How to Ensure Compliance with ASTM B117 Salt Spray Testing

A Practical Guide Supported by ASTM B117 Salt Spray Corrosion Chamber Design

ASTM B117 is one of the most widely referenced salt spray corrosion test standards in the world. It is commonly specified for evaluating the corrosion resistance of metallic materials, coatings, and surface treatments across industries such as automotive, electronics, industrial manufacturing, and surface finishing.

However, conducting a salt spray test does not automatically mean the test is ASTM B117–compliant.

In practice, many unreliable or disputed test results are caused by:

• Inaccurate salt solution preparation
• Unstable chamber temperature
• Uneven salt fog distribution
• Unverified salt spray deposition rates

ASTM B117 compliance depends on whether the entire test process-not just individual parameters-is controlled and verifiable. This places clear demands on both test procedures and the design of the salt spray corrosion chamber.

ASTM B117 defines a continuous neutral salt spray (NSS) test with tightly controlled environmental conditions. Its purpose is to provide repeatable and comparable corrosion exposure, rather than to directly predict real-world service life.

Key requirements include:

• Salt solution concentration: 5% sodium chloride by mass
• pH value: 6.5–7.2
• Chamber temperature: 35 °C ± 2 °C
• Salt spray deposition rate: 1–2 mL/80 cm²·h
• Continuous operation without drying or cycling

To meet these requirements consistently, the chamber must support stable operation, precise monitoring, and practical verification throughout the test duration.

ASTM B117 testing is widely used for comparative corrosion resistance evaluation, especially during product development, quality control, and supplier qualification.

Common application areas include:

Automotive and EV components (fasteners, brackets, housings, connectors)

Surface coatings and plating (electroplating, anodizing, passivation, paint systems)

Electronics and electrical enclosures

Industrial hardware and construction materials

In all these applications, the credibility of test results depends on how accurately and consistently the ASTM B117 test environment is maintained.

ASTM B117 compliance is not achieved by a single setting. It is the result of a controlled testing process in which solution preparation, temperature, spray generation, and verification work together as a system.

The following sections explain how each key step of the ASTM B117 test process is supported by ASTM B117 salt spray corrosion chamber design.

ASTM B117 specifies a 5% sodium chloride solution by mass, with strict control of concentration and pH value.

To support this requirement, the chamber is equipped with a dedicated salt water tank with a built-in brine mixing system:

The salt solution is mixed in the tank and delivered by compressed air

Concentration is maintained at 5 ± 1% NaCl by mass

The pH value is controlled within 6.5–7.2, in accordance with ASTM B117

This configuration helps maintain consistent salt solution conditions throughout long-duration tests and reduces variability caused by manual preparation.

ASTM B117 requires the chamber temperature to be maintained at 35 °C ± 2 °C during continuous salt spray exposure.

The chamber supports this requirement through:

A heating system suitable for salt spray environments

PT-100 Class A temperature sensors for continuous monitoring

A PID programmable controller to regulate temperature

By continuously monitoring and adjusting the chamber temperature, the system helps ensure stable test conditions throughout extended testing periods.

Uniform salt fog distribution is essential for ASTM B117 compliance.

Salt fog is generated and distributed using:

A salt spray tower that mixes compressed air (preheated to 35 °C ± 2 °C) with the salt solution

Quartz nozzles selected for corrosion resistance and high-temperature stability

A controlled spray pressure of 83 kPa, meeting ASTM B117 requirements

The spray volume can be adjusted by changing the height of the spray tower, allowing operators to maintain consistent fog conditions inside the chamber.

ASTM B117 requires verification of salt spray deposition using collectors placed inside the chamber.

The chamber is equipped with salt spray collectors connected to measuring cylinders, allowing operators to:

Observe and record salt spray deposition during testing

Verify compliance with the required 1–2 mL/80 cm²·h deposition rate

Retain measurement data for test reports and audit purposes

This direct measurement method ensures that compliance is documented, not assumed.

ASTM B117 is a continuous exposure test, often running for hundreds or thousands of hours.

To support long-term operation in a corrosive environment, the chamber is designed with:

Structural materials suitable for salt spray testing

A sealed lid structure to reduce salt spray leakage

Durable spray components intended for continuous use

This construction helps maintain stable performance over time and reduces the risk of test condition drift during long-duration testing.

To translate process control into reliable operation, the ASTM B117 salt spray corrosion chamber integrates functional components designed specifically for ASTM B117 testing.

1. Salt spray tower with adjustable height and controlled spray pressure
2. Salt water tank with built-in brine mixing system
3. Quartz nozzles for stable atomization in corrosive environments
4. Salt spray collectors for deposition verification
5. Workroom with flexible sample holders, including V-grooves and round rods
6. Pneumatic open/close lid for consistent operation
7. PID touchscreen controller with multi-language support and Ethernet connectivity
8. PT-100 Class A temperature sensors for stable temperature monitoring

The following sections explain how each key step of the ASTM B117 test process is supported by chamber design.

Each component supports a specific step of the ASTM B117 test process, forming a complete and verifiable testing system.

1. Besides ASTM B117 basic salt spray testing, what other salt spray test chambers does LIB industry provide?

In addition to ASTM B117 Neutral Salt Spray (NSS) chambers, LIB industry also provides:

CCT cyclic corrosion test chambers, combining salt spray with drying and humidity stages

SSC test chambers, with controlled SO₂ gas injection for sulfur dioxide corrosion testing

These systems are available with configurable chamber sizes and test parameters.

2. Does the equipment require continuous water supply, or is there a reservoir to refill periodically?

The chamber does not require a continuous water supply.A salt water tank (690 × 440 × 365 mm, 110 L) is used for prepared salt solution and needs to be refilled periodically.A saturation barrel is used to heat and humidify compressed air and consumes very little water, so refilling is infrequent.

3. Can the manual transparent cover be replaced with a pneumatic fiberglass cover?

Yes.The standard manual transparent cover can be upgraded to a pneumatic fiberglass cover.LIB industry supports non-standard customization based on customer requirements.

Ensure Your ASTM B117 Tests Are Performed Under Verifiable Conditions.
Contact LIB industry sales@libtestchamber.com to configure an ASTM B117 Salt Spray Corrosion Chamber that supports stable operation, standard compliance, and long-term testing reliability.

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