If your gym doesn`t have a Power Rack - ask for one. (and also ask the question why there isn`t one there in the first place!)
We`re pretty sure any serious bodybuilding or strength gym will have at least one of these essential pieces of weight training equipment, but we feel that even "fitness" gyms and personal training studios would benefit from also, to ensure safety and confident training as well as results.
And if you are training alone at home without a power rack then you really should have plans to get one in place, space and budget permitting. A power rack with a good sturdy, adjustable flat-to-incline dumbbell is the cornerstone of a sound home weight training set-up.