Re: [PSES] Reduce Speed of Moving Part to Reduce Risk

[John Woodgate]

Indeed, you can't share it with the list, but, as I expect you know, you 
can consult anyone in private communication who can contribute to the 
work. It is a Technical Report, and recent rules changes closely 
restrict what a TR can include. It is more or less confined to 
statements of fact. Not even recommendations are permitted.


On 2024-01-31 23:02, Doug Nix wrote:

List members,

There is currently a draft in development, ISO/TR 21260, /Safety of 
machinery — Mechanical safety data for physical contacts between 
moving machinery or moving parts of machinery and persons./ This 
document has a planned publication date that has already slipped by. 
The importance of this document is high, so I don’t think there is any 
likelihood of the work being lost, but the development of the document 
has taken a lot more time than was originally foreseen.


Unfortunately, the document is in the Committee Draft stage, so I 
can’t share anything with the list now. When it gets to the public 
review stage, that will change.


I think this document will prove to be very important.

Best regards,

Doug Nix
d...@ieee.org
+1 (519) 729-5704




On Jan 29, 2024, at 19:50, sgbrody  wrote:

That standard is ISO 15066 which is Collaborative Robots.  After 
measuring force and then determining the surface areas of the part 
contacting whatever, you can determine the pressure.


This standard provides tables for allowable forces and pressures - 
both are needed - to determine if the robot 'crash' is within 
acceptable range.


For example, I have two clients using robots which are billed by 
their manufacturers as collaborative, but it is the end effector when 
tested for the 'crash' force and pressure, that will confirm they are 
collaborative in that specific application.


In both cases they were confirmed collaborative.

However, if the flat surface of the end effector was replaced with a 
needle,  they would not be collaborative.   They would be dangerous 
and guarding would be required.


Thanks,




Sent from my T-Mobile 5G Device


 Original message 
From: Douglas Powell 
Date: 1/29/24 7:05 PM (GMT-05:00)
To: EMC-PSTC@LISTSERV.IEEE.ORG
Subject: Re: [PSES] Reduce Speed of Moving Part to Reduce Risk

All valid points; however, I was taking my information from the 
established ISO/IEC standards for machinery, with which I am 
familiar. I do recall another standrd some years ago, mentioning 
contact surface area when I was looking into finger crush as well as 
sharp edges. And the original question was solely about speed, so 
that's how I responded.


All the best,  ~ Doug


Douglas E Powell
Laporte, Colorado, USA
doug...@gmail.com
LinkedIn 

(UTC-06:00, US-MDT)


On Mon, Jan 29, 2024 at 4:41 PM Richard Nute  wrote:

Hi Doug and Brian:

I thought I would offer my (radical) point of view on the issue
of “speed of moving parts.”

Consider moving aluminum foil and moving aluminum block, both at
the same speed.  The aluminum foil has very little mass, while
the aluminum block has relatively high mass.  The foil is not
likely to cause injury, while the block may cause injury.

Consider an aluminum needle and an aluminum block, both having
the same speed and mass. The needle is likely to cause injury,
while the block is not likely to cause injury.

Consider the time of contact with a moving part.  If the time is
long, then injury is not likely.  If the time is short, then
injury is likely.

So, in addition to speed, we must consider mass of the block,
contact area, and duration of the contact in predicting injury.

In other words, energy per area (mv^2 per area in this case)
whether mechanical, thermal, radiant, chemical, or electrical,
transferred to a body part for a (usually short) period of time,
causes injury.  The same energy magnitude transferred over a long
period of time is not likely to cause injury.

An injury occurs only when energy per contact area of sufficient
magnitude and duration is imparted to a body part.  Both the
safety science article and the IRSST paper discuss energy of
moving parts and area, but do not address the other parameters. 
Both introduce (to me) the concept of “force” on various body
parts.  I’m not sure of how this fits into this safety discussion.

Consideration of speed alone is over-simplification.

Best regards,

Rich

*From:* Doug Nix 
*Sent:* Monday, January 22, 2024 11:16 AM
*To:* EMC-PSTC@LISTSERV.IEEE.ORG
*Subject:* Re: [PSES] Reduce Speed of Moving Part to Reduce Risk

Hi Brian,

In the machinery sector, 250 mm/s has long been used as the
threshold for avoidability. This figure comes from the robot
standards and has been used for about 30 years. Studies done at
the Polytechnique de Montréal [1] and IRSST [2] have shown that a
speed closer to 140 mm/s is more 

Re: [PSES] Reduce Speed of Moving Part to Reduce Risk

[Doug Nix]

List members,

There is currently a draft in development, ISO/TR 21260, Safety of machinery — 
Mechanical safety data for physical contacts between moving machinery or moving 
parts of machinery and persons. This document has a planned publication date 
that has already slipped by. The importance of this document is high, so I 
don’t think there is any likelihood of the work being lost, but the development 
of the document has taken a lot more time than was originally foreseen.

Unfortunately, the document is in the Committee Draft stage, so I can’t share 
anything with the list now. When it gets to the public review stage, that will 
change.

I think this document will prove to be very important.

Best regards,

Doug Nix
d...@ieee.org
+1 (519) 729-5704



> On Jan 29, 2024, at 19:50, sgbrody  wrote:
> 
> That standard is ISO 15066 which is Collaborative Robots.  After measuring 
> force and then determining the surface areas of the part contacting whatever, 
> you can determine the pressure.
> 
> This standard provides tables for allowable forces and pressures - both are 
> needed - to determine if the robot 'crash' is within acceptable range.
> 
> For example, I have two clients using robots which are billed by their 
> manufacturers as collaborative, but it is the end effector when tested for 
> the 'crash' force and pressure, that will confirm they are collaborative in 
> that specific application. 
> 
> In both cases they were confirmed collaborative.
> 
> However, if the flat surface of the end effector was replaced with a needle,  
> they would not be collaborative.   They would be dangerous and guarding would 
> be required.
> 
> Thanks,
> 
> 
> 
> 
> Sent from my T-Mobile 5G Device
> 
> 
>  Original message 
> From: Douglas Powell 
> Date: 1/29/24 7:05 PM (GMT-05:00)
> To: EMC-PSTC@LISTSERV.IEEE.ORG
> Subject: Re: [PSES] Reduce Speed of Moving Part to Reduce Risk
> 
> All valid points; however, I was taking my information from the established 
> ISO/IEC standards for machinery, with which I am familiar. I do recall 
> another standrd some years ago, mentioning contact surface area when I was 
> looking into finger crush as well as sharp edges. And the original question 
> was solely about speed, so that's how I responded.
> 
> All the best,  ~ Doug
> 
> 
> Douglas E Powell
> Laporte, Colorado, USA
> doug...@gmail.com 
> LinkedIn 
> 
> (UTC-06:00, US-MDT)
> 
> 
> On Mon, Jan 29, 2024 at 4:41 PM Richard Nute  > wrote:
>>  
>> 
>> Hi Doug and Brian:
>> 
>>  
>> 
>> I thought I would offer my (radical) point of view on the issue of “speed of 
>> moving parts.”
>> 
>>  
>> 
>> Consider moving aluminum foil and moving aluminum block, both at the same 
>> speed.  The aluminum foil has very little mass, while the aluminum block has 
>> relatively high mass.  The foil is not likely to cause injury, while the 
>> block may cause injury. 
>> 
>>  
>> 
>> Consider an aluminum needle and an aluminum block, both having the same 
>> speed and mass.  The needle is likely to cause injury, while the block is 
>> not likely to cause injury.
>> 
>>  
>> 
>> Consider the time of contact with a moving part.  If the time is long, then 
>> injury is not likely.  If the time is short, then injury is likely.
>> 
>>  
>> 
>> So, in addition to speed, we must consider mass of the block, contact area, 
>> and duration of the contact in predicting injury. 
>> 
>>  
>> 
>> In other words, energy per area (mv2 per area in this case) whether 
>> mechanical, thermal, radiant, chemical, or electrical, transferred to a body 
>> part for a (usually short) period of time, causes injury.  The same energy 
>> magnitude transferred over a long period of time is not likely to cause 
>> injury.
>> 
>>  
>> 
>> An injury occurs only when energy per contact area of sufficient magnitude 
>> and duration is imparted to a body part.  Both the safety science article 
>> and the IRSST paper discuss energy of moving parts and area, but do not 
>> address the other parameters.  Both introduce (to me) the concept of “force” 
>> on various body parts.  I’m not sure of how this fits into this safety 
>> discussion.
>> 
>>  
>> 
>> Consideration of speed alone is over-simplification.
>> 
>>  
>> 
>> Best regards,
>> 
>> Rich
>> 
>>  
>> 
>>  
>> 
>> From: Doug Nix mailto:d...@ieee.org>> 
>> Sent: Monday, January 22, 2024 11:16 AM
>> To: EMC-PSTC@LISTSERV.IEEE.ORG 
>> Subject: Re: [PSES] Reduce Speed of Moving Part to Reduce Risk
>> 
>>  
>> 
>> Hi Brian,
>> 
>>  
>> 
>> In the machinery sector, 250 mm/s has long been used as the threshold for 
>> avoidability. This figure comes from the robot standards and has been used 
>> for about 30 years. Studies done at the Polytechnique de Montréal [1] and 
>> IRSST [2] have shown that a speed closer to 140 mm/s is more universally 
>> avoidable by people 

Re: [PSES] [EXTERNAL] Re: [PSES] Reduce Speed of Moving Part to Reduce Risk

[Brian Kunde]

I appreciate the replies on this topic.

My original question had less to do with how speed of motion affects the
injury and more to do with how speed affects the User/Operators ability to
Avoid the hazard in the first place. The IEC 61010-1 standard mentions how
velocity factors into the Risk Assessment for avoiding the hazard, but it
does not elaborate.

Thanks again to all.
The Other Brian

On Tue, Jan 30, 2024 at 9:01 AM Jim Hulbert 
wrote:

> ISO/TS 15066:2016 is a standard for Collaborative Robots (COBOTS).   While
> COBOT specific, it does contain a great deal of information on risk of harm
> based not only on the mass and velocity of the moving part of the COBOT,
> but also the duration of contact with the body, body part impacted, and
> surface area of contact.   Lots of interesting equations.
>
>
>
> Jim Hulbert
>
>
>
> *From:* Douglas Powell 
> *Sent:* Monday, January 29, 2024 7:04 PM
> *To:* EMC-PSTC@LISTSERV.IEEE.ORG
> *Subject:* [EXTERNAL] Re: [PSES] Reduce Speed of Moving Part to Reduce
> Risk
>
>
>
> All valid points; however, I was taking my information from the
> established ISO/IEC standards for machinery, with which I am familiar. I do
> recall another standrd some years ago, mentioning contact surface area when
> I was looking into finger crush as well as sharp edges. And the
> original question was solely about speed, so that's how I responded.
>
>
>
> All the best,  ~ Doug
>
>
>
>
>
> Douglas E Powell
>
> Laporte, Colorado, USA
>
> doug...@gmail.com
>
> LinkedIn
> 
>
>
>
> (UTC-06:00, US-MDT)
>
>
>
>
>
> On Mon, Jan 29, 2024 at 4:41 PM Richard Nute  wrote:
>
>
>
> Hi Doug and Brian:
>
>
>
> I thought I would offer my (radical) point of view on the issue of “speed
> of moving parts.”
>
>
>
> Consider moving aluminum foil and moving aluminum block, both at the same
> speed.  The aluminum foil has very little mass, while the aluminum block
> has relatively high mass.  The foil is not likely to cause injury, while
> the block may cause injury.
>
>
>
> Consider an aluminum needle and an aluminum block, both having the same
> speed and mass.  The needle is likely to cause injury, while the block is
> not likely to cause injury.
>
>
>
> Consider the time of contact with a moving part.  If the time is long,
> then injury is not likely.  If the time is short, then injury is likely.
>
>
>
> So, in addition to speed, we must consider mass of the block, contact
> area, and duration of the contact in predicting injury.
>
>
>
> In other words, energy per area (mv2 per area in this case) whether
> mechanical, thermal, radiant, chemical, or electrical, transferred to a
> body part for a (usually short) period of time, causes injury.  The same
> energy magnitude transferred over a long period of time is not likely to
> cause injury.
>
>
>
> An injury occurs only when energy per contact area of sufficient magnitude
> and duration is imparted to a body part.  Both the safety science article
> and the IRSST paper discuss energy of moving parts and area, but do not
> address the other parameters.  Both introduce (to me) the concept of
> “force” on various body parts.  I’m not sure of how this fits into this
> safety discussion.
>
>
>
> Consideration of speed alone is over-simplification.
>
>
>
> Best regards,
>
> Rich
>
>
>
>
>
> *From:* Doug Nix 
> *Sent:* Monday, January 22, 2024 11:16 AM
> *To:* EMC-PSTC@LISTSERV.IEEE.ORG
> *Subject:* Re: [PSES] Reduce Speed of Moving Part to Reduce Risk
>
>
>
> Hi Brian,
>
>
>
> In the machinery sector, 250 mm/s has long been used as the threshold for
> avoidability. This figure comes from the robot standards and has been used
> for about 30 years. Studies done at the Polytechnique de Montréal [1] and
> IRSST [2] have shown that a speed closer to 140 mm/s is more universally
> avoidable by people working in various environments, but the long use of
> 250 mm/s has entrenched that higher speed. Related to that is the IRSST’s
> Repoer R-956. I’ve attached copies of these documents for you.
>
>
>
> You can find the 250 mm/s number quoted in most machinery safety standards
> where reduced speed is considered for risk reduction. The origin is in
> ANSI/RIA R15.06 1992, which made its way into CSA Z434 and then eventually
> to ISO 10218.
>
>
>
> [1]  Y. Chinniah, B. Aucourt, and R. Bourbonnière, “Study of
> Machine Safety for Reduced-Speed or Reduced-Force Work R-956,” IRRST -
> Institut de recherche Robert-Sauvé en santé et en sécurité du travail,
> Montreal, 2017.
>
>
>
> [2]  Y. Chinniah, B. Aucourt, and R. Bourbonnière, “Safety of
> industrial machinery in reduced risk conditions,” Safety Science, vol. 93,
> pp. 152–161, Mar. 2017, doi: 10.1016/j.ssci.2016.12.002.
>
>
>
>
>
> Best regards,
>
>
>
> Doug Nix
>
> d...@ieee.org
>
> +1 (519) 729-5704
>
>
>