The firefighting water reserve is a central element of preventive and organizational fire protection – especially for concrete demolition, special demolition, building gutting and cutting, rock excavation and tunnel construction, as well as special operations. Where hydraulic demolition technology such as concrete demolition shear or rock wedge splitter and concrete splitter is used (including hydraulic rock and concrete splitters), high mechanical energies, potential ignition sources, and complex construction logistics converge. Reliably planned and with operational safety, a firefighting water reserve ensures that, in the event of an incident, sufficient water is available in the right quantity, at the right place, and at the right time – regardless of whether the initial action is taken by on-site crews or the fire department.
Definition: What is meant by firefighting water reserve
A firefighting water reserve is the deliberately maintained quantity of firefighting water kept ready for the initial attack and to bridge the time until a secured firefighting water supply is established. It can be stationary (e.g., cistern, underground tank, fire pond) or mobile (e.g., water tanks on vehicles, construction site water tanks). Unlike the general firefighting water supply (e.g., public hydrant network), the firefighting water reserve addresses object- or construction site-specific risks, defining minimum volume, required flow rate, and standby duration. It is part of the fire protection concept and integrates extraction points, pumping technology, access routes, and firefighting water retention both organizationally and technically.
Planning and sizing of the firefighting water reserve
The size and configuration of a firefighting water reserve derive from a risk-oriented assessment. Determinants include use, fire loads, spatial extent, accessibility for responders, and the time until external support arrives. For demolition, deconstruction, and cutting works the material mix, separation methods, and construction site environment significantly influence the need and provisioning form of the reserve.
- Risk profile: materials (concrete, steel, composite components), residual contents (e.g., tanks), fire sections, neighboring buildings.
- Accessibility: access roads, setup areas, hose routes, differences in elevation, tunnel portals.
- Performance data: required flow rate (L/min), minimum pressure, standby duration for the initial attack.
- Redundancy: second extraction point, alternative feed-in, emergency power supply for pumps.
- Environment: firefighting water retention, protection of soil and water bodies, separation of wastewater and rainwater.
In urban settings, the reserve can often be supplemented via high-capacity hydrants. Outside built-up areas, in tunnel or rock construction sites, and in special operations, object-specific stocks (e.g., cisterns, tanks) are the norm. Typically, standby durations for the initial attack are chosen to bridge the critical phase until a stable firefighting water supply is ensured. Instead of blanket numbers, project-specific calculation based on the fire protection concept and local requirements is recommended.
Types of firefighting water reserve and extraction points
The appropriate type of firefighting water reserve depends on project size, construction sequence, and location. Crucial are accessibility, extraction options, and safe operation across all construction phases.
- Stationary storage: underground or above-ground firefighting water tanks, cisterns, supplied fire ponds with suction points.
- Mobile solutions: water tanks on construction logistics vehicles, transportable tanks, modular containers with couplings for rapid extraction.
- Public and private hydrants: feed-in to the firefighting water line, performance test evidence, and functional fittings.
- Alternative sources: usable surface waters or wells – if legally permissible and with suitable extraction technology.
Extraction, pressure maintenance, and handover points
Extraction points must be planned so that hose routes are short, trip and collision risks are low, and signage is clear. Pressure maintenance can be achieved via pumps or elevation-related pressure gradients. Handover points to the fire department (couplings, suction points) are clearly marked and kept unobstructed.
Interface with demolition and cutting methods
Mechanical methods such as concrete demolition shear in concrete demolition and rock wedge splitter and concrete splitter in rock excavation or tunnel construction are considered low-spark methods, but they do not eliminate fire risk entirely. Hydraulic oils, energized lines, tipping points, and residual contents in components can provide ignition sources. For metal separation with shears (e.g., steel shear, combination hydraulic demolition shear, multi cutters) or when opening vessels (e.g., tank cutters), an increased firefighting water reserve for the initial attack is sensible, as embers, sparks, and heat input can occur.
- Concrete demolition and special demolition: reserve at the demolition edge and at material transfer points; consider exposure of reinforcement and spark generation from steel cutting.
- Building gutting and cutting: increased fire loads due to residual materials, temporary storage areas; short routes to extraction points.
- Rock excavation and tunnel construction: limited access, longer hose runs; cisterns or feed-in points at tunnel portals.
- Special operations: work on tanks, coated components, or hard-to-access structures requires adjustments to flow rate and standby duration.
Dust suppression versus firefighting water reserve
Water used for dust suppression is not a substitute for the firefighting water reserve. Both needs must be planned separately so that, in the event of a fire, the initial attack is not impaired by parallel dust suppression.
Firefighting water retention and water protection
In an incident, firefighting water can be contaminated with hazardous substances, fine dust, and leachates from construction materials. Therefore, proactive firefighting water retention is an essential part of planning. The aim is to prevent contamination of soil and water bodies and to control orderly runoff.
- Area management: sealing of exposed zones, directing runoff, preventing uncontrolled discharge into sewers or water bodies.
- Retention volume: dimensioned basins or mobile barriers that can be activated at short notice.
- Separation: clear separation of rainwater, wastewater, and potentially contaminated firefighting water.
- Disposal: organizational provisions for pumping out, interim storage, and proper disposal after the operation.
Special aspects in deconstruction
In deconstruction, legacy substances, coatings, or built-ins may contaminate the firefighting water. This is taken into account in the hazard assessment; measures for retention and disposal are defined in advance and coordinated with responders.
Operation, maintenance, and documentation
Reliable availability of the firefighting water reserve requires clear responsibilities, regular inspections, and robust documentation. This applies to both stationary and mobile systems.
- Inspections: fill level, tightness, accessibility, function of fittings and couplings, signage.
- Functional tests: extraction and delivery tests under realistic conditions; logging of results.
- Winter operation: frost protection, heating or circulation, protection against icing at extraction points.
- Hygiene and separation: no connection to drinking water installations; backflow prevention and clear marking of non-potable water.
- Documents: site plans, hydrant and extraction point plans, contact lists, response and alarm procedures.
Practical planning: step by step
- Risk assessment: record use, fire loads, construction phases, accessibility, and response times.
- Demand derivation: define volume, flow rate, standby duration, and redundancies.
- System selection: define stationary or mobile storage, extraction points, and pumping technology.
- Retention: size firefighting water retention and runoff control and anchor them organizationally.
- Integration: embed into construction site and operational workflows; ensure signage and unobstructed access.
- Trial: functional tests with responders; adjust plans after testing.
- Maintenance: regular inspections, seasonal protective measures, and updated documentation.
Technical key figures and verification
Clear key figures are required for planning, procurement, and operation: reserve volume (liters/cubic meters), required flow rate (liters per minute), minimum pressure at the extraction point, standby duration (minutes), as well as extraction points with hose lengths and elevation profiles. Verification includes location and schematic drawings, inspection and functional test records, details on retention, and coordinated response procedures. Changes in the construction sequence are tracked so that extraction points and access routes remain usable in later phases.
Reference to products and application areas of Darda GmbH
In projects with concrete demolition shear in concrete demolition and special demolition, a nearby, well-marked, and always unobstructed extraction point is advisable, as fire sources often emerge at the separation point or at material transfer. When using rock wedge splitter and concrete splitter in rock excavation or tunnel construction, the distance to the firefighting water reserve is often greater; accordingly, intermediate extraction points or mobile tanks are sensible. Cutting operations on steel beams or tanks (e.g., with steel shear, hydraulic demolition shear, multi cutters, or tank cutters) require increased attention to the initial attack reserve due to potential spark formation and heat input, as well as to firefighting water retention, since metallic dusts and residual substances can enter the firefighting water. In building gutting and cutting inside existing buildings, building physics, shafts, and escape routes additionally influence the arrangement of extraction points and the standby duration.
Example scenarios from practice
- Concrete demolition on a multi-story existing building: reserve at the crane location, second extraction point near the demolition edge, short hose routes via intermediate floors.
- Tunnel heading with rock wedge splitter and concrete splitter: cistern at the portal, mobile storage in the tunnel center, pressure maintenance via intermediate pump; dedicated retention at the low point — see rock demolition and tunnel construction.
- Opening a steel tank: increased standby duration, two independent extraction points, blocking of surface runoff, and prepared retention means.
Roles, responsibilities, and coordination
Defining the firefighting water reserve succeeds through close coordination between the client, planners, contractors, fire protection officers, and local responders. Responsibilities for maintenance, inspections, keeping areas clear, and replenishment are clearly regulated. Drills increase operational confidence and reveal optimization potential in setup and extraction.