NEMA 5-15 outlet orientation

Is there a standard that says how a NEMA 5-15 should (not must) be installed? I ask because I'm in Panama. They use NEMA 5-15 for residential wiring, but all outlets are installed sideways. I asked an electrician, and he said the fire department safety folks demand that common be down. I always learned ground is down. My problem is, all my molded plugs and adapters seem to assume ground is down. My rechargeable battery charger will break if used in the electrical outlets here (it is designed to be used vertically, the plugs rotate out of the charger, no cord involved). This goes for several other devices I have as well, all assume a vertical, vice horizontal, outlet installation.