Full Face gaskets are a flat sealing element, consisting of an inner and outer diameter, and a specified number of bolt holes, the center of which are evenly spaced around a bolt circle. Full face gaskets are designed to fill the entire space between flat-faced flanges, with bolt holes that match the size and arrangement of the bolt holes in the intended flanges. ASME B16.21 and ASME B16.47 govern the dimensions of full face gaskets for standard and large diameter pipe flanges. Viton is the trade name for a fluoroelastomer that was developed by DuPont in 1957. 70 durometer fluorocarbon elastomers exhibit excellent resistance to high temperature and low compression set. They respond very well with resistance to ozone, high temperatures, oxygen, mineral oil, synthetic hydraulic fluids, fuels, aromatics and many organic solvents and chemicals. Gas permeability is very low and similar to that of butyl rubber.