Ask Our Tech Expert: Essential Measurements for the Installation Gap

In Part One of our series, we explored the Installation Gap (IG) and why it’s vital for ensuring a perfect BFM® fitting installation.

Here are the critical measurements in determining the right IG and how they impact your system’s performance. Precision here isn’t just about making things fit—it’s about ensuring long-term reliability, safety, and efficiency in your powder processing operations.

 

Key Measurements for Achieving the Perfect IG

Getting the IG right means knowing exactly how each measurement affects your installation. Here’s what you need to consider:

 

measuring for a bfm fitting example

  • Connector Length (CL):
    The length of the flexible, transparent section between the cuffs. Standard CLs are available in sizes 100, 150, 200, and 250 mm. The IG is always slightly shorter than the CL to provide a secure, snap-fit connection.
  • Spigot Length (Measurement “A”):
    The upper and lower spigots typically measure 89mm (3 1/2”), although the tail can be trimmed to a minimum of 37mm (1 29/64″) if space is limited. Note that the upper and lower spigot lengths may differ.
  • Deduction for Installation:
    To ensure there’s enough room for easy installation and removal—and to allow for connector flexibility—a minimum of 10 mm (25/64”) should be deducted from the CL for an in-line, stationary installation. If your application involves offsets or movement, you must account for additional space (represented as ‘X’ in our diagrams).
  • Total Available Space:
    This is the gap between the two pipe ends that need to be connected. Accurately measuring is important to ensure your IG is set correctly.

For installations that involve vertical movement or offsets, refer to our detailed guidelines on adjusting your IG accordingly.

 

What happens if the IG is incorrect?

  • IG Too Big:
    When spigots are too far apart, the connector becomes overstretched. This makes installation and removal more difficult and compromises the 100% dust-tight seal. Over time, this extra stress can reduce the connector’s service life.
  • IG Too Small:
    If the spigots are positioned too close together, the connector may develop excessive creases and increase product contact. This friction can cause premature wear, reduce the connector’s aperture, and ultimately restrict product flow, affecting performance and safety

 

PSI’s Unmatched Product Expertise

At PSI, we enhance the BFM® sizing process by further evaluating your specific operational needs. While BFM’s® installation guide provides a good starting point, our powder experts can assist you with measurements to ensure a perfect fit that improves efficiency and performance.  

With over 25,000 installations since 2006, PSI’s team of BFM® experts offers unmatched industry expertise. Selecting the correct BFM® fitting requires more than measurements; our engineering experts deliver the best powder processing solutions for your system, reducing risks and optimizing your process.

 

Always Use the BFM® IG Calculator

To eliminate any guesswork, we highly recommend using the BFM® IG Calculator. Available as a downloadable app from the BFM® fitting website, Google Play, and the Apple App Store, this tool ensures that every measurement is precise—no matter your installation’s complexity. It even provides guidance on adjusting for movement and offsets, making it an indispensable resource for any technician.