Exclusive to Compliance Magazine —Oct. 99 issue

Making the Grade: A Review of Industry Standard Test Methods
For Protective Apparel

By Debra Welchel
Manufacturing Brand Manager
Kimberly-Clark Away From Home Sector

Virtually every supplier of protective apparel and protective apparel fabrics refers to test results to back up their claims of product performance and superiority. How can safety managers, industrial hygienists and others responsible for selecting the right protective apparel for their employees sift through the confusing and sometimes misleading test data?

Following are the industry standard tests that apparel purchasers should expect their suppliers to conduct before making performance claims.

Physical Properties
• Static Decay (NFPA 99) — Electrostatic properties of fabrics are evaluated by inducing an electric charge of 5,000 volts (positive and negative) on the surface and measuring the time required to dissipate that charge. The specimen may be tested to 100%, 90% or 50% dissipation. The charge must decay, or dissipate, within 0.5 seconds to pass this test.
• Flammability (CPSC 1610) — This test measures a fabric’s burn rate and burn characteristics. A standardized flame is placed against the lower edge of the sample for one second. The time for the flame to spread five inches is recorded in seconds. This test reports a classification (class) of the fabric’s flammability:

• • Class 1 — Normal flammability
  • Class 2 — Intermediate flammability
  • Class 3 — Rapid and intense burning

• Tensile Strength and Elongation (ASTM D 1682) — This test measures the strength of the material. An area is clamped within a fabric sample. The sample is pulled at a constant rate in opposite directions. The force required to break the fabric is measured. The results are reported in pounds or grams and the amount of elongation (stretch) in the fabric before the break.
• Trapezoid/Trap Tear (ASTM D 1117.4) — This test measures how well a fabric resists tearing. A trapezoid-shaped fabric sample is cut on one edge and is clamped along the nonparallel sides. Force is applied to the sample, causing the small cut to continue across the fabric. The results are measured in pounds or grams, which represent the force required to tear the fabric.
• Mullen Burst (ASTM E96-80) — This test measures the strength of fabric subjected to hydraulic pressure. A 4" x 4" sample of the fabric is clamped in a frame. Water is used to apply force to the sample until the fabric bursts. The result is a pressure to break that may be reported in pounds per square inch (psi) or in kilopascals (kPa).

Barrier Properties
• Hydrohead (AATCC 127-1989) — This test measures a fabric’s resistance to the penetration of water. Under controlled conditions, a sample is subject to water pressure that increases at a constant rate until leakage appears on the material’s lower surface. This test may report in centimeters (cm), which represents the height of the column of water that can be supported by the fabric, or in pressure such as psi or kPa.
• Spray Impact (AATCC 42-1985) — This test measures the fabric’s resistance to the penetration of water under varying conditions. A specified volume of water is allowed to spray down against a taut surface of a sample of fabric mounted at a 45 degree angle. The sample of fabric is backed by a blotter which is weighed before the test, dry. Water that penetrates the fabric sample is absorbed by the blotter which is re-weighed at the end of the test. The results are reported in grams, representing the amount of water that has penetrated the fabric.
• Gutter Splash (ISO 6530) — This test measures splash resistance of a fabric to a liquid chemical. Isopropyl alcohol is run over the fabric’s surface. The quantity of alcohol that penetrates the surface is reported in percentages (the proportion of liquid that penetrates the fabric).

Comfort Properties
• Air Permeability (ASTM D737) — This test measures the rate and volume of air flow through a fabric. Under controlled conditions, a suction fan draws air through and area of fabric. The results are reported in cubic feet per minute (the volume of air that passes through the fabric over the duration of the test).
• Moisture Vapor Transmission Rate (ASTM E96-80) — This test determines the rate of water vapor movement through a fabric sample. A container of liquid is covered with a sample of fabric. The container is put into an over for 24 hours, then measured to see how much liquid has evaporated. The results of MVTR are measured in grams per meter squared per a 24 hour period (g/m2/24h), which is the amount of vapor that will pass through a square meter of surface over a 24 hour period.