Definition Critical Component Definition

[RoxaneB]

Re: Critical Component Defined

regarding the point that all the components are critical, I am not with you on that.

I did not say that every component is critical, but I asked HOW to determine what is critical above other aspects. I wanted you to provide more of a definition that what you originally said and your response above provided that...hopefully to the Original Poster's use.

 

[somashekar]

Re: Critical Component Defined

We mfg a medical device and currently going through CE mark for a new product. I guess I am looking for a general definition of critical component. We test the product 100%. The component is an oscillator. There is no UL/Safety marks on the component.

No UL/Safety mark is fine.
Is your medical device subjected to safety tests and approvals by a recognized test house ?
When this is done, the test house along with your designers will decide which of the components are critical and list them in the report. You may then have to respect this in your purchasing and inspection controls.
This decision is taken based on safety analysis of your device. Safety concerned to the patient / user.
Usually termed as safety critical components
You can further add components to this list based on your design analysis for performance as well, and get your bunch or critical components.
.
..
Further my interpretation ...
When a component is critical to the medical device effectiveness in the sense that the lack of effectiveness could lead to death or major irreversible damage, such a component is into safety critical component.

 

[Sullen-gent]

Hoping some one responds but what Regulatory requirements is there to define parts as 'critical'? I see Critical comes up one the Electrical side and is a requirement of 60601-1. However for non-active device, what clauses would we not meet by not defining 'critical' parts components etc. Background I'm working on older devices where DFMEA were never created as part of D+D.

 

[ChrisM]

A little late but....
generally recognised definition is "a critical component is one whose failure could result in a hazardous situation". (I know that this is a bit vague). Examples quoted are failure of insulation on a mains power lead (as someone could get an electric shock if they were to touch it), fuse (may not blow when it should and therefore allow higher current than designed to pass), batteries, relays etc

 

[Ed Panek]

It can be tied to risk or what the device's "essential performance" is tied into. For example, a car would have a differential, brakes, and engine as part of its essential performance. Lighting, seat belts, airbags as part of its risk mitigation.

I would think cup holders, radio, and speakers would be not critical.

 

[RoxaneB]

It can be tied to risk or what the device's "essential performance" is tied into. For example, a car would have a differential, brakes, and engine as part of its essential performance. Lighting, seat belts, airbags as part of its risk mitigation.

I would think cup holders, radio, and speakers would be not critical.

There is the risk to the "essential performance" and there is also the risk of not meeting customer requirements. If a part is not necessary to essential performance but (a) is tied to the customer requirements and (b) has a long lead time and low inventory, it could be deemed critical.

If, sticking with the car analogy, the customer wanted the cup holders to be made from titanium or some fancy marble (silly, but work with me here), and these were not common requirements so there is low inventory (with a long lead time for delivery), a delay in the ability to install could result in a failure to provide the customer's product on time (i.e., risk).

This is why, as part of the risk analysis, it's important to look beyond pure performance specs and use a numbers-based (i.e., math) approach to calculating the criticality level of each component. We may say that a part is critical from a customer requirement perspective but that carries less weight than a part that is vital to the performance. So be it...but at least we've done the exercise.

 

[ChrisM]

So what happens with a small device with very limited electronics? The failure of any single component would affect the performance/operation of the device, so are all components "critical" or only those where safety becomes a risk upon failure ?

 

[Ed Panek]

So what happens with a small device with very limited electronics? The failure of any single component would affect the performance/operation of the device, so are all components "critical" or only those where safety becomes a risk upon failure ?

Possibly. A car remote is very simple. I suspect every item is critical in the electrical layout. Is the color of the plastic enclosure? Maybe but I could see production with the slightly off color plastic under deviation being ok

it’s also important though for specific customer requirements. If the car is a Bentley that color might be really important to the Bentley image or brand as Roxane stated.

 

[Miner]

Part of your answer will depend on your particular industry. These terms are not consistently applied across industries.

In the automotive industry, the term Critical is reserved solely for safety characteristics governed by FMVSS (Federal Motor Vehicle Safety Standards) or the local country's equivalent standards. The terms Significant (Ford) and Key (GM) are used for characteristics that are important to the function of the product.

 

[AndreB]

For my point of view, after conducting a criticality evaluation of components which is based on severity, occurence (RPN2) and also detectability (RPN3), this latest is normally conducted during developpement process, the final evaluation after implementation of apprpriate mitigationswill normally reveals components elected to be critical components. It becomes important to keep such evlauation traceable in the DHF of the medical devices.