Inspection of throttle equipment for hydraulic inspection - Water and Wastewater

Definition of Task: Metrologic inspection of throttle equipment according to German self-control ordination (EKVO). Verification of approved pipe volume of Q = 10 l/s (readings must not vary by more than 20 % from reference value).

Planning / Conception

  • Gathering of information on stormwater tanks and throttle equipment already before tendering
  • Visual inspection of throttle equipment
  • Inspection concept considering local conditions
  • Definition of measurement points considering accessibility and hydraulic conditions
  • Planning of work to be undertaken and selection of measuring equipment


  • Assessment of throttle equipment under operating conditions regarding condition of throttle equipment, impoundage marks, hydraulic conditions and similar.
  • Check-up of relevant dimensions (heights, lengths and cross-sectional areas).
  • Installation of measuring equipment for detection of tank filling level and throttle discharge.
  • Provoked impoundage of stormwater tank by feeding river water.
  • Comparative measurement for recording of discharge curve (characteristic).
  • Compilation of inspection documentation.


  • Verification of data and plausibility
  • Evaluation of discharge curve (characteristic)
  • Comparison between characteristic and setpoint value and calculation of deviation

Data Handover

  • Report on implementation of inspection: documentation of all applicable throttle equipment data as well as inspection methods and inspection results.
  • Catalogue of measures regarding upgrading of throttle equipment considering German ATV-A 111 regulation (an average deviation of > 60 % compared to the setpoint value has been detected).
  • Two copies of inspection certificate