These systems set principles and criteria for the management of forests and timber, and certification is only granted after an assessment by an independent third party. These schemes all set different standards on forest certification and chain of custody certification.
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This highlights the need to convey to the Australian public how certification works and what to look for when buying wood. There are three main certification systems in Australia, the Forest Stewardship Council (FSC), the Australian Forestry Standard (AFS) and the Programme for the Endorsement of Forest Certification (PEFC).
The results of the Planet Ark survey found that only one out of three people (35%) thought that it was relatively easy to find certified wood, and that only one out of five people (18%) said they trusted the current forest and wood certification systems.
Without certification is can be difficult or impossible to know whether wood was taken illegally or from high conservation value forests. Despite its importance there is a high level of confusion regarding certified wood.
Be Certain It’s Certified
Certification ensures that the wood comes from legally harvested and well-managed forests and plantations. Certified forests are managed with environmental, social and economic factors as a priority, and ensure that when a tree is harvested another one is planted in its place. In fact, sprinkler systems have been shown to be one of the primary factors in limiting fatalities and fire damage in structures of all types. Injury rates (per 1,000 fires) by sprinkler protection status and building material combustibility shows again how sprinklers have the best effect in preventing deaths.
A study that examined the rate of injury from hotel, motel and aged care home fires in America and Canada from 1980 to 1998 found that the presence of sprinklers had a greater impact than the combustibility of the building material.
Fire can also raise the temperature of steel enough to compromise its strength, with a reduction in its load carrying capacity by one third when heated above 540°C causing beams to buckle and floors to collapse.
Just because steel is a non-combustible material does not mean it is unaffected by fire. The thermal conductivity of steel is significantly greater than wood (200-1000 times more). This creates a thermal bridging effect, allowing heat from a fire in one part of a building to spread rapidly to other parts.
In light timber frame constructions the walls and floors are typically encased in non-combustible gypsum plasterboard to provide protection from fire. This provides the same level of fire resistance as a completely non-combustible material.
An additional benefit to heavy timber is the ease of repair after a fire. The charred sections can visually be assessed and evaluated for residual capacity, and the damaged timber can then be cut away and replaced. This is in contrast to steel, which buckles under extreme heat.
Charring creates a protective layer that acts as insulation and delays the onset of heating for the cold layer below. With continued exposure to fire the char layer grows, increasing the insulation and slowing down the burning rate, providing greater time for escape or intervention.
Heavy timber constructions have an inherent level of fire resistance. This resistance increases with the thickness of the wooden elements because when timber is exposed to fire the outer layer burns and turns to char.
Engineers and fire researchers today have a significant body of knowledge of how timber constructions perform in fire. The structural stability of timber is well understood and importantly it is predictable, allowing timber constructions to be created that meet the same fire safety codes as steel and concrete buildings.
Fire Safety
A common concern raised in regard to the use of wood as a building material is whether or not there is an increased risk of fire. The Martian Embassy was a runner up in the Interior Fitout category of the Australian Timber Design Awards.
Project partners Will O’Rourke and The Glue Society stated that the warm tones of wood transformed the previously long, dark and unloved shop into a source of inspiration that kids are excited to walk into.
Construction was simplified by the flexibility of plywood. Flat sheets were cut into 1068 ribs, which were then put together like a giant puzzle to create a three-dimensional space. The acoustic qualities of timber further enhanced the sounds, smell and lights of the red planet that animated the space.
The Martian Embassy in Redfern Sydney is a creative writing centre for young people. The Centre is designed to be a fusion between a whale, a rocket and a time tunnel, created by oscillating plywood ribs, red planet light and sound projections in order to provoke fun and unleash creativity.
Airtightness directly affects the energy efficiency and thermal insulation capacity of a building. Therefore, although much consideration and/or the insulation value was maximized, it will have minimal effect if the airtightness value has not been addressed.
Regardless of how insulated a home is, with the highest R value, etc. - all goes to waste with inefficiency in airtightness. Most conventional stick frame homes have a low airtightness rating (unless specially targeted during construction) whereas Holz100's tongue-and-groove system ensures a high level of airtightness throughout.
Maximizing a building system's potential airtightness is necessary when desiring to achieve passive house standards. Having a high airtightness rating means more energy conservancy and less heating required to keep warm during winter.
Thoma Holz100 has been certified through the Blower Door Test and achieved the airtightness required for passive housing. Airtightness is a very important and integral part of an exceptional building system.
The Candlebark library won the 2012 Australian Timber Design Award. Judges stated that they were greatly impressed by the expert use of engineered timber, its careful detailing and timber selection, and the use of recycled and salvaged timbers to create a natural reading environment.
The design of the library highlights how wood can be used in bushfire-prone areas, one of the greatest misconceptions people have regarding the use of wood. Internal temperatures during a bushfire would only peak at 29°C.
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