Cutting torches are central tools in metal cutting, in the deconstruction of plants, and in the demolition of steel-reinforced components. In many projects involving concrete demolition and special deconstruction, strip-out and cutting, as well as special operations, they are deliberately combined with hydraulic equipment. For example, concrete cross-sections can be opened with concrete pulverizers, while the cutting torch separates exposed reinforcement. In combination with stone and concrete splitters, steel shears, or tank cutters, this creates a plannable, safe approach for dismantling tasks with steel components.
Definition: What is a cutting torch
A cutting torch is a hand-held or machine-guided tool for thermally separating carbon and low-alloy steels using oxygen and fuel gas. The process is referred to as oxy-fuel cutting. A preheating flame brings the material along the cut line to ignition temperature. Afterwards, a concentrated jet of pure cutting oxygen oxidatively severs the steel. Typical fuel gases are acetylene, propane, or natural gas; the choice influences heating behavior, cutting speed, and surface quality. Cutting torches are used in the dismantling of steel structures, in the disassembly of tanks and vessels, and in freeing reinforcing steel during deconstruction.
Operating principle and oxy-fuel cutting process
During oxy-fuel cutting, the preheating flame creates temperatures well above the steel’s ignition temperature. The entering cutting oxygen oxidizes the heated steel to iron oxide, which is blown out of the kerf as slag. Depending on torch guidance, the cut edge shows a characteristic striation pattern and a heat-affected zone. Quality depends on nozzle setup, oxygen purity, gas pressures, torch guidance, and the condition of the nozzle.
Applications in deconstruction: interaction with hydraulic tools
In deconstruction projects, cutting torches are rarely used in isolation. The efficient approach is to combine them with hydraulic tools powered by hydraulic power packs. Concrete pulverizers open and crush concrete members so that reinforcement becomes accessible. These steel components can then be separated with the cutting torch or, alternatively, with steel shears. Stone and concrete splitters generate defined crack patterns in massive cross-sections, reducing vibration and noise and creating access points where subsequent cuts can be made on inserts, anchors, or rails. In strip-out and when cutting plant components, cutting torches are used on beams, lines, and supports; for tanks and pipelines, in sensitive situations, tank cutters or hydraulic cutting tools without an open flame are an option.
Differentiation and alternatives: cold cutting instead of flame
Thermal cutting is powerful but introduces heat, sparks, and gases. Where fire or explosion hazards exist, cold alternatives are appropriate. Steel shears and combination shears separate sections, rebar, and sheet without a flame. Multi cutters cover a wide range of materials when different cross-sections must be processed in short time. In concrete demolition, concrete pulverizers perform the bulk of the fragmentation so the material flow can be cleanly separated: mineral to mineral, metal to metal. Tank cutters are designed for the safe cutting of vessels and boilers, especially when residues or coatings must be considered. The selection depends on the material mix, the location of the component, the safety requirements, and the permissible emissions profile.
Material and process limits
Cutting torches are suitable primarily for unalloyed and low-alloy steels. High-alloy steels, aluminum, or copper alloys cannot be cut, or only inadequately, with classical oxy-fuel cutting because the oxide layer cannot be removed in a molten state. Alternative processes are used here. For galvanized or coated components, pay attention to fume generation and decomposition products. Near concrete, heating can cause spalling; therefore, concrete surfaces are opened in a controlled way with concrete pulverizers before reinforcement is cut deliberately.
Selection criteria for cutting torches and gases
The selection is based on material thickness, required cut quality, mobility, and environmental conditions. Acetylene enables very rapid heating; propane offers economical operation with a stable flame. Nozzle geometry must match plate or section thickness. High oxygen purity and stable pressures improve piercing behavior and cut cleanliness. For deconstruction work in hard-to-reach areas, compact hand torches and safe hose routing are advantageous. For continuous cutting, ergonomic torch handling is important to keep guidance stable and limit heat input.
Occupational safety and health protection
Using cutting torches requires a systematic hazard analysis. Open flame, sparks and slag, oxygen enrichment, hot parts, and gases are key risks. Personal protective equipment includes heat-resistant clothing, eye protection with an appropriate shade, gloves, and hearing protection. Extraction or ventilation is important when working on coated or oily components. In sensitive areas where ignition sources are not permitted, cold methods such as steel shears, combination shears, or tank cutters are preferable. Safety distances, firefighting equipment, controlled ignition and shutdown procedures, and regular leakage tests of hoses and fittings are essential. Compliance with relevant rules of practice and general requirements is necessary; specific requirements must always be checked on a project-by-project basis.
Process chain in deconstruction: from opening to separation
In practice, a sequential approach has proven effective: first, components are relieved and secured. Concrete pulverizers open the concrete cross-section until reinforcement is sufficiently exposed. Stone and concrete splitters introduce defined cracks to relieve stresses. The cutting torch then separates the accessible steel along marked lines. Where sparks would be critical, steel shears or combination shears take over the separation. Finally, cut interfaces are cooled or shielded in a controlled manner before components are transported away and sorted by material fractions.
Cut quality, tolerances, and rework
A good cut edge shows fine striations, minimal burr formation, and uniform heat input. Parameters such as torch angle, cutting speed, stand-off distance, and oxygen pressure directly influence quality. For thicker sections, multi-stage pierce starts and steady guidance are crucial. Rework includes removing heat tint for weld preparation, removing remaining burrs, and checking for heat-related defects on load-bearing components. In deconstruction, separability takes precedence over appearance as long as safety-relevant edges and heat effects are taken into account.
Maintenance and operating supplies
Regularly cleaned nozzles, tightly closing valves, and intact hose bundles are basic prerequisites. Pressure regulators should be checked and protected against damage. Safe work organization also includes clear separation of gas cylinders, protection against tipping, and shutting off media after work ends. Hydraulic power packs that simultaneously supply steel shears, combination shears, or concrete pulverizers should be positioned in the work area so that hose routing does not cross or become thermally stressed.
Environmental and resource aspects
Thermal cutting generates slag, scale, and gases. Organized collection facilitates recycling. By combining concrete pulverizers for the mineral fraction and cutting torches or steel shears for the metals, clean material streams are created. This reduces disposal costs and improves the recycling rate. Where possible, spark and heat shields should be used to protect adjacent components.
Limits of use in rock excavation, tunnel construction, and natural stone extraction
In rock excavation and tunnel construction, the cutting torch is not a primary tool for the rock itself. It is used there to cut steel components such as support profiles, rails, anchors, or formwork parts. Actual rock breaking and shaping is performed mechanically, for example with stone and concrete splitters. In natural stone extraction, the cutting torch plays only a minor role for metallic inserts; stone processing is performed by pressure or splitting techniques.
Planning and documentation
Robust planning includes cutting sequences, supports, load transfer, protective measures, and the interaction between thermal and hydraulic techniques. Cut lines, access points, and emergency measures should be documented and coordinated with the team. In complex deconstruction projects, a clear assignment of when concrete pulverizers, stone and concrete splitters, steel shears, or tank cutters replace the cutting torch is central to safety and pacing.
Avoiding common mistakes
Typical problems arise from oxygen pressure that is too high or too low, worn nozzles, excessive stand-off, or overly fast travel. This leads to burr formation, angled cut faces, and unnecessarily large heat input. Poorly prepared cut lines on reinforced concrete extend cutting time and increase the risk of spalling. Better is coordinated preparatory work with concrete pulverizers that clearly expose the reinforcement before cutting. Where fire protection cannot be ensured, switch to cold methods.
Quality assurance and qualification
Clean results require trained personnel, suitable equipment, and ongoing process control. Short test cuts on the original material help to fine-tune parameters. A calm, repeatable guidance and well-maintained torches are crucial, especially on load-bearing components that must be released in a controlled manner. Integrating hydraulic alternatives such as steel shears, combination shears, and concrete pulverizers improves process safety and pacing consistency.