Do Two Single Check Valves = One Double Check Valve?

[TheNamek]

From a regs point of view, is it acceptable to fit two single check valves in line instead of a double check valve?

It was a royal pain in the butt to down tools to go and buy one when I thought I must have a double in amongst my clobber. Then to add insult to injury I ran out of reducers (22mm valve obto 15mm pipe work) so had to go back and buy more of those ! OK I should check my own inventory but let's not detract from the question. I could have fitted two full bore 15mm single check valves instead as I had these if this is acceptable in lieu of a double.

 

[TheNamek]

I think this is the answer:

http://www.wras.co.uk/List_printer_all.asp see Schedule 2 paragraph 15(5)

It says as long as they are at max distance apart of twice the bore size.