How often should extinguisher gauges be replaced?

Replace at every 5-year refill as a best practice. Replace immediately if the lens is cracked, the pointer is stuck, the dial face is faded or illegible, or the gauge reading is inconsistent with actual cylinder pressure.

What does it mean if the gauge reads in the green but the extinguisher feels light?

A gauge reading green on a suspiciously light extinguisher may indicate a stuck pointer (internal mechanism failure) or a slow leak where pressure is maintained but agent has been expelled. Weigh the extinguisher and compare against the gross weight on the IS plate. If under-weight, tag it for service immediately.

Should I use glycerine-filled gauges?

Glycerine-filled gauges are recommended for extinguishers mounted on vibrating equipment (generators, compressors, vehicles) or in humid/marine environments. The glycerine dampens needle vibration and prevents internal condensation that fogs the lens.

Can I calibrate a faulty gauge in the field?

No. Bourdon-tube gauges are factory-calibrated mechanical instruments. A faulty gauge must be replaced, not adjusted. Attempting to bend the pointer or adjust the mechanism will create a dangerously inaccurate reading.

What is the correct gauge range for my extinguisher?

Match the gauge range to the extinguisher's working pressure: 0–20 bar for most stored-pressure ABC/BC units, 0–28 bar for high-pressure stored-pressure models, and 0–35 bar for CO₂ extinguisher valve gauges (rare). The green band must be centred on the OEM-specified charge pressure.

How do I incoming-inspect a batch of gauges?

Take a 5 % random sample, connect each to a calibrated dead-weight tester or reference manometer, pressurise to mid-green, and verify the reading is within ±2.5 % of the reference. Reject the entire batch if more than one sample fails.

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Fire Extinguisher Pressure Gauge – Bourdon Tube (Colour-Coded Dial)

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Product Details

TypeBourdon tube, direct-reading

Dial Diameter25 mm / 37 mm

Pressure Ranges0–20 bar / 0–28 bar / 0–35 bar

Colour ZonesRed (low) – Green (OK) – Red (high)

Connection¼″ BSP male thread

Case MaterialChrome-plated steel

LensAcrylic / polycarbonate

Bourdon ElementPhosphor-bronze / BeCu

Accuracy±2.5 % full scale (Class 2.5)

Glycerine FilledOptional (for vibration / marine)

StandardIS 3624 / EN 837-1

PackagingBox of 10 / 50 / 100 pcs

Extinguisher Replacement Parts

Fire Extinguisher Pressure Gauge – Bourdon Tube (Colour-Coded Dial)

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Description

The pressure gauge is the only visual indicator of an extinguisher's readiness. A single glance at the dial tells the inspector, the building occupant, and the fire auditor whether the unit is charged, over-pressured, or has lost its propellant. In monthly inspections per IS 2190, the very first checkpoint is: "Is the gauge needle in the green zone?" A missing, fogged, or stuck gauge is an automatic service tag.

This bourdon-tube gauge is a direct-reading mechanical instrument. A curved phosphor-bronze or beryllium-copper tube (the "bourdon tube") flexes proportionally with internal pressure, driving a gear-and-pinion mechanism that rotates the pointer across a colour-coded dial. The design requires no power supply, no electronics, and no calibration equipment in the field—it simply works, reliably, for years.

The dial face is divided into three zones: a red zone (under-charged) on the left, a wide green zone (service pressure) in the centre, and a red zone (over-charged) on the right. Typical service-pressure ranges are 14–16 bar for stored-pressure ABC/BC extinguishers and 8–12 bar for water and foam types. The gauge range is selected to match the extinguisher working pressure, with the green band centred on the nominal charge pressure.

The connection thread is ¼″ BSP male, fitting standard valve gauge ports. A brass adapter ring may be required for certain older valve models. The gauge case is typically 25 mm or 37 mm diameter, chrome-plated steel, with an acrylic or polycarbonate lens. For outdoor or marine applications, glycerine-filled variants are available—the glycerine dampens vibration-induced pointer flutter and prevents lens fogging.

Gauges should be replaced at every 5-year refill, or immediately if the lens is cracked, the pointer is stuck, the dial face is discoloured, or the gauge reads green on an obviously discharged or leaking extinguisher (indicating internal mechanism failure). A stuck gauge is more dangerous than a missing one—it provides false assurance.

For quality assurance, incoming gauges should be batch-tested against a calibrated reference manometer. A random sample of 5 % of each batch, pressurised to mid-green and compared against the reference, is sufficient to catch manufacturing defects before they enter service.