city and guild powerpoint extraction

© 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



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.



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.



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

http://www.hse.gov.uk/woodworking/videos/wood-dust-exposure.mp4



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.



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.



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.



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.



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.



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.



Example of ducted extraction systems

Image courtesy of WOODWEB.com – The Information Resource for the Woodworking Industry, www.woodweb.com. Reproduced with permission.



Example plan layouts for ducted systems



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

http://www.hse.gov.uk/pubns/wis23.pdf

http://www.hse.gov.uk/woodworking/wood-dust-exposure.htm



Any questions?

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