Compressed air line

Compressed air lines form the central infrastructure for pneumatics on construction sites, in workshops and underground. In the context of concrete demolition, special demolition, rock excavation, tunnel construction and natural stone extraction they ensure the supply for cleaning, control and drive tasks. Even though Darda GmbH’s core processes – such as the use of concrete demolition shears as well as rock and concrete splitters – are hydraulic, the compressed air line plays a supporting role: from blowing out boreholes to supplying pneumatically driven hydraulic power units to tool maintenance and safe, efficient operation in special deployments.

Definition: What is meant by a compressed air line?

A compressed air line is a pipe or hose system for distributing, storing and regulating compressed air. This includes stationary networks (e.g., as a ring main with take-offs) as well as mobile hose lines with couplings, manifolds, shut-off and safety elements. Typical operating pressures in construction and deconstruction range between 6-10 bar. A compressed air network often includes filters, water separators, dryers, pressure regulators and optional lubricators to ensure quality (particles, moisture, oil content) and pressure stability. The design is based on volume flow demand, permissible pressure drop, line lengths, environmental influences and operational safety requirements. For air quality, internationally used classes according to ISO 8573-1 define particle, water and oil limits; the pressure dew point should be selected with adequate margin to ambient conditions to prevent condensation and icing.

Core aspects of a practice-oriented compressed air line in demolition and tunnel construction

For rugged applications – such as in concrete demolition, rock heading or natural stone extraction – the compressed air line must be mechanically robust, operationally safe, well drained and energy efficient. Key factors are a sufficiently sized cross-section for low pressure losses, reliable couplings with venting and check functions, suitable materials (galvanized steel, stainless steel, aluminum or plastic pipes as well as abrasion-resistant hoses) and air treatment that delivers dry, clean air. Working together with Darda GmbH’s hydraulically operated products – especially concrete demolition shears and rock and concrete splitters – the compressed air line supports blowing out drill dust, operating pneumatically driven hydraulic power units in sensitive areas, cleaning tools and pressure control for consistent process quality. In potentially ignitable atmospheres, antistatic or conductive hose grades and equipotential bonding contribute to reduced ignition risk.

Requirements from the perspective of concrete demolition shears and stone and concrete splitters

With concrete demolition shears, stone splitting cylinders and stone and concrete splitters, hydraulics take center stage. Nevertheless, the compressed air supply directly affects process reliability – for example through borehole cleaning, air-hydraulic drives and the provision of service air.

Borehole cleaning and dust management

For controlled splitting of concrete or rock, precisely and thoroughly cleaned boreholes are essential. Compressed air is used to blow drill dust and fine particles out of the hole before inserting stone splitting cylinders or wedges. This increases the reproducibility of the splitting effect, reduces sliding or jamming situations and supports tool service life. An adequate flow rate and a well-routed hose line (kink-resistant, abrasion-resistant) are crucial for this.

• Use blow-out tubes or lances with checkable flow to ensure repeatable cleaning depth and coverage.
• Combine blowing with dust extraction or wet suppression where required by site policy to minimize airborne dust.
• Secure hoses with whip checks and vent before disconnection to prevent uncontrolled motion.

Pneumatically driven hydraulic power units

In special deployments – for example in potentially explosive atmospheres or in sensitive indoor environments – air-driven hydraulic power units are often used to safely power Darda GmbH hydraulic tools (e.g., concrete demolition shears, combination shears, multi cutters, steel shears or tank cutters). The compressed air line must provide a stable supply pressure and the required volume flow and be operated free of condensate in order to avoid pressure drops and icing.

• Supply stability: Maintain working pressure with minimal fluctuation at peak flow; place regulators close to the unit.
• Dryness: Select a pressure dew point sufficiently below ambient (rule of thumb: at least 10 K margin) to mitigate icing at throttles and motors.
• Cleanliness: Particle and oil limits aligned with the pneumatic motor’s specification, typically per ISO 8573-1 class selection.

Design: volume flow, pressure drop and nominal sizes

Sizing is based on the sum of consumers, line length, number of couplings and fittings, and the permissible pressure differential at the most remote take-off point. The goal is to keep the working pressure at the consumer nearly constant at full load.

• Keep routing short and straight; avoid unnecessary bends, restrictions and couplings.
• Prefer ring mains to minimize pressure drops and provide redundancy.
• Select nominal size with regard to volume flow; increase cross-section over long distances.
• For mobile applications, provide sufficiently large hose cross-sections (e.g., 3/8″, 1/2″, 3/4″) depending on demand and length.
• Place pressure regulators close to the consumer to balance fluctuations.
• Limit total pressure drop to a defined budget (e.g., 0.3-0.5 bar) between compressor and point of use.
• Use equivalent-length methods for fittings and couplings when estimating frictional losses to avoid undersizing.

Illustrative example

If an air-driven hydraulic power unit requires a high volume flow at 6-8 bar and the compressor is 40-60 m away, generously sized main hoses, few couplings, a ring main (if stationary) and a downstream regulator are advisable. This keeps the working pressure for the hydraulic tools – such as concrete demolition shears – stable and reduces energy consumption by avoiding excessive compressor setpoints.

Material selection and connection technology

The environment determines the material choice: damp tunnels, abrasive dust and weather exposure place high stress on lines and couplings. Material compatibility with lubricants, cleaning agents and ambient conditions is essential to prevent premature aging.

Pipe systems for stationary networks

Galvanized steel or stainless steel pipes are robust and durable; aluminum composite pipes are lightweight and corrosion resistant. Plastic pipes (e.g., PA, PE) offer easy installation but require protection against UV, impact and high temperatures. Metallic push-fit or press systems speed up installation and allow modular extensions. For metals, ensure internal surface quality to minimize friction and particle release; for plastics, verify temperature and pressure ratings with adequate safety margin.

Hose lines for mobile applications

Abrasion-resistant, oil- and cold-resistant hoses with kink protection are standard on construction sites. Safety couplings with venting function reduce whipping hazards. Check valves, dust caps and strain relief sleeves increase operational safety and service life. Color coding or clear labeling supports correct allocation of pressure levels and circuits, particularly on multi-tool manifolds.

Layout, ring main, branches and slope

Ring mains supply take-off points from two sides and improve pressure stability. Where possible, branches are tapped from above to prevent condensate carry-over. On long runs, a slight slope with condensate collection points and automatic drains is useful. In frost-prone areas, place drains at protected low points and consider heated or insulated sections to avoid ice formation.

Manifolds and take-off points

Take-off points are equipped with filter-regulator units, pressure gauges and easily accessible shut-off valves. For rough applications, mechanical protection of the fittings against vehicle impact and blows is recommended.

• Provide isolation per outlet and include non-return elements to prevent cross-flow between consumers.
• Use clear identification (tags, QR-based documentation) for pressure level, air quality class and last inspection date.

Air treatment: filtration, drying and pressure regulation

Clean, dry air reduces malfunctions, corrosion and icing. In tunneling and winter operations, drying is especially important.

• Filtration: Particulate and coalescing filters protect valves, regulators and air motors.
• Condensate management: Water separators, automatic drain valves, correct slope.
• Drying: Refrigeration dryers for general applications, adsorption dryers for low pressure dew points.
• Pressure regulation: Stable setpoints close to consumers mitigate load changes.
• Lubrication: Only where air motors require it; otherwise operate oil-free.
• Dew point strategy: Select a target dew point at least 10 K below the lowest expected ambient temperature in the line to prevent condensation.
• Monitoring: Install differential pressure indicators on filters and dew point sensors on critical sections for proactive maintenance.

Safety and testing

Safe operation of compressed air lines is essential. Lines are pressurized, can whip, and can accelerate particles. Protective measures are therefore an integral part of planning.

• Use safety couplings and lanyards to counteract whipping.
• Inspect hoses regularly; replace damaged components immediately.
• Vent before uncoupling; provide depressurization at take-off points.
• Secure lines against tripping and vehicle impact; use marking.
• Carry out inspection intervals and pressure tests according to generally accepted rules of engineering practice.
• In sensitive areas (e.g., possible explosive atmosphere) use only suitable power units, lines and couplings; the applicable regulations must always be observed.
• Align the design and operation with recognized rules for pneumatic systems (e.g., principles from ISO 4414) and with applicable pressure equipment requirements.
• Document pressure tests, leak checks and corrective actions to maintain traceability over the lifecycle.

Personal protective equipment

Eye and hearing protection, gloves and dust-capable respiratory protection systems are common – depending on task and environment. When blowing out boreholes at high flow velocities, suitable PPE significantly increases safety. For impact protection, use safety glasses with side shields or face shields and select hearing protection with appropriate SNR values for the measured sound levels.

Operation, maintenance and efficiency

Leaks waste energy and performance. An efficient compressed air network increases the readiness of hydraulic tools and reduces operating costs.

• Leak detection: Check regularly (audible and measurable) and rectify leaks promptly.
• Optimize pressure level: As high as necessary, as low as possible.
• Run-on and shutdown: Avoid unnecessary compressor idling.
• Spare parts management: Keep couplings, seals and hoses in stock.
• Documentation: Record network layout, pressure points, inspections and changes.
• Condition monitoring: Track compressor energy, flow and pressure profiles; use ultrasonic leak detection for targeted repairs.
• Filter and dryer service: Replace elements based on differential pressure and hours; verify dew point after service.

Typical scenarios in the fields of application

Concrete demolition and special demolition

During building gutting, the compressed air line supplies blow guns for boreholes and cleaning tasks, while concrete demolition shears cut and crush hydraulically. Short, large-diameter hose lines and well-placed regulators keep airflow stable, and dust is removed in a targeted manner. Where multiple teams work in parallel, manifolds with clearly assigned outlets prevent bottlenecks.

Rock excavation and tunnel construction

Underground, long line routes are common. Ring mains or generously sized main runs with branches ensure supply over long distances. In rock demolition and tunnel construction, dust-free, dry blowing of boreholes is essential; air-driven hydraulic power units benefit from dry, condensate-free air to avoid icing and pressure drops. Corrosion-resistant materials and protected routing extend service life in wet, abrasive environments.

Gutting and cutting

In indoor environments with limited ventilation, oil-free, dry compressed air is recommended for cleaning and service tasks. If a Darda GmbH hydraulic tool – such as a concrete demolition shear, combination shear, multi cutter or tank cutter – is fed by an air-driven power unit, short line routes and a sufficiently large hose cross-section are crucial for performance stability. Noise control and point extraction help maintain occupational hygiene limits.

Natural stone extraction

In the quarry, dust and weather challenge compressed air components. Abrasion-resistant, cold-flexible hoses, robust couplings and dust caps increase availability. Blowing out boreholes for stone splitting cylinders remains a key step for reproducible splitting results. Protective routing and periodic inspection reduce downtime in exposed areas.

Special deployment

In sensitive areas – such as potentially ignitable atmospheres – the compressed air line can provide a safe drive source for hydraulic power units. Material selection (e.g., stainless steel), conductive hose grades, suitable couplings and controlled grounding contribute to an overall safe system. Specific requirements are always based on the generally accepted rules of engineering practice and the applicable regulations.

Remote and temporary sites

For short-term operations or hard-to-access zones, modular manifolds and preassembled hose sets accelerate setup. Quick verification of pressure at the point of use with compact gauges prevents underperformance due to line losses.

Planning and practice checklist

The following overview summarizes key steps for reliable compressed air supply – from concept to operation in conjunction with Darda GmbH hydraulic tools:

1. Determine demand: volume flows, pressure, simultaneity, line lengths, operating environment.
2. Plan the network systematically: prefer a ring main, take-offs from above, condensate collection points.
3. Define nominal sizes: design cross-sections to pressure-drop limits, minimize the number of couplings.
4. Specify air treatment: filter stages, water separators, dryers, pressure regulators, optional lubrication.
5. Select materials: corrosion and abrasion resistance, cold flexibility, protection against mechanical impacts.
6. Implement the safety concept: safety couplings, venting, fastening, PPE, inspection intervals.
7. Installation and commissioning: leak test, flushing, pressure setting, functional test at the consumer.
8. Operation and maintenance: leak program, filter and condensate management, documentation, training.
9. Verify performance under peak load: measure flow and pressure at the most remote take-off and adjust if necessary.
10. Review after initial operation: evaluate energy, stability and wear data to fine-tune settings and components.