Examples of inherent safety by design

[Roland chung]

Hi everyone,

Can you give me some examples of inherent safety by design? Thx.

 

[Marcelo]

Inherent safety by design is related to the option in which the device itself controls the risk (not depending on action by a third party. It was kwon, in some literature, as "unconditional safety".

This include things such as a enclosure to control the risk of electrical shock, a change in device material to remove a toxicological hazard, and a self-destroying device in the case of a single use device.

 

[Roland chung]

Hello Marcelo,

The examples you given are more like protective measures.

 

[Marcelo]

Nope, protective measures (as the second option for risk control) depends on action from a third party (such as the operator - that why it was originally known as conditional safety), and the ones I gave, don't.

 

[Roland chung]

If I am reading you correctly, protective measures mean reaction.

Does any ISO document try to explain the inherent design and protective measures?

 

[Marcelo]

If I am reading you correctly, protective measures mean reaction.

Does any ISO document try to explain the inherent design and protective measures?

The best (and most cited) example for a protective measure is an alarm, in which the device tells the user that something is wrong, and the action (or inaction) of the user will control the risk.

There's some conflicting definitions in ISO and IEC documents about protective measures and inherent safe design, so I would take care with them. Anyway, you can find a lot of examples in the risk management literature (please remember that standards usually do not create nothing new, they just standardize good practices from a specific field).

 

[Marcelo]

For example, ISO/IEC guide 51 has definitions for both:

3.5
inherently safe design
measures taken to eliminate hazards (3.2) and/or to reduce risks (3.9) by changing the design or
operating characteristics of the product or system

risk reduction measure
protective measure
action or means to eliminate hazards (3.2) or reduce risks (3.9)
EXAMPLE Inherently safe design (3.5); protective devices; personal protective equipment; information for
use and installation; organization of work; training; application of equipment; supervision.

But the definition of protective measure is really what ISO 14971 calls risk control measure.

 

[Roland chung]

In IEC, the protective system is defined to protect the patient against safety hazards which may arise.
Could you please share a typical RM literature?

 

[Roland chung]

According to the guide 51, I would think enclosure should be protective measure. It seems that guide 51 is not that helpful.

 

[Marcelo]

In IEC, the protective system is defined to protect the patient against safety hazards which may arise.
Could you please share a typical RM literature?

I think we are confusing things here, what I mentioned was what is in

ISO 14971 6.2 b) protective measures in the medical device itself

See attached for one example of what I mentioned.

You can also look at classical documents such as mil-std-882, UK HSE documents Reducing risks, protecting people HSE’s decision-making process and Research Report Improving inherent safety and , the FAA system safety handbook, the NASA System Safety handbook, and several others. There's simply too many literature to cite (safety engineering has some 50-70 years of literature on risk management, as it is, and ISO 14971 tries - and not always achieves - to condense those in ONE set of good practices).