My friend popay,
from what I read from your posts you must be very new in the company. Welcome!
I think what the others are trying to say here is that most rosters are really stretched to the limits, 90+ hours is more a rule then an exception and a lot of us are flying backt to back flights with crossing over 8 timezones in between.
You might be one of the lucky ones now with your roster but believe me, it will not stay like that.
It is true, you can refuse a flight because you think it is not safe. At least, thats whats written in the red book, but I would not recommend it. It might follow you around much longer then you want it to.
Once again, rosters are heavy, a lot of nightflying and not an awfull lot of days of. But hey, thats the industry we have chosen to work in and its the same thing all over this little planet.
Good luck