Water - simulation and calculation
Gas - simulation and calculation
Heating and cooling - simulation and calculation
Chemical products - simulation and calculation
Kaverne - Simulation und Berechnung
Oil - simulation and calculation
Waste water - simulation and calculation
Steam - simulation and calculation

Areas of application, objectives & benefits

SIR 3S® has been the leading tool for the calculation, simulation, analysis and optimization of flow processes in gas/water/heat supply networks, plants, pipelines and caverns for 35 years now.

  • Steady-state and transient calculations for water and other fluids, gases and steam
  • Optimize network structures and operating procedures
  • Experience offline and online simulations from a single source
  • Understand all aspects of your networks, plants, pipelines and caverns by mapping them as a digital twin
  • Analyze, evaluate and ensure security of supply and quality of supply

Program features

SIR 3S® offers a variety of different calculation options ranging from analyses of the actual state to planning calculations for individual operating and expansion states as well as transport calculations and questions for operational simulations and automation.

Model creation

  • Import functions for data from GIS and CAD as well as LSO standards (elevation, house coordinates) and data from commercial billing (address, consumption or load)
  • Model workshop with extensive functions for automated merging of the different data sources
  • Network level for the correct modeling and representation of the pipe system
  • Block level for modeling stations as flow schemes
  • Mapping of automations via a control signal model
  • Interfaces for bidirectional data exchange of object data, transaction data (processing of measured values, setpoints, messages) and with other network calculation programs

Hydraulic elements and other objects

  • Elements for water and other liquids
  • Elements for heating and cooling systems
  • Elements for gas
  • Control signal model
  • Graphic and informative elements

Analysis of the actual state

  • Network topology analyses
  • Daily and annual cycle calculations / annual duration curve (full load to low load)
  • Detailed station modeling
  • 3D view

Planning calculations (individual operating and expansion states)

  • Design calculations / dimensioning
  • Consideration of minimum supply pressure / sufficient differential pressure
  • Capacity calculations, e.g. fire water plans, flushing plans
  • Nominal diameter optimization
  • Brown-field and green-field calculations
  • n-1 supply reliability

Transport calculations

  • Quality parameter spreading
  • Mass and heat transport
  • Heat losses due to exchange with the environment / heat storage
  • Heating due to exchange with environment (drinking water networks, cooling networks)
  • Flow times (“water age”)
  • Spheres of influence, source spectra

Pressure surge calculations

  • Proof of plant safety (avoidance of excessive pressure, negative pressure/cavitation, vibrations)
  • Determination of forces from pressure surge
  • Simulation of pressure surge triggering events (pump switching / pump failure / valve strike, turbine switching / load shedding, opening / closing of valves in the flow path, sudden volume flow changes due to large withdrawals, e.g. opening / closing of hydrants, leakage / pipe rupture)
  • Dimensioning and verification of the effectiveness of pressure surge protections (pressure wind tanks / hydrophors / membrane containers / vessels, safety valves and control valves / aerators / vacuum breakers, pump protection / check valve damping, valve transit times (OPEN/CLOSED/STOP) / throttle characteristics)

Operational simulations and automation

  • Characteristic curve calculation for pumps, turbines and control valves
  • Simulation of operating strategies
  • Simulation of control concepts (ideal and real control behavior)
  • Determination of optimum operating modes under consideration of restrictions (pumps / valves / vessels / supply pressure / differential pressure)
  • Online simulation / in-process / optimization proposals / What-If
  • Interactive simulation / training simulators


Single-user, multi-user, and floating-user are available license types.
License options are purchase, hire-purchase and leasing – including access to the 3S helpdesk and regular updates with an active maintenance contract.



You can be trained by 3S engineers directly in the use of SIR 3S in your models on a daily basis – on-site at your location, at a 3S location or online as a web meeting.



You, as a user, license and maintenance customer, talk to 3S engineers in the helpdesk who work on similar, if not the same, tasks every day with the same tools.