Because more people are using propane for heating, outdoor lights and grilling, the smaller propane tanks are making a lot of impact on communities. People used to drive to the gas station and fill a 5-gallon tank with propane for a camping trip. Now you can go to special storage areas and exchange your empty tank for a full one at a set price. Perhaps there is one at your local supermarket. The storage cabinet has good ventilation and easily accessible doors. There is quite a bit of open space to avoid the buildup of fumes. Propane needs a special storage area.
Of course you will never need that big of a storage rack at home but you will definitely need something on that order if you have propane tanks. While you are looking at the different styles, consider a safe storage area for oxygen and acetylene tanks, as well. Depending on where the cabinet or storage cabinets will be located, consider a fire safe cabinet. The danger of pressurized gas in a tank is that it can explode. Even a small fire extinguisher can blow up and cause loss of life if the tank is not contained.
You already know not to store tanks under stairways used during earthquakes or fires. The caution about not storing propane tanks near power lines, overlooked at times, is as important as the caution about turning in cracked or rusty tanks and storing them in an upright position. The vented doors reduce any buildup of heat within the cabinet and prevent busy fingers from causing trouble. Keep a minimum of ten feet clearance on all sides of a storage cabinet. Do not store tanks in the house, garage, or under the barbecue grill. Your local propane company and most likely fire department have additional suggestions for responsible, safe propane use. Start it with a quality cabinet designed to protect you, your family and property.