Moved a norstar 3x8 dr5 last week for a customer to a new building. All phones are t7316. In the warehouse area there is one office with one phone. Outside this office is a storage area and a loadout bay. They would like some kind of speaker or horn in both of these areas that woud go off when that phone rings or when someone pages that extension so that it can be heard outside the office. What are some options for this?

I've used viking M2W in similar situations

https://www.vikingelectronics.com/product-details.php?pid=185

I like Algo products for the small things like that:
https://www.algosolutions.com/products/audible-and-visual-alerting.html

or Bogen's TPU15 if you want a talk back application which allows up to two speakers if I recall: https://www.bogen.com/products/telephonepaging/
If noisy environment then forget it.

The Viking unit - you need to tear apart the phone, solder in wires off the speaker and run to the unit. Then everything the speaker does is amplified - ringing and if you use speaker phone your conversation. OOOPS ! ! !

I would go with the Algo - connect to the Aux Relay. Make sure nothing else rings the Aux ringer except that phone. Then when that phone rings you hear it. Unless you put it on DND.

Would the Algo speaker also come on if someone did an internal page (F610) or a voicecall to that extension?

I have taken an 8 ohm speaker and "wired" it into the speaker of the phone before, but am hoping to avoid that this time as they would like two speakers and they would be outside of the room where the phone physically sits now.

F610 is internal page to all phones. Voicecall is to ONE phone only. If you want sound going ONLY to that phone, NO it will not on the Algo. To get this you would tear apart the phone and use the Viking.

BUT - If you use F630 which is all phones AND external speaker, then wire to the Algo from the phone system will go through the page speaker on the Algo. You may want to contact Algo to see how many speakers you can connect to the Algo. 604.454.3790

I personally would go with one cable from phone system to Algo. One pair to Aux Ring and one pair for page. Then you can make ONLY that one phone ring through the speaker. And using the F630 get the paging through the speaker.
I would not want to tear apart a phone and connect a speaker. First time they forget and use speaker phone everyone can hear the conversation.

You can also go from headset port on the phone to the Algo but keep it at 15 feet tops from the phone....see the manual here: https://www.algosolutions.com/pdf/user_guides/1825_Duet_Plus_Installation_Guide_English.pdf

You could go from headset to Algo then mount Algo beside the sets jack & power receptacle on the wall then run a cable to each additional speaker (or daisy chain)....in this scenario you would set the jumper to turn off the Algo speaker since the remote speakers would be used.
Or mount the Algo just outside the office 15 feet tops from the headset jack to service that area then run additional speakers.

you can have up to three speakers behind the Viking unit wired out to wherever you need them

for speaker phone use either a toggle switch or unplugging the amp will work .

Thanks for the suggestions guys. I'll look into these and get something to go. I like the idea of connecting to the aux ringer on the 3x8 the best.