Means of Egress and Emergency Openings

Means of Egress

The Florida Building Code defines “means of egress” as a travel system that provides a continuous, unobstructed and undiminished path from an occupied point in a building or structure to a public way.

A means of egress is required by the building code to provide a point of emergency escape and rescue. The term “egress” is used in most building codes to specify areas of access or exits, typically doors, windows, and hallways. The phrase “means of egress” refers to the ability to exit the structure, primarily in the event of an emergency, such as a fire.

A means of egress comprised of three distinct parts: the path of travel to an exit, the exit itself, and the exit discharge (the path to a safe area outside).

Here are definitions of these terms, as well as some other important definitions for understanding the means of egress system.

Definition of Means of Egress Terms

1. EXIT ACCESS: The portion of a means of egress system that leads you from occupied space to an exit. It includes any room or space occupied by a person and any doorway, aisle, corridor, stair, or ramp traveled on the way to the exit.
2. EXIT: The portion of a means of egress system that is between the exit access and the exit discharge or public way. This area is separated from other interior spaces by fire-resistance-rated construction and opening protectives as required. It can be very basic, such as an exterior door, or it can include enclosed stairwells and ramps. In some special cases, it can include exit corridors or passageways. The building materials used for an exit require higher fire ratings than the materials for exit access.
3. EXIT DISCHARGE: The portion of a means of egress system between the termination of an exit and the public way. It can be inside a building such as the main lobby, or outside a building such as an exterior vestibule, courtyard, patio, small alley, or other safe passageway.
4. PUBLIC WAY: An area exposed to open air that leads to a street permanently appropriated for the public and public use. This area can be a street, alley or other land parcel, but by definition has a minimal clear width and height of 10’. What distinguishes a public way from an exit discharge is its size. For example, any alley can be an exit discharge, but if it is 10 feet wide and 10 feet high and it leads to a public street, it is a public way.

Exit Doors

The number of exits required for a structure is based on its intended use and occupancy. Because the normal number of occupants in a residence is less than in a similarly-sized non-residential space, determining a safe level of means of egress is not as complicated.

The Building Code requires all dwellings to have at least one egress door that has direct access from a continuous unobstructed path of travel from all portions of the dwelling to the exterior, without requiring travel through a garage.

The required exit door must be side-hinged and cannot be less than 32” wide by 6’ 6” high. Other doors to the exterior are allowed to have smaller widths.

Each exterior door is required to have a floor or landing on each side of the door except when a stairway with two or fewer risers is located on the exterior side of the door.

The width of the landing should not be less than the width of the door and should have a minimum dimension of 36 inches measured in the direction of travel.

Emergency Exits

Basements and each sleeping room need to have at least one operable emergency escape and rescue opening with a minimum clear opening of 5.7 square feet, which opens directly into a public street, public alley, yard, or court.

Emergency escape openings can have a minimum net clear opening height of 24 inches or a minimum width of 20 inches, and must have sill height within 44 inches of the floor.

Emergency escape openings must be operable from the inside of the room without the use of keys or tools or special knowledge. This gives occupants in each sleeping area a method of escape in case of a fire.

Windows and Glazing

The light and ventilation requirements of the building code have a major effect on window type, size and placement. Window glass, called glazing, has come a long way since the days when windows had only a single pane of glass. Today’s energy-efficient windows come with glazing “systems” that incorporate multiple panes of glass, gas fillings, and high-tech, heat-sensitive coatings. These new and improved windows may cost more but they pay off in increased comfort and reduced energy costs.

Window Glazing – Ratings:
Window glazing is rated on three criteria: how well it insulates, how much light it lets through, and how effectively it blocks heat from the sun. By taking these values into consideration, you can effectively choose the best windows for the climatic conditions of the property, and even tailor individual windows to best suit specific rooms in the house.

Window Glazing- Hazardous Locations:
The Building Code requires each pane of glass to bear the manufacturer’s label, indicating the type and thickness of glass or glazing material. This safety glazing label has to be acid etched, sandblasted, ceramic-fired, embossed mark, or once applied unable to be removed without being destroyed.

The following are considered hazardous locations for glazing and require special attention or detailing:

1. Glazing in swinging doors and storm doors.
2. Glazing in sliding and bifold closet doors.
3. Glazing in unframed swinging doors.
4. Glazing in doors, enclosures, walls and fences enclosing hot tubs, saunas, bathtubs, andshowers.
5. Glazing in an individual fixed or operable panel next to a door where the nearest verticaledge is within 24 inch arc of the door and the bottom edge is less than 60 inches above anywalking surface.
6. Glazing in railings.
7. Glazing next to stairways, landings and ramps within 36 inches of walking surface.

Window Glazing- Habitable Rooms:
The FBC states that all livable rooms need to have a combined glazing area of not less than 8 percent of the floor area of that room. Natural ventilation should be provided through windows, doors, louvers, or other approved openings to the outside air. These openings need to be readily accessible and controllable by the building occupants. The minimum openable area to the outdoors should be 4 percent of the floor area being ventilated.

Window Glazing- Bathrooms:
Bathrooms have different requirements: There should not be less than 3 square feet of combined glazing area in windows in bathrooms, water closets and similar rooms, half of which is readily controllable.

You can avoid this requirement by providing artificial light and a mechanical ventilation system. The minimum ventilation rates are 50 cubic feet per minute for intermittent ventilation or 20 CFM for continuous ventilation (which is a constant and controlled level of ventilation). Don’t forget ventilated air must always be exhausted directly to the outside.

Window Glazing- Opening Details:
Required glazed openings need to open directly onto a street, public alley, yard, or court located on the same lot as the building.

They can open onto a roofed porch as long as the longer side of the porch is at least 65 percent open and unobstructed and there’s a ceiling height of not less than 7 feet.

Windows are permitted to open into sunroom additions or patio covers that look onto a street, yard or court as long as more than 40 percent of the exterior sunroom walls are open, or are enclosed only by insect screening and if the ceiling height is not less than 7 feet.

The alternative to providing openable windows is to provide mechanical ventilation. Mechanical heating and cooling will be discussed in more depth in Section 5 of this module.

Exit Access- Stairways

Stairs can often dictate the layout of an entire structure. Because of their importance in the design process, stairs must be considered early on. The location of railings and balusters, the width and depth of treads, and the height of risers can all affect a stairway’s ease and safety of use, both in terms of everyday use and as part of a means of egress system. Therefore, these dimensions are regulated by most building codes.

The Florida Building Code requires that exterior landings, decks, balconies, stairs and similar facilities, must be positively anchored to the primary structure to resist vertical and lateral forces or shall be designed to be self-supporting. Attachment cannot be completed with nails, such as toenails, that are subject to withdrawal.

Treads, Risers & Landings:
The maximum height of a stair riser is 7 ¾ inches. Within any flight of stairs, the actual measurement cannot be more than 3/8” difference between the greatest riser height and the smallest.

The minimum tread depth cannot be less than 10 inches. As with the stair risers, to achieve uniformity of motion, the actual measurement of the tread depth cannot be more than 3/8” difference between the greatest depth and the smallest.

Headroom must also be considered. In all parts of the stairway the minimum headroom is 6 feet 8 inches. This is measured vertically from the sloped plane created by adjoining tread nosings as well as from the finished floor of the landing or platform.

Allowing for this required headroom influences wall placement on an upper floor over the stairwell. Stairways can’t have less than 36 inches clear width between the height of the handrail and the headroom.

Landings should be provided at the top and bottom of each stairway. No vertical rise of more than 12’ is allowed between floor levels or landings. Additionally, the width of the landing can’t be smaller than the stairway it connects to, and every landing needs a minimum dimension of 36 inches measured in the direction of travel. The pitch of treads and landings cannot exceed 2%.

Stairway Lighting:
Lighting is an important element in stairway design. It does not need to be especially bright, but the risers and treads should have sufficient light to ensure that they can be distinguished. All interior and exterior stairways, including landings and treads, must be provided with a means of illumination.

Interior stairways must include an artificial light source located in the immediate vicinity of each landing, capable of illuminating the steps a minimum of 1 foot-candle. Exterior stairways need an artificial light source located at the top landing. Interior stairways with 6 or more risers need to include a light switch on the wall at both the top and bottom of the stairs. Exterior stairways need a light switch that can be controlled from inside the house. However, if the stairway lighting is continuously illuminated or automatically controlled, these switch requirements are not necessary.

Handrail Requirements:

Guards and handrails are needed by a variety of people for very different purposes. For example, they protect people from falling off the edge of the stair tread or landing but also help people keep their balance and provide leverage when ascending/descending stairs.

The maximum projection of the handrails off the wall is 4.5” on either side of the stairway. The space between the wall and the inner edge of the handrail can’t be less than 1- ½”. For a stairway with a handrail on only one side there must be a minimum clear width of 31.5 inches at the height of and below the handrail projection. For a stairway with handrails on both sides, this clear width can’t be less than 27”.

Any stairway with 4 or more risers has to have a handrail on at least one side. The height of which should be between 34 and 38” from the sloped plane created by adjoining adjacent nosings.

Handrails should be continuous for the full length of the flight and the ends should be either returned or terminated in newel posts or safety terminals.

The outside diameter of circular-shaped handrails must be between 1 ¼” and 2 inches. Handrails with a non-circular cross section need a perimeter dimension of 4 to 6 ¼ inches.

Ramps & Guards:
A ramp is an inclined plane that functions with or instead of stairs. Ramps permit wheelchair users, as well as people pushing strollers, carts, or other wheeled objects, to traverse an elevation change.

The maximum slope of a ramp is 8.3 percent. A 3’ by 3’ landing is required at the top and bottom of the ramp, where ramps change directions, and where a door opens onto a ramp.

Guards are building components located at the open side of an elevated walking surface, its purpose is to minimize the possibility of a fall to the lower level.

Porches, balconies, ramps, or raised floor surfaces that are 30 inches or more above the floor below require 36” minimum guards. Stairways that rise 30” or more above the floor below must have 34” minimum guards on the open side of the stair. Screened porches, sunrooms and decks 30” above the ground or floor elevation also required guards.

Where guards are required they should be equipped with intermittent rails or ornamental closures which do not allow passage of a sphere 4 inches or more in diameter.

Smoke Alarms
A means of egress system is designed to provide safe and continuous passage of emergency escape out of a structure and into public space. In addition to this travel corridor in an emergency situation there are other building components which contribute to safe escape. Such items include effective lighting, properly placed exit signs, and operable smoke alarms. Of course for residential design the latter is of the upmost importance.

According to the Residential Florida Building Code, smoke alarms should be installed in each bedroom, outside each separate sleeping area in the immediate vicinity of the bedrooms, and on each additional story of the dwelling, including basements but not including crawl spaces and uninhabitable attics.

If the dwelling is split level without an intervening door between adjacent levels, a smoke alarm on the upper level will suffice for the adjacent lower level, as long as it is less than a full story difference. To prevent false alarms, when locating fire alarms, be sure to avoid close proximity to the kitchen or fireplace.

All smoke alarms need to be listed in accordance with UL 217, a standard for electrically operated single and double station fire alarms intended for residential applications. Smoke alarms should be installed in accordance with the household fire warning equipment provisions of the National Fire Protection Association, NFPA 72.

Additionally, smoke alarms must be installed so as to receive primary power from the building’s electrical wiring, but should also contain a battery-powered back up system; and if more than one alarm is required they should be interconnected so that if one alarm activates, all the alarms in the dwelling unit will sound.