Quick Code Q&A: Flush Bolts

Last month, we looked at code exceptions that allow deadbolts to be used on doors along egress paths. Although deadbolts are often acceptable for use on egress doors, a section of the International Building Code (IBC) is sometimes misinterpreted as prohibiting deadbolts. The section is called Bolt Locks.

The Bolt Locks section of the I-Codes does not address deadbolts; it contains the requirements for flush bolts and surface bolts used to secure the inactive leaf of a pair of doors. These bolts project into the frame head and into a floor strike and may be manual or automatic. While automatic flush bolts (including constant-latching designs) do not pose many difficulties for code compliance, provided eligibility requirements are met, manual flush bolts can, as they have more stipulations that govern their use.

Question: Are inactive leaves that are not required for egress allowed to have manual flush bolts?

This is a common question for doors with inactive leaves meant for convenience, aesthetics or the movement of equipment. The IBC, International Fire Code (IFC) and National Fire Protection Association’s Life Safety Code (NFPA 101) limit the use of manual flush bolts in means of egress doors, but these codes also contain exceptions that may allow their use.

Eligibility Requirements

Typically interpreted to limit the use of manual flush bolts as a means of egress, NFPA 101 prohibits their use when an inactive leaf is needed to provide the requisite egress capacity. This code will allow automatic flush bolts if certain criteria are met.

In section 1010.2.5 of the 2021 edition of the IBC, called “Bolt Locks,” manual flush bolts or surface bolts are prohibited on egress doors unless they meet one or more of the following four exceptions:

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