What this product reference covers.
Fire-resistant hydraulic fluids reduce ignition or flame-propagation risk in high-temperature environments and require chemistry-specific testing.
Products within the family.
Names used in commerce can overlap. Use the nominated standard and exact grade rather than relying on a generic product label.
HFA high-water fluid
HFA high-water fluid is a recognised fire-resistant hydraulic fluid category whose exact composition, grade limits and suitability must be confirmed from the governing specification and equipment requirement.
HFB invert emulsion
HFB invert emulsion is a recognised fire-resistant hydraulic fluid category whose exact composition, grade limits and suitability must be confirmed from the governing specification and equipment requirement rather than inferred from the generic label.
HFC water-glycol
HFC water-glycol is a recognised fire-resistant hydraulic fluid category whose exact composition, grade limits and suitability must be confirmed from the governing specification and equipment requirement rather than inferred from the generic label.
HFD anhydrous synthetic fluid
HFD anhydrous synthetic fluid is a recognised fire-resistant hydraulic fluid category whose exact composition, grade limits and suitability must be confirmed from the governing specification and equipment requirement rather than inferred from the generic label.
What the product is built from.
| Component | Technical role |
|---|---|
| Water carrier | Provides the continuous phase and controls concentration and freezing behaviour. |
| Active functional chemical | Delivers the product’s primary technical function. |
| Inhibitor / stabiliser package | Controls corrosion, storage stability and material compatibility. |
| Trace contaminants | Unwanted ions, solids or organics can disturb performance and equipment life. |
Define the decision before selecting the panel.
- 01
Confirm new fire-resistant hydraulic fluid identity, grade and fitness for the intended application.
- 02
Detect contamination, degradation, mixing or storage-related change.
- 03
Investigate abnormal equipment, combustion, filtration or handling behaviour.
- 04
Establish a representative baseline for later comparison.
- 05
Support specification, maintenance and root-cause decisions with corroborated evidence.
What each result contributes.
“High” and “low” are directional investigation prompts, not pass/fail decisions. Corroborate them using the correct specification, baseline and companion evidence.
Open ASTM, ISO, IS/BIS, DIN and companion methods →| Test / parameter | Typical methods | Why it matters | Possible causes when high | Possible causes when low |
|---|---|---|---|---|
| Concentration / active component | Product specification, density or refractive index | Confirms mixture strength and detects dilution or concentration. | Over-concentration, evaporation or incorrect make-up. | Water dilution, leakage, wrong product or degraded active component. |
| pH | Product-specific ASTM / ISO method | Indicates acid-base condition, inhibitor state and contamination. | Excess alkalinity, wrong additive or contamination. | Acid formation, depletion, wrong water or contamination. |
| Conductivity / ionic contamination | Product-specific conductivity method | Screens dissolved ionic material and water quality. | Salt contamination, degraded inhibitors, hard water or wrong product. | Purified formulation, dilution or depleted ionic additives. |
| Elemental / ion profile | ICP-OES, ion chromatography or product specification | Confirms inhibitors and detects contamination or component ingress. | Additive overdose, corrosion products or external contamination. | Dilution, inhibitor depletion or different formulation. |
| Appearance / insolubles | Visual, gravimetric or filtration method | Screens precipitation, corrosion debris and foreign matter. | Degradation, mixing, corrosion, biological growth or dirt. | Clean fluid; settled or unrepresentative sampling can under-report. |
| Particle count / cleanliness | ISO 11500; reporting to ISO 4406 | Quantifies solid-particle cleanliness where component clearances and servo reliability are sensitive. | Dirt ingress, active wear, ineffective filtration, maintenance debris or wrong sampling point. | Effective filtration or clean new oil; settling, dilution or non-representative sampling can under-report. |
| Foaming tendency and stability | ASTM D892; ASTM D6082 where high-temperature sequence is relevant | Screens air-handling behaviour associated with reservoir foaming, compressibility, oxidation and pump or clutch performance. | Air leaks, contamination, additive depletion, overfilling, wrong oil or poor reservoir return design. | Low foam is generally favourable; antifoam overdose can impair air release even when surface foam is low. |
| Water separability / demulsibility | ASTM D1401; ISO 6614 | Assesses the oil's ability to release water in circulating, turbine, gear and hydraulic systems. | Report as persistent emulsion or longer separation time: oxidation products, incompatible mixing, detergency or contamination. | Faster separation is usually favourable but does not prove absence of dissolved or free water. |
| Copper corrosion | ASTM D130; ISO 2160 | Screens corrosivity toward copper-containing bearings, coolers, bushings and yellow-metal components. | Reactive sulfur, acidic degradation, contamination or formulation incompatibility; report uses a corrosion rating rather than concentration. | A low corrosion rating is favourable but does not rule out in-service copper wear. |
Condition-monitoring application.
Once the product is in service, the question changes from “does it meet a product requirement?” to “what has changed, why, how confident are we and what action is proportionate?”
- 01Use a stable, representative sampling point and document operating hours, top-ups, transfers and maintenance.
- 02Trend method-consistent results rather than treating one value as a complete diagnosis.
- 03Separate new-product conformance from in-service condition and machine-wear questions.
- 04Escalate correlated evidence and rate of change; confirm surprising results before major action.