Give Props to Propane

Dec. 1, 2010
Liquid propane is an efficient, powerful and safe choice for fuelling lift trucks. However, managers and equipment operators need regular reminders to respect its greatest value: combustibility.

Your lift truck fleet is probably very reliable. So reliable, in fact, that it becomes easy to overlook basic things like daily maintenance and safety considerations. When it comes to propane, remembering safety is important. Fortunately the elements of propane safety are easily conveyed and easily followed.

You probably have all the necessary propane handling practices integrated into your overall safety program. Your lift truck operators know that propane is flammable. It's flammability that makes propane useful. But it also flags propane as a safety concern, and a periodic refresher about proper handling is always a good idea. Keep in mind, though, this article is not intended to replace or supersede bona-fide safety training (which should be part of any facility's standard practices).


In the United States, OSHA requires that MSDS (Material Safety Data Sheet) information be made accessible to any user of any potentially harmful substance used in the workplace. It covers chemistry, exposure risk, first aid and other essential facts. The associated risks of any chemical used in the workplace should be known by the workers before engaging in the work.

A propane MSDS should be posted and made available to everyone in the facility where propane is used. It is up to the employer to provide the resource. It is up to the workers to familiarize themselves with the material.

The Cylinders

Normally, lift trucks and similar vehicles/machines are fueled from either of two different sizes of portable and mountable cylinders. The cylinders have capacities of either 33.5 or 43.5 pounds of liquefied propane (generally referred to as 33 pounders and 43 pounders).

If the cylinders are filled by a propane supplier, and delivered as packaged propane, you can generally rely on the supplier to have filled them properly. It may be good practice to weigh each cylinder at delivery to verify proper fill (see steps below).

Some facility operators prefer to have propane delivered to a bulk supply container, and refill their own cylinders from the bulk container. This approach may have cost benefits if propane consumption is high. However, it should not be undertaken without thorough training of personnel to include:

  • Fill technique

  • Cylinder inspection

  • Bulk container inspection

  • Fill hose and valve inspection and maintenance

  • Other finer points of bulk dispensing

  • Consult your Safety Officer, propane supplier and local officials (zoning, land use, fire department, HazMat, etc.) for additional information.

Cylinders of less than 200 lb water capacity should only be filled by weight (using the standard 0.42 conversion factor, 200 lb water capacity converts to 84 lb propane capacity). Cylinders should never be filled by depending on the overfill protection device (OPD) to stop the filling process.

The fill level of any filled, in-process, or empty cylinder can be easily checked:

  1. Weigh the filled cylinder (e.g., 57.9 lb)

  2. Subtract the tare weight - typically stamped TW on the cylinder neck (e.g., 24.4 lb)

  3. The difference is the weight of the contained propane (in this example, 57.9 minus 24.4 equals 33.5 lb of propane)

Never overfill a propane cylinder — the minimal extra “runtime” between cylinder change outs is not worth the risk involved. An overfilled cylinder is a dangerous cylinder.

Liquid propane expands significantly with modest increases in temperature. An overfilled cylinder does not have room for that expansion. A cylinder that is overfilled may look perfectly safe in the shade of a storage area in the cool morning, but when that cylinder is put on a lift truck and is exposed to the hot afternoon sun, it could easily experience a 50 degree temperature increase. That will cause the pressure in the cylinder to increase and potentially cause the relief valve to activate, releasing propane into the atmosphere and causing a potential explosion risk if there is an ignition source nearby.


OSHA requires that forklifts and cylinders should be inspected before each shift. That includes all fuel connection lines and fittings. Feel for tightness and do a “sniff test” to check for leaks. Frost formation around a fitting can also indicate a leak, although it might just be a sign of usage depending on weather conditions. Always wear gauntlet style gloves approved for propane when connecting, disconnecting or checking liquid propane connections to protect from frost bite.

During inspection, be alert for any of the following conditions:

  • Internal or external corrosion

  • Denting or bulging

  • Damage to the cylinder foot ring

  • Damage to the cylinder valve or valve protection

  • Evidence of fire exposure (cylinder must be re-qualified before placing it back into service)

  • Cylinder is beyond the requalification test date (note that the contents may still be used; but cylinder cannot be refilled until requalified)

In case of any of the above, return the cylinder to the supplier for requalification. Contact your supplier before returning it because it may not be in a condition that is safe for transportation. If you ever have any question about the integrity of a cylinder, contact your supplier for guidance.


Propane cylinders should be stored:

  • In a dedicated storage location that is covered, but well-ventilated and constructed with non-combustible and minimally combustible materials (recommended: outdoors; in a covered shed with no walls; in a “cage” with cover; in a walled shed with active ventilation).

  • Indoor storage of cylinders in industrial buildings is limited to 300 lbs capacity unless special requirements are met. This is equivalent to nine 33 pounders or six 43 pounders.

  • Cylinders with more than 1 lb of capacity are not allowed to be stored in a building frequented by the public or in residences.

  • Out of direct sunlight, unexposed to weather (rain, snow, ice).

  • On a dry, well-drained surface (to prevent rust at the foot ring) .

  • At least 20 feet away from oxidizing gases.

  • Grouped separately from other flammable gases, but may be stored with other flammable gases. Note that Class 2 flammables (propane) cannot be stored with class 3 flammables (gasoline, methanol) without 20 feet separation.

  • Away from other stored chemicals, liquids.

  • Away from any other stored combustibles, such as paper or wood.

  • Away from sources of heat, cold, electricity, source of spark.

  • Away from casual traffic.

Ignition Sources

Beware of these most common sources of ignition:

  • Open flame

    • Pilot light
    • Match
    • Cigarette lighter
  • Spark

    • Electric motors
    • Flint/steel spark from cigarette lighter
    • Some thermostats
    • Some light switches
  • Vehicle exhaust system

  • Static electricity

Risk is diminished in actively ventilated areas. Risk is increased when filling on-site.

Biggest Danger: Complacency

Hold daily safety meetings. Five to ten minutes at the start of the day, discussing not only propane, but equipment, tools, facility conditions, work habits, and other things will demonstrate management's commitment to safety. So will…

  • Requiring, scheduling and enforcing regular inspections of safety and emergency equipment, as well as lift truck fuel systems. Keep written records.

  • Requiring and scheduling regular safety meetings on a larger scale than the daily meetings.

  • Setting safety goals and offering safety awards.

After all, while everyone should take responsibility for their own safety, management should set the tone and encourage good safety practices.

Dave Bertelsen is national product manager for propane at Matheson, supplier of compressed gases for industrial, welding, laboratory, and semiconductor applications. Visit

External Resources

There are many local, statewide, and regional propane associations. These associations can help you find local information on availability, fire and safety codes, and other information. Local authorities, zoning officials, and fire departments are also important resources for propane users. Here are some good places to start at the national level: