Accurate gasket measurement is essential for ensuring proper sealing performance. Whether you're working with circular flanges or rectangular frames, understanding the correct measurement techniques will help you specify exactly what you need. This comprehensive guide covers the key measurement methods for the most frequently encountered gasket configurations.
Measuring Flange Gaskets
Method 1: The PCD (Pitch Circle Diameter)
Full-face gaskets feature bolt holes around the gasket face. To measure these correctly, you need to establish the Pitch Circle Diameter - this represents the diameter of an imaginary circle passing through the centres of all bolt holes. A practical measurement technique is to use a tape measure from the inner edge of one hole to the outer edge of the opposite hole, which gives you the PCD directly (assuming all holes are identical in size). Don't forget to record the material thickness, as this is crucial for complete gasket specifications.
Method 2: The IBC (Inner Bolt Circle) Gasket
Ring-style gaskets without holes on the gasket face require a simpler measurement approach. These gaskets are defined by just two key dimensions: the outer diameter (OD) and inner diameter (ID). Measure straight across the widest points of both the outer and inner edges using a tape measure positioned edge-to-edge. Recording the material thickness alongside these diameters provides all the information needed for accurate quotation and manufacture.
Flange Gasket Tables - Please follow the link to view all standard flange gasket tables.
Measuring Picture Frame Gaskets
Rectangular and square gaskets require careful measurement of both external and internal dimensions. Use a tape measure to establish the outer length and width, then measure the internal aperture in the same way. Most picture frame designs incorporate bolt holes around the perimeter - while these are typically evenly spaced and uniform in diameter, it's worth verifying this rather than assuming. The diagram above illustrates all the critical measurements needed for an accurate picture frame gasket specification.
Struggling with complex gasket measurements? Our technical team can help. We offer several support options: detailed telephone guidance to help you measure yourself accurately, site visits where our engineers measure on your behalf, or sending us an existing gasket sample for us to replicate. Contact our sales team to discuss which approach best suits your situation.
Further Things to Consider When Measuring Gaskets
To provide an accurate quotation, we'll need some key details about your requirements:
Order Quantity
Application:
- What system or equipment will the gasket seal?
Size Details:
- Reference to standard flange type (if applicable)
- All measurements as shown in the diagrams above, including hole quantity and material thickness.
- Technical drawings for non-standard configurations.
Material Selection Criteria:
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Type of media being sealed (gas, liquid, powder)
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Operating temperature range (minimum and maximum)
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Chemical compatibility requirements (acids, alkalis, solvents, hydrocarbons etc.)
- System pressure rating.
- Installation environment (internal/external pipework, exposure to weather, UV, etc.)