Final answer:
Exceptions to egress doors being openable from both sides are primarily due to security and safety considerations, and local building codes should be consulted for specific regulations.
Step-by-step explanation:
The exceptions to interior stairway egress doors being openable from both sides typically relate to security, safety, or specific building codes. Generally speaking, egress doors must be openable from the inside without the use of a key or any special knowledge or effort, according to life safety and fire codes. However, there are situations where doors can be locked from the outside, such as in certain high-security areas or in cases where unrestricted access may pose a threat to the occupants or operations within the building. For instance, in dormitories or apartment complexes, the main entrance to the building may be lockable from the outside to prevent entry by non-residents, but it must remain readily openable from the inside. Additionally, codes may allow for controlled access systems where occupants can exit the stairwell at certain floors but may not be able to re-enter the stairwell from those floors without a key or security code. Each jurisdiction may have specific variations and building codes should always be consulted for detailed requirements.
In most cases, interior stairway egress doors are required to be openable from both sides for safety reasons. However, there are a few exceptions to this rule.
One exception is when the building code allows for a single means of egress. This means that if there is another exit or stairway nearby, the interior stairway egress door may not need to be openable from both sides.
Another exception is when the door is part of a fire-rated assembly. Fire-rated doors are designed to limit the spread of fire and may have special requirements that do not allow them to be openable from both sides.