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June 17, 2013, 04:31 PM

Salvage for which a market exists should be sold and reused

By Thornton Kay

Mark McGowan on slightly tarry reclaimed setts at St Paul's Cathedral during Salvo's successful 'Reuse before Recycling' campaign

Somerset, UK - Must reclaimable setts on which there are traces of tarmac be sent to landfill as hazardous waste? Absolutely not.

Salvo was asked this question recently by a dealer who had been told that they should. We checked with the Environment Agency (EA) which replied that it did not consider reclaimed paving as waste, so the issue of its possible contamination did not arise. Whether the setts were still in-situ or had been removed and sold is academic.

The Waste Regulations 2011 waste hierarchy 'reuse before recycling' legally require the disposer of an item to sell it if a market exists. The EA informed Salvo on another occasion that it would intervene if it was told that someone was sending reclaimable materials to landfill, provided a market existed.

Reclaimed setts with tar on them laid outdoors cannot be considered a safety hazard any more than existing tarmac itself. However, Salvo would recommend that dealers advise customers when reusing tarry reclaimed setts that they are only suitable for reuse outside as paving. Where there is a clean face it would seem obvious to relay the setts with the tarry side down.


Some handy information on tarmac
- - - - - - - - -

Tarmac or bitmac laid before 1980 is likely to contain chemicals which can be potentially classified as hazardous in sufficiently high concentrations, of which benzopyrene is considered the worst which is found in creosote. Other petroleum oil distillates, such as naptha, are less toxic.

A guidance note (see pdf attached) about road materials containing tar states that

From the mid-1800s road tar, derived from the high-temperature distillation of coal in the production of domestic town gas, was used on UK roads. It had good adhesive and waterproofing properties which made it eminently suitable for use as a binder in tarmacadam mixes and also as a spray application in surface dressing (which was commonly termed 'tar-spray and chippings'). However, an alternative - bitumen - derived from the refining of petroleum oil, became available from the early 1900's and increasingly gained in market share.

Coal tar continued in use on UK roads to a certain extent until the late 1970s/early 1980s when it became increasingly scarce due to the closure of town gas works with the advent of natural gas and of other sources such as coke ovens at steelworks. At the same time, concerns were being expressed regarding the possible carcinogenic (cancer-causing) nature of coal tar. For these reasons the use of tar on roads in the UK was largely discontinued by the early/mid 1980's and bitumen became the sole binder for macadam mixes (now generally termed asphalt) and for surface dressing.

Coal tar and bitumen are two entirely chemically different products and should not be confused. While coal tar has now been classified as carcinogenic, numerous studies have found no link between bitumen and cancer, and bitumen is not classified as carcinogenic anywhere in the world.

The difference between the degree of hazard posed by coal tar and bitumen arises from the levels of Polycyclic Aromatic Hydrocarbons (PAHs). Some PAHs are known to have carcinogenic effects and levels of these are very high in the case of tar, but extremely low in bitumen. Indeed, smoke from a domestic barbecue contains concentrations of PAHs many times higher than the fumes from hot bitumen.


Tony McCormack of the website PavingExpert explains the difference between bitumen, tarmacadam and asphalt, and is careful to avoid the use of the word 'tarmac' because it is the trade name of Tarmac - the plc with the same name.

Tarmacadam, properly referred to as bituminous macadam or 'Bitmac' for brevity Tarmacadam has become a popular, although technically incorrect, term for both bitmac and for asphalt used to surface pavements, highways and even internal floors.
Note that the the term 'Tarmac' (TM) is the name of a publicly listed company [which sets] lawyers upon those who take their name in vain and use it to refer to the material 'tarmacadam', even though the name has entered the vernacular in the same way as, for example, "Hoover", "Biro" and "Sellotape".

To get the terminology correct, here's a brief explanation:

Bitumen is a product of the oil-refining and petro-chemical industries.

Macadam is a process of binding together smaller aggregates, as pioneered by the legendary John MacAdam in the 19thC. His work resulted in the development of tar-based macadams, which became abbreviated to Tar-mac. Nowadays, we use bitumen from the oil industry rather than naturally occurring tar, and therefore we now have bitumen macadam or, as we call it in the trade, 'bitmac'.

Asphalt, according to British and European (CEN) definitions, is a mixture of bitumen and minerals. However, in the US, they use the term 'asphalt' for what we in Britain and the rest of Europe refer to as a 'bitumen'.

There are literally dozens of different types of 'tarmacadam'.

Older tars and tarmacs, especially those laid before 1980, tend to contain more benzopyrene. Salvo wrote about this in 2003 when the EU passed a directive restricting the reuse of old creosoted railway sleepers which are subject to the EU Directive 2001/90/EC and 76/769/EEC (Creosote). This law forbids the use of reclaimed wood treated with creosote being placed inside buildings, in toys, playgrounds or gardens where there is a risk of frequent skin contact, or in garden furniture. However these sleepers are still able to be sold and reused for raised beds, provided a flower bed is placed in front of them, or ivy grown up the sides, to prevent frequent skin contact. Raised beds for wheelchair gardening are fine provided the sides of the sleepers are ivy clad, and the top of the sleepers are covered. For example, use a plank of non-creosoted wood or flat tile coping drilled and nailed.

We attach below an old note guidance note from (possibly 2008) the County Surveyors Society about recycling of tarmac contaminated products. This note is wrong in some respects and in my opinion cannot be applied to old reclaimable setts.

If in any doubt, please ask an environmental lawyer for information on the latest case law and inaccuracies or misleading information in this article.

Campaign for planning conditions to save demolition materials

Demolition happy

Salvo campaigns for reuse as a planning condition

Did an Edwardian demolition in Sheffield break the law?

Paving Expert

Paving Expert: Tarmacadam, the basics
County Surveyors Society: Guidance Note: Road materials containing tar

Story Type:  Opinion

ID: 75843

Date Modified: June 19, 2013, 10:04 AM

        
 
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