ST98 Mass Flow Meter

Yellow FCI ST meter series; remote, box, insertion meter

Mass Flow Meter Summary

The ST98 insertion-style mass flow meter is the flow measurement solution for virtually any gas or gas mixture in line sizes from >2 inches up to 42 inches [50 mm to 1066 mm].1 With ST98, FCI combines superior, equal mass thermal-dispersion flow sensing elements and precision electronics with exacting actual fluid calibration and a choice of rugged, industrial enclosures to deliver accurate, highly repeatable flow measurement and long lasting service for the most demanding processes.

Note 1: For line sizes 2 inches [50mm] and smaller, see in-line style Models ST100L and ST75.


  • No moving parts
  • No scheduled maintenance
  • All welded wetted parts
  • Rugged, all metal enclosures
  • HART option
  • Direct mass flow measuring
  • Flow, total flow, and temperature
  • Gas temperatures to 850ºF [454ºC]
  • Integral and remote electronics versions
  • Extensive global agency approvals


Flow Range: 0.75 SFPS to 600 SFPS [0,21 NMPS to 172 NMPS] 
(Air at standard conditions of 70ºF and 14.7 psia [0ºC and 1013,25 mBar(a)].)

Accuracy: (at calibrated conditions)
  • Flow: ± 1% reading + 0.5% full scale
  • Temperature: ± 2º F [± 1º C]
  • Temperature Coefficient:
With optional temperature compensation; valid from 10% to 100% of full-scale calibration
Flow: Maximum ± 0.015% of reading/ºF up to 850ºF [±0.03% of reading/ºC up to 454 ºC]

  • Flow: ± 0.5% reading
  • Temperature: ± 1ºF [± 0.6ºC]

Turndown Ratio: Factory set and field adjustable from 10:1 to 100:1 within the calibrated flow range

Temperature Compensation: 
  • Standard: ± 30º F [± -1º C]
  • Optional: ± 100º F [± 38º C]

Agency Approvals: FM, ATEX, IEC, CSA, CRN, GOST/RTN, NEPSI, CPA, PED, CE Marking (system approvals)
Complies with Canadian Electrical code requirements of ANSI / ISA 12.27.01-2011 as a single seal device.

Calibration: NIST certified and traceable test lab calibration

MTBF (calculated): 110 Years

Flow Element

Materials of Construction: All welded 316L stainless steel or Hastelloy-C for all wetted surfaces.

Process Connection:
  • Standard: 0.75" or 1" MNPT stainless steel compression fitting with adjustable Teflon ferrule rated up to 150 psig [10 bar (g)] and 200ºF [93ºC], or metal ferrule rated up to 250 psig [17 bar (g)] and 350ºF [177ºC]

Optional: Thread-on ANSI or DIN flanges, or retractable sensing element

Insertion Lengths (Field Adjustable):2
  • 1to 6" [25 mm to 152 mm]
  • 1" to 12[25 mm to 305 mm]
  • 1" to 21[25 mm to 533 mm]
  • Customer specified fixed lengths are available; consult FCI

Operating Temperature (Process):
  • Standard: -40ºF to 350ºF [-40ºC to 177ºC]
  • Optional high temp: -40ºF to 500ºF [-40ºC to 260ºC]; 
  • Optional ultra-high temp: -40ºF to 850ºF [-40ºC to 454º C]

Operating Pressure: To 250 psig [17 bar(g)]; de-rated with Teflon ferrule

Note 2: After installation, stainless steel ferrule will be permanently fixed at the installed length.

Flow Transmitter

Operating Temperature: 0ºF to 140º F [-18ºC to 60ºC]

Input Power (Field Selectable): 85 Vac to 265 Vac, 22 Vdc to 30 Vdc; 7 watts max; 230 mA max.

  • Analog output: 4-20 mA, 1-5 Vdc, 0-5 Vdc, or 0-10 Vdc; user selectable
(mA: 700 ohm max. load; output per NAMUR guideline NE 431, field selectable for high =21.6mA or low =3.75mA. Isolated from input power in AC powered mode only.) (Vdc 100K min. load.) 
  • Digital Communications:
RS-232C Serial I/O standard.
  • Options: HART

Digital Display: Optional LCD, 2 lines by 16 characters per line. Indicates flow rate and process temperature or totalized flow (field selectable) with engineering units displayed.

Remote Configuration: Transmitter may be mounted up to 1000' [350 m] from flow element

Enclosure Options:
  • NEMA 4/IP66 rated carbon steel box, approved for installation in Nonincendive Class I, Div.2, Groups A,B,C,D and suitable for Class II, Div.2 Groups F, G; Class III, Div. 2.
  • NEMA 4X/IP66 rated aluminum box, approved for installation in Nonincendive Class I, Div.2, Groups A,B,C,D and suitable for Class II, Div.2 Groups F, G; Class III, Div. 2.
  • Hazardous location, Ex-type aluminum, approved for installation in Class I, Div.1, Groups B,C,D,E,F,G; ATEX II2, GD, Exd IIC, T4.


Model FC88: Field Programmer/Communicator. Hand-held plug-in interface used to perform instrument set-up, programming, and for trouble-shooting.

VORTAB® Flow Conditioners: For use in piping installations with inadequate straight run, inline or out-of-plane elbows, control valves or any other obstructing configurations to improve flow meter performance.


  • ATEX
  • CCoE
  • CE
  • CPA
  • CRN
  • CSA
  • FM
  • EAC/TR CU (Russia)
  • IECEx
  • IECEx Test Report
  • HART