Propane

At 15°C and 1.013 bar absolute, Air Liquide gives gaseous propane density of 1.899 kg/m³, so 5 kg is about 2.63 m³ of equivalent gas. That volume is on a gas reference basis. Check the actual withdrawal rate, usable supply and cylinder arrangement separately. Air Liquide property data

Identity and reference conditions

Propane (C₃H₈, CAS 74-98-6) is supplied liquefied under pressure. Specify composition, odorization and withdrawal. Airgas lists non-odorized specialty grades separately from ordinary fuel service. Airgas pure-gas catalog, propane

Air Liquide's encyclopedia gives propane's normal boiling point as approximately −42.1°C at 1.013 bar, and critical temperature as approximately 96.7°C. It lists gas density around 1.899 kg/m³ at 15°C and 1.013 bar; its liquid density of approximately 581 kg/m³ is specifically at the normal boiling point, not at room temperature. Keep phase and reference conditions attached to values. Gas volume, liquid volume, cylinder water capacity, and net fuel mass are different quantities. Air Liquide propane properties

For the stated gas conditions, 5 kg ÷ 1.899 kg/m³ ≈ 2.63 m³. Verify withdrawal capacity and cooling behavior for the actual supply. Air Liquide property data

Liquid storage and withdrawal

In vapor service, withdrawing gas lowers pressure and causes liquid to evaporate. Evaporation consumes heat and cools the contents; heat from the surroundings must pass through the container wall to sustain delivery. RegO's August 2022 field topic identifies liquid-wetted surface area, ambient temperature, and liquid level as important vapor-capacity factors. A larger regulator cannot supply heat missing from this evaporation process. RegO, Determining Propane Vapor Capacity, pp. 1–2

Pressure therefore needs interpretation alongside temperature and demand. While liquid and vapor coexist, a pressure reading is not a linear indication of remaining fuel mass. A cylinder can have fuel remaining but insufficient vapor capacity for a large heating tip in cold conditions. Size the supply using the supplier's method for the expected load, lowest temperature, and minimum operating liquid level; a room-temperature static pressure reading alone cannot establish suitability. RegO vapor-capacity guidance

Vapor withdrawal and liquid withdrawal require their respective equipment. Flame Engineering instructs users to keep vapor cylinders upright, use vapor equipment only with vapor-withdrawal valves, and use liquid equipment with cylinders designed for liquid withdrawal. It explicitly prohibits inverting a vapor cylinder to dispense liquid and applying flame to increase pressure. Identify the cylinder/valve service from its documentation before connecting it; changing orientation is not a conversion method. Flame Engineering propane information and safety

Oxyfuel process role

Propane is used for oxyfuel heating and cutting with suitable equipment. In oxyfuel cutting, oxygen reacts chemically with the hot metal; the fuel and preheat oxygen establish the necessary preheat. The cutting oxygen stream and fuel/preheat circuit perform different functions. A propane flame's ability to heat a workpiece does not by itself establish cutting capability for every material or section. Use the equipment's process and material limits. Linde oxyfuel cutting

Heating, brazing, and fusion-welding approvals are separate. A propane cutting setup does not establish approval for an acetylene welding procedure. Harris requires the torch, tip, mixer, and handle combination to agree with the fuel and operation. Harris safety and operating instructions, pp. 3–4

Fuel-specific hardware

Harris's model table gives a useful compatibility example: 62 is listed for acetylene, 62-F for propane/natural gas, and 62-E for multiple gases. Its H28/28 tip-mix torches use 2890-F tips for acetylene and 2890-P for propane/natural gas. These distinctions show why the model suffix, mixing arrangement, and tip family matter. They do not authorize arbitrary swapping among similarly shaped tips. Harris instructions, p. 3

For heating or brazing, verify the mixer marking and its fit to the handle, then select the approved tip/tube assembly. Use the manufacturer's chart for the actual fuel, tip size, thickness or heat duty, pressures, and consumption. Treat chart pressures as working conditions to be checked under the specified operating state, not interchangeable settings for any torch. Harris instructions, p. 4

Hose compatibility is another independent requirement. CONCOA specifies Grade R for acetylene only and Grade T for other fuel gases, including propane. Its legacy product listing identifies 9080425-01 as a 25 ft, 1/4 in ID Grade T twin hose for acetylene, propane, and other fuel gases. That is a bounded product example, not a recommendation that this diameter or length suits every demand. Check current hose approval, fittings, pressure rating, and pressure loss for the installation. CONCOA torch-hose specifications

Grade and composition

Do not equate commercial fuel with analytical propane. Airgas lists Research propane at 99.99%, including a 3 ppm water specification, and Instrument propane at 99.5%, including 5 ppm water. Its table states concentrations are ppm by volume unless otherwise specified and identifies these products as non-odorized with less than 1 ppm sulfurs. These are that supplier's specialty-grade specifications, not universal meanings of “propane” or LPG. Specify the contaminants and odorization relevant to the application. Airgas propane grade table and notes

A contrasting fuel-product document is Worthington's WC002 propane SDS, version 05, revised 29 June 2026. Its ingredient ranges include propane, propylene, ethane, butane, and ethyl mercaptan additive, with gas concentrations stated by volume. Those hazard-disclosure ranges are not a batch assay or a high-purity product guarantee. Obtain the supplier's applicable fuel specification or certificate when composition matters. Worthington propane SDS, sections 1 and 3

Hazards and operating boundaries

Worthington's SDS classifies its supply as extremely flammable, liquefied gas under pressure, and a simple asphyxiant. It warns of container failure if heated, oxygen displacement, and frostbite from liquid contact. It also identifies carbon monoxide exposure from incomplete combustion. Ventilation must therefore address both unburned fuel and combustion products. Use the actual supplied product's current SDS and local operating requirements. Worthington SDS, sections 2 and 16

Flame Engineering notes that LPG can collect in low areas and calls for ventilation and equipment inspection. Fuel smell warrants action under the site's leak procedure, while a non-odorized specialty supply cannot provide that warning. Confirm the gas identity, approved assembly, delivery capacity, and leak-free condition before use; follow the particular torch's lighting, shutdown, and protective-device instructions. This reference supplies selection context, not a universal pressure, flow, or startup recipe. Flame Engineering handling guidance; Airgas non-odorized grades

Related reference

Welding methods