Propane patio heaters and outdoor heaters are becoming very popular and are increasingly visible at restaurants and on backyard patios. As their name implies, outdoor heaters are for outdoor use, not for temporary indoor use. Although an outdoor heater may seem suitable for a replacement indoor heat source, it is not designed or intended for indoor use simply because it's dangerous, very dangerous. Although outdoor propane heaters are generally portable, attempting to move them while in use can be dangerous.
Outdoor propane heaters are for the most part portable and use LP Gas cylinders as a fuel source which makes them ideal for construction job sites, backyards, outdoor events and of course, patios. Outdoor propane heaters are available in different models that emit heat by convection, forced air or through infrared heating. These LP Gas heater models vary in capacity, output adjustability, size and capability to heat areas of differing square footage. An overview of outdoor portable propane heaters is as follows:
Outdoor propane heaters offer the convenience of portability and mobility and although moving them is a simple task, moving a propane outdoor heater and/or propane cylinder while in use is not safe. The reason for this is because consumer LP Gas cylinders are designed for vapor service when used in this capacity. Moving them while in use can cause liquid propane to enter the hose and burners, creating a potentially unsafe situation. Outdoor propane heaters should be turned off and disconnected prior to relocation.
Much like space heaters, outdoor propane heaters are for heating small areas and because they are portable, as well as the cylinders, safety is an issue. Most often seen in public places such as a restaurant patio, outdoor heating incorporates the use of multiple heaters to heat numerous "smaller areas" or zones. Because these outdoor heaters can emit intense heat either through infrared means or forced air, propane cylinder storage is a topic of extreme importance. NFPA 58 states that "heaters used for temporary heating shall be located at least 6 feet from any cylinder". The actual purpose of the rule does not imply that the cylinder supplying to heater has to be 6 feet away because that really isn't possible as the referenced patio heaters are designed with a small cabinet at the base of the heater. The rules further explain that heaters incorporating protection from infrared or direct heat are exempt from this distance requirement (in relation to the cylinder being used).
Cylinders that are not in use shall be located 20 feet away from heaters that are being used. This distance rule creates enough space between the heat source and cylinder storage location so that the cylinders awaiting use are not subject to intense heat. The purpose of this rule is to minimize the chance of actuating the safety relief valve due to volume expansion of the liquid in the cylinder. To simplify, don't store propane cylinders within 20 feet of an outdoor heater that is in use. Also, if a forced air heater is being used, don't aim the heater at cylinders that are awaiting use.
NFPA 58 states that portable outdoor propane heaters "shall not be located within 5 feet of exits from an assembly occupancy". This rule is in reference to restaurants and the like that use these portable heaters for outdoor heating. Outdoor propane heaters commonly used in these settings are the stand-up type patio heaters and the reasoning behind this rule is simply so they are not easily knocked over by people entering or exiting the building. Outdoor patio heaters should be placed so that they are not subject to "foot traffic". Common sense plays a major role in the use of all outdoor heating applications but any questions should be directed to your propane company.