1.1 ,This test method covers the determination of the reliability of glass coating on metal and is intended for use by manufacturers of equipment that is designed to withstand highly corrosive conditions where a failure of the coating in service would cause extreme damage to the exposed metal. Its use outside the manufacturer's plant is discouraged because improper or indiscriminate testing can cause punctures that are difficult to repair without returning the equipment to the manufacturer's plant. This test method detects not only existing discontinuities in the glass coating, but also areas where the glass may be thin enough to be likely to result in premature failure in service.