DOT Propane Cylinders
Most often referred to as bottles, most consumers are familiar with 20# cylinders used for a gas grill. There are different sizes and shapes of propane cylinders used by consumers for a variety applications ranging from cooking and grilling to weed burning. These consumer type cylinders are commonly used in residential and agricultural applications and operate in vapor service similar to that of an ASME propane tank. These propane cylinders conform to DOT (Department of Transportation) standards and are sometimes referenced as "DOT bottles" or "DOT Cylinders".
Propane Bottle Operation
Propane cylinders will only operate properly when they are vertically upright. While certain types of cylinders are designed for liquid service, most consumer propane bottles are designed for only vapor service, such as with a gas grill. It's important to undestand that propane cylinders up to 40# in size are required to have valve known as an Overfill Prevention Device (OPD), which is designed to prevent the cylinder from being overfilled.
Overfill prevention device (OPD) equipped cylinders, along with cylinders not equipped with OPD valves (propane cylinders over 40#) will allow liquid through the service valve if placed on their side or inverted. Cylinders such as these are designed for vapor service only and will create a potentially dangerous situation if placed in a position other than upright which would allow liquid propane through the service valve. Consumer propane cylinders such as these use dedicated LP Gas bottle regulators that are designed for use in low BTU appliances, such as with propane gas grills.
Propane Cylinder Sizes
The dimensions presented below are approximate measurements of common size propane cylinders found in service today. The measurements are not exact so contact your propane company or container manufacturer for precise cylinder dimensions.
20 Lb. Cylinder
| Capacity (gallons) | 4.7 |
| Weight (empty) | 18 lbs. |
| Weight (full) | 38 lbs |
| Overall Height | 18" |
| Diameter | 12.5" |
| BTU Capacity | 430,270 |
- 20 lb propane tanks are the most popular size cylinder for gas grills
- Used for smaller RV's and travel trailers
30 Lb. Cylinder
| Capacity (gallons) | 7.1 |
| Weight (empty) | 24 lbs. |
| Weight (full) | 54 lbs |
| Overall Height | 24" |
| Diameter | 12.5" |
| BTU Capacity | 649,980 |
- 30 lb propane tanks are used in grilling and outdoor fryers
- Most commonly found on RV's
40 Lb. Cylinder
| Capacity (gallons) | 9.4 |
| Weight (empty) | 29 lbs. |
| Weight (full) | 70 lbs. |
| Overall Height | 29" |
| Diameter | 12.5" |
| BTU Capacity | 860,542 |
- 40 lb. propane tanks are commonly used for cooking and heating RV's.
- Used for outdoor kitchens with larger grills and more than one appliance
100 Lb. Cylinder
| Capacity (gallons) | 23.6 |
| Weight (empty) | 68 lbs. |
| Weight (full) | 170 lbs |
| Overall Height | 48" |
| Diameter | 14.5" |
| BTU Capacity | 2,160,509 |
- 100 lb. propane tanks are generally used in commercial and industrial applications
- Commonly used in mobile kitchens
- OPD is not required
Propane Cylinder BTU Capacities
The BTU capacities listed above for cylinders indicate the total number of BTU's for a full cylinder. This information is useful when determining the total appliance running time. Naturally, larger propane cylinders will allow for longer running times but sometimes larger cylinders are not practical for use in certain applications due to space, hose length, etc. To calculate the total propane bottle supply time, divide the total BTU's of the cylinder by the appliances BTU rating. Keep in mind that listed BTU appliance ratings indicate the total BTU load when the appliance is running at 100%. In other words, a gas grill with a listed rating of 50,000 BTU implies the grill will use 50,000 BTU's per hour when all burners are turned on running at capacity.