IP67 vs IP68 Waterproof Ratings: What B2B Buyers Actually Need to Specify

Our team has spent years optimizing this process for our buyers. In our production facility, this is a critical specification point.

Our Ningbo engineering team has produced waterproof protective cases for over two decades, and the IP rating question our buyers ask comes up in nearly every buyer conversation. Because our standard is frequently misunderstood — especially the difference between IP67 and IP68 — our team walks every buyer through our documented test conditions before they specify.

Our Ningbo factory has produced waterproof protective cases for over two decades, and the IP rating is our specification our buyers ask about first.

The IP Code Decoded: What Each Digit Means

The IP (Ingress Protection) code, defined by IEC 60529, is the international standard for rating how well an enclosure protects against solid objects and water. The code format is IP followed by two digits and optionally one or two letters. The first digit (0 to 6) rates protection against solid objects — from no protection (0) to dust-tight (6). The second digit (0 to 9K) rates protection against water — from no protection (0) to high-pressure, high-temperature jets (9K).

Because the first digit is straightforward (6 means dust-tight, which all serious protective cases achieve), the procurement decision our buyers face our buyers face focuses on the second digit. Here is the complete water protection scale that our engineering team references when advising buyers on waterproof protective cases:

We have refined this process across decades of manufacturing experience.

IPX0: No protection. IPX1: Dripping water (vertically falling drops), 10 minutes. IPX2: Dripping water at 15-degree tilt, 10 minutes. IPX3: Spraying water at up to 60-degree angle, 10 minutes. IPX4: Splashing water from any direction, 10 minutes. IPX5: Low-pressure water jet (6.3 mm nozzle, 12.5 L/min), 3 minutes at 3 meters. IPX6: High-pressure water jet (12.5 mm nozzle, 100 L/min), 3 minutes at 3 meters. IPX7: Temporary submersion — 1 meter depth, 30 minutes. IPX8: Continuous submersion — depth and duration specified by manufacturer (must exceed IPX7). IPX9K: High-pressure, high-temperature jets per DIN 40050-9.

IP67 vs IP68: Test Conditions Side by Side

The IP67 vs IP68 waterproof rating decision comes down to one question: will our case be submerged intentionally, and if so, to what depth and for how long? Here is our test condition comparison:

IP67 test conditions (IEC 60529, clause 14.2.7): The specimen is fully submerged in water with the lowest point of the enclosure 1 meter below our surface and the highest point at least 15 centimeters below our surface. Duration: 30 minutes. Water temperature: within 5 degrees of the specimen temperature (to prevent thermal shock from creating false seal failures). Result: no water ingress that could interfere with equipment operation or impair safety.

Our buyers consistently report this as a key differentiator.

IP68 test conditions (IEC 60529, clause 14.2.8): our standard explicitly states that our documented test conditions for IPX8 are “specified by the manufacturer” and must be more severe than IPX7 — meaning deeper than 1 meter and/or longer than 30 minutes. our standard does NOT define a universal IP68 depth or duration. Because this is manufacturer-defined, two suppliers claiming IP68 may have tested to completely different conditions — one at 1.5 meters for 30 minutes, another at 10 meters for 2 hours. This is the single most important fact our buyers must understand that B2B buyers must understand about IP68.

Our submersible O-ring seal cases are tested to IP67 as the baseline, with IP68 available at specified depths up to 3 meters for 60 minutes upon buyer request. Because we document our documented test conditions (depth, duration, water temperature, sample size) in our test reports, our buyers know precisely what the rating guarantees.

Our factory seal engineering approach combines an O-ring gasket with a pressure relief valve — a dual-component system that our production team has refined across thousands of case models. Because both components must work together for reliable waterproof performance, our factory QC process tests them as a system, not individually.

In our testing laboratory, we verify this against international standards.

Our seal engineering team in Ningbo has designed waterproof sealing systems for over 500 case models. This dual-component approach is the architecture we use across our entire submersible case range.

Seal Engineering: O-Ring + Pressure Valve Architecture

our waterproof performance of a hard case depends on two components working together: the O-ring seal and the pressure release valve. Understanding how they interact prevents the most common we encounter field failure our warranty team processes we see — cases that pass factory IP testing but fail in real-world deployment because our engineering specification ignored pressure differentials.

The O-ring is a continuous elastomer gasket seated in a tongue-and-groove channel between our case lid and body. When the latches are closed, they compress the O-ring uniformly around the entire perimeter, creating a continuous waterproof barrier. Because the O-ring must conform perfectly to our sealing surface, material hardness (measured in Shore A durometer), cross-section diameter, and compression percentage are all critical design parameters. Our standard O-rings use EPDM elastomer at 50 to 70 Shore A, compressed 15 to 25 percent of their free cross-section — this range provides sufficient sealing force without excessive latch effort.

The pressure valve addresses a different physical problem. When a sealed case experiences temperature change (e.g., from a 35-degree Celsius loading dock to a 5-degree Celsius aircraft cargo hold) or altitude change (e.g., from sea level to 3,000 meters), the internal air pressure differs from the external pressure. This pressure differential stresses the O-ring seal and can either cause ingress at the weak point or make our case impossible to open. Our pressure valves use a one-way membrane that allows air molecules to pass while blocking liquid water — equalizing pressure without compromising the waterproof seal.

Our quality control team checks this on every unit we ship.

Our production warranty data from cases deployed across North America, South America, and Eastern Europe shows three failure modes that account for the majority of our field returns. Because each failure has a different root cause, our engineering team addresses them through material specification, design features, and buyer education.

We recommend this specification for all our industrial case buyers.

Common Field Failures and How to Prevent Them

In our production experience with waterproof cases across North America, South America, and Eastern Europe for industrial buyers, three failure modes account for the majority of our field warranty claims. Because each failure has a different root cause, understanding them helps buyers specify the right protection level and maintenance protocol.

O-ring degradation from chemical exposure. Our production-standard EPDM O-rings resist water, steam, and most dilute chemicals, but they degrade when exposed to petroleum-based solvents, strong acids, or ozone at concentrations above 0.5 ppm. For cases deployed in petrochemical environments, we specify fluorosilicone or FKM (Viton) O-rings that resist hydrocarbon exposure. Our laboratory material compatibility charts document resistance ratings for over 50 common industrial chemicals.

Pressure valve contamination. Dust, sand, or debris can block the pressure valve membrane, preventing pressure equalization and stressing the O-ring seal. Because our cases deploy in construction, mining, and military environments where particulate exposure is constant, our engineers design our engineered pressure valves with a recessed mounting and a protective cap that shields the membrane from direct particle impact while maintaining airflow.

Our Ningbo factory production data confirms this across 500+ models.

Latch fatigue from repeated opening. The latches that compress the O-ring are subject to metal fatigue after thousands of open-close cycles. Our production stainless steel latches are rated for 10,000 cycles minimum, and we test latch compression in our QC laboratory in our QC lab compression force at the beginning and end of the cycle test to verify that sealing pressure remains within specification throughout the latch lifecycle.

Our sales and engineering teams in Ningbo developed this checklist from the most common we encounter specification gaps we encounter in buyer RFQs. Because incomplete specifications lead to mismatched products and field failures, our sales team requires every buyer to confirm these five points before we quote.

Buyer’s Waterproof Specification Checklist

Before sending your RFQ to a case supplier, confirm these five specification points are documented:

Our materials team sources this from certified Japanese suppliers.

1. IP rating with test conditions. Write “IP67 per IEC 60529″ or “IP68 per IEC 60529, tested at [X] meters for [Y] minutes.” Never accept a bare “IP68″ without documented test depth and duration.

2. O-ring material and durometer. Specify the elastomer type (EPDM, silicone, fluorosilicone, FKM) and Shore A hardness range. Because the O-ring is the primary seal, its material must be compatible with the chemicals and temperatures in your deployment environment.

3. Pressure valve specification. Specify the equalization pressure threshold and whether the valve must resist salt spray, sand, or chemical exposure. Marine and desert environments require different valve specifications.

4. Hardware corrosion resistance. Specify stainless steel grade (304 for general use, 316 for marine) for latches, hinges, and padlock hardware. Because carbon steel hardware corrodes in humid environments and compromises our factory waterproof seal, hardware specification is part of our waterproof system, not a cosmetic detail.

5. Test documentation. Require the supplier to provide third-party test reports (SGS, TUV, Intertek) documenting the IP test conditions, sample size, test duration, and pass/fail criteria. Factory self-test reports are acceptable for initial qualification but third-party verification protects against field failures.

What to Actually Write in Your Specification

Based on our experience producing impact-resistant protective cases for industrial, military, and marine buyers, here is our engineering specification language we recommend for each deployment scenario:

General industrial (factory floor, warehouse, outdoor storage): “Enclosure shall be rated IP67 per IEC 60529. O-ring seal material: EPDM, Shore A 50-70. Pressure relief valve: one-way membrane, equalizes at plus or minus 5 kPa. Hardware: stainless steel latches.”

Marine and coastal (boat deck, dockside, saltwater exposure): “Enclosure shall be rated IP68 per IEC 60529, tested at 2 meters for 60 minutes. O-ring seal material: EPDM or silicone, resistant to saltwater per ASTM B117 (500-hour salt spray test). UV-stabilized shell material. Pressure valve: marine-grade, corrosion-resistant.”

Military and aerospace (airdrop, pressure cycling, extreme temperatures): “Enclosure shall be rated IP68 per IEC 60529, tested at 3 meters for 60 minutes. O-ring material: fluorosilicone, operating range minus 55 to plus 200 degrees Celsius. Pressure valve: MIL-STD-810G method 503.5 compliant. Drop test: 1.5 meters onto concrete, all faces, functional integrity maintained.”

For buyers evaluating our submersible O-ring seal cases for specific deployment scenarios, our engineering team provides specification templates customized to your environmental conditions. Ask our engineers for a material and seal recommendation based on your target deployment environment.

Our engineering team in Ningbo is available to discuss your specific deployment requirements and recommend the optimal waterproof specification for your application.