UL 778 O-Rings and Seals
for Motor-Operated Water Pumps
A UL 778-certified seal is what keeps water and live current apart inside a motor-operated pump. ISMAT manufactures two UL Recognized Component compounds — an FKM and an FDA-grade NBR — independently tested by UL against the ageing, underwater cycling and electrical requirements in UL 778 and UL 157.
Send us your pump's operating temperature, water conditions and seal dimensions — our engineering team responds within one working day with the right compound and batch test report.
The seal carries the real safety load
UL 778 is the Underwriters Laboratories safety standard for motor-operated water pumps rated up to 600 volts — sump pumps, well pumps, sewage pumps, condensate pumps, fountain pumps and general water pumps used in normal locations under the National Electrical Code.
The standard doesn’t just test the pump housing, wiring and motor. It tests every gasket, seal and rubber component that keeps water away from live electrical parts. A pump cannot be certified unless its seal material independently passes UL’s ageing, underwater cycling and electrical withstand requirements — a general elastomer datasheet isn’t enough.
How UL 778 seal testing works
What a seal compound has to survive before it can carry UL Recognized Component status under UL 778.
Any part touching drinking water must be safe and rust-resistant per standard plumbing practice. Material choice starts here.
Before ageing, the rubber must stretch at least 250% at 1,500 psi. After lab-based accelerated ageing, it must retain most of that stretch and strength, with compression set held under 15%.
A submersible pump switches on and off in water continuously for 30 days, each cycle nearing the motor's maximum tested temperature.
Leakage current and dielectric withstand are rechecked after underwater, flooding and humidity tests — resistance to the metal body must stay above 50,000 ohms throughout.
What a UL-certified compound gives you
Six reasons OEMs specify UL Recognized Component material over a general-purpose datasheet.
KIFK22BN and KINB24 are tested by UL against UL 778's specific pass/fail limits — not just a generic elastomer spec sheet.
Minimal hardness, tensile and elongation shift after hot-air ageing means the seal holds its shape at the pump's real running temperature.
Both compounds hold compression set well inside UL's limits, keeping the sealing gap stable through long duty cycles.
KINB24 is formulated to FDA-grade standards for pumps in potable and process water contact.
Every production batch is tested to the same specification as the original UL submission, with reports available on request.
Manufactured under ISO 9001 and IATF 16949 quality systems, with the same revalidation data generated on every lot.
UL 778 Certified Compounds
Two ISMAT compounds carry UL Recognized Component status under Certificate No. MH66111 — Vertex FC 22BN (FKM) and Cerulean N 24 (NBR). Match the compound to your pump's water conditions and running temperature.
| Compound | Material | Key Properties | Best Suited For |
|---|---|---|---|
| KIFK22BN / Vertex FC 22BN | FKM, 70±5 Shore A, Brown (Copolymer Fluoroelastomer) | -18°C to +204°C; tensile 7 MPa min; elongation 175% min; compression set 15% max (22h @ 23°C) / 25% max (22h @ 175°C); lower volumetric swell; FDA-compliant | Submersible and non-submersible motor-operated water pumps where the seal sits near the motor winding and sees sustained running heat — sump, sewage, well and condensate pumps. |
| KINB24 / Cerulean N 24 | NBR, 65±5 Shore A (FDA-Grade Nitrile) | -40°C to +110°C; tensile 8 MPa min; elongation 250% min; compression set 50% max (22h @ 100°C); low gas permeability; FDA-compliant | Potable and general-purpose water pumps where FDA-grade material contact and wide low-temperature flexibility are required — well pumps, sump pumps, drinking-water-contact gaskets and seals. |
Trade names: KIFK22BN = Vertex FC 22BN; KINB24 = Cerulean N 24. Certified under UL Certificate No. MH66111 (issued 2023-08-04), Report References MH66111-20230803 (FKM) and MH66111-20230802 (NBR). Full TDS and batch revalidation reports available on request.
KIFK22BN / Vertex FC 22BN — Material Data
| Property | Test Method | Unit | Spec |
|---|---|---|---|
| Hardness | D 2240 | Shore A | 70±5 |
| Colour | - | - | Brown |
| Tensile Strength | D 412 | MPa | 7 (Min) |
| Elongation @ break | D 412 | % | 175 (Min) |
| Compression Set 22hrs@175°C | D 395 Method B | % | 25 (Max) |
| Compression Set 22hrs@23°C | D 395 Method B | % | 15 (Max) |
Operating temperature: -18°C to +204°C. Features: lower volumetric swell, higher resistance to a wide range of fluids under pressure, very good chemical compatibility, suitable for FDA applications. Applications: valves, pumps, mechanical seals, compressors and reactors. Product range: O-rings, backup seals, U-cup seals, X-rings, lip seals, wiper seals.
KIFK22BN — UL 778 Batch Revalidation Data (200°C Test Series)
| Property | Test Method | Unit | Spec | Observed |
|---|---|---|---|---|
| Hardness | ASTM D 2240 | Shore-A | 70±5 | 72 |
| Density | ASTM D 792 | gm/cc | 1.86±0.05 | 1.870 |
| Tensile Strength (Min) | ASTM D 412 | Mpa | 7 | 10.15 |
| Modulus @100% Elongation (Min) | ASTM D 412 | Mpa | NA | 5.93 |
| Elongation @ break (Min) | ASTM D 412 | % | 175 | 191.50 |
| Compression Set (22 hrs @ 200°C, max) | ASTM D 395, Method B | % | 25 | 14.5 |
| Compression Set (70 hrs @ 200°C, max) | ASTM D 395, Method B | % | 35 | 22.4 |
| Hot Air Ageing (70h @ 250°C) — Hardness Change | ASTM D 573 | Shore A | ± 5 | +1 |
| Hot Air Ageing (70h @ 250°C) — Tensile Change | ASTM D 573 | % | -25 | 2.5 |
| Hot Air Ageing (70h @ 250°C) — Elongation Change | ASTM D 573 | % | -50 | -17.3 |
The 200°C series is the batch data generated for UL Recognized Component testing and revalidation — run at a higher temperature than the standard published TDS to demonstrate performance margin under UL 778's ageing requirements.
KINB24 / Cerulean N 24 — Material Data (TDS)
| Property | Test Method | Unit | Spec |
|---|---|---|---|
| Hardness | D 2240 | Shore A | 65±5 |
| Tensile Strength | D 412 | MPa | 8 (Min) |
| Elongation @ break | D 412 | % | 250 (Min) |
| Compression Set 22hrs@100°C | D 395 Method B | % | 50 (Max) |
Operating temperature: -40°C to +110°C. Features: low permeability to gas, resistance to swelling by hydrocarbon oils, good abrasion resistance, better low-temperature flexibility, suitable for FDA applications. Applications: valves, pumps, mechanical seals, FDA-compliant equipment. Product range: O-rings, bellows diaphragms, gaskets, X-rings, custom-molded parts.
KINB24 — UL 778 Batch Revalidation Data
| Property | Test Method | Unit | Spec | Observed |
|---|---|---|---|---|
| Hardness | ASTM D 2240 | Shore A | 65 ± 5 | 62 |
| Density | ASTM D 792 | gm/cc | 1.1±0.05 | 1.088 |
| Tensile Strength (Min) | ASTM D 412 | Mpa | 8 | 15.30 |
| Elongation at Break (min) | ASTM D 412 | % | 250 | 416.2 |
| Compression Set (22 hrs @ 100°C, max) | ASTM D 395, Method B | % | 25 | 6.7 |
| Compression Set (70 hrs @ 100°C, max) | ASTM D 395, Method B | % | 30 | 9.2 |
| Hot Air Ageing (168h @ 113°C) — Hardness Change | ASTM D 573 | Shore A | ± 15 | +2 |
| Hot Air Ageing (168h @ 113°C) — Tensile Change | ASTM D 573 | % | ± 30 | -25.2 |
| Hot Air Ageing (168h @ 113°C) — Elongation Change | ASTM D 573 | % | -50 | -43.0 |
Batch revalidation data shows tighter compression set (6.7%–9.2%) than the published TDS spec (50% max) — the UL-tested batch performs well inside the published limit. Grade data is indicative of typical batch results; final selection depends on full operating conditions. Contact ISMAT for application-specific recommendations.
Why engineers choose ISMAT seals
KIFK22BN and KINB24 carry UL Recognized Component status in their own right — not a claim of "meets UL requirements" without independent testing.
Every production batch is revalidated against the same spec sheet shown above, with reports available on request for your equipment file.
KINB24 is available in FDA-grade formulation for pumps in potable or process water contact.
Our team helps match FKM or NBR to your pump's actual duty cycle rather than defaulting to the higher-cost option.
O-rings, gaskets, custom-molded seals and grommets supplied in standard and custom sizes in both compounds.
Every shipment is traceable to raw-material batch and manufacturing date through our ISO 9001:2015 system.
40+ years of high-performance sealing expertise
ISMAT holds UL Recognized Component certification under UL 157 and UL 778, alongside ISO 9001, IATF 16949, API 6A and NORSOK M-710 qualifications across our material range — built on decades of solving real sealing problems for OEMs.
Equipment we support
UL 778-certified seals from ISMAT are specified into a wide range of motor-operated water pump equipment. Beyond UL 778 pump duty, both compounds are also produced across ISMAT's standard product range — O-rings, backup seals, U-cup seals, X-rings, lip seals, wiper seals, bellows diaphragms, gaskets and custom-molded parts.
Frequently asked questions
UL 778 is the UL safety standard for motor-operated water pumps used in normal locations under the National Electrical Code, covering pumps rated up to 600 volts — including sump, well, sewage, fountain and condensate pumps.
A UL Recognized Component compound has been independently tested by UL against the specific ageing, compression set, underwater cycling and electrical withstand requirements in UL 778 and UL 157. A general FKM or NBR datasheet may look similar on paper but hasn’t been tested against those specific pass/fail limits.
NBR (KINB24 / Cerulean N 24) is the standard choice for potable and general water pump service across a wide -40°C to +110°C range, at lower cost and with good low-temperature flexibility. FKM (KIFK22BN / Vertex FC 22BN) is the better choice when the seal sits closer to the motor winding and sees continuous running temperature up to 204°C, or needs better resistance to a wider range of fluids under pressure. Both are FDA-compliant. Our engineering team can help match the compound to your pump’s actual duty cycle.
Yes. Every production batch of KIFK22BN and KINB24 is tested to the same specification shown above and reports are available on request for your equipment certification file.
Yes. We supply precision-molded O-rings, gaskets and custom seals directly to pump manufacturers and OEMs, working to production volumes with full lot traceability and UL Recognized Component documentation for your certification file.