We have seen many changes in our industry, the most recent of which involves proposals involving reductions in emission of one of the most commonly used flame retardants Decabromodiphenylether (Deca_BDE). Whist this material has not been identified as posing a health risk, it has been shown to be “persistent” within the environment. Environmental concerns regarding this chemical have prompted our industry to take action. This has taken the form of an Industry Code of Practice, an initiative that Textiles F.R. has helped develop. This short case study describes some simple changes to our working practice that have reduced the emission brominated flame retardants to the environment.
Production Methods: A description of our processing methods is given in the Textile Processing section of our web site. In brief, chemical application is achieved using one of a number of production techniques. These include backcoating (utilising a Stork rotary screen printer) and chemical impregnation (wet padding). Each of our two production lines uses a custom designed gas drier offering complete flexibility for drying/curing bulk production runs and short cut length fabrics.
Code of Good Practice: Decabromodiphenylether (Deca_BDE) is widely used by textile finishers involved in the application of flame retardant coatings on fabrics used for upholstery. This chemical has been used since the introduction of the Furniture and Furnishings (Fire) (Safety) Regulations in 1988. This Statutory Instrument defines the UK legal requirements regarding fire safety for domestic furnishings. Deca_BDE exhibits properties which enable coated fabrics to meet the requirements laid out in the 1988 Statutory Instrument.
One such property is its extremely stable structure under normal temperatures & conditions. Only when subjected to high temperatures (such as those experienced from an ignition source) does Deca_BDE breakdown liberating materials which actively and efficiently suppress the ignitability of the substrate to which it has been applied. This beneficial property of high stability has unfortunately led to environmental concerns regarding its persistence in the environment. A 10 year European Union risk assessment programme has been unable to demonstrate that Deca_BDE represents any risk to the environment or human health. However, to address concerns regarding its persistence in the environment, The Textiles Finishers Association (TFA) has introduced an industry voluntary agreement which sets out a Code of Good Practice. Textiles F.R., along with other members of the TFA who support this agreement, are committed to reduce the emission of Deca_BDE.
Managing Emissions of Persistent Chemicals by Proactive Commitment to Good Practice is published by The Textile Finishers Association and The Bromine Science and Environmental Forum.
Our commitment to the Code of Good Practice ensures that Textiles F.R. will
The code also ensures that suppliers of Deca_BDE will offer guidance on correct handling and processing of this material and provide literature on best practice for its disposal. Suppliers will seek confirmation that the Code of Practice is being adhered to and may refuse to supply those companies who are unable to offer such assurances.
Emission Reduction Study: The Textiles Finishers Association is a trade organisation representing a wide range of interests within the textile industry. As members of this association, we along with a number of other companies, of diverse size and scope, have played an active part in establishing the Code of Good Practice for our industry. We have undertaken an audit of our working practice with a view to reducing the emission of brominated flame retardants. Some simple changes to working practice have made a considerable impact on our emissions. In the following text, all quantities are expressed as weight of active brominated flame retardant rather than the weight of overall commercial product (which includes a number of ingredients in its formulation) received from our chemical supplier.
Chemical Barrels: Waste associated with residual chemical adhering to the sides of barrels used during processing had been identified previously and we have for many years been recovering this material by simply scraping the sides of the containers with “half-moon” scrapers manufactured by ourselves. We are negotiating with our chemical supplier regarding the return & disposal of used barrels.
Wash Down: The majority of discharge occurs during wash down. The rotary screen, the squeegee, pump/filter and pipes supplying chemical during production are major sources of emission.
Rotary Screen: We have manufactured a simple scraper consisting of a circular rubber gasket secured to a rod which passes through wooden guide posts. The paste remaining within the screen after processing is pushed into a plastic basin and recovered. This represents a saving of approximately 1.2 kilogrammes per wash down.
Squeegee: The stainless steel squeegee dispenses paste during coating and is fully charged once production ends. The normal wash down procedure involves blasting a jet of water & compressed air through the squeegee tube at high pressure. We have simply introduced an additional step and overridden the initial compressed air injection. The first step now involves gently introducing water at mains pressure which slowly pushes the paste within the pipe into a plastic basin. This represents a saving of approximately 1.5 kilogrammes per wash down.
Pump/filter & pipes: The chemical contained within the pumping system can be recovered. Once production has ended, the pump & pipe work is still fully charged with chemical. Since the pneumatic pump has to remain “primed” with a fluid medium in order to operate, we transfer it into a barrel of clean water and run it slowly whilst holding the delivery pipes over a plastic basin. The pipes are withdrawn once water starts to be ejected. Any water passed into the collector tends to float above the very viscous paste and can easily be poured off. This represents a saving of approximately 1.2 kilogrammes per wash down.
Further Study: Flocculation & filtration tanks are a possibility for recovering further waste. Such plant does represent a problem since space within the production area is restricted. However, pumping washings into settling tanks from a sump might be a possibility. We are currently assessing the logistics of such an undertaking. Such changes take time and involve significant cost to our company. However, we recognise the need to move towards a controlled & recorded procedure for waste emissions in which no brominated material is discharged as aqueous waste.