Glasgow City Council
The Council has a statutory obligation under Section 34 of the Roads (Scotland) Act 1984 to take such steps as it considers to be reasonable, to prevent snow and endangering the safe passage of pedestrians and vehicles over public roads.
Major refurbishment has been carried out to the Clyde Tunnel over the last few years and a major part of this was to replace and restore its cast iron frame that was heavily corroded caused to a great extent by salting over the years. Out of a total cost of £20m around £8m was attributable to corrosion.
Traditionally Glasgow City Council used dry rock salt to treat their highway network in order to keep their road system clear from frost formation, ice, and snow. A liquid de-icer (Glycol) was used to treat foot paths and bridge decks because of its powerful de-icing and anti-freezing ability.
When treating the highway 6mm rock salt was spread at a rate of 20gms per metre² for standard pre-cautionary salting, and 40gms per metre² for snow events. A fleet of 53 gritting vehicles were used to treat the 38 routes within 180 minutes.
It was becoming increasing apparent that the effects of de-icers used to treat the network caused not only a corrosion concern but also questions towards the impact to the environment. Regeneration projects have been in progress for a number of years now throughout Glasgow. Increasing concerns were raised when the refurbishment of the Clyde Tunnel took place and the cast iron pipes were found to be heavily corroded. Bridge decks over motorways and the rivers were also noticeably deteriorating at a significant rate due to the nature of corrosion.
Jim Knox (Winter Service Area Manager) at Glasgow City Council decided to investigate alternative materials to combat against the corrosion issues without any risk of jeopardising the service the authority provided. Jim was aware of Safecote having used Procoat salt which is a fast acting high purity marine salt coated with Safecote (a known corrosion inhibitor).
Procoat was being used at shopping centre locations as a premium fast acting de-icer and is ideal in contained areas, however is not economically viable to be used across vast areas.
Another option available on the market was pre-wetted salt, which consists of rock salt and salt brine mixed together upon application by the gritting vehicle. Although trialling this would have proved a worthless exercise as this method of de-icing is not only highly aggressive in terms of corrosion but also very costly to implement.
Safecote Information & Research
It was determined during researching Safecote that a number of other local authorities in the UK had been using it pre-treated to their standard rock salt and purchased directly from their salt supplier applied at 3% weight by weight and were spreading the salt reduced rates as low as 7gms per metre².
Safecote is an agricultural co-product, its main ingredient being molasses and is made to a stringent specification by Tate & Lyle in the UK. Known as a salt enhancer it has been used in the USA for 20 years and was introduced to the UK in 2002. As of winter 2009/2010 the number of Safecote users was in the region of 60 in the UK, the majority being local authorities.
Safecote enhances salt by giving a number key benefits, control distribution, longevity, corrosion inhibition, lower freezing point depression, greater resilience and is environmentally friendly.