Because API 650 manway connections are severely under bolted and generally have weak flanges, VSP created an OPRA™ design to seal at a lower bolt load with a weak flange
Typical ring gaskets in API manway connections lead to damaged flanges if the bolts are overtightened. To solve this problem VSP Technologies has developed the API 650 OPRA™ design. This design uses reduced area full face gasket technology to seal the gasket at a much lower bolt load. Another common problem with these connections is the size of the bolts. The standard bolt size is 3/4" which is not large enough to adequately seal the connection. This is another great use case for the OPRA™ design which requires less stress to seal the connection.