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IEC EN 60601-1-8: What defines a visual alarm?

craiglab

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#1
We make a doppler device for monitoring cerebral blood flow. We do not have any alarms - audible or visual - but we do have a pop-up at power up that advises of some precautions, like not to exceed a certain (ultrasound) power in a certain application, and to always use the lowest amount of power (ALARA). The user has to cancel the pop-up to continue.
Would this be considered a visual alarm? It only occurs the one time.
If when adjusting a parameter (like power level) we decided to pop-up a similar message, is that an alarm?
 
#2
It's a good question.

The definitions of "alarm system" and "alarm condition" in IEC 60601-1-8 are not really tight enough to exclude an information message, since it is still to indicate a potential hazard.

It appears the scope statement (Clause 1.1) that the decision to use an "alarm system" is up to the manufacturer. Some particular standards specify that an alarm must be provided, also there are some MDD essential requirements that specifically reference alarms. In all other cases the risk management process will decide if an alarm is needed.

Just for additional justification, although nowhere stated, the principle of IEC 60601-1-8 alarms is to bring the users attention to the equipment generating the alarm, in an environment where there may be many medical devices or where the user may have their attention on other things.

In your case the user is already siting in front of the device, looking at the screen, and has just made a change in setting that might trigger the message. Thus, there is no need to try and grab the user's attention to your device, such as by providing a lamp, audible sound etc.

So perhaps an improved definition of an "alarm system" in IEC 60601-1-8 would indicate that such systems are specifically intended to get the user's attention from a distance, through the use of audible and visual signals.
 
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