Safety Question(s)

[nmurray]

So first off I know everyone hates directly answering safety questions and I want to start by I will take no ones opinion as rule but looking for guidance and hopefully some direct answers with references to back them up.

So I have 2 questions:
1:
Lets say I have a machine with a light curtain for operators to load.
The machine frame from the ground up goes up 2 feet then has a large opening, large enough you could crawl into the machine if one was determined.

There are light curtains to detect when someone is in the load area.
The safety circuit shuts off power to a indexer and some pneumatics.

Can this light curtain auto reset when the operator leaves the light curtain?
When the cycle starts there are some sensor checks to make sure parts are in the correct position, clamps close to hold the part then the indexer will index.

Or is this a scenario where the light curtain MUST be manually reset. I ask because I have been searching for something that directly states this but I am having trouble finding it.

2:
So lets say I have a 2ft x 2ft opening with a light curtain that gets broken when the area is entered. While you are breaking the curtain power is off and machine is safe but you could crawl into the opening and after you get 5 feet further there are devices not powered off from the light curtain you broke to enter.
Once again I am struggling to find direct answers to this.

 

[mk42]

1) Every major standard I've seen says a safety trip requires a manual reset.

I've seen certain systems do things like automatically reset a safety comms fault when an AGV goes through a point where it is known it will roam, because it is expected and therefore not a "fault". Not every comms fault, just under certain conditions. That's taking the ownership of the decision onto themselves, though.


2) I don't see your question but my initial reaction is that if the light curtain protects a large area, you must deactivate the whole area. If its part of the same hazard (someone crawls into small opening) it's the same safety zone, and it all needs to be shut down, unless you have further light curtains to break it up, I guess. Honestly, that just seems like a nightmare, because what if someone resets the machine with someone in the crawlspace?

 

[drforsythe]

In my opinion, scenario 1 would require a manual reset of the light curtain safety circuit if you can get past the light curtain and into the machine. If it automatically reset, and the person had crawled past the light curtain, the person could be in the machine after they passed the light curtain.

In scenario 2, you would need to evaluate the hazard(s) of each device that the operator can reach if they crawl into the machine.

 

[SCADA_Joe]

I just want to add a little side note.

The reset is to give the operator a chance to confirm the area is safe to operate and return to operation, so no tools or people left in area. I believe they are supposed to be located in an area where the operator can visually see the entire area of the machine.

I have had to do a few that required two reset buttons to be pressed. This is for larger machines with multiple areas that can be entered. I guess you could even do two buttons that have to be pressed simultaneously if you had two operators? Think of the big press machines that require 2 buttons simultaneously to operate.

Cognex and Keyence both have great safety groups that could give you some great ideas and a vast array of safety devices to work with.

 

[joseph_e2]

We have one system that has 2 reset buttons for each door. Push the inside one, close the door, press the outside one. All within a certain amount of time. This is to remind the operator to verify the area is empty. The light curtains that the operators reach through are manually reset. There are some that divide the machine into zones that moving parts of the machine breach. Those are automatically reset unless the operator's light curtain is breached at the same time, at which point you need a manual reset. The little areas inside the light curtains that someone could climb into are protected with horizontal light curtains that are ganged off of the ones the operators reach through and therefore require a manual reset.



On our newest systems, we have area scanners to make sure no one is inside before the doors can be reset.



Personally, my opinion (which is worth every penny you paid for it...) is to require manual resets for the light curtains and some other presence sensing device (horizontal light curtain or area scanner) to verify the space is clear. If that's not possible, then I'd consider the dual reset button (inside/outside the protected area) approach and definitely require a manual reset every time.

 

[JeremyAdair87]

1. I have used a two handed start button's safety relay, as my reset for operators manually loading a machine's light curtain station. We had a ton of two handed start stations, and the physical placement would cause the operator to be in a safe position when starting the machine. The light curtain was redundant, and an addition to ensure the safety was broken the entire time they were reaching into the mill. It passed our own personal risk assessment.

2. A safety should stop potential energy. We don't kill power to drives because it kills them over time, but they have safety rated STO signals, robots are the same. There will also be inputs that have power, and stack lights typically have power in that scenario as well. If you trip that light curtain, and you can force stuff to move without resetting that light curtain...... It would be a red flag in my book.

I was trained in a time before safety PLCs. We couldn't "program safeties". We set up our safety's to kill all potential energy when entering a work envelope. Pneumatics dropped air, spring return valves kept valves open/closed, breaks on motors defaulted to engaged when power was lost for hanging applications, and all dangerous things were safe when we entered a work envelope.

After you read all of these, you should be good to go on making a decision.

Have fun.
The Law (code)
NEC, NPFA70, CEC

Adoptable Standards (suggestions, but you get sued regardless)

European Standards (EN/IEC):
• IEC 60204-1: Safety of machinery - Electrical equipment of machines - Part 1: General requirements
• IEC 61439-1: Low-voltage switchgear and control gear assemblies - Part 1: General rules
• IEC 61800-5-5: Adjustable speed electrical power drive systems - Part 5-5: Safety requirements

American Standards (NFPA, UL, CSA):
• NFPA 79: Electrical Standard for Industrial Machinery
• UL 508A: Standard for Industrial Control Panels
• CSA 22.2 No 14: Industrial Control Equipment
• UL 845: Motor Control Centers
• UL 508C: Power Conversion Equipment
• CSA 22.2 No 274: Industrial Control Panels and Assemblies



6. Additional Standard references.

ISO Standards:
• ISO 12100: Safety of Machinery - General Principles for Design - Risk Assessment and Risk Reduction: This standard provides a framework for risk assessment and risk reduction in the design and use of machinery. It outlines general principles and a structured approach to identifying and mitigating hazards.
• ISO 13849-1: Safety of Machinery - Safety-Related Parts of Control Systems - Part 1: General Principles for Design: ISO 13849-1 specifies principles for the design and integration of safety-related control systems in machinery.
• ISO 13850: Safety of Machinery - Emergency Stop Function - Principles for Design: This standard defines the principles for designing and implementing emergency stop functions on machinery.
• ISO 13855: Safety of Machinery - Positioning of Safeguarding Devices with Respect to the Approach Speed of Parts of the Human Body: ISO 13855 provides guidelines for determining the minimum safe distance between safeguarding devices and hazardous machine parts.
• ISO 14119: Safety of Machinery - Interlocking Devices Associated with Guards - Principles for Design and Selection: ISO 14119 outlines principles for designing and selecting interlocking devices used in conjunction with guards on machinery.
• ISO 14122: Safety of Machinery - Permanent Means of Access to Machinery - Various Parts: The ISO 14122 series covers requirements and guidelines for the design and construction of permanent means of access, including stairs, platforms, and walkways.
• ISO 13857: Safety of Machinery - Safety Distances to Prevent Danger Zones Being Reached by Upper and Lower Limbs: This standard specifies safety distances to prevent danger zones from being reached by the upper and lower limbs.
• ISO 16092: Machine Tools - Safety - Machining Centers: ISO 16092 addresses safety requirements specific to machining centers, including milling and turning centers.
• ISO 20607: Safety of Machinery - Instruction Handbook for Machinery: This standard provides guidelines for creating instruction handbooks for machinery, including information on safe use, maintenance, and troubleshooting.
• ISO 22400: Industrial Automation Systems and Integration - Key Performance Indicators (KPIs) for Manufacturing Operations Management: ISO 22400 is related to the monitoring and performance measurement of industrial machinery and systems.
• ISO 4413: Hydraulic Fluid Power - General Rules and Safety Requirements for Systems and Their Components: This standard outlines general rules and safety requirements for hydraulic systems used in industrial machinery.
• ISO 4414: Pneumatic Fluid Power - General Rules and Safety Requirements for Systems and Their Components: ISO 4414 focuses on general rules and safety requirements for pneumatic systems and their components in industrial machinery.
• ISO 13849-2: Safety of Machinery - Safety-Related Parts of Control Systems - Part 2: Validation: Part 2 of ISO 13849 provides guidelines for validating the safety-related parts of control systems in machinery.
• ISO 16092-1: Machine Tools - Safety - Part 1: General Purpose Machines: This standard addresses safety requirements for general-purpose machine tools used in various industries.
• ISO 16092-2: Machine Tools - Safety - Part 2: Numerically Controlled (NC) Turning Machines and Turning Centers: ISO 16092-2 specifically covers safety requirements for numerically controlled turning machines and turning centers.

 

[JeremyAdair87]

Part 2
• ISO 16092-3: Machine Tools - Safety - Part 3: Press Brakes: This part of ISO 16092 deals with safety requirements for press brakes used in metalworking and manufacturing.
• ISO 16092-4: Machine Tools - Safety - Part 4: Milling Machines (Including Boring Machines): ISO 16092-4 addresses safety considerations for milling machines, including boring machines.
• ISO 16092-5: Machine Tools - Safety - Part 5: Grinding Machines: This standard covers safety requirements for grinding machines used in industrial applications.
• ISO 16092-6: Machine Tools - Safety - Part 6: Sawing Machines for Cold Metal: ISO 16092-6 focuses on safety aspects of sawing machines used for cutting cold metal.
• ISO 16092-7: Machine Tools - Safety - Part 7: Gear Cutting Machines: This part of ISO 16092 provides safety guidelines for gear cutting machines.
• ISO 13856-1: Safety of Machinery - Pressure-Sensitive Protective Devices - Part 1: General Principles for Design and Testing of Positioning Monitoring Devices: This standard addresses pressure-sensitive protective devices used in machinery safety.
• ISO 13856-2: Safety of Machinery - Pressure-Sensitive Protective Devices - Part 2: General Principles for Design and Testing of Pressure-Sensitive Bumpers and Pressure-Sensitive Plates: Part 2 of ISO 13856 deals with pressure-sensitive bumpers and plates for machinery safety.

ANSI Standards:
• ANSI/ISA-95 (IEC 62264): Enterprise-Control System Integration: This standard defines models and terminology for the integration of enterprise and control systems, facilitating communication and data exchange between different levels of an organization.
• ANSI/ISA-88: Batch Control: ANSI/ISA-88 (also known as ISA-88 or S88) provides guidelines for the design and implementation of batch control systems, which are commonly used in process industries.
• ANSI/ISA-101: Human-Machine Interfaces for Process Automation Systems: This standard focuses on the design and implementation of effective and user-friendly human-machine interfaces (HMIs) for process automation systems.
• ANSI/ISA-18.2: Management of Alarm Systems for the Process Industries: ANSI/ISA-18.2 provides recommendations for designing, implementing, and managing alarm systems to improve safety and operational effectiveness in industrial processes.
• ANSI/ISA-84 (IEC 61511): Functional Safety: ANSI/ISA-84 (also known as ISA-84 or S84) outlines principles and requirements for the design, installation, and operation of safety instrumented systems (SIS) to ensure process safety.
• ANSI/ISA-100: Wireless Systems for Automation: This standard addresses the use of wireless technology in industrial automation systems, providing guidelines for reliable and secure wireless communication.
• ANSI/ISA-TR18.2.3: System Considerations for SCADA Systems: This technical report discusses considerations and best practices for supervisory control and data acquisition (SCADA) system design and implementation.
• ANSI/ISA-TR18.2.2: Safety Instrumented Systems for the Process Industry Sector - Part 1: Framework, Definitions, System, Hardware, and Application Programming Interface (API): This technical report provides guidance on safety instrumented systems (SIS) in the process industry sector.
• ANSI/RIA R15.06: Industrial Robots and Robot Systems - Safety Requirements: This standard focuses on safety requirements for industrial robots and robotic systems used in automation applications.
• ANSI/RIA R15.07: Industrial Robots - Robot Payload, Identification and Rated Load: ANSI/RIA R15.07 addresses the identification and rated load of industrial robots to ensure safe operation.
• ANSI B11 Series: Machine Safety Standards: The ANSI B11 series includes various standards related to machine safety, guarding, and risk assessment, which are applicable to automation equipment and machinery.
• ANSI Z535 Series: Safety Signs and Labels Standards: The ANSI Z535 series covers safety signs, labels, and color codes, which are important for conveying safety information in industrial automation environments.
• ANSI/ISA-TR18.2.4: Considerations for the Integration of Safety Instrumented Systems with Fire and Gas Systems: This technical report provides guidance on integrating safety instrumented systems (SIS) with fire and gas detection and control systems to enhance industrial safety.
• ANSI/ISA-TR18.2.5: Safety Instrumented Systems for the Process Industry Sector - Part 2: Guidelines for the Application of ANSI/ISA-84.00.01-2004: This technical report offers guidelines for applying the principles of ANSI/ISA-84 to safety instrumented systems in the process industry.
• ANSI/ISA-TR18.2.6: Safety Instrumented Systems for the Process Industry Sector - Part 3: Guidance for the Determination of the Required Safety Integrity Levels (SILs): This technical report provides guidance for determining the appropriate safety integrity levels (SILs) for safety instrumented systems in the process industry.
• ANSI/ISA-101.01: Human-Machine Interfaces for Process Automation Systems - Part 1: Roles and Responsibilities: Part 1 of ANSI/ISA-101 focuses on the roles and responsibilities related to the design and management of human-machine interfaces (HMIs) in process automation systems.
• ANSI/ISA-101.02: Human-Machine Interfaces for Process Automation Systems - Part 2: Functional Requirements: Part 2 of ANSI/ISA-101 outlines functional requirements for designing effective and user-friendly HMIs in process automation.
• ANSI/RIA R15.08: Industrial Robots - Robot System Risk Assessment: This standard addresses risk assessment for industrial robot systems, helping ensure that safety measures are appropriately implemented.
• ANSI/ISA-TR12.13.01: Guidance on the Identification and Control of Erosion and Corrosion Damage in Control and Safety Instrumented Systems: This technical report offers guidance on identifying and mitigating erosion and corrosion damage in control and safety instrumented systems.
ANSI/ISA-TR12.13.02: Guidance on the Identification and Control of Erosion and Corrosion Damage in Control and Safety Instrumented Systems: This technical report provides additional guidance on addressing erosion and corrosion damage in control and safety instrumented systems.

 

[Jeev]

You forgot to mention EN619 and all the Type C conveyor standards

 

[JeremyAdair87]

lol I had them in onenote. I just typed ISO into the search bar and copied and pasted from my old massive notebook/filing cabinet.

Seriously, If you have more standards lol, I need to add them to my list. Its taken me a long time to purchase a lot of those and read them. I've been coming out of pocket around a grand a year for a long time just to be able to read about safety.

I don't tell my employers I've read them as much as I have though. I don't want to fight people designing widowmakers for a living.

It all started 10 years ago when they wanted to use an operator leaving a light curtain as a start button.

 

[James Mcquade]

nmurray,

your post is very vague and leaves lots of questions.

if you can crawl under, over, around, or go through a light curtain opening or hole not covered by the light curtain or safety barrier so that you can get to any machine that is automatically running, your machine is not protected. even if the light curtain had the ability to do blanking, a gap big is not allowed. Any machine that i have ever designed has always required a manual reset.

what type of machine?
where is the light curtain in reference to the loading area, and what is this large opening?
More details please.
regards,
james

 

[bill4807]

lol I had them in onenote. I just typed ISO into the search bar and copied and pasted from my old massive notebook/filing cabinet.

Seriously, If you have more standards lol, I need to add them to my list. Its taken me a long time to purchase a lot of those and read them. I've been coming out of pocket around a grand a year for a long time just to be able to read about safety.

I don't tell my employers I've read them as much as I have though. I don't want to fight people designing widowmakers for a living.

It all started 10 years ago when they wanted to use an operator leaving a light curtain as a start button.

Thats awesome! You have been purchasing and reading all of these. Nice list.
There is so much with so many different situations to adapt the standards to. Its almost to much to be confusing, especially when you deal with different countries.

 

[JesperMP]

The machine frame from the ground up goes up 2 feet then has a large opening, large enough you could crawl into the machine if one was determined.
[..]
So lets say I have a 2ft x 2ft opening with a light curtain that gets broken when the area is entered. While you are breaking the curtain power is off and machine is safe but you could crawl into the opening and after you get 5 feet further there are devices not powered off from the light curtain you broke to enter.

In either case, crawling into a machine to do something (clean, inspect, troubleshoot, repair ?) is not an emergency, but is also not an operational stop (insert parts into a machine for machining). The way this is described, it falls into service entry, and then it is a clear case of LOTOTO procedure needed. This cannot be covered by a light curtain. You need manual isolation devices that remove all energy from the area, and these isolation devices must be lockable.
Especially since the opening is small and the man can crawl deep into the machine, automatic reset would be an accident waiting to happen.

When the cycle starts there are some sensor checks to make sure parts are in the correct position, clamps close to hold the part then the indexer will index.

Can these parts fall onto a person that has crawled into the machine ? If so, that has to be considered, even if you have removed all energy from the area. Especially if the parts are held in place by force.

Important disclaimers:

There is not enough information available, and these comments does not constitute a proper training in safety standards.
A risk assessment must be made by someone proficient in safety standards.

Since you are in the US, be careful if you can be pointed out as responsible for any accidents that may happen in the future. You can be taken to court, no matter that you were not proficient in safety standards.
Be sure to have in writing from your management that they decide anything relating to safety on the machine.

 

[Jeev]

lol I had them in onenote. I just typed ISO into the search bar and copied and pasted from my old massive notebook/filing cabinet.

Seriously, If you have more standards lol, I need to add them to my list. Its taken me a long time to purchase a lot of those and read them. I've been coming out of pocket around a grand a year for a long time just to be able to read about safety.

My corner of the world is mostly the AS 4024 Series, AS 60204, and AS 62061 - Which are mostly adaptations of IEC/ISO/EN Machine Safety Standards. We use EN619 as a reference, because that has not yet been adapted in AS4024.