A fastener in sheet metal should not be any closer than four to six diameters from the next one. For example, if you are using a 1/8-in. Pop Rivet, the nearest another rivet should be is between 1/2 to 3/4 in. By using this rule, you will reduce the chances of damaging a part, as well as make optimum use of your fasteners.
Place humidifiers and dehumidifiers away from walls and bulky furniture. These appliances work best when air circulates freely around them. Be sure to clean the unit often to prevent unhealthy mold and bacteria from developing.