Tex. Local Government Code § 214.301

(a) A municipality may exercise the authority under this section regardless of whether the municipality has adopted local amendments to the International Building Code under Section 214.216(c).

(b) A municipality may authorize an apartment building to have a single stairway only if the building:

(1) does not have more than six stories above grade plane and is not a high-rise as defined by the International Building Code, as adopted under Section 214.216;

(2) does not have more than four dwelling units on any floor;

(3) has automatic sprinkler locations in each interior exit stairway, regardless of the type of stairway construction, that comply with the requirements prescribed by National Fire Protection Association Standard 13 for combustible stairways;

(4) has:

(A) an exterior stairway; or

(B) an interior exit stairway for which the doors:

(i) into the stairway from the interior of the building swing into the stairway regardless of the occupant load served; and

(ii) from the interior exit stairway to the building exterior swing in the direction of exit travel;

(5) has interior exit stairway enclosures that:

(A) have a fire resistance rating of not less than two hours; and

(B) do not contain an elevator opening;

(6) has on each floor a corridor from each dwelling unit entry or exit door to an interior exit stairway, including any related exit passageway, that has a fire resistance rating of at least one hour;

(7) does not have more than 20 feet between the entry or exit door of a dwelling unit and an exit stairway;

(8) does not have more than 125 feet of exit access travel distance;

(9) has an exit serving the portion of the building that contains two or more dwelling units that does not discharge through a portion of the building with a different occupancy category, including an accessory parking garage;

(10) has an exit that terminates in an egress court for which the court depth does not exceed the court width, unless it is possible to exit the egress court to the public way in either direction;

(11) does not have an opening within 10 feet of an unprotected opening into an exit stairway other than a required exit door that has a fire resistance rating of at least one hour;

(12) has emergency escape and rescue openings that comply with Section 1031 of the International Building Code as adopted under Section 214.216 on each floor served by a single exit;

(13) does not have an electrical receptacle in an interior exit stairway; and

(14) has an automatic smoke and fire detection system that activates an occupant notification system that complies with Section 907.5 of the International Building Code as adopted under Section 214.216 installed in each:

(A) common space outside of a dwelling unit;

(B) laundry room, mechanical equipment room, and storage room;

(C) interior corridor serving a dwelling unit; and

(D) main floor landing or interior or exterior exit stairway.