Dux Qest Pipe

A history lesson…In the 1970’s New Zealand’s economy was in recession. Our traditional export market, Britain, joined Europe.  There was an oil crisis. Inflation was out of control. The country tried to reduce imports by making products locally. This was the time of the “Think Big” projects such as smelters for aluminium & steel, synthetic fuel production and electrification of the railway. But not all schemes were successful - one major failure that still affects us today is a black plastic water pipe system often branded as Dux Qest.

Dux Qest pipes are a black flexible piping with crimped joints. It was used widely in the 1970’s and 1980’s.  Unfortunately, this pipework becomes brittle with age and is prone to rupture. The crimped joints are also unreliable.   Should the pipes fail under the house this is this can be a curse but when they burst in wall linings and/or in ceiling spaces it can be disastrous.

Even if the Dux Qest branding is not obvious there is cause for concern. Firstly, with age the labelling can fade; and secondly some older black butylene systems that replaced the Qest pipes are themselves unreliable.

When confronted with old black plastic water pipes that have burst we do not advise a simple patch -  if it has gone in one place it will burst again nearby. Insurers have become increasingly unwilling to cover damage caused by failure of this substandard product. Councils that approved construction that included this pipework are silent.

SEAL Plumbing & Gas still comes across homes with old Dux Qest pipe – owners are normally unaware of the looming risk to their property nor of how lucky they have been to get away with it for so long. Our belief is that it is best to be proactive and replace old black plastic pipe before it fails. A stitch in time, in this case, can save more than nine.  If it is in your home, get rid of it. 

How do know if you have this dodgy pipework? You can check your home yourself or we can inspect it for you.  The pipework may be more readily seen under the house, in the ceiling space or in kitchen/bathroom cabinets – it is black plastic pipe that may be stamped “Qest Dux” in white.

The assessment becomes difficult if Dux Qest lurks undetected only in wall linings. The experienced staff at SEAL Plumbing can look for telltale connections and offer an opinion. If needs be, inspection hatches can be cut into wall linings to verify that all is well.

If you have old black water pipes, particularly Dux Qest, call SEAL Plumbing and together we can make a plan, to rid you of this menace.