Propane cylinders are a portable source of energy providing fuel for the applications for which they are intended. However, because they are portable and easily refilled, propane bottles are sometimes used in settings for which they are not intended.
Although it may seem harmless, the improper use of a propane cylinder can place users, homes or property in potentially dangerous situations. As discussed in detail below, the two primary factors that make up proper cylinder use are:
The proper use of a propane cylinder involves the appliance(s) being serviced. Propane appliances and equipment that utilize cylinders are specified as such and are not to be used as a replacement for an empty bulk propane tank for several reasons that center around fixed piping systems, regulators and use specific application. Also, bottles that are used in vapor service such as a barbeque grill or fish fryer cannot be replaced by a forklift propane cylinder, as LP Gas forklift cylinders use liquid propane for their specific engine fuel applications (see Propane Liquid and Vapor). The lesson to be learned here, as outlined below, is that LP Gas cylinders are not interchangeable with ASME bulk propane tanks or with other types of cylinders that are approved for specific LP Gas applications.
Connecting a Propane Bottle to House Line - Propane cylinders are often thought to be an acceptable temporary replacement for residential propane tanks in the event the bulk tank is empty. However, propane cylinders are designed and used for portable applications and are not designed for use in fixed piping systems, such as that of a home. First of all, if the bulk propane tank is empty, service has been interrupted and a leak test must be performed prior to placing the system back in service. Second, propane bottles are designed for use in conjunction with a bottle regulator that delivers LP Gas pressures at a rate much lower than the rate required by household propane appliances. Bottle regulators are not interchangeable with tank regulators and vice-versa; this is very dangerous. Additionally, trying to fuel a household propane system with a cylinder would be like trying to illuminate a stadium with a lamp light. There is not enough container surface area (in a bottle) that will vaporize the liquid propane at a rate required by the downstream appliances. Also, attempting to connect a propane forklift cylinder to a house line will result in liquid propane being delivered to appliances. Liquid propane being delivered to appliances through a piping system designed for vapor distribution will burn a house down.
Connecting Liquid Service Cylinders to Vapor Lines - As mentioned above, connecting a propane cylinder designed for liquid service, such as a forklift cylinder to a vapor system or vapor line will result in fire danger. The same is true for outdoor appliances and equipment that work by using propane vapor. Grills, fish fryers and patio heaters are propane vapor service appliances that will be damaged by the introduction of liquid propane as well as create a very hazardous situation. In the same regard, do not turn cylinders over during operation. This will introduce liquid into propane gas lines, regulators and burners that are only to be used with propane vapor. Using LP Gas cylinders and bottles improperly or using them for an application for which they are not designed will harm equipment, appliances and can seriously burn users and bystanders.
Everyone is familiar with the phrase "location location location" when discussing topics ranging from "where to live" to "where to fish". If in doubt about where to use a propane cylinder, remember the phrase "outdoors outdoors outdoors". The only place to properly use a propane gas cylinder of any size is outside, as required by NFPA 58. Using a cylinder indoors is not only illegal, it is terribly unsafe. Keep in mind that a full propane barbeque cylinder contains enough liquid to produce over 300 cubic feet of vapor. A fuel source such as that should not only be stored outdoors, it should never be used indoors. See Propane Cylinder Storage for information about where bottles should be kept when not in use.
When using cylinders outdoors for whatever approved purpose or application, keep the propane bottle away from other sources of heat and use in a well ventilated area. Additionally, make sure the cylinder relief valve is not pointed at any source of ignition. Use the appropriate length of hose between the appliance and cylinder and be sure that the bottle is of course, upright when in use. Although unenclosed, covered patios are generally accepted as safe for propane bottle use and storage, garages and similarly enclosed spaces are not viewed as safe places for bottle usage or storage. Extra precautions for propane cylinder use include keeping clear of flammable and combustible materials, keeping a safe distance from building openings and walls and having a fire extinguisher in case of emergency. Although not widely known or publicized, a very important rule when using cylinders is to make sure they are stable and not moved while in use. If the cylinder is jarred or moved while actively being used, liquid propane may escape through the cylinder service valve resulting in excessive flames.