Ventilation line

The ventilation line is an inconspicuous but central component in many construction and deconstruction projects. It ensures pressure equalization, the safe discharge of gases, and the functional reliability of systems. In the context of concrete demolition, strip-out, rock excavation, tunnel construction, as well as the dismantling of tanks and pipelines, understanding the design, function, and risks of the ventilation line is essential. The same applies when using hydraulic technology such as concrete demolition shears, stone and concrete splitters, hydraulic power packs, or tank cutters from Darda GmbH, so that processes remain controlled, low-emission, and safe.

Definition: What is a ventilation line

A ventilation line (also ventilation pipe, vent pipe, or pressure equalizing line) is a line that specifically discharges or draws in air or gases from a system or medium in order to avoid negative or positive pressure. Typical applications include soil stacks and wastewater risers in buildings (roof venting), storage tanks and pipelines (tank venting), as well as hydraulic systems (reservoir and cylinder venting). Venting stabilizes flow processes, reduces odor and gas accumulation, and minimizes material stress. In safety-critical applications, the ventilation line also provides a protective function, for example through flame arresters, filters, or defined blow-off points.

Design, mode of operation, and typical materials

Ventilation lines are designed differently depending on the application. In buildings they usually run vertically as an extension of downpipes above the roof. In tanks and pipelines, they serve as intake and exhaust vents with non-return or pressure-retaining functions. In hydraulic systems, vents on the tank cap (breather filters) and bleed screws on cylinders handle air discharge.

The mode of operation is based on pressure equalization: When a medium flows in a pipe, a vacuum is created without ventilation, which can siphon traps dry or slow down flow. In tanks, vents prevent dangerous overpressure when gases expand or are released. In hydraulics, venting reduces compressible air pockets that would otherwise impair force, precision, and service life.

Material selection and equipment depend on the medium and operating environment:

• Plastics such as PVC-U, PP, or PE for residential and commercial wastewater venting
• Steel and stainless steel for industry, tank venting, and higher temperature/media resistance
• Internal devices such as breather filters, activated carbon filters, flame arresters, rain caps, and insect screens
• Pressure and flow fittings (e.g., non-return, pressure relief, vacuum valves)

Importance in concrete demolition and specialized deconstruction

In the deconstruction of buildings, service cores, and shafts, ventilation lines are a critical trade. When concrete demolition shears, combination shears, or multi cutters are used for selective dismantling, the remaining vent routing influences the function of downstream sanitary and building services risers. Unnecessary interruptions lead to odor issues, backflow, or uncontrolled gas release.

Damage prevention in selective deconstruction

• Record existing soil stacks and roof vents before starting work
• Set up temporary bypasses or auxiliary vents when risers are separated in construction phases
• Create safe endpoints (above the roof, outside occupied areas)
• Keep pipe cross-sections and flow paths clear, no constrictions due to debris
• Seal open branches with suitable plugs; do not use makeshift foil solutions

When using concrete demolition shears, the precise, low-vibration working method offers advantages for exposing, separating, or preserving vent risers and adjacent installations in a controlled manner. hydraulic rock and concrete splitters can also release components with low stress, so connected vent pipes are exposed to fewer unwanted vibrations.

Ventilation lines in tank dismantling and tank cutting

In decommissioned tanks, silos, and pipelines, flammable or toxic gases can accumulate. Properly routed ventilation lines are a prerequisite for safely discharging gases and avoiding pressure spikes—especially when tank cutters, steel shears, or concrete demolition shears are used in potentially explosive environments.

Technical focal points

• Defined blow-off point with sufficient distance from ignition sources
• Flame arresters and, if necessary, activated carbon filters to reduce emissions and odors
• Earthing/equipotential bonding of system components to avoid static charging
• Slow, controlled opening of manways combined with continuous effective venting

Process recommendation (general, non-binding)

1. Arrange for residual media removal and gas-free measurements
2. Set up a permanent ventilation line, document functional testing
3. Cordon off the work area and keep ignition sources away
4. Prefer cold-cutting methods; tank cutters from Darda GmbH provide a suitable working approach
5. Carry out cutting/separation work with continuous atmospheric monitoring

Important: Measures must always be adapted to local conditions and applicable regulations. Exercise particular caution with unknown media and deposits.

Hydraulic venting in everyday operations

Hydraulic power packs, concrete demolition shears, stone splitting cylinders, and other Darda GmbH attachments operate reliably when air in the system is minimized. Air bubbles make hydraulics “spongy,” reduce peak force, promote cavitation, and increase oil temperature.

Practical rules for hydraulic power packs and cylinders

• Keep breather filters on the hydraulic tank clean and install them dry
• Pre-fill hose lines and make connections free of stress
• Bleed at high points (position the cylinder, briefly open bleed screws)
• After maintenance: test run with slow movements, monitor temperature and noise
• In case of foaming, check oil level and viscosity; schedule oil settling times if necessary

For precise work—such as flush cutting with concrete demolition shears or force-controlled splitting with stone and concrete splitters—a cleanly vented hydraulic system is an essential quality factor.

Planning, sizing, and execution

The performance of a ventilation line depends on cross-section, routing, and internal devices. Cross-sections that are too small generate flow noise, siphon traps dry, or promote condensate formation. Long horizontal runs without slope increase the risk of standing water and reduce effective venting.

Principles

• Select cross-sections to suit demand; avoid abrupt changes of direction
• Provide slope on horizontal sections to prevent water accumulation
• Permanently seal penetrations (roof, slab) and decouple vibrations
• Protect endpoints from weather; do not place intake areas in occupied or fresh air intake zones
• For temporary routing: mechanical protection against kinking and crushing

In deconstruction and strip-out measures, routing should be considered early in the schedule to coordinate necessary bypass vents with cutting and separation work without conflicts.

Safety, health, and environmental protection

Ventilation lines influence emissions, odors, and potentially hazardous atmospheres. When working with tanks, separators, and contaminated lines, protective measures must be defined project-specifically. These include, among others, technical ventilation, personal protective equipment, and the safe routing of emissions through filters or suitable blow-off points. Statements here are always to be understood as general guidance; binding requirements arise from the applicable regulations and authority directives.

Typical mistakes and their consequences

• Unintentional disconnection of the roof vent: negative pressure, siphon emptying, odor nuisance
• Narrowed or kinked temporary setups: insufficient air exchange, backflow, and noise generation
• Missing flame arrester in tank venting: increased ignition and flashback risk
• Makeshift sealing with foil: suction, leaks, uncontrolled leakage
• Hydraulics operated without venting: loss of performance, cavitation, accelerated component fatigue

Practical notes for strip-out and cutting

In the selective dismantling of installation shafts, firewalls, and technical centers, the sequence of work steps has a major impact on safety and quality. Concrete demolition shears, combination shears, and multi cutters allow controlled separations close to lines—provided that vents are identified and secured.

Recommended sequence in existing buildings

1. Create a line register (soil stacks, vents, media lines)
2. Mark function-critical vents and plan bypass solutions
3. Expose with concrete demolition shears; release massive components with minimal vibration where possible
4. Re-clamp or secure the ventilation line, only then cut or separate
5. Document temporary setups and carry out regular visual inspections

Relation to rock excavation, tunnel construction, and special operations

In tunnel and gallery construction, temporary intake and exhaust ventilation often uses lines that carry away gases, dust, and exhaust fumes. Even if the term is used somewhat differently here than in building services, the principle applies: controlled pressure and air exchange. Where stone and concrete splitters or concrete demolition shears are used in enclosed spaces, vent and extraction lines should be routed so that exhaust gases and aerosols are reliably discharged and fresh air streams are not short-circuited.

Maintenance and documentation

Ventilation lines—whether on buildings, tanks, or hydraulic power packs—require regular inspection. This includes leak tightness, clear cross-sections, the condition of filters and internal devices, as well as checking temporary solutions during the construction sequence. Simple, traceable documentation of functional tests facilitates coordination with cutting and deconstruction trades and reduces interruptions in the project.