to last 60 minutes before failing each respective category.
Stair nosings and inserts are tested against Australian Standard ISO 9239-1 ‘Reaction to fire tests for flooring – Part 1 Determination of the burning behaviour using a radiant heat source’, which covers building classes 2 through to 9.
The test takes place in a laboratory under controlled conditions, with product samples being heated by an inclined radiant panel. Upon ignition, the test conductor will measure the distance the flame has travelled before extinguishment. From this data the conductor will determine the Critical Radiant Flux (CRF), which represents the minimum radiant energy needed to sustain a flame. Products which receive a low CRF rating have a high propensity to spread flame and should not be used in areas of a building designed to exclude fire (e.g. concrete corridor), whilst those with a higher CRF rating receive a superior fire safety score.
A thorough examination of product fire safety tests for the following properties:
- Flame Spread
- Smoke Density
- Burn Rate
- Flash Over
- Heat Release Rate
Why Safety Products Need Fire Testing
Whilst products such as stair nosings, tactile ground surface indicators (TGSI’s), covers and trims only make up a small portion of any building, they are always an essential safety aid – particularly so in the event of a fire. To fulfil the NCC’s requirements of occupant safety, the products need to be able to withstand high temperatures so that they can provide people with directional and situational cues, as well as reduce the risk of trips and falls when navigating stairways during evacuation.
Products which have not been tested for fire safety could have catastrophic consequences, as they may assist the spread of the fire throughout the entire building or contribute towards the development of black smoke. A thorough testing and certification process will help to ensure that the building maintains structural integrity for as long as possible, maximizing the chance of survival and minimising damage to the building.
Put simply, a product which melts or catches fire will fail to serve its purpose and will only add fuel to the fire. At Classic, safety is our number one priority – and for this reason our products undergo extensive fire safety testing before being brought to market. This provides builders, engineers and future occupants with peace of mind that the building they inhabit will not pose a significant risk to safety in the unfortunate event of a fire.
Classic – We Put Safety First
Fire resistance is an important factor to consider when specifying building materials. Classic go the extra mile in ensuring that our extensive range of safety products will withstand the effects of fire for as long as possible and will not contribute towards rapid spread of fire or excess smoke production.
We hope this article has helped you to better understand the need and purpose of fire safety testing and how it can contribute towards the development of safer buildings which meet BCA and NCC requirements.
Building Products (Safety) Act 2017 No 69
CSIRO Fire Safety Capabilities & News: https://research.csiro.au/infratech/fire-safety/
YouTube Video demonstrating reaction to fire tests for flooring