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Posted By Owen Needles
Hi folks, quick question. We have a vertical band saw at work with is operated by a foot pedal. The machine only operates when the footpedal is pressed (i.e. take your foot off and it stops). Does this machine require an emergency stop? I've looked under PUWER and i think i'm looking in the right area but i'm struggling to see the answer.
I'd be grateful for any comments.
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Posted By Mitch
Owen,
Yes it will require an emergency stop and a brake.
Mitch
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Posted By Ian G Hutchings
Hi Owen
You could end up with various answers on this one I believe.
When the power is removed (foot off pedal) how long does it take to stop?
Could someone trap a hand (or limb) or have another issue where it may be hard for them to quickly remove their foot from the pedal. So someone else has to operate the emergency stop (if you had one)?
Are these covered in your risk assessment and do you feel comfortable with the answer?
My reading of PUWER (if I am correct) does not seem to state that an emergency stop must always be fitted on a machine. It is based on the risk. However, I am not entirely sure about CE requirements and whether a stop is expected to be fitted.
PM33 the HSE food bandsaw guidance doesn't seem to mention an emergency stop, but does state the blade needs to stop asap when the machine is stopped or a guard opened. The British Standard includes more detail about stopping times and safety standards BS EN 12268:2003. Not sure if this has been updated.
Ian
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Posted By Ian G Hutchings
Owen
Just reading my response I refer to food industry, which your question doesn't.
Ian
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Posted By Chris Jerman
Owen
Please read that guidance carefully before proceeding with any alterations to your saw.
This guidance is about braking - not emergency stops. In the case of a bandsaw, I would advise a strategically placed E stop button simply to cut the power in an emergency, but not to add additional braking. Stopping a bandsaw too quickly is not safe.
The guide is very clear that this is a 'you work it out for yourself and act accordingly' solution.
Chris
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Posted By Mitch
Chris,
As Owen has already considered PUWER my advice was given with crediting him/her (you never know these days!) with some intelligence. The publication I referred to clearly states the considerations to be taken in respect of braking. If my advice was (mis)leading I apologise.
Mitch
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Posted By Tabs
Owen, if you have access to an electrician, they will tell you that electrical switches can fail, foot pedals can jam.
S's Law tell you that it will be when you don't want it to do either ... therefore an E-stop is vital.
PUWER guidance is "An emergency stop control should be provided where the other safeguards in place are not adequate to prevent risk when an irregular event occurs." The irregular event here is the only stop switch fails energised.
Further ... A person caught in a band saw may not have the reactions to lift their foot. People in terror act oddly.
It is correct that stopping a band saw too quickly can lead to a lethal whip of saw steel as the band snaps. Not all, but some.
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Posted By Chris Jerman
No, Mitch I thought the link was to a very useful document. It was your original statement 'Yes it will require a stop and a brake' that I found difficult to understand as you had not seen the machine yourself and the guidance that you then raised did not draw the same definitive conclusion.
Owen's original question was on stops, rather than on brakes. The machine (outwardly) would seem to have (A) a 'clutch' operated by the foot. In other words pressing the pedal engages the drive. So taking foot of disengages drive. (B) It could be the opposite of course that pressing the pedal disengages a brake, releasing it puts the brake on.
So really my query was how did you know this. That's all. Not really misleading.
Chris
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Posted By Mitch
Clarification,
First posting my (strong) opinion based upon guidance linked in posting 2 and having used myself , managed and controlled the use of band saws, beleive their inherent design, the use of inertia wheels, require adequate braking hence the improvement of legislation to implement this.
As an aside I also belive that all vertical bandsaws are possessed by evil entity's whose sole purpose is to injure and destroy, I don't like them don't use them and have always designed out or replaced the use of them by other equipment.
PS direct braking of the inertia wheel avoids blades bursting
Mitch
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Posted By Chris Jerman
Mitch, I had a bandsaw - it was an 'IMP', so maybe you're right! Not quite sure it was possessed.
CJ
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Posted By Owen Needles
Many thanks for your comments and suggestions. Very grateful.
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