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] > mailto:[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/ 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] mailto:[email protected] > Rick Linford at: [email protected] mailto:[email protected] > > For policy questions, send mail to: > Jim Bacher at: [email protected] mailto:[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
