api 5000Refer API 6a 6b And 6bx Flanges Weht Chart According to ASME B16.5 And (American Petroleum Institute) API 6A 5000 Flange Dimensions. Api 6a Flange Material Specification.The API 5000 system is desned for quantitative analysis of small molecules. This application involves measurement of specific molecular weht compounds, usually a drug or metabolite in