You're welcome...

My workplace does the same, and we have the complicating factor that several of our workspaces with extremes of temperature (as high as 40C when it was 28C outside) are Level 2 Containment facilities, with restrictions on what can be done within the facilities - eating a banana as Andrew suggested constitutes a breach of containment for which we risk having our facility shut down by our regulator. Consumption of actual food requires that we leave our work areas to consume it, then return. While we can have a cold water fountain in the gown-up area, storage of food is prohibited. Something that does not work particularly well for a laboratory facility will certainly be worse for a prison,

The OIA released by National does not have any risk assessments (with the associated physical evidence), nor does it have any information about whether incidents had occurred as a result of the temperatures. This is the information that I would be using to determine whether or not action had to be taken in my own workplace.

To put it another way Andrew, the reason you don't see anything in the OIA response that suggests anything other than waste of money is that the OIA response answered a specific question, and that question only. No one bothered to follow up and ask Corrections to present the evidence that justified the expenditure. There's a website for OIA requests if you are so inclined (https://fyi.org.nz/) - I've been watching to see if anyone will file such a request, will it be you? If you do, make it better than the time-waster who asked what Corrections favourite flavour slushie was.

I will no longer be bothering with this topic.

Lets face it Jonathan. There are three types of risk assessments.

Theres your Theoretical / Imaginative Assessment.
To do this you need a safety qualification and belong to a safety club, be in a safety job and draw a safety wage. You need to do a review of the literature and an analysis of all relevant research, codes, regulations, books and any other current or historical information; form a safety group and review options after first multiplying, adding and subtracting values on variables and then come to a view which is that your coldest prison in the middle of winter will be at risk of heat related illness therefore we need to provide slushy machines in summer.

Then theres your Realist Assessment. Here you take your hottest prison in the hottest ever summer with the largest ever prison muster and end up with no serious heat related incidents

And then theres your Two Sense Assessment which is if it looks like a turd and smells like a turd it is most probably a turd. Proof of concept has shown that if it looks like a pudding and smells like a pudding then pudding is the risk..

I shant be bothering with a further OIA as the answers are in the original answer. And by your own admission (teachers coffee machines) we already know tax payers are being ripped off so not much point confirming what already is known.

Seems not that long ago Dept of Corrections was saying their 8 hour shifts were so dangerous in summer that slushy machines were needed to reduce core body temperature to prevent dire consequences to heat stressed staff.

Well, bugger me. This now seems to have been forgotten as Corrections are set on introducing new shifts that will see 3 consecutive 12 hour shifts being worked. Https://www.stuff.co.nz/national/113578935/prison-officers-will-work-12-hour-shifts-in-new-roster.

I smell something not quite right..............