Thanks, Mike. We use pencils, chopsticks, carrots, interns :) and though it does provide some data, it is still just a best guess. Today, our new, young, mechanical engineers with their 3D modeling software, but don't know what end of a screwdriver to hold, wants numbers, forces, contact pressures, which we cannot provide. I was hoping by now this information would be available.
Thanks to all for your help. The Other Brian On Tue, Nov 12, 2024 at 8:00 PM MIKE SHERMAN < [email protected]> wrote: > Brian -- > > There just isn't much out there yet that I'm aware of. > > At one time I used another unscientific approach: if it broke a #2 pencil, > it failed. Don't know where I first heard that. > > Rich Nute did find and share a while back some sharp point research from > the early 1970s: > https://nvlpubs.nist.gov/nistpubs/Legacy/ > RPT/nbsreport10673.pdf > > Lastly, there is the sharp edge tester from UL 1439. It uses a tape > sandwich intended to mimic the skin layers. You can buy testers > commercially. This tape sandwich was also borrowed by UL 1450 to mimic skin > for injection testing of painting spray tips. > > Validation testing any of the above is challenging. I believe some testing > has been done on cadaver skin, and some on pig skin, but I don't recall the > details. > > Mike Sherman > Sherman PSC LLC > > > > On 11/12/2024 10:33 AM CST Brian Kunde <[email protected]> wrote: > > > This is a follow-up of my earlier email. Hopefully, more to the point. > > Let's focus on the Finger and Hand. What forces or Contact Pressure would > cause a Serious Injury vs just a Moderate Injury? Can the line be drawn > between these two or at least narrow the gray area? The required Safety > Measures between these two are huge and guessing wrong can price your > product out of the running for a contract, for instance, so it is very > important to get it right. > > For instance, to break a bone in the finger takes somewhere between 300 > and 1400 N/cm2. That is a very broad margin. To "break the skin" in the > hand takes as little as 69N/cm2 but would require something sharp, but how > sharp (no contact area was provided)? Has anyone compiled this kind of > information? > > It is fairly easy to calculate the Contact Area between two moving parts > coming together, but what about Shear Hazards? How do you calculate > Contact Area with two parts that pass by each other but never touch? > > In our case, the movement our users can be exposed to is very slow. > Someone would have to deliberately want to get hurt to actually get hurt, > but still, we want to know, and our customers want to know. Our Engineers > look to our Compliance Team for answers. We usually ask, "would you put > your finger in there?" If they say "No", then it is a fail. But this > method is not very scientific. We are hoping to get help to develop > information to use as a guide. > > As always, thanks. > The Other Brian > > > On Tue, Nov 5, 2024 at 10:01 AM Brian Kunde <[email protected]> wrote: > > We evaluate the safety of Laboratory Equipment by applying the IEC/EN/UL > 61010-1 safety standard. For equipment that has accessable moving parts, > such as sample loaders, we apply section 7.3 "Moving Parts". Under 7.3.4, > it states, > > - " The physical levels specified below are *not considered to be > hazardous.*" > - " The maximum tolerable continuous contact pressure is 50 N/cm2 , > with a maximum force of 150 N. > > > So for continuous contact pressures greater than 50 N/cm2, we have to > apply the Risk Assessment in section 7.3.3. > > The First step in the Risk Assessment is to define the Severity of the > hazard or injury. You have two choices; Moderate and Serious. The > standard does attempt to define the potential injury, but this is very > subjective. How do you test for a dismembered body part? My Engineers want > numbers, not guesswork. > > I was hoping there are numbers, such as a Contact Pressure that would draw > a line between Moderate and Serious. For pinch, crush, and maybe shear > hazards, there should be a way to come up with a N/cm2 number or test that > can make this determination. Are there such numbers, rules of thumb, > industry standards, that would better define the difference? Having > something like this would really help. > > Thanks to all, > The Other Brian > > > > > ------------------------------ > > This message is from the IEEE Product Safety Engineering Society emc-pstc > discussion list. To post a message to the list, send your e-mail to > [email protected] > All emc-pstc postings are archived and searchable on the web at: > https://www.mail-archive.com/[email protected]/ > > > > Website: https://ewh.ieee.org/soc/pses/ > Instructions: https://ewh.ieee.org/soc/pses/list.html (including how to > unsubscribe) <https://ewh.ieee.org/soc/pses/list.html> > List rules: https://ewh.ieee.org/soc/pses/listrules.html > > For help, send mail to the list administrators: > Mike Sherman at: [email protected] > Rick Linford at: [email protected] > > For policy questions, send mail to: > Jim Bacher at: [email protected] > ------------------------------ > > To unsubscribe from the EMC-PSTC list, click the following link: > https://listserv.ieee.org/cgi-bin/wa?SUBED1=EMC-PSTC&A=1 > > ------------------------------ > > This message is from the IEEE Product Safety Engineering Society emc-pstc > discussion list. To post a message to the list, send your e-mail to > [email protected] > All emc-pstc postings are archived and searchable on the web at: > https://www.mail-archive.com/[email protected]/ > > Website: https://ewh.ieee.org/soc/pses/ > Instructions: https://ewh.ieee.org/soc/pses/list.html (including how to > unsubscribe) <https://ewh.ieee.org/soc/pses/list.html> > List rules: https://ewh.ieee.org/soc/pses/listrules.html > > For help, send mail to the list administrators: > Mike Sherman at: [email protected] > Rick Linford at: [email protected] > > For policy questions, send mail to: > Jim Bacher at: [email protected] > ------------------------------ > > To unsubscribe from the EMC-PSTC list, click the following link: > https://listserv.ieee.org/cgi-bin/wa?SUBED1=EMC-PSTC&A=1 > - ---------------------------------------------------------------- This message is from the IEEE Product Safety Engineering Society emc-pstc discussion list. To post a message to the list, send your e-mail to [email protected] All emc-pstc postings are archived and searchable on the web at: https://www.mail-archive.com/[email protected]/ Website: https://ewh.ieee.org/soc/pses/ Instructions: https://ewh.ieee.org/soc/pses/list.html (including how to unsubscribe) List rules: https://ewh.ieee.org/soc/pses/listrules.html For help, send mail to the list administrators: Mike Sherman at: [email protected] Rick Linford at: [email protected] For policy questions, send mail to: Jim Bacher: <[email protected]> _________________________________________________ To unsubscribe from the EMC-PSTC list, click the following link: https://listserv.ieee.org/cgi-bin/wa?SUBED1=EMC-PSTC&A=1
