Should window manufacturers know/test how airtight their frames are under pressure?

for example if a house is being built with a predicted airtightness of X, should the window manufacturer be advised? and should a builder get confirmation that the window frame will offer X?

I foresee windows being the weak link in a SIP-build?
is this the case?

lots of windows leak through the frames even more round the frames

Until they found they cd do triple seals in open-out.

I would have thought that air pressure from the outside-in was greater than inside-out leading to open out windows being more airtight (i.e. windows pushed into their seals by wind etc) ?