Video | Agriculture | Confidence | Economy | Energy | Employment | Finance | Media | Property | RBNZ | Science | SOEs | Tax | Technology | Telecoms | Tourism | Transport | Search

 


Innovative wood treatment gets building code approval

Innovative wood treatment gets building code approval


Click for big version.

Large dimension plywood after the H1.2 decay test. The Azotek-treated sample is at the bottom and the untreated sample at the top

An engineered wood product that has the potential to transform building construction has been included in the New Zealand Building Code.

Laminated beams made from glued veneers of radiata pine are well known for their strength, stability and uniform sizing. Now improved durability can be added to the list. 

Laminated veneer lumber (LVL) treated with Azotek, a novel product developed by New Plymouth-based Zelam Limited, has been included in the NZ Building Code as an acceptable solution for internal framing. 

“This is a world-first,” says Zelam marketing manager Noel Coxhead. “It essentially makes wet solvent treatments for LVL and plywood obsolete and opens the door to much wider use of LVL framing in building construction.

“LVL is the key to precision construction using wood. But because of the well-known difficulties associated with wet solvent treatment of LVL, wood processors have been reluctant to go down that track. 

“It is difficult to get traditional treatments to penetrate the glue layers that bond the layers of LVL and plywood. The liquids involved also affect the dimensional stability of the finished product – which needs to be dried after treatment. 

“In contrast, our new treatment takes place during manufacture, so the finished timber is dry and ready for use as soon as it rolls off the production line. Because the treatment compounds are present from the surface to the core of the timber, it can be drilled, sawn and notched during building construction without any loss of integrity or need for retreatment.”

Azotek-treated LVL has been available on the NZ market for more than 12 months, enjoying a steadily growing market share from designers and builders seeking precision wood products. Its first commercial use was in Christchurch’s cardboard cathedral, where LVL beams were used for the main structural elements. 

But despite having Standards approval as a treatment, the previous lack of formal Building Code approval has been a barrier to the wider use of Azotek-treated LVL, says Nelson Pine Industries (NPI) Australasian sales engineer Andrew van Houtte. 

NPI has been producing Azotek-treated H1.2 LVL since 2012. Because it is a dry process, van Houtte says treated beams have precise tolerances, adding to the dimensional stability that LVL is known for. 

“To my mind Azotek is the best treatment on the market. In a technical sense it is better than anything the industry has ever seen – exactly the right amount of chemical is applied and it penetrates throughout the product. It takes durability to a whole new level. It also has great environmental and health and safety credentials.”

He says most of the LVL produced by NPI is used in common structural applications, such as beams, rafters, joists, lintels and bearers. 

Coxhead says Azotek is made up of two fungicides that are widely used on food crops, but are new to wood treatment – triadimefon and cyproconazole – plus bifenthrin, a standard wood treatment insecticide.

“Finding suitable fungicides was a long journey for Zelam. We had many set-backs. Not only did the active ingredients have to be fit-for-purpose, they had to be readily available and affordable,” he says.

“Azotek is the only combination that met all the essential criteria. Having two fungicides in the mix means it provides broad spectrum protection against rot and decay organisms, and a barrier against selection for resistance.”

Before Azotek was approved as an H1.2 treatment for LVL it was tested in rigorous trials by Scion and in-house by Zelam. These were designed to determine Azotek’s performance in conditions designed to simulate what happens when water leaks into a wall cavity. 

Although Azotek-treated LVL has New Zealand and Australian Standards approval for H1.2 treatment, it is sold only in New Zealand, because the H1.2 standard does not apply in Australia. Trials of Azotek H2 and H3-treated LVL and plywood are now underway and Coxhead says these are looking very promising.

H2 treated framing is widely used in Australia, because this standard of treatment provides termite protection. When approvals come through for Azotek H2 and H3-treated LVL and plywood, these are likely to be well received by wood processors and builders on both sides of the Tasman. 

“But the bigger prize is likely to be the United States, where a lot of engineered wood is used in housing construction. Already wood processors there are showing a lot of interest.”

ENDS

© Scoop Media

 
 
 
 
 
Business Headlines | Sci-Tech Headlines

 

Must Sell 20 Petrol Stations: Z Cleared To Buy Caltex Assets

Z Energy is allowed to buy the Caltex and Challenge! petrol station chains but must sell 19 of its retail sites and one truck-stop, the Commerce Commission has ruled in a split decision that acknowledges possible retail price coordination between fuel retailers occurs in some regions. More>>

ALSO:

Huntly: Genesis Extends Life Of Coal-Fuelled Power Station To 2022

Genesis Energy will keep its two coal and gas-fired units at Huntly Power Station operating until 2022, having previously said they'd be closed by 2018, after wringing a high price from other electricity generators who wanted to keep them as back-up. More>>

ALSO:

Dammed If You Do: Ruataniwha Irrigation Scheme Hits Farmer Uptake Targets

Enough Hawke's Bay farmers have signed up for water from the proposed Ruataniwha Water Storage Scheme for it to go ahead as long as a cornerstone institutional capital investor can be found to back it, its regional council promoter announced. More>>

ALSO:

Reserve Bank: OCR Stays At 2.25%

Reserve Bank governor Graeme Wheeler kept the official cash rate at 2.25 percent, in a decision traders had said could go either way, while predicting inflation will pick up as the slump in oil prices washes out of the data and capacity pressures start to build in the economy. More>>

ALSO:

Export Values Down: NZ Posts Biggest Annual Trade Deficit In 7 Years

New Zealand has recorded its biggest annual trade deficit since April 2009, reflecting weaker prices of agricultural commodities such as dairy products, beef and lamb, and increased imports of vehicles and machinery. More>>

ALSO:

Currency Events: NZ's New $5 Note Wins International Banknote Award

New Zealand’s new Brighter Money $5 note has been named Banknote of the Year in a prestigious international competition. The $5 note was awarded the IBNS Banknote of the Year title at the International Bank Note Society’s annual meeting. More>>

ALSO:

Get More From Scoop

 
 
 
 
 
 
 
 
 
Business
Search Scoop  
 
 
Powered by Vodafone
NZ independent news