6 tips to distinguish between corrugated asbestos Super Six fence sheets and modern non asbestos Hardifence.
Corrugated fibre cement sheets have been used in Australia for over 40 years in either for fencing or roofing. The original product was an asbestos cement product known as Super Six manufactured by James Hardie & Co. and later it became known as Hardifence based on the much safer cellulose fibre. Both products look very similar but how do you distinguish between the two?
The original corrugated “Super Six” asbestos cement sheets were manufactured by James Hardie & Co. from the 1950′s and ceased in 1985. It was widely used as fencing and for roof sheeting with much original Super Six fencing is still in use today.
However, from after 1985 Super Six was replaced by a similar looking product known as Hardifence. This new product eliminated the deadly asbestos fibres and replaced them with the much friendlier and safer cellulose fibre, which is essentially made from wood pulp.
Hardifence is still manufactured to this day and is an excellent product.
To the untrained eye, Super Six and Hardifence look quite similar. However, dealing with Super Six requires special precautions to be taken during its handling and for its disposal due to its asbestos content. Be careful not to dispose of any Super Six sheeting in general waste or skip bins not designed for asbestos disposal as you risk being charged a hefty asbestos disposal fee or even worse, a fine for illegal asbestos disposal.
Is it asbestos Super Six or modern Hardifence?
6 Tips to identify Super Six(asbestos) and Hardifence(non asbestos).
1. Age of the house:
A house built in the late 1980′s and onwards is less likely to have asbestos Super Six fencing installed. Although it’s possible second hand asbestos Super Six sheeting may have been reused the incidence of this is probably low. Likewise an older house is more likely to have asbestos Super Six asbestos fence, which may have been installed in the 1960′ or 70′s.
2. Count the number of ridges:
The latest version of Hardifence has 5 ridges which is a sure sign of being the asbestos free Hardifence rather than Super Six which has 7 ridges.
However, to make matters confusing, early versions of Hardifence have the same profile (7 ridges) as Super Six. See picture above.
These early versions of Hardifence were prone to breakage and often cracked off at the bottom. Also breakage near the diamond washer/nut & bolt fixing is also quite common.
Hardies soon improved Hardifence with deeper corrugations and eliminated the washer, nut & bolt with the top metal capping becoming an integral part to keep the sheets from separating at the top.
If possible, examine the edge of the sheet to see any indentifiable markings. Hardifence has “Hardifence” printed on there along with a date of manufacture. Early styles of Hardifence have “Manufactured without asbestos” and a manufacturing date mark.
4. Capping: metal or asbestos cement.
If the fence is fitted with fibre cement capping, then it’s a sure sign that the fence is asbestos.
However, if the fence has metal capping then it’s most likely the fence is Hardifence and does not contain asbestos.
The most recent version of Hardifence is always fitted with metal capping as this is an integral part which keeps the sheets from separating at the top. However, bear in mind that there are plenty of fences where no capping is fitted at all.
5. Finger nail scratch test.
Use your fingernail to scratch the surface of the sheet. If you can gouge a mark in it, then this is a good indicator of being Hardifence rather than Super Six. Generally Hardifence is slightly softer than Super Six.
6. Using digital camera in macro mode:
If you have a digital camera then use the macro mode setting to take a close up picture. Next, find a suitably broken corner or edge to photograph. You can then examine the type of material composition from the comfort of your computer monitor.
Whilst asbestos fibres are microscopic, the asbestos fibre used in the manufacturing process of asbestos cement sheeting was in large clumps or bundles. These fibrous bundles can be seen sticking out near a breakage point or sometimes on a edge of the sheet when you examine the close up photo of your sample. From this you can determine whether or not the material is asbestos cement or not.
By contrast, the cellulose fibres used in Hardifence tend to be bonded more uniformly and fibre lengths tend to be shorter and not as strong. As a result, broken edges of Hardifence almost resemble the appearance of torn cardboard with a soft fuzzy edging. In addition, broken edges of Hardifence may tend to have a layered appearance, probably due to the manufacturing process.
Warning: Do not break any suspect asbestos cement sheeting when taking a close up photo as this will release deadly asbestos fibres which may be breathed in. Better to find an existing broken corner or edge to photograph.
If all else fails, you can take samples to a certified testing laboratory where they can be examined microscopically for asbestos. A list of laboratories can be found on the NATA(National Association Testing Authorities) website – www.nata.asn.au
Links to more asbestos identification tips.
Check out Darwin based builder and asbestos removalist Bill Bradley who has some solid advice on identifying and dealing with asbestos cement in buildings for do it yourself renovators.