On Fri, 1 May 2009 14:47:39 -0700 (PDT), had this
to say:

Stephen wrote:
Hello,

What size spanners do you need for 22mm straight compression fittings?
The nuts are 32mm but what about the flange on the middle of the body?
I measured it with a vernier calliper and I think it was 28.5mm, which
seems an awkward size. Rounding that up to 29mm, I could not find any
29mm spanners anywhere. Would a 30mm spanner be too big or do you
"cheat" and use adjustable ones?

Thanks,
Stephen

Thats 1 & 1/8th inch, and ISTR thats a whitworth size.

ISTR that the _original_ size for BSW spanners was 1½D + 1/8" (where D
is of course the bolt diameter), and that this was reduced a bit
during WW2 to economise on metal.

--
Frank Erskine