One of our labs is asking who can perform the annual test of safety showers and eye-wash as per AS 4775. I've suggested that the tests all seem to be relatively straight forward (mostly flowrates, temperatures, heights, etc), so they could do it themselves - but does anybody else get in an "accredited" person to do these tests?
Blackwoods have a Safety Shower Test Kit for sale on their website Chris, if your Safety Showers have back flow preventers, that's IQP territory. The suppliers of these items have a fair amount of advice on what checks are required. Are your people giving them a 10 second weekly operational check?
For Eye Wash Stations, Reinol sell a test gauge. You'll find shower socks there too.