Solvents that are green
July 1st 2006 Green is the colour for companies using solvents says says Mark Nursall, technical specialist, 3M UK 'Green issues' are high on government agendas right now and with legislation looming, manufacturing and industrial companies will be forced to adopt it as their colour of choice. One of the main areas to be affected, particularly in the immediate future, is solvents. Required in a variety of different industrial end-user applications, the primary function of solvents is to dissolve contaminants through a physical cleaning process.
One cannot dispute the fact that traditional halogenated solvents, numbering trichloroethylene and n-propylbromide (nPB), are very effective cleaning and degreasing products, especially in areas of high-volume production applications. Unfortunately their cleaning power does not outweigh the fact that prolonged skin contact exposure and inhalation of the solvents vapours can trigger some very serious side effects, including cancer or fertility problems.
The European Union has noted these risks and implemented the Solvent Emissions Directive (EC Directive 1999/13/EC) which places very strict limits on the emissions of volatile organic compounds (VOCs) from industrial processes. The introduction of the Directive aims to cut dramatically the amount of VOCs released into the environment by approximately 50% by 2010, based on 1990 levels. Companies that rely on such solvents for cleaning parts and subassemblies during manufacture have until October 2007 to comply with the Directive.
There are a range of reduction options available. These include bringing in abatement equipment to minimise employee exposure to solvent emissions, right up to replacing harmful chemicals with alternative, environmentallyacceptable cleaning options. However, these alternatives must comply with the Solvents Emissions Directive (SED). Don't underestimate the impact With an EU deadline breathing down their necks, companies are taking a serious look at how their strategies stack up against the directive and what imminent changes they need to make to put them in the 'green zone'.
1,1,1-trichloroethane was banned from October 2000 because it contributed to ozone depletion. A common alternative trichloroethylene was then re-classified in 2002 to a category 2 carcinogen. The reclassification falls into the category of CMR (carcinogenic, mutagenic and reproductive toxins) as defined by the Solvent Emissions Directive. The SED, however, requires the replacement of trichloroethylene (often called Trike), in the 'shortest possible time', or compliance with stringent emission limits by 31 October 2007, where replacement is not possible and the consumption of solvent, such as trichloroethylene, exceeds 1 tonne per annum. In addition, the CMR regulations apply to other volatile organic compounds (VOCs), including perchloroethylene. nPB has been suggested as an alternative, but it also likely to fall foul of the CMR directive.
The SED requires Member States to issue operating permits for industrial installations and relevant authorities are already reviewing these. Small and medium enterprises should not kid themselves that they will fall outside the SED net, because most solvent uses are affected by the SED... With a cut off point of one or two (depending on solvent used) tones per year, the majority will also have to apply for permits.
A change for the better
Companies should not see the SED as an albatross and some companies have realised there are advantages to be gained from the change. While they may be a bit more expensive, alternative solvents do provide sufficient cleaning power and even require less to be used, making them more cost-effective in the long run. BAE Systems' Electronics, for example, recently made the switch from trichloroethlyne to 3M Novec HFE-72DE fluid from Acota for the solvent cleaning of delicate sonar transducers during manufacture.
Solvents such as HFE-72DE are ideal replacements for chlorinated solvents because, in addition to performance characteristics, they have important safety and environmental properties including nonflammability, low toxicity, zero ozone depletion potential and low global warming potential. In a range of tests carried out for and by 3M, HFE-72DE was shown to have excellent safety and low toxicity benefits compared to traditional solvents.
Sitting target
Once SED is in place, the industry cannot afford to sit still. This will definitely not be the last directive to come thumping down on the desks of decision makers trying to do a job, whilst keeping ahead of the green game. Instead of running scared, the manufacturing and engineering industries have to start looking forward and second guessing legislation around the corner. No-one can claim that they have not been warned and it is clear that there is no time to lose. More articles from 3M UK PLC: | 
