Fowler Associates Labs

ESD Journal Approved Tests Method
ATP Triboelectric T-1000
March 11, 2003

"SHOE SHINE" STATIC TEST

The Naval Weapons Laboratory used this test as early as the 1960's for evaluation of garments used in electrostatically sensitive areas, especially in the handling of primary explosives. It has been used by Brunswick for the development of upholstery fabrics and is now used by at least two ESD Labs for testing of fabrics and garments: Fowler Associates and K&S Labs.

This tests method is intended to determine the potential on a person wearing garments made from various fabrics who has been rubbed across the person's back with the material under test. Variations of this test may include the subject wearing a test garment and being rubbed by a various range of fabrics. This test method may also be used to determine the potential on a test material when rubbed on a test subjects clothed back.

Procedure: This test method requires two technicians: an operator and a test subject.

The operator folds a "scarf" of rubbing material to a size of about 5' long by 5" wide.

The test subject stands on any insulative surface ( greater than 1E13 Ohms) and holds a lead or wears a wrist strap with no resistor which connects to a suitable high impedance recording volt meter, e.g., a charged plate monitor.

The test subject grounds himself and the operator neutralizes any surface charges from the test subject's back, tests materials and soles of the test subject's shoes. The feet of the test subject must be kept still during the test.

The operator grasps the scarf near the ends, first ionizing it to remove any residual charges from handling. The operator then smartly strokes the upper back of the test subject five times in the manner of a shoe shine rag polishing a shoe. After the last stroke, the operator quickly steps back away from the test subject to a distance of three to five feet to exclude the effect of the field coming from the scarf.

The criterion of static is the maximum body potential on the test subject.

While this test was originally used to qualify personnel garments, it is equally useful in measuring the performance of, for example, upholstery material, in which case various upholstery scarves are used against various clothing or draped cloth materials. Some suggested clothing and seat materials may include;

Denim, Linen, Silk, Rayon, Wool, Rayon/PE, Cotton & Polyester

Quantitative indexing is a little difficult due to the wide variations in the way that people slide and stand up, differences in shoes and floor coverings, etc. However, the maximum voltage achieved in this test is an excellent ranking parameter and can be tailored to closely approximate worst-case real life conditions.

The additional measurement of the potential on the scarf material may also yield useful information. This may be accomplished with or without the operator wearing gloves for isolation of the scarf material. For this measurement, the scarf material is immediately after the strokes, held in front of a non contacting volt meter and the volts/inch recorded.

These tests are intended to be carried out at 12% RH, 720 F after 72 hours of conditioning at these conditions.