The State Building Code (SBC) provides a set of statewide standards and requirements related to building construction. The SBC is comprised of various international model codes, including building, residential, fire, and plumbing codes (model codes) adopted by reference by the Legislature. The model codes are promulgated by the International Code Council.
 
The State Building Code Council (SBCC) is responsible for adopting, amending, and maintaining the SBC. The SBCC must regularly review updated versions of the model codes and adopt a process for reviewing proposed statewide and local amendments.
 
Cities and counties may amend the SBC as applied within their jurisdiction, except that amendments may not be below minimum performance standards, and no amendment affecting single or multifamily residential buildings may be effective until approved by the SBCC. Current SBC rules specify there must be a minimum of one stairway for access and exit for buildings and structures three stories or 36 feet. If the building structure is more than three stories or 36 feet, the structure must have two or more stairways.
 
Local Development Regulations. Cities and counties engaging in comprehensive planning may enact ordinances regulating the use of land and zoning certain development and activities. Such regulations generally include:

• the location;
• construction and size of buildings for residence;
• industry, trade, and other purposes;
• the height, construction, and design of buildings and structures;
• the size of yards, open spaces, lots, and tracts;
• the density of population;
• the set-back of buildings; and
• the subdivision and development of land.

The legislative body of a county or city may adopt amendments to the SBC to allow for multifamily residential buildings to be served by a single stair exit under certain conditions, including but not limited to:

• the building is no more than five stories;
• the building does not have more than six stories above grade plane;
• the building does not contain a boarding house;
• the building does not have more than four dwellings on any floor;
• the building is constructed with not less than one-hour fire-resistive construction and is equipped with an automatic sprinkler system in accordance with the International Building Code and residential-type sprinklers must be used in all habitable spaces in each dwelling unit;
• there are no more than two single exit stairway conditions on the same property for buildings four stories tall or higher; and
• an exterior stairway or interior exit stairway is provided;

 
A city that intends to adopt amendments to allow for single stair exits under certain conditions must meet the following criteria prior to adoption:

• the city is served by a municipal fire department or fire district; and
• the city does not have a current restriction on development due to lack of fire flow capacity.

 
A city may determine it does not have appropriate fire apparatus or hydrant networks to serve single stairwell buildings.

The provisions authorizing a county or city to amend the code to adopt amendments that allow for multifamily residential buildings to be served by a single stair exit expire on July 1, 2026.

By July 1, 2026, the SBCC must adopt, by rule, standards to allow for up to five stories of multifamily residential buildings to be served by a single exit and make them available for local adoption.

The committee recommended a different version of the bill than what was heard.  PRO: Single-stair entry apartments greater than three stories high are not allowed to be developed outside of Seattle. An advantage of these buildings is when there is one stairway instead of two, it can be squeezed into a smaller lot. On many lots, it is inefficient to have a second stairway because there will not be enough room leftover to justify the development. Typical multi-family development in the US is large buildings with corridors down the middle, and small units on either side. They do not have the ability to cross-ventilate, they do not have daylight. The single exit building is the foundational multifamily development in cities and suburbs across the world. Instead of developers having to accumulate two or three adjacent lots, they can fill in one lot. There can be more family sized apartments to accommodate various family sizes. This will give families an option who may not be able to afford single family homes. This bill includes language that has been agreed upon and addresses public health and safety concerns.

OTHER: There are some technical concerns. Section 1.3 of this bill adds new provisions to RCW 19.27.060. Besides the good intent, building code language in the statute in general is uncommon and problematic. Adding code language to RCW 19.27 may create conflicts with the model codes. The one exit rule in Seattle has more than 10 additional criteria which are not included in this bill. RCW 19.27.031b refers to the international residential code which does not contain any occupancy classification. This creates another conflict with the statutory language in the code.