Section 1010.9.1.3, including explanatory notes, for your reading pleasure:
1010.1.9.3 Locks and latches.
Locks and latches shall be permitted to prevent operation of doors where any of the following exist:
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1.Places of detention or restraint.
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2.In buildings in occupancy Group A having an occupant load of 300 or less, Groups B, F, M and S, and in places of religious worship, the main door or doors are permitted to be equipped with key-operated locking devices from the egress side provided:
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2.1.The locking device is readily distinguishable as locked.
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2.2.A readily visible durable sign is posted on the egress side on or adjacent to the door stating: THIS DOOR TO REMAIN UNLOCKED WHEN THIS SPACE IS OCCUPIED. The sign shall be in letters 1 inch (25 mm) high on a contrasting background.
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2.3.The use of the key-operated locking device is revokable by the building official for due cause.
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3.Where egress doors are used in pairs, approved automatic flush bolts shall be permitted to be used, provided that the door leaf having the automatic flush bolts does not have a doorknob or surface-mounted hardware.
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4.Doors from individual dwelling or sleeping units of Group R occupancies having an occupant load of 10 or less are permitted to be equipped with a night latch, dead bolt or security chain, provided such devices are openable from the inside without the use of a key or tool.
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5.Fire doors after the minimum elevated temperature has disabled the unlatching mechanism in accordance with listed fire door test procedures.
❖ Where security and life safety objectives conflict, alternative measures, such as those permitted by each of the listed situations, may be applicable.
Item 1 is needed for jails and prisons or locations where someone must be kept inside for their own safety (i.e., dementia wards, psychiatric wards).
Item 2 permits a locking device, such as a double-cylinder dead bolt, on the main entrance door to a building or space. It must be immediately apparent that these doors are locked. For example, such locking devices may have an integral indicator that automatically reflects the “locked” or “unlocked” status of the device. In addition, a sign must be provided that clearly states that the door is to be unlocked when the building or space is occupied. The sign on or adjacent to the door not only reminds employees to unlock the door, but also advises the public that an unacceptable arrangement exists if one finds the door locked. Ideally, the individual who encounters the locked door will notify management and possibly the building official. Note that the use of the key-locking device is revocable by the building official. The locking arrangement is not permitted on any door other than the main exit and, therefore, the employees, security and cleaning crews will have access to other exits without requiring the use of a key. This allowance is not limited just to multiple-exit buildings but also to small buildings with one exit. This option is an alternative to the panic hardware required by Section 1010.1.10.
In Item 3, an automatic flush bolt device is one that is internal to the inactive leaf of a pair of doors. The device has a small “knuckle” that extends from the inactive leaf into an opening in the active leaf. When the active leaf is opened, the bolt is automatically retracted. When the active leaf is closed, the knuckle is pressed into the inactive leaf by the active leaf, extending the flush bolt(s), in the head or sill of the inactive leaf (see Commentary Figure 1010.1.9.3).
Automatic flush bolts on one leaf of a pair of egress doors are acceptable, provided the leaf with the automatic flush bolts is not equipped with a doorknob or other hardware that would imply to the user that the door leaf is unlatched independently of the companion leaf.
Item 4 addresses the need for security in residential dwelling and sleeping units such as hotel rooms, apartments, dormitory rooms or townhouses. The occupants are familiar with the operation of the indicated devices, which are intended to be relatively simple to operate without the use of a key or tool. Note that this item only applies to the door leading from individual dwelling or sleeping units in a building. This item would not be applicable for doors locked as part of a security system in a multiunit building.
Item 5 is in recognition of required test procedures (UL 10B or UL 10C) for listed fire doors, which include the disabling of the locking mechanism when a fire door is exposed to the elevated temperatures of a fire.
I don’t think any of those exceptions apply here: not a jail or prison*, clearly djdn’t remain unlocked while the building was occupied, not an automatic flush bolt, not a residential dwelling or sleeping unit, not a fire door.
*I mean, at that specific moment, someone was being detained but it would be utterly insane to believe that the act of locking people in against their will ipso facto makes it legal to lock people in against their will.
