Chain Shot – Industry meeting held

[Oregon Engineer]

Here is an interesting report from Tasmania about chain shot and their efforts to test and regulate safety measures.



TFCA (Tasmania Forest Contractors Association)

15/09/05 - Executive Officer Report September 2005
Executive Officer Report September 2005


Chain Shot – Industry meeting held:

On the 31st of August 2005 the TFITB Safety Standards Committee called an extraordinary meeting of industry stakeholders to discuss the issue relating to excavator mounted hydraulic cut off saws and the phenomenon we call in the industry as 'Chain Shot'. Chain Shot is created when a chain brakes during operation of the cut off saw and there is a whip like effect created by the broken chain that has the potential to dislodge a section of the chain which then becomes a high speed projectile.

When the initial hydraulic cut off saws where designed and the manufacturers conducted a risk assessment it was deemed (in the majority of cases) that 6mm polycarbonate was sufficient and included a suitable safety margin as it was bullet proof (.22 calibre) and could not be penetrated by an Olympic arrow travelling at 350 km per hour. However now that the effects of chain shot are better understood it is now apparent that the chain projectile is travelling at approximately 300 to 500 metres per second as opposed to initial beliefs of 30 metres per second!!

Much debate took place at this meeting and Komatsu Australia provided a lot of information about their research efforts to date and also outlined their immediate plans where a K-Saw unit is currently undergoing extensive real life testing under lab' scrutiny overseas.

Workplace Standards representative, Mr. Peter Rigby stated that the Law in Tasmania under the Section 14 of the Workplace Health and Safety Act places the onus on the designer and or manufacturer and the Australian Standard AS 4360 also supported this approach. Clearly the responsibility for a safe place of work rests with all of us, especially as employers, and we urge you if you have not been in consultation with your supplier, and in addition briefed all of your employees about the safe operating procedures of these saws, please do so immediately.

A suggested list of modifications and or work practices that would better manage any risk associated with these saws was discussed in the group and we have provided this below for your information.

• Update information in the manufacturers manuals including;
o Maintenance inspections of chain
o Specify use of high-speed chain only
o Make exclusion zone a 'pie shaped' area in front of excavator
• Fitment of 'soft start' valves
• Fit saw shut-off solenoid to excavator stick @ < 90 degrees to boom.
• Retro fit 'chain guard' where available (Komatsu have so-far 'under lab' conditions caught rearward projected 'chain shot' in 100% of cases with the fitment of this device).
• Reduce chain speed and bar pressure – at least to original factory settings.
• Decrease the pressure relief settings for hydraulic stall-out.
• Consideration of license supplement to excavator ticket and include addition safety procedure in the TFCA SMS.
• Consider minimum polycarbonate screen thickness @ 12mm unless proven differently.

[tiny3]

hi
we just had that mod done to our 2 komatsu excavators,seems to work well
tiny

[Dom]

I received this link in an email. Its good to see companies are trying to prevent chain shot.

Oregon Chain shot

[Oregon Engineer]

DOM -  Did you get that email from me or was it forwarded from another source?????   I appreciate you passing it on to any audience that is involved in mechanical timber cutting equipment.

[Jeff]

Good to see you poke yer head back in.  ;)

[Dom]

DOM -  Did you get that email from me or was it forwarded from another source?????   I appreciate you passing it on to any audience that is involved in mechanical timber cutting equipment.

I received it from my employer. I'm often on the look out to see what other suppliers are producing, and where they are concentrating their offerts. I like that fact that Oregon is taking this matter seriously.

[Oregon Engineer]

Dom - I'm quite happy to hear the information is being passed on!! The original email anouncement for the website was directed at 110+ engineers and engineering managers at companies making timber cutting equipment or government representatives dealing with safety.


One other issue in the email was to show that ISO is considering the chain shot issue:

At a recent ISO meeting hosted by the Finnish Standards Association, several "chain shot" related presentations were made by members of Technical Committee 23, Subcommittee 15 (Machinery for Forestry). One outcome of the meeting was a decision to draft proposals for two new work items related to the escapement of thrown objects. The work items could lead to future standards related to reducing "chain shot" injuries. Clearly, "chain shot" is an important technical issue that needs to be addressed by everyone involved in the mechanized timber cutting market.

Dom- Thanks for posting the website and helping keep this issue before the loggers!!

[SwampDonkey]

Jeff, aren't ya glad I invited him over? ;D

[Oregon Engineer]

For you guys down under there is a chain shot safety seminar coming up November 10th 2006 in Sydney Australia. The seminar will be taught by Komatsu Australia's National Engineering Services Manager.  smiley_clapping

I believe he will be discussing his chain shot and protective window testing that was conducted this year. I've seen some of the information and it's shocking what the chain can do to a window. If you get a chance be there. Sure wish I could.


The attachment gives a few more details and a website that you can visit for additional info.