Metal End Caps – Why they are important

Metal end caps or top caps are used with mortised flush bolts and Von Duprin CVR hardware and were developed as a response to reports of door failure.

After thorough research and additional testing, we found that damage was occurring when force was applied to a door when the top latching hardware had not been released.  This would happen when the force was being applied to the door instead of the hardware panic bar or the hardware did not fully release when the mechanism was operated.


The goal of our tests was to identify the amount of force required to cause door failure as well as options that would allow a higher application of force before damage occurred to the door. There is not an established value for this type of performance. Consequently, results are measured against the force required to damage the currently installed assemblies.

We came to the conclusion that when doors machined for Von Duprin 9947 top latch hardware are subject to forces in excess of normal operation a 4” long stainless steel cap, having 15/32” legs, should be used in conjunction with the top latch.

Top Rail of Damaged Door


  • 20 gauge Stainless Steel end caps are required on all doors (1-3/4″ & 2-1/4″) machined for Von Duprin 33, 55, and 99 series top rod only CVR hardware (rated and non-rated).
  • The cap will have to be installed for the full warranty to apply.
  • Caps are shipped loose and will arrive separately from your door order.
  • Caps are not required for fire approvals.
  • End caps are attached to the top rail and overlap the door. They cannot be mortised.
  • They are designed to be pinch-fitted to the top rails, allowing the latching bolt to project through the hole.
  • For a tighter fit, pinch flanges together.
  • End caps can be bonded in place with 2-part epoxy if needed to eliminate any tampering that could occur.
  • The caps can be installed on bottom latches of full rod CVR hardware, but would have to be permanently attached with epoxy.

Here are the top cap drawings for both 1-3/4″ and 2-1/4″ doors and also an end cap installed.

Screen Shot 10-21-15 at 10.22 AM



Please download our installation instructions for more information.

Please let us know if you have any questions regarding top caps or let us know if you have a different question or a subject you feel we should explore further on the Eggers Blog.
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