Flowmetering Inserts

Accurate bubbler measurement for temporary monitoring sites – with no manhole entry.

Flowmetering InsertsTeledyne ISCO Flowmetering Inserts provide a quick and accurate means of measuring and recording flow in round sewer pipes. Their unique design allows you to install the metering inserts from ground level, eliminating the costs and hazards of manhole entry. 

The metering inserts are designed for use with the Teledyne ISCO 730, Signature Portable Bubbler, and 42​30 bubbler flowmeters. They are ideal for short-term (a few hours) or long-term (several weeks) flow measurement studies. 

Teledyne ISCO Flowmetering Inserts allow you to accurately measure flow from 1 to 640 GPM in pipes from 6 inch to 12 inch diameter, in manholes up to 16 feet deep.


When you purchase instruments from Teledyne ISCO, you not only receive innovative, high quality products, you also receive excellent customer service and product support. Your initial purchase is only the beginning of Teledyne ISCO's ongoing commitment to their customers.


Isco Flow Metering Inserts DatasheetDatasheet
Flow Metering Inserts System Safety and Certification SheetSafety and Certification Sheet
Flow Metering InsertsUser Manual


​​​​​​​​​​​​​​​​​Flowmetering Inserts

Equipment Provided: One Flowmetering Insert with attachable 60° V-notch weir plate and 20 ft (6.1 m) inflation/bubbler hose; Five 2.5 ft (0.76 m) pole sections; Foot pump for inflation of rubber bladder; Right angle pole
Metering Insert Sizes: 6, 8, 10 and 12 inches (150, 200, 250 and 300 mm)
Maximum Manhole Depth (approximate): 16 ft. (4.9 m)
Typical accuracy (for pipe slopes of 2 ½% or less). Maximum error for indicated flow range ​
Below 20 GPM (1.3 l/s): ±1 GPM (±0.063 l/s)
20 to 40 GPM (1.3 to 2.5 l/s): ±2 GPM (±0.13 l/s)
Above 40 GPM (2.5 l/s): ±5% of reading

Flow Rate Range

for 6" (150 mm) Flowmetering Insert ​

with V-notch weir: 1 to 90 GPM (0.063 to 5.7 l/s)
with round orifice: 5 to 180 GPM (0.32 to 11 l/s)

Flow Rate Range

for 8" (200 mm) Flowmetering Insert ​

with V-notch weir: 1 to 160 GPM (0.063 to 10 l/s)
with round orifice: 10 to 320 GPM (0.63 to 20 l/s)

Flow Rate Range

for 10" (250 mm) Flowmetering Insert ​

with V-notch weir: 1 to 230 GPM (0.063 to 15 l/s)
with round orifice: 20 to 480 GPM (1.3 to 30 l/s)

Flow Rate Range

for 12" (300 mm) Flowmetering Insert ​

with V-notch weir: 1 to 320 GPM (0.063 to 20 l/s)
with round orifice: 40 to 640 GPM 2.5 to 40 l/s

​For a full list of product specifications, see the datasheet.



Standard Features

  • Tested and calibrated by St. Anthony Falls Hydraulics Laboratory at the University of Minnesota.
  • Constructed of durable, corrosion-resistant aluminum and plastic.
  • Each metering insert includes an integral round orifice for measuring higher flow rates.
  • Attachable 60° V-notch weir plate provides higher accuracy at lower flow rates.