NCIDQ-Chap 28-Means of Egress
What is a stair?
A change in elevation consisting of one or more risers.
Define public way.
Any street, alley or similar parcel of land unobstructed from the ground to the sky that is permanently appropriated to the public for public use and has a clear width no less than 10'.
In a 90,000 feet squared, single-story office building, what would be of greatest concern in space planning? A.) dead-end corridors B.) corridor widths C.) horizontal exits D.) travel distances
D is correct. A 90,000 ft. squared building would be approximately 300 ft. squared or about 250 ft. wide and 360 ft. long. The size combined with typical rectangular planning of corridors would create very long distances to exits.
The two most important factors in determining the number of exits required for a particular room or space are A.) occupancy and the distance from the room exit to the building exit B.) the exit widths and common path of egress travel C.) the occupant load and building size D.) the occupancy and the occupant load
D is correct. The occupancy and occupant load are used to determine the number of exits. See Fig. 28.3
What is panic hardware?
Hardware that unlatches the door when pressure is applied against it rather than requiring a turning motion as with a door knob or level handle.
When is exiting permitted through adjoining rooms? When is it NOT permitted?
If it provides direct, obvious, and unobstructed means of travel to an exit corridor or other exit as long as the toilet maxiumum travel distances are not exceeded. If foyers, lobbies, and reception rooms are rated with a 1-hour wall, they are permitted as places to exit though. NOT permitted through kitchens, storerooms, restrooms, closets or spaces used for similar purposes.
What is a stairway?
One or more flights of stairs, either exterior or interior with the necessary landings and platforms connecting them to form a continuous and uninterrupted passage from one level to another.
UBC codes on 20 minute doors and 3/4 hour doors and 1 1/2 hour doors
S-rated, 20 minute door should be used in: 1.) A 1-hour rated exit access corridor 2.) Where a "smoke & draft assembly" is required. Must be a tight fitting smoke and draft assembly where gasketing must be placed on both jambs and the head to prevent the passage of smoke when the door is closed. C-rated 3/4 hour rated door used in: 1.) a 1-hour occupancy separation or 2.) a 1-hour rated exit stair B-rated 1 1/2 hour rated door used in: 1.0 Multi-floor projects in a 2-hr rated exit enclosure (stairway)
The following abbreviated table includes requirements for occupancy loads. A restaurant on the ground floor contains 3500 ft squared of dining area, a 1000 ft squared, and a 1200 ft. squared bar. What is the total occupant load? A.) 202 occupants B.) 318 occupants C.) 380 occupants D.) 410 occupants
See page 514 of study guide for chart. See page 587 for answer.
How is the total width of exits in inches determined?
Take the occupant load and multiply it by .3 for stairways and .2 for exits. The factor is in inches. i.e. Occupant load = 157 x .2 (exits) = 31.4" The corridor would have to be at least this wide.
Define travel distance.
The measurement of the distance between the most remote, occupiable point of an area or room to the entrance of the nearest exit that serves it. It is part of the exit access and is measured in a straight line along the path of exit travel.
Define occupant load.
The member of people that a building code assumes will occupy a given building or portion of building. Based on the occupany classification. It assumes that a certain type of use will be more densely packed than other types of use. i.e. an auditorium needs more exits than an office space of the same area b/c more people will need to evacuate the auditorium.
Define exit.
The portion of the egress system that provides a protected path of egress between the exit access and the exit discharge. It's fully enclosed and protected from all other interior spaces by fire-resistant rated construction with protected openings (doors and windows). i.e. exterior exit doors @ ground level or exit enclosures for stairs, exit passageways, and horizontal exits, exterior exit stairways and ramps. Must have either a 1 or 2 hour rating. Travel distance isn't an issue once the exit is needed.
Define arrangement of exits.
When 2 exits are required they must be place a distance apart = to not less than 1/2 the length of the maximum overall diagonal dimension of the building or area to be served. L=1/2 D maximum or L=the distance between 2 exits The exits must be far enough apart that they will not be blocked in an emergency. If 3 exits are required, 2 need to abide by this and one needs to be reasonably far apart in case one is blocked. If building is fully sprinklered: L = 1/3 maximum.
According to the IBC, dead-end corridors in unsprinklered buildings are limited to a maximum of A.) 10 ft B.) 20 ft C.) 40 ft D.) 50 ft
B is correct. The IBC limits dead-end corridors to 20 ft in unsprinklered buildings.
According to the UBC, the minimum width of a stair when handrails are required on either side is A.) 36 in. B.) 42 in. C.) 44 in. D.) 60 in.
C is correct. Under the UBC, any stair 44 in or wider requires handrails on both sides.
What are the VBC does about corridors?
1.) Dead end corridors are limited to 20' max length. 2.) Minimum width is figured by multiplying occupany load x 2, BUT if the occupant load is 50 or more the corridor must be 44" for use than 50 minimum width is 36". 3.) Width must be unobstructed by handrails and fully opened doors can only protrude 7" total, trim can only by 1 1/2" thick 4.) When serving occupant load of 10 or more, must be a 1 hour rated. This includes walls and ceilings If ceiling isn't rated walls must extend to deck under this, doors must be 20 min rated and have smoke and draft seals and automatic closers or self closing. Glass must be 3/4 hour rated with the total area not exceeding 25%. Ductwork in corridor must have fire dampers.
What are the 3 parts of the means of egress?
1.) Exit access 2.) Exit 3.) Exit discharge **These must lead to a public way.
What are the requirements for exit doors?
1.) Must be pivot hinged or side hinged and must swing in the direction of travel 2.) Must not swing into a required pat of travel - most are recessed. 3.) Must be a min. of 3'-0" w & 6'-8" H but no more more than 4' wide. 4.) Some occupancies require panic hardware 5.) Must have a fire rating compatible with the walls they are located 2 hr partition require 1 1/2 hr. door; 1-hr wall requires 20 min. door with similar smoke and draft seal. 6.) Must have automatic closers and approved hardware 7.) Glass in exit doors must be wired glass and it's total area is limited depending on the doors fire rating 8.) In most cases special doors like revolving and sliding can't be used as exit doors.
What are the requirements for handrails?
1.) Must be provided on both sides of the stairway unless the stairs are less than 44" w or if they are residential they only need 1. 2.) Stairways wider than 88" need and intermidiate stairway 3.) Top of handrail must be 34-38" above the nosing. 4.) Top of handrail must not exceed 12" beyond the top and bottom riser and must be returned or terminate in a newel post 5.) the gripping must be 1 1/2"-2" in cross section 6.) The space between the wall and the handrail must be 1 1/2" w.
What are the requirements for residential exiting?
1.) One exit is required either from the basement or 2nd floor. 2.) Basements & Bedrooms must have an escape window with a minimum openable area of 24" H x 20" W and larger than 44" aff. 3.) Exits can pass through kitchens, storerooms, etc... 4.) Corridors can be 36" W 5.) Doors can swing inot rooms so there is no problem with corridors being blocked. 6.) Houses can have deadbolts if the locking device is on the inside and doesn't require a key or tool. 7.) Houses can have door knobs instead of lever handles.
What are the requirements for handrails?
1.) Stairways for 50 or more occupant load must be 44" at least 2.) Stairways for less than 50 occupant load must be 36" at least 3.) Handrails can project into the required width 3 1/2" 4.) Risers must be 4"-7" and treads must be 11" 5.) Treads must have an acceptable nosing design 6.) Winding, circular, and spiral staircases can only be used on rare instances if they meet code. 7.) Landings must be present @ top and bottom of stairway. The dimension in the direction of travel must not be less than the width of the stairs but doesn't need to be more than 44" if the stair is a straight run.
What are some common rules to remember when determining the number or exits required for a space?
1.) When the occupant load exceed the number given in a bldg. code then at least 2 exits are required. 2.) Areas above the first floor must have at least 2 exits if the occupant load is 10 or more. 3.) 3 exits are required when the occupant load is from 501-1000 people (legends) 4.) 4 exits are required for occupant loads over 1001. **The determination of when 2 exits are required is primarily based on occupancy and occupant load.
How is the occupant load determined?
= Area/ occupant load factor. Basically means for the purpose of determining exits one person is occupying the # of square feet listed in the occupant load factor column of the table. For mixed occupancies, each area is calculated w/ it's respected occupant load and then they are all added together to get a total.
Define means of egress.
A continuous and unobstructed path of horizontal and vertical egress travel from any point in a building or structure to a public way.
What is an exit court?
A court or yard considered part of an exit discharge that provides access to a public way for one or more requried exits. In the IBC it's called an egress court.
What is an exit enclosure?
A fully enclosed portion of an exit that is only used as a means of egress either in a vertical or horizontal direction. In most instances, these mean protected stairways. Depending on construction type and building type, these must have iether a 1-hour or 2-hour rating and all openings must be protected. Must lead to an exit discharge or public way.
What is an exit passageway?
A horizontal fully enclosed portion of an exit that is only used as a means of egress. It leads from an exit doorway to an exit discharge or public way. An example is an exit from the door at the ground level of an interior stairway that leads through the building to an outside door.
Exits are always A.) protected by fire-rated construction B.) limited in length C.) corridors or stairways D.) required in buildings without sprinklers
A is correct. Exits are not limited in length (because they are protected), can be something as simple as a door, and are usually required in buildings with sprinklers.
Exits may NEVER pass through A.) kitchens B.) foyers C.) reception rooms D.) lobbies
A is correct. Exits may never pass through kitchens.
Which of the following is an INCORRECT statement about corridors? A.) Corridor construction must be fire-rated B.) Corridors are part of the exit access. C.) Corridors must be used exclusively for egress D.) Corridors are included in calculating travel distance.
A is correct. The main thing to rememer is that corridors are part of the exit access. This means that they are used for calculating travel distance, but they do not necessarily have to be fire-rated (although they usually are). Also, by definition they must be used exclusively for egress.
Define exit access.
A portion of the means of egress that leads to the entrance to an exit - it may or may not be protected depending on occupancy and construction type. Could include rooms, spaces, aisles, hallways, intervening rooms, corridors, ramps, and doorways. Does not provide a protected path of travel. It's the portion of the building where travel distance is measured and regulated.
What is an area of refuge?
An area where persons unable to use stairwasy can remain temporarily to await instructions or assistance during emergency evacuation.
Define a corridor.
An enclosed exit access component that defines and provides a path of egress travel to an exit. It may or may not be protected depending on particular requirements of code.
What is a horizontal exit?
An exit through a minimum two-hour rated wall that divides a building into two or more separate exit access areas to afford safety from fire and smoke.
Which two factors most typically determine whether a room must have at least two exits? A.) occupancy and travel distance B.) occupant load and occupancy C.) travel distance and occupant load D.) exit width factor and occupancy
B is correct. As shown in Fig. 28.3, the two most important variables are the use of the space (occupancy) and the number of people must exit the space (occupant load). This is similar to question 10.
Which of the following is an INCORRECT statement about fire-rated door assemblies? A.) Either hinges or rated pivots may be used. B.) Under some circumstances a closer in not needed. C.) Labeling is required for both the door and frame D.) Glass area is limited based on rating.
B is correct. Closers are always required with fire-rated door assemblies (protected openings).
A client has requested a new entry to her consulting business, which is located in an old, unsprinklered building. The client's space must conform to current IBC requirements. The current entrance consists of a pair of all-glass doors mounted on floor closers. The entrance opens onto a 1 hour rated building corridor. What should the designer tell the client to expect regarding the new entrance? A.) smoke seals will have to be located around the edges of the glass doors. B.) the glass doors will have to be replaced C.) One of the doors will have to be removed. D.) The floor closers will have to be changed to hinges.
B is correct. Smoke seals will be required, but the most important thing is that the glass doors will have to be replaced, either with solid, 20-minute rated doors with glass that is also 20-minute rated. Because this will significantly change the apperance of the existing entry, it the first thing the client should be told to expect. Either pivoted floor closers or hinges may be used as long as they are also fire-rated and the door is side-swinging.
The three parts of a means of egress include the I. public way II. exit III. exit access IV. exit enclosure V. exit discharge VI. corridor A.) I, II, and III B.) I, III, and VI C.) II, III, and V D.) II, IV, and V
C is correct. Normally, the three parts are identified as they go from the least protected to the most protected: exit access, exit, and exit discharge.
Working under the IBC, a designer has calculated that a total exit width of 8 ft is required from a store. What combination of door widths would meet most exiting requirements? A.) one 36 in door remotely located from a pair of 34 in doors B.) a pair of 32 in doors remotely located from one 38 in door C.) three 36 in doors remotely located D.) three 34 in doors remotely located
C is correct. Options A, B, and D include doors that would provide less than a clear 32 in wide opening.
What is included in the rise of a stair? A.) the vertical distance from one nosing to the next B.) the average height of a step C.) the distance from finish floor slab to finish floor slab D.) the number of steps between landings
C is correct. Refer to Fig. 18.7. Option A describes a riser.
A designer is developing a space plan for a full floor tenant in a high rise building. What two things does the designer need to know when determining the maximum travel distance? A.) the construction type and height of the building B.) the occupancy classification and whether the design involves an exit or exit access. C.) the occupancy classification and whether the building is sprinklered. D.) the construction type and whether the building is sprinklered
C is correct. The primary consideration for travel distance is whether or not the building is sprinklered. Then the codes may decrease the distance for certain occupancies.
Define travel distance. What's the minimum travel distance?
The distance an occupant must travel from the most remote point in the occupied portion of the exit access to the entrance to the nearest exit. According to the UBC the max. travel distance = 200' in an unsprinklered bldg. and 250' in a sprinklered one. The travel distance can be increased 100' if the increase travel distance is the last portion of the distance and is entirely w/in a 1 hour rated exit corridor.
Define common path of travel.
The portion of exit access that occupants are required to traverse before 2 separate and distinct paths of egress travel to two exits become available. If this exceeds 75' then two exits from a space are required even if the occupant load doesn't require it. (All except H-1, H-2, and H-3).
Define an exit discharge.
The portion of the egress system between the termination of an exit and public way. Included portions outside exterior walls such as exterior exit balconies, exit courts. May also include lobbies of multi-story buildings if one of the exit stairways opens onto the lobby and 1.) the exit doors in the lobby is clearly visible 2.) the level of discharge is sprinklered. 3.) The area is separated from areas below by the same fire-resistant ratings as for the exit enclosures thta open onto it.
