Jacoby Tarbox FM Approved Dual Window Sight Flow Indicators — Northeast Controls Inc.
Northeast Controls Inc.

Jacoby Tarbox — Sight Flow Indicators

FM Dual Window Indicators

FM Approved · Dual Window · Class I Div 1 & 2 · Hazardous Area Installations

Jacoby Tarbox FM-approved dual sight window for hazardous locations

FM-Approved Dual Window Sight Flow Indicators

FM (Factory Mutual) approved for classified hazardous locations — Class I Division 1 & 2. Dual window design provides redundant containment and through-lighting capability. Required where flammable vapors, gases, or combustible dusts may be present.

FM-approved sight flow indicators are required in classified hazardous locations where flammable vapors, gases, or combustible dusts may be present. The FM (Factory Mutual) approval certifies that the indicator's construction will not provide an ignition source in these environments. The dual window design provides through-lighting capability for improved visibility in dark process fluids.

Available Models

Series FM-100 — FM Approved Dual Window, NPTFM Approved

FM-approved dual window sight flow indicator with NPT threaded connections for hazardous area installations. The FM (Factory Mutual) approval certifies the indicator for use in classified locations where flammable vapors or gases may be present. Dual windows allow through-lighting for improved visibility in dark process fluids.

Sizes

1/4" – 2" NPT

Pressure

150 PSI WOG

Temperature

Up to 300°F

Body

Carbon Steel standard; 316 SS available

Glass

Borosilicate glass discs (both sides)

Indicator

Viewing only; optional flapper

Series FM-200 — FM Approved Dual Window, FlangedFM Approved

FM-approved dual window sight flow indicator with ANSI 150# flanged connections. The flanged design simplifies installation and maintenance in hazardous area piping systems. FM approval covers use in Class I, Division 1 and Division 2 locations. Available in carbon steel and stainless steel.

Sizes

1/2" – 4" (ANSI 150# flanges)

Pressure

285 PSI @ 100°F (ANSI 150# P-T curve)

Temperature

Up to 500°F (material dependent)

Body

Carbon Steel standard; 316 SS available

Glass

Borosilicate glass discs (both sides)

Indicator

Viewing only; optional flapper or rotary

Series FM-300 — FM Approved, High-PressureFM Approved

FM-approved sight flow indicator for high-pressure hazardous area service. Combines the FM approval for classified locations with the high-pressure capability of the bulls-eye design. Used in refineries, chemical plants, and other hazardous area installations with elevated pressures.

Sizes

1/4" – 2" NPT

Pressure

3000 PSI WOG

Temperature

Up to 400°F

Body

Carbon Steel standard; 316 SS available

Glass

Borosilicate glass disc (heavy duty)

Indicator

Viewing only; optional flapper

FM Approval Details

ItemDetails
Approval BodyFM Global (Factory Mutual)
ClassificationClass I, Division 1 & Division 2
GroupsGroups A, B, C, D (contact for specific groups)
Temperature ClassT3 (200°C / 392°F) standard
Enclosure RatingNEMA 4 (weatherproof)
DocumentationFM certificate available upon request

Dual Window Benefits

→Through-lighting dramatically improves visibility in dark or opaque fluids
→Second window allows placement of a light source on the opposite side
→Useful for dark oils, molasses, chocolate, and colored process fluids
→Improves visibility in low-ambient-light installations
→Both windows are independently sealed and replaceable
→Available with built-in illuminator bracket for light source mounting

Hazardous Area Applications

→Petroleum refinery process lines
→Chemical plant solvent lines
→Offshore oil and gas platforms
→Petrochemical plant piping
→Fuel handling systems
→Flammable gas distribution
→Paint and coating manufacturing
→Explosive dust environments

FM-approved sight flow indicator sales & hazardous area compliance

Contact us for model selection, FM certificates, and area classification requirements.

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