Main Entry: span·ner
Pronunciation: \ˈspa-nər\
Function: noun
Etymology: German, instrument for winding springs, from spannen to stretch; akin to Middle Dutch spannen to stretch — more at span
Date: circa 1790
1chiefly British : wrench
2: a wrench that has a hole, projection, or hook at one or both ends of the head for engaging with a corresponding device on the object that is to be turned
[spanner illustration]
this was from merrium webster on line , the illistrations show basic Pin spanners along the lines of a Booster line type ... http://www.merriam-webster.com/art/dict/spanner.htm
The Brits still refer to "spanners" as we do "wrenches" Now as far as how the fire service adopted or more importantly "kept" the terminology would be the interesting part to dig up....:).. I guess it figures we would refer to them as "spanner wrenchs" since we do seem to enjoy redundancies...lol