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© 2013 City and Guilds of London Institute. All rights reserved. 1 of 14
Level 2 Diploma in Site Carpentry
PowerPoint presentationExtraction
Unit 211: Set up and operate a circular saw
© 2013 City and Guilds of London Institute. All rights reserved. 2 of 14
Level 2 Diploma in Site Carpentry
Types of extraction systems used with circular saws
Enable learners to:
• describe types of dust extraction for circular saws
• state the importance of dust extraction on circular saws.
Image courtesy of www.drapertools.com. Reproduced with permission.
© 2013 City and Guilds of London Institute. All rights reserved. 3 of 14
Level 2 Diploma in Site Carpentry
Dust at circular rip saws
Woodworking machines produce fine dust and chippings as a result of cutting timber or
timber based products.
The removal of this dust is vital because of the damage that can be caused by breathing
it in.
Not only will the dust become a health hazard but it will also collect around the saw
causing problems such as:
• rise and fall of the saw blade
• moving fences
• adjusting guards
• fire risks.
All these will result in potential injuries.
© 2013 City and Guilds of London Institute. All rights reserved. 4 of 14
Level 2 Diploma in Site Carpentry
How wood dust affects your health
Wood dust can cause serious health problems. It can cause asthma, which carpenters
and joiners are four times more likely to get compared with other UK workers.
Hardwood dust can cause cancer, particularly of the nose.
Settled dust contains the fine particles that are most likely to damage the lungs.
www.hse.gov.uk/woodworking/videos/wood-dust-exposure.mp4
© 2013 City and Guilds of London Institute. All rights reserved. 5 of 14
Level 2 Diploma in Site Carpentry
Fire risks at circular saws
• The fine dust and chippings can build up around motors and pulleys on the machine.
• Through friction and heat, this collection of dust becomes a fire risk.
• Woodworking machines must be fitted with an efficient means of collecting the dust or
chippings produced during the machining process.
• This is also known as local exhaust ventilation or LEV.
© 2013 City and Guilds of London Institute. All rights reserved. 6 of 14
Level 2 Diploma in Site Carpentry
Positioning of extraction used on top of circular saws
Dust collection points on a circular saw should be:
• both on top and below the saw
• at the top of the blade incorporated into the crown guard.
Images courtesy of www.drapertools.com (left) and www.axminster.co.uk (middle and right). Reproduced with permission.
© 2013 City and Guilds of London Institute. All rights reserved. 7 of 14
Level 2 Diploma in Site Carpentry
Examples of extraction used below the saw
• Below the saw incorporated into the machine casing.
• Smaller, portable saws do not tend to have the top extraction hose.
Image courtesy of www.drapertools.com. Reproduced with permission.
© 2013 City and Guilds of London Institute. All rights reserved. 8 of 14
Level 2 Diploma in Site Carpentry
Types of extraction used for circular saws
The dust and chippings are usually taken away from the saw by two methods:
• a simple portable vacuum type cleaner is connected to the saw via a hose
• the vacuum will have dust bags that will require regular emptying
This type of extraction is more suitable to potable saw units.
These units now come with an automatic start feature that starts when the saw is started
and stops as the saw is switched off, ensuring the system is always on when required.
© 2013 City and Guilds of London Institute. All rights reserved. 9 of 14
Level 2 Diploma in Site Carpentry
Two examples of portable dust extractors
This type of extractor has a large collector
bag below a filter.
This smaller type of vacuum has the
collection encased with the body of the
vacuum.
Images courtesy of www.axminster.co.uk. Reproduced with permission.
© 2013 City and Guilds of London Institute. All rights reserved. 10 of 14
Level 2 Diploma in Site Carpentry
Fixed ducting extraction
On fix position machines a better method of extraction is to use an extensive system of
‘ducting’.
• This type of system can serve multiple machines.
• Within a factory environment this type of system is preferable and cheaper to run.
• The term ‘ducting’ refers to the lengths of pipes between the main extractor unit and
the individual machines.
© 2013 City and Guilds of London Institute. All rights reserved. 11 of 14
Level 2 Diploma in Site Carpentry
Example of ducted extraction systems
Image courtesy of WOODWEB.com – The Information Resource for the Woodworking Industry, www.woodweb.com. Reproduced with permission.
© 2013 City and Guilds of London Institute. All rights reserved. 12 of 14
Level 2 Diploma in Site Carpentry
Example plan layouts for ducted systems
© 2013 City and Guilds of London Institute. All rights reserved. 13 of 14
Level 2 Diploma in Site Carpentry
Safe working practices around wood dust
An example of safe working practices in controlling wood dust:
www.hse.gov.uk/pubns/wis23.pdf
Video on wood dust:
www.hse.gov.uk/woodworking/wood-dust-exposure.htm
© 2013 City and Guilds of London Institute. All rights reserved. 14 of 14
Level 2 Diploma in Site Carpentry
Any questions?