How much kPa is measured by IP protection level and how to set the parameters of the air tightness tester?

With the increasing requirements for waterproof rating in electronics manufacturing, new energy, home appliances, security and automotive industries, theIP66, IP67, IP68, IP69, etc. "High Protection Class Certification". It has become an indispensable key node for product development and mass production.

In the day-to-day production of a manufacturing company, many engineers encounter a critical problem:

The customer wants to pass IP67/IP68, but how much test pressure should I use for airtightness testing? How long does it take to equalize and stabilize the pressure? How to set the leakage limit?

This problem may seem simple, but it involves complex engineering decisions. BecauseThe IP rating defines water resistance, while the gas tightness test uses gas.--The conversion relationship between the two is far more complex than a simple pressure value.

Ⅰ. Why do IP protection ratings need to be verified with an airtightness test?

The essence of IPX7/IPX8/IPX9 waterproofing is that "the waterproofing ofExternal water pressure does not enter the product".
And there is a convertible relationship between water pressure and air pressure, so by applying theequivalent air pressureThe "air check" can simulate immersion or flushing pressures. The air test has the following advantages:

1. No damage to the product: To avoid electronic failure due to water immersion of the whole machine.
2. Fast testing speedThe speed of judgment is as fast as 3~5 seconds, which is suitable for mass production factories.
3. Quantifiable leakage: Test data more accurate than water tests(microleakage level)The
4. fully inspectable: Reduce the risk of sampling omissions and avoid the flow of defective products into the market.

Independence of Precision EngineeringFour-channel airtightness meter

Therefore, in the mass production segment, theAirtightness TesterBecome the primary means of verifying the "water resistance" of different IP ratings.The

II. Reference value of airtightness test pressure for IP66/IP67/IP68/IP69

The following pressure values are industry proven equivalent water pressure conversion values, taking into account safety margins, structural strength and line efficiency.
Suitable for most consumer electronics, home appliances, automotive and security products(If the customer has special working conditions, additional verification should be carried out)The

● IP66 (powerful water jet)

• corresponding equivalent pressure: 5~10 kPa (positive pressure)
• Recommended Testing Instruments: JC-TC SeriesStraight pressure air tightness tester/JC-LM5008 Gas Flow Detector
• Typical test duration: 5~10 seconds

IP66 is more concerned with orifice sealing under the spray and is not looking for deep water pressure, so the pressure does not need to be too high.

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● IP67 (30 minutes immersion in 1 meter of water)

1 meter depth ≈ 9.8 kPa water pressure
Considering the detection safety margin, it is recommended:

• test pressure: 10~15 kPa (positive or negative pressure)
• Recommended Testing Instruments: JC-TC SeriesStraight pressure air tightness tester/JC-FY80rangeNegative Vacuum Leak Detector
• Typical test duration: 10~30 seconds

Suitable for bracelets, watches, small electronic products, outdoor lighting equipment and so on.

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● IP68 (continuous submersion in water to a depth defined by the manufacturer)

The essential problem with this definition: There are no uniform standards.

Common Definition:

• Consumer electronics: 1.5~3 meters (15~30kPa)
• Industrial equipment: 3~5 meters (30~50kPa)
• Special applications: above 10 meters (>100kPa)

Recommended Test Pressure Range: 15 to 100 kPa (as defined in corporate standards)

• Recommended Testing Instruments: JC-TC SeriesStraight pressure air tightness tester/JC-LZ10020rangeQuantitative Air Tightness Tester
• Typical test duration: 10~40 seconds

IP68 has more stringent requirements for sealing structures and relies more on assembly consistency, so device stability must be high.

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● IP69 / IP69K (high-temperature, high-pressure flushing)

IP69(or IP69K)is the highest level of waterproofing standard.
Combination of 80±5℃ high temperature + 80~100bar flushing water.

Since water pressure → air pressure cannot be directly converted in equal proportions, the industry uses empirical values as equivalent tests:

• Recommended Test Pressure: 80~120 kPa(up to 150 kPa for some complex products)
• Recommended Testing Instruments::JC-DL2-HH100 Positive and Negative Pressure Quantitative Airtightness Tester/JC-CD10005 Differential Pressure Quantitative Air Tightness Tester
• Typical test duration: 30~60 seconds

take note of::IP69 rating must be combined with structural strength verification (pressure test)The

III. How to define valid airtightness test parameters?

1. Scientific determination of test pressure

derived formula::

Test Pressure = Operating Depth Conversion Pressure × Factor of Safety × Structural Correction Factor

Typical value of safety factor:
- Rigid structures (metal): 1.3-1.5
- Flexible structure (plastic): 1.5-2.0
- Composite structures: 2.0-2.5

Structural correction factor:
- Simple seal (single lane seal): 1.0
- Complex seals (multiple seals): 0.8
- Adhesive structure: 1.2-1.5

2. Optimization of stabilization time

Physical significance of the voltage stabilization process:Allow the gas to fully diffuse into all corners of the product interior to achieve pressure equilibriumThe

factor::

• Product Volume: Larger volume requires longer pressure stabilization time
• connection line: Long piping increases gas transfer delays
• Sealing elasticity: elastomer seals take time to recover from compression

Typical empirical values::

V < 50cm³: stabilization time 0.5-1 sec.
50cm³ < V < 500cm³: stabilization time 1-3 seconds  
V > 500cm³: stabilization time 3-5 seconds

Optimization technology from Precision Engineering: ByIntelligent algorithms monitor pressure profiles in real timeThe moment of completion of voltage stabilization is determined dynamically.Reduces stabilization time by 30~50%The

3. Trade-offs in testing time

Longer time = higher sensitivity = lower throughput

This is a typical multi-objective optimization problem in engineering.

decision model::

Optimal test time = f(Leak detection rate, production beat, misjudgment cost)

When the following conditions are met, the test time can be shortened:
1. Simple product structure and single leakage model
2. High pass rate (>99%), no need for excessive screening
3. Tight production schedules

When extended testing time is required:
1. Risk of slow leakage of products
2. Extremely high quality requirements (medical, aviation)
3. Rework costs are much higher than testing costs

4. Quantification of decision criteria

Two expressions::

style of expression (grammar)	unit (of measure)	physical meaning	Applicable Scenarios
pressure decay	ΔP (Pa or kPa)	Pressure drop value during test time	Rigid structural products
leak rate	Q (Pa-m³/s or ml/min)	Gas leakage per unit time	Flexible structures or breathable products

Experimental methods of determining the criterion::

Step 1: Prepare 10 samples of known qualification
Step 2: Prepare 10 samples with known nonconformities (manufacturing defects)
Step 3: Test separately and record data distribution
Step 4: Select the upper limit of the 95% confidence interval of the eligible samples as the decision threshold.
Step 5: Verification of Failed Sample 100% Detected

Precision Industrial Technology can provide "The best solution" in combination with the verification prototype.Limit value backcalculation services", helping customers quantify leaks more scientifically.

Ⅳ. How to choose test methods for different products?

Product Type	Recommended Testing Methods	Statement of reasons
smart wearable	Volumetric method/negative pressure method	Small cavity, high sensitivity requirements
Cell phone parts	Positive Pressure / Differential Pressure	Fast, stable and suitable for mass production
Automotive lamps and lanterns	Flow method / Differential pressure method	Large internal volume, need for stability
Battery case	Pressure Burst Test + Differential Pressure Method	High strength requirements
security camera	Volumetric method / Positive pressure method	polytope

Tens of thousands of applications in multiple industries have proven that Precision Industrial TechnologyChoosing the right test principle is more important than simply increasing the test pressure.

V. How do you establish enterprise-level IP airtightness testing standards?

Stage 1: Parameter exploration period (1~2 weeks)

goal: Finding an initial feasible range of parameters

Key tasks::

1. Collect 10-20 samples of known eligibility
2. Collection of 5-10 samples with known non-conformities (or manufacturing defects)
3. Testing the ability to discriminate under different pressures
4. Initialization of parameter ranges

Phase 2: Parameter validation period (2 to 4 weeks)

goal: Optimize parameters and verify stability

Key tasks::

1. Small lot testing (100 to 500 pieces) using preliminary parameters
2. Statistical pass rate, misclassification rate, miss rate
3. Adjustment of parameters to achieve target quality level
4. Preparation of Operating Instructions for Gas Tightness Testing

Phase 3: Parameter solidification period (1~2 months)

goal: High-volume production validation

Key tasks::

1. Full rollout to mass production lines
2. Continuous monitoring of process capability indicators such as CPK, PPK, etc.
3. Establishment of parameter change management process
4. Completion of final certification of equipment and processes

Stage 4: Continuous optimization period (long-term)

goal: Continuous improvement based on data

Key tasks::

1. Analyze test data trends on a monthly basis
2. Identify abnormal batches and trace the cause
3. Adjustment of test parameters according to product improvement
4. Regular equipment calibration and maintenance

Summarize

The parameterization of the airtightness test for IP waterproof rating is essentially aEngineering optimization issues, rather than a simple numerical lookup table.

Three core principles::

1. Understanding the nature of physics: Gas is not the same as water, and test pressure is not a simple conversion.
2. Data-based decision-making: experimentally verified rather than empirically guessed
3. Continuous optimization iterations: Parameters are not static fixed values

A core formula::

Optimization parameters = f(product characteristics, quality requirements, productivity, cost constraints)

When you are able to clearly analyze each variable of this function, you have found the most suitable parameter setting solution for your product.

If you are faced with the challenge of parameterizing an IP-rated airtightness test.Precision Engineering provides free technical consultation and parameter optimization services.We provide not only the equipment but also the methodology. We not only provide the equipment, but also the methodology.

Original Statement:this paper was written byShenzhen Jingchenggongke Technology Co., Ltd.Written by the technical team, reproduced with attribution.Data sources:Precision Engineering internal test data and customer cases.