We do not use this specific Adaptec card, but those Adaptec cards get really hot. You need a lot of direct air flow to the card. We run 4 fans at full speed and the temperature on the Adpatec card is between 50C - 55C, which is pretty high.
Without a good air flow, the card will get extremely hot and will die. So make sure to get extra fans for cooling and set the fans to full speed.
We've been running Adaptec cards for quite a few years now and we've never had a problem with them getting too hot and we set system fans to run at 15% duty cycle minimum, only spinning up more if they need to.