Safety Standards (USA)

[mk42]

don't forget about nfpa 70e - arc flash.
we designed the system with 480 volts in 1 panel, 240 in another panel then pipe the control wires into the 110 / 24 volt panels. this solved a lot of headaches.
james

This is definitely a best practice. Separate 24V DC into one panel, higher voltage stuff into another. Note that even the 24V DC power supply needs to be outside the 24V panel, because you feed 480/etc to it.

 

[plvlce]

From a criminal standpoint, the company operating the equipment is responsible for safety. If someone gets hurt, the company gets sued.

There is no 'sued' in criminal cases. The word you may be looking for is 'prosecuted'.

We also have something here called "civil" court. Theoretically, anyone can sue anyone else in civil court. Here the injured party or their survivors could theoretically sue anyone involved in the design, build, delivery, maintenance etc of the machinery.

Correct; absolutely anyone can file a civil suit for any reason, although clearly frivolous suits tend to get tossed fairly quickly.

A conviction in criminal court tends to make civil suits against the offender quite likely to succeed due to the difference in burden of proof.

 

[mk42]

The controls portion is only a small piece of "safety", but as an FYI, most safety vendors have canned application notes that describe how to utilize X product in Y situation according to Z safety rating: Estop with safety relay to cat4/PLe/SIL3, etc. It'll include wiring options, any DIP switch/software settings that are relevant, etc.


Personally, I'm a fan of safety PLCs, because it makes it easy to manage multiple safety functions, but there are absolutely systems where it's overkill. Just an estop and a light curtain? Safety relays could totally make sense.


Most of the standards that I've read encourage you to design out hazards first, control hazards you can't, and then put on the finishing touches with administrative controls (PPE, etc). Every standard involves a Risk Assessment to figure out what all the potential hazards are, during all phases of the machine (operation, maintenance, etc). If you aren't comfortable doing taking responsibility for this, don't. There absolutely are firms that will assist or do it for/with you. It is a great and admirable goal to go out and get all the applicable standards and figure it out yourself, just remember that you're allowed to admit you're a human being with limitations, and you only know what you know.



The safe thing isn't ALWAYS to just cut power; sometimes you need to use a very low speed, or maintain a holding current to prevent motion. This is something that has evolved over time in the standards.

 

[arpus4KM]

The controls portion is only a small piece of "safety", but as an FYI, most safety vendors have canned application notes that describe how to utilize X product in Y situation according to Z safety rating: Estop with safety relay to cat4/PLe/SIL3, etc. It'll include wiring options, any DIP switch/software settings that are relevant, etc.


Personally, I'm a fan of safety PLCs, because it makes it easy to manage multiple safety functions, but there are absolutely systems where it's overkill. Just an estop and a light curtain? Safety relays could totally make sense.


Most of the standards that I've read encourage you to design out hazards first, control hazards you can't, and then put on the finishing touches with administrative controls (PPE, etc). Every standard involves a Risk Assessment to figure out what all the potential hazards are, during all phases of the machine (operation, maintenance, etc). If you aren't comfortable doing taking responsibility for this, don't. There absolutely are firms that will assist or do it for/with you. It is a great and admirable goal to go out and get all the applicable standards and figure it out yourself, just remember that you're allowed to admit you're a human being with limitations, and you only know what you know.



The safe thing isn't ALWAYS to just cut power; sometimes you need to use a very low speed, or maintain a holding current to prevent motion. This is something that has evolved over time in the standards.

Absolutely. That's why even with safety relays they have ones with timers built in to allow for safe stopping of motors and kinetic energy sources when needed.

SIL ratings are a lucrative business these days.

 

[Plastic]

Concerned

Your declared uncertainty is alerting.

I understand your employer looks at this project as simply buy automation parts and making the project happen "in house"... To save monies spent to outside resources.

I don't want to scare you away, but make you aware of things that your employer may not consider.

Injection molding machines by themselves are safe if they are relatively new (less than 20 years old). The reason is there are stringent standards that all OEMs of IMM machines adhere to, that ensure their machinery is safe to owners and operators.

Injection molding machines that are older than 20 years have vulnerabilities to be aware of.

If anyone alters an Injection Molding Machine of any vintage, yes you must upgrade and adhere to ANSI B151.1 Standards of current date.

One thing I assume from your original post is that you are INSERT molding, where a metal product is inserted into an empty injection mold tool, and then the IMM will inject thermoplastic to encapsulate the metal insert to be an integral component of the total finished product.

One assumes that they are hand loaded by persons now, and management wants to automate the process.

You did not state if your IMM is a HIMM Horizontal Injection Molding Machine or a Vertical Clamp Injection Molding Machine VCIMM.

Note a slightly different ANSI Standard applies if VCIMM. ANSI B151.29.

NFPA 70 is not overtly applicable. The Scope of NFPA 70 is for premises such as Residential, Commercial, Industrial Buildings.

NFPA 79 is somewhat applicable on how to wire an industrial machine, but not how to safely guard it or operate it.

UL508A is only applicable to the construction of the electrical control panel, and has nothing to do with the safety of and IMM or associated automation.

If you are adding robotic automation to an existing IMM, here are key standards that must be utilized:
Euromap 67 Electrical Interface Between IMM and Handling Device
Euromap 67.1 Electrical Interface Between VCIMM and Handling Device
Euromap 73 Electrical Interface Between IMM and External Safety Device

I do not know all of the auxiliary equipment that you plan on adding, but there can be many more safety standards applicable.

If your company does not purchase, understand, and adhere to these consensus standards, then do not do the project.

Your company can hire a qualified Systems Integrator with IMM automation experience. There may be a perceived extra cost, but this will reduce the exposure to your fellow employees to be able to operate the equipment safely, and go home at thed of the day alive, and with all of their body parts intact.

Regards

Plastic

 

[James Mcquade]

ndzied1,

you are incorrect, Not only is the company liable for the machine, but the individual(s) as well. Any individual(s) that takes on the responsibility of designing an electrical system also assumes the liability that goes along with it.
They are making a statement that they are qualified to do so and have the necessary credentials / experience to go along with their work. Many will not agree with me, that is your right. from personal experience i know that the families of those who get hurt will go after the company and those who designed the system. i was there once myself and it was others at the customer who made the mistake. we were cleared of any wrong doing.
james

 

[James Mcquade]

i had to go to a down machine.
The USA is a lawsuit happy country and the lawyers can and in many cases name the company and all who worked on the project as co defendants. they want as much money as they can get! if this ever happens to you and you are named in a case like this, my best advise is to find yourself a good lawyer. BECAUSE, the company you work for no longer has your best in mind, but their best interest. they will try to pin everything on you. someone got hurt on a machine that i designed, oversaw the wiring of, and did the programming. the company was in a massive panic, when we got the program emailed to us, i was in charge of looking at the program (i was the only programmer) and defining the changes. i documented everything,(NO COVER UP OR ALTERATIONS) changes, dates, and had backup copies of all the program changes (i keep 99 backups as default). there were several program changes made to the copy we given. this information was given to the company owner. what happened after that, i don't know. several days later, we were cleared.
i do apologize if i offend anyone in these posts.
if this violates forum policy, please delete this post and pm me so i do not violate forum policy again..
regards,
james

 

[I_Automation]

... Not only is the company liable for the machine, but the individual(s) as well. Any individual(s) that takes on the responsibility of designing an electrical system also assumes the liability that goes along with it...

This is especially very true in the stamping press field, and not just designing but repairing.
Plus, it's not only civil lawsuits from survivors, but criminal prosecution for wrongful death or bodily injury and maiming I have been involved in just for repairing a press that later had changes made to the controls I had nothing to do with and was then sold to another plant.

I know a used machinery dealer that was a middleman in the sale of a disassembled & crated machine that the new owner assembled themselves without a copy of the complete schematic and as soon as it was turned on it killed a technician. That dealer had to fly across the country, retain a local lawyer and fought that wrongful death case over a year at an expense to him over $150,000 including flights, hotels, cars, lawyers, etc on a sale he only made $12,000 on - plus he was sweating it out until the judge finally ruled all responsibility was the fault of the assembling company, but wouldn't remove him from the suit every time it was asked as he never even handled or saw the crates it was in.
If a stamping press injures or kills someone then ANYONE and EVERYONE that they can find that worked on the controls of that press, even if just replaced a bad relay or sensor, will be brought into court - along with every owner of that press ever and every machinery dealer that handled a sale of that press. Also the press manufacturer and the OEM that built the controls if it was sold by the press manufacturer without controls - this used to be very common years ago, and I work on presses that were built in the 1940's still being run today.
When I go to a machine and I see anything that I determine is a safety hazard I stop working on that machine and tell the owner in writing the safety issue and that it needs corrected before anything else is done to that machine. Most of the time I end up leaving and the customer calls in another person to get it running that doesn't check things out first.

 

[ValeoBill]

Check out companies like "Sick", "Pilz" and "Allen Bradley" or any other manufacturer of safety hardware. They will all quantify the degree of safety required. I recently took the week long cerification course offered by Pilz. Course is geared to the risk assessment and designing safety into a machine as it's built.

 

[BOWILLY]

Haven't heard any feedback from requester. How about a status update?