Generally, for sensitive safety systems like this, Light and Siren are visible to those using the facility. So if problem developed, all patrons would be going "Umm, you know your sauna has flashing red light and siren going off?" after they all left the facility.

Yes, they still have to work but first off, both of those are extremely reliable systems, alarm circuits have extremely low risk of failure. Second, testing them takes 5 minutes a week/month, press the button, look for flashing light and listen to wailing noise.

It's inexcusable to think that email/slack or whatever is acceptable as anything other than notification system so people not in facility can be notified that alarms are going off.

EDIT: You are defending this setup and I'm not sure why. This seems email only setup seem indefensible.

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croes an hour ago | parent [-]

Because we don’t live in an ideal world.

Testing requires staff and you can be sure those parks are understaffed.

Best thing is to avoid them, next best thing is a cheap solution with low maintenance by the staff to notify as much people as possible.

Email wins.

Not a good solution but the best you will get for the price they are willing to pay

	▲	ssl-3 43 minutes ago \| parent [-]
		Things do break, so all alarms need periodic testing, whether they consist of email and/or something else. Whether it breaks because a relay has corroded due to years of service in a chlorine-enriched environment, or because O365 is down, or because O365 tightened up on DMARC requirements: It needs tested. And it's not a binary choice. This isn't the World Cup, the Super Bowl, or Highlander. There can be more than one. The alarm system can wear a belt, and suspenders. It can send emails, and it can flash a bright light, and it can also sound an audible alarm.