UL 1581 Swellling and Blistering in water

1043.1 The specifications for this test are located in Swelling and Blistering when Immersed in Fluid, in the Standard for Wire and Cable Test Methods, UL 2556.
1043.1 revised July 28, 2008
1043.2 Deleted July 28, 2008

1043.3 The cord does not comply where there is any evidence of blistering. Where there is no blistering, the maximum and minimum diameters of the cord are to be measured immediately at each of the five marked points. The sum of these ten measurements is to be divided by 10 and recorded as D, the average diameter of the cord after immersion. The cord does not comply where the increase I in average
diameter (swelling) calculated as follows exceeds 20.0 percent.

I = 100(D − d)/d

1044 – 1059 Reserved for Future Use

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1. Overview
The **UL 1581** standard includes a test for evaluating the swelling and blistering of cable insulation and jackets when exposed to water. This test is critical to ensure the reliability of cables in environments with high moisture or water exposure.

Purpose: To determine the resistance of cable insulation and jacket materials to water-induced swelling, blistering, or other damage.

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2. Test Procedure
The swelling and blistering test involves exposing cable samples to water under controlled conditions and inspecting for material changes.

• a. Sample Preparation:
  - Prepare cable samples with insulation and jacket materials as specified in the standard.
  - Ensure samples are free from damage or defects prior to testing.
• b. Test Setup:
  - Immerse the cable samples in water at a specified temperature (commonly **70°C ± 2°C**) for a defined period (e.g., **168 hours**).
  - Ensure complete submersion of the test samples.
• c. Observation During Testing:
  - Inspect the samples periodically for signs of swelling, blistering, or separation of the material layers.
• d. Post-Immersion Inspection:
  - Remove the samples from the water and allow them to cool at room temperature.
  - Visually inspect the samples for surface changes, blistering, or swelling.
  - Measure the dimensional changes in the insulation or jacket.

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3. Evaluation Criteria
Cable insulation and jacket materials pass the test if:

• No significant swelling, blistering, or delamination is observed after testing.
• The dimensional changes remain within the allowable tolerance specified in the standard.
• Material integrity and performance are unaffected by water exposure.

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4. Importance of the Test
The swelling and blistering test ensures:

• Material Durability: Verifies that cable materials can withstand prolonged exposure to water without degradation.
• Environmental Suitability: Ensures cables are fit for use in wet or submerged conditions.
• Safety Assurance: Prevents potential failures caused by weakened insulation or jackets.

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5. Applications
This test is essential for cables used in:

• Marine and Offshore Environments: Ensures reliability under water exposure.
• Underground Installations: Verifies performance in high-moisture areas.
• Industrial Settings: Confirms resistance to water ingress in harsh environments.

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6. Conclusion
The **UL 1581 Swelling and Blistering Test** evaluates the ability of cable insulation and jackets to resist water-induced damage. By adhering to this standard, manufacturers ensure that cables remain reliable and durable in wet or submerged conditions.

Key Points:

• Test temperature: **70°C ± 2°C**.
• Test duration: **168 hours (7 days)**.
• Criteria: No significant swelling, blistering, or material separation.

References: UL 1581, cable testing standards, and industry best practices.