Rising copper prices have seen attention turn to aluminium-based alternatives for conventional RAC pipework
With copper prices increasing and, as a consequence, copper-based products becoming a target for opportunistic thieves, it is clear to see how pipework of other metals can be attractive. It requires a strong nerve to ask the industry to consider changing its time-honoured practices, but there are currently two different firms seeking to do exactly that.
The first, Lawton Tubes, launched its Lawton Dual, an aluminium pipe with a copper core, earlier in the year, and has now developed brazing rods to enable it to be handled in exactly the same way as copper (see below).
The second, Gateshead-based Eco Facilities Solutions, has just launched the UK’s first all-aluminium general RAC tube.
Building on the success of aluminium in automotive air conditioning, and taking advantage of significantly increased wall thicknesses that have brought a new robustness to such a product, Eco’s aluminium refrigerant pipe claims a range of advantages over copper beyond mere price – though this factor is pretty significant, being currently less than a third of the cost of copper.
According to Eco boss Tony Madden, the combination of low weight with excellent formability and low corrosion makes for a compelling combination. “We are telling contractors that this could help them get a competitive edge on price with a product that is so light they can carry the pipe on site themselves if they want to.”
A further advantage for HVAC applications, claims the firm, is that its thermal conductivity ratio is almost 50 per cent lower, leading to lower heat gain and loss than copper. And the aluminium pipe claims a whole set of advantages when brazing, which works in exactly the same way as copper, says Mr Madden, including a brazing speed that is claimed to be four times faster than copper.
In addition, the lower melting point of the aluminium should bring substantial savings on the gas and brazing rod required, the firm says – and there is no need for nitrogen purging for oxidisation either.
“The only difference is that because there is no colour change in the pipe, it needs a bit of practice on the temperature control,” says Mr Madden. The key, he says is the special brazing rod, which has the flux inside, allowing a strong bond.
The product has been certified to a pressure of 2400 psi, and is available in standard diameters from 1/4 inch to 3/4 inch. Early in the new year it will become available in straight lengths and T-pieces as well as the current coils.
The firm has been in discussion with a number of companies in the RAC supply chain and has a split system running at its offices with the aluminium tube for those who want to see it in action. “It is an education process for many, but once people have seen it in action, they get the message,” says Mr Madden. “With copper physically running out, and aluminium one of the most abundant metals on earth, it could be time for a revolution.”
Best of both worlds
Lawton Tubes launched its copper/aluminium Lawton Dual pipe last spring, and now following feedback from the market, Lawton has launched dedicated brazing rods enabling the pipes to be brazed as well as soldered together.
Metallurgically bonding an inner copper layer to an outer aluminium layer, the Dual is claimed to be a lighter and cheaper product than traditional copper tube, while retaining the strength of a copper core.
The manufacturer says customer feedback showed that the majority of users preferred to braze rather than solder, so it has now launched dedicated brazing rods, comprising 78 per cent zinc and 22 per cent aluminium. The rods claim a melting temperature of 420 deg C to 460 deg C, enabling users to braze Dual joints, as well as to join Dual to copper and vice versa.
Lawton says that no new tools are needed, users just need to braze at a lower temperature. “We wanted to make the Dual as easy to use as possible,” says managing director Oliver Lawton. “We listened when people told us they wanted to braze it.”
Designed for a working pressure of up to 55 bar, and available in standard diameters from 1/4 inch to 5/8 inch, the Dual is well suited for AC applications, the firm says