Page 44 - Design Criteria.qxd

45 ® Welcome to the Next Generation of Sealing Technology
Gasket Description Gasket Cross Section Flange Surface Flange Surface
Finish Microinch Ra Finish Micrometer Ra
Spiral Wound Gaskets 125 - 250 3.2 - 6.3
Flexpro Gaskets 125 - 250 3.2 - 6.3
Metallic Serrated Gaskets 63 MAX 1.6 MAX
MRG 125 - 250 3.2 - 6.3
Solid Metal Gaskets 63 MAX 1.6 MAX
Metal Jacketed Gaskets 100 - 125 2.5 MAX
Mat’l < 1.5MM Thick Mat’l < 1.5mm Thick
125 - 250 3.2 - 6.3
Soft Cut Sheet Gaskets
Mat’l > 1.5mm Thick Mat’l > 1.5mm Thick
125 - 500 3.2 - 12.5
Gasket Installation
For critical applications a more sophisticated method for bolt up may be considered such as heating rods, bolt tensioners, or ultrason-
ic extensometer.
Bolting Up Sequence
Stage 1 - Torque bolts up to approximately 30% of the final torque value following the diametrically opposed sequence specified in
table on page 56.
Stage 2 - Repeat Stage 1, increasing the torque value to approximately 60% of the final torque value.
Stage 3 - Repeat Stage 2, increasing the torque value to the final required torque value.
Stage 4 - A final tightening should be performed following an adjacent bolt-to-bolt sequence to ensure that all bolts have been evenly
stressed.
Note: See Page 46 for bolt torque sequence.
Surface Finish Requirements
Important - Under no circumstances should flange sealing surfaces be machined in a manner that tool marks would extend radially
across the sealing surface. Such tool marks are practically impossible to seal regardless of the type of gasket used.