The Need for Fume Extraction
Many types of dust and fume are hazardous to health if inhaled. People can become permanently sensitised to fumes which means that continued exposure, even to very small amounts of fume, may cause asthma attacks or other respiratory diseases. A high performance fume extraction system will help to:-
- Protect employee health.
- Ensure compliance with Health & Safety regulations such as OSHA, NIOSH C.O.S.H.H, MAK, AFNOR, or equivalent.
- Increase production speeds.
- Reduce complaints by operators due to odours, dust and vapours.
- Avoid possible cost of health compensation claims.
- Reduce the cost & time to cleaning laser lenses, conveyors, guarding, soldering machines and other equipment.
- Reduce product contamination.
- Provide a better working environment.
- Reduce downtime.
Which Extraction System?
These are usually two types of extraction system available:-
- External - pump contaminated air into the environment outside the building
- Internal - at source capture and filtration or LEV (local exhaust ventillation) system
In our opinion the best system to use is an LEV system such as a Purex. These capture fumes at the source thereby preventing fumes escaping into the workplace. They also filter hazardous particles and gasses which would otherwise be pumped into the outside environment causing pollution.
Using an internal filter system also avoids issues with environmental regulations and potential complaints from neighbouring businesses about fumes and odours.
Purex LEV systems sit next to the process and the extraction rate can be altered precisely to suit the application. Purex machines are also easy to move if the process moves.
LEV systems have additional benefits over external exhaust systems.
Examples of hazardous fumes
Processes that create hazardous dust and fume
Many industrial processes can generate harmful dust and fume. Essentially any operation where a material is cut, marked or physically altered in any way has the potential to produce harmful materials.
Some common processes which produce harmful fumes:
- Laser & Inkjet Coding
- Laser Engraving
- Hand & Machine Soldering
- Pharmaceutical Manufacture
- Laboratory & Cleanroom Work
Soldering - An example of a hazardous process.
HSE statistics (2004/05) showing incidence rates of occupational asthma reported by chest physicians puts rosin based solder flux fume in the top ten.
Occupational asthma is an allergic reaction that can occur in some people when they are exposed to certain substances in the workplace, for example solder fume. These substances are called 'respiratory sensitisers' or asthmagens. They can cause a change in people’s airways, known as the 'hypersensitive state'. Not everyone who becomes sensitised goes on to get asthma. But once the lungs become hypersensitive, further exposure to the substance, even at quite low levels, may trigger an attack.
Early symptoms from fume exposure can include:
- watering, prickly eyes
- running or blocked nose
- sore throat
- coughing, wheezing, tight chest and breathlessness.
Rosin based solder flux fume is generated when rosin based solder flux is heated. During hand soldering the fume rises vertically on thermal currents created by the heat of the iron, entering the breathing zone of the worker as they lean over their work. The quantity of fume emitted will depend on a number of variables including: the rosin content; the solder temperature; and the size, spread and number of joints being worked.
Assuming substitution is not possible and the lowest rosin content solder flux for the job has been selected the main emphasis is to optimise the solder temperature and to provide effective fume extraction. Solder machines should always be enclosed and extracted. Whilst for hand soldering the extraction control solutions will depend on:
- the soldering temperature,
- the soldering time,
- the size, spread and number of joints being worked,
- the shape of the workpiece,
- the size of the work area; and
- the number of people soldering per period.
Rosin based solder flux fume (RBSFF) is a hazardous substance under COSHH 2002 (as amended) and has been assigned both a “sen” notation and a “skin” notation indicating it is capable of causing both occupational asthma and skin sensitisation. RBSFF has Work Place Exposure Limits (WELs) of:
- 0.05 mg/m3 – 8 Hr time weighed average (full shift exposure averaged over eight hours); and
- 0.15 mg/m3 – 15 minute TWA (15-minute reference period)