NFPA 2112 Testing

Types of Test

• Manikin Test: This test assesses the garment's ability to protect against burn injuries by subjecting a stationary manikin wearing the garment to a burning chamber for 3 seconds. Sensors measure the percentage of 2nd and 3rd-degree body burns, providing critical data on the garment's effectiveness in shielding against heat and flames.

• Thermal Shrinkage Test: By exposing a pre-washed fabric specimen to a high temperature of 500°F in an oven for 5 minutes, this test evaluates the fabric's resistance to heat-induced shrinkage. The absence of melting, separation, or ignition during exposure is indicative of the fabric's ability to maintain its integrity under thermal stress.

• Vertical Flame Test: This test involves suspending a strip of fabric vertically and exposing it to a controlled flame for 12 seconds. After the flame is removed, the after-flame and char length are measured to assess the fabric's flammability characteristics. A fabric that exhibits minimal after-flame and char length demonstrates better resistance to ignition and flame spread.

• Heat Transfer Performance Test: By positioning a fabric specimen horizontally with heat sources below and a heat sensor above, this test evaluates the fabric's insulative properties against convective and radiant heat. The sensor measures the temperature transferred to the opposite side of the fabric, simulating the heat exposure experienced by the wearer's skin. This test helps determine the fabric's ability to provide effective thermal protection against heat transfer.

  Together, these tests provide a comprehensive understanding of the fabric's protective capabilities against heat, flames, and thermal hazards, enabling informed decisions regarding its suitability for use in environments where such hazards are prevalent.

Manakin Test

ASTM F1930, often referred to as the manikin test, indeed provides a standardized procedure for measuring the average predicted body burn of flame-resistant fabrics. This test is crucial for assessing the protective capabilities of such fabrics against flash fires in laboratory settings.

One notable aspect of ASTM standards, including ASTM F1930, is that they primarily focus on test methods rather than establishing pass/fail criteria. These standards lay out the specific procedures and methodologies for conducting tests, ensuring consistency and accuracy across different laboratories and over time. However, they typically do not specify performance criteria or thresholds for determining whether a material meets certain safety requirements.

As a result, ASTM standards like F1930 serve as valuable tools for evaluating the performance of materials but often require additional context or reference to other standards or regulations to determine compliance or suitability for specific applications.

The Thermal Shrinkage Test and Heat Resistance test provide important insights into the protective performance of fabrics or garments, particularly in high-temperature environments. By subjecting the fabric to a controlled heating process and evaluating its response, these tests help assess the fabric's ability to withstand heat exposure without compromising its integrity or safety.

In the Thermal Shrinkage Test, the fabric is exposed to elevated temperatures in a 500°F oven for a specific duration. Following this exposure, the fabric is inspected for any signs of undesirable changes such as dripping, melting, separation, or ignition. Additionally, the degree of shrinkage is measured, with a maximum allowable shrinkage of 10% specified by the test criteria. Fabrics that exhibit shrinkage exceeding this threshold are deemed to have failed the test, while those with shrinkage below 10% are considered to have passed.

The results of these tests provide valuable information for workers and employers when selecting protective garments for use in environments where exposure to high temperatures is a concern. By ensuring that fabrics meet the established criteria for thermal shrinkage and heat resistance, workers can have confidence in the protective capabilities of their clothing while performing their job duties.

Thermal Shrinkage Test

To begin, we start with a 12” long, 3” wide piece of fabric. We hang the fabric vertically, then expose the bottom 3” edge of this fabric to a flame for 12 seconds. If the fabric ignites and continues to burn until it is consumed (BEL- Burn Entire Length), then clearly it is not flame resistant. If it does not continue to burn after the vertical flame is removed then we measure the damaged area, called char length. Char length is the portion of the blackened area that will easily tear, and standards set maximum length pass/fail criteria.

The measurements obtained in this test are:

• Char length – the length of the char from the exposed flame

• After-flame – does any flame remain after the test ends?

• After-glow – is there any heat glow which remains after the test ends?

Both after-flame and after-glow are measured and recorded but are not pass/fail parameters. Char length on the other hand is pass/fail. The maximum acceptable char is different depending on the standard. NFPA 2112 the flash fire standard requires a char length of 4” or less, whereas ASTM F1506 which is the arc flash standard requires a char length of 6” or less.

The test is the repeated five times and the data is averaged to determine the char length or “test results” for that fabric.

The Vertical Flame Test is essential to analyzing the relative protective performance of a specific fabric or garment. These results guide workers to garments that offer the protection they need on the job. ALERT-this is an excellent test for standard apparel fabrics, but is not well suited to analyzing rainwear fabrics, because they can shrink away from the flame. Tyndale recommends ASTM F1891 (arc) and ASTM F2733 (fire) for FR rainwear.

Vertical Flame Test

Heat Transfer Test

The Heat Transfer Performance test, as outlined, is a crucial procedure for quantifying a fabric's insulative ability and its ability to protect against both convective and radiant heat sources. This test is essential for assessing the suitability of fabrics for use in environments where there's a risk of exposure to heat and flame, such as in industrial settings.

By subjecting the fabric to both a burner (flame) and a heating lamp, the test simulates real-world conditions where workers may encounter both convective and radiant heat. The use of a calibrated thermocouple allows for the accurate measurement of temperature increase through the fabric, with a focus on predicting when a second-degree burn might occur.

The NFPA 2112 Heat Transfer Performance Test sets specific criteria that fabrics must meet to pass. These criteria ensure that the fabric provides adequate protection for workers. The minimum calorie ratings required (3-calorie rating in-contact or 6-calorie rating spaced) serve as benchmarks to indicate the fabric's ability to withstand heat exposure without causing second-degree burns.

Overall, the Heat Transfer Performance test plays a vital role in evaluating the protective capabilities of fabrics and helps ensure that workers are provided with garments that offer the necessary level of protection against thermal hazards in the workplace.