Risk Assessments and Safety Standards

I'm trying to get a better handle on safety standards, but the more I read the more lost I feel.

Being a US machine standard, you would think that NFPA 79 would give some clear direction, but it just makes some references to ANSI B11, ISO 12100, IEC 62061, ISO 13849, but as I understand it they are informational and not actually required as part of NFPA 79.

There seems to be several risk assessments. There's IEC 61508 which then leads you down the SIL rating path or ISO 13849 which takes you down the PL path. Then there's ANSI B11. How do you know which one should be used?

Any help or guidance would be appreciated.

Does any of those references start with a Shall or should?

I'm not a lawyer, but as regulations and standards were taught to me, if a sentence starts with a shall it means a requirement. So if a piece of regulation says that so and so installation shall comply with ISO 12100, they effectively transposed ISO 12100 to law.

Hopefully the more experienced guys can chime in with more information.

RIA has a technical report for a 'Task-based Risk assessment Methodology'. It is RIA TR R15.306-2016.
Another good document is ANSI B11.0 – 2015 'Safety of Machinery'

Yeah, ANSI B11 and B11.19 are common ones we reference in URS'. Or B155.1 when packaging equipment is in scope.

cardosocea said:

Does any of those references start with a Shall or should?

I'm not a lawyer, but as regulations and standards were taught to me, if a sentence starts with a shall it means a requirement. So if a piece of regulation says that so and so installation shall comply with ISO 12100, they effectively transposed ISO 12100 to law.

Hopefully the more experienced guys can chime in with more information.

Click to expand...

There are "shalls" for things that have to be done (E-stop categories, for example) based on the outcome of the risk assessment. So the standard requires you to do one, but they don't define it further than that. The references to the other standards are in the Annex, so not required.

A.3.3.85 Risk. Examples of references to risk assessment
include ANSI B11.0 and ISO 12100.

AJZ said:

RIA has a technical report for a 'Task-based Risk assessment Methodology'. It is RIA TR R15.306-2016.
Another good document is ANSI B11.0 – 2015 'Safety of Machinery'

Click to expand...

RIA is for robotics, so is that acceptable for other things like conveyors? Are they all interchangeable? I think the general idea of all of them are the same, but would they guide you to the same equipment design?

The RIA risk assessment can be used for other machines. And the B11.0 reference/mention it.

A risk assessment does not tell you how to design. It tells you what risks need to be addressed and to what performance level the safety design should be designed

The RIA one has a feature that will greatly help with the post assessment. You will notice it once you start using it

A very general statement is that if there is a standard specific for the type of machine you are building then you should start with that.

For instance, if you are building a hydraulic or pneumatic power press in the US, then you should use ANSI B11.2 Safety Requirements for Hydraulic and Pneumatic Power Presses. The standards specific to particular type of machinery are sometimes called Type C standards. Type A are basis or foundation standards and are very generic and Type B are generic safety standards dealing with types of safeguards that can be used across a wide variety of machines. Like all 'good' standards, they all reference each other until you get dizzy but B11.2 is actually pretty readable. And also, every machine is different so it may be that you make a pneumatic press that has a robot feeding it and so you would need to look safety standards for robots well.

The major issue is that you have to do something and document what you did to make the machine safe.