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step adjoining pathway which is sloped and serves as a landing as well.

S

SUNTHAR

Member
Joined
Aug 21, 2015
Messages
4
Location
Australia
What is the building code which deals with such a stair construction. The picture of a stairway adjoining a sloping pathway as displayed by the link.

https://www.dropbox.com/s/sbbhszah8vr6gcv/imp%20pathway%20attributes.jpg?dl=0

imp%20pathway%20attributes.jpg
 
Well welcome!!!

How did you find us???

I think you may be the farthest away ??
 
The first answer would be the building code for that area.

Doesn't Australia have a national building code?
 
Not a stair expert but this is from the International Building Code.

There maybe a better section that applies

1009.9 Spiral stairways. Spiral stairways are permitted to be used as a component in the means of egress only within dwelling units or from a space not more than 250 square feet (23 m2) in area and serving not more than five occupants, or from galleries, catwalks and gridirons in accordance with Section 1015.6.

A spiral stairway shall have a 71/2 -inch (191 mm) minimum clear tread depth at a point 12 inches (305 mm) from the narrow edge. The risers shall be sufficient to provide a headroom of 78 inches (1981 mm) minimum, but riser height shall not be more than 91/2 inches (241 mm). The minimum stairway clear width at and below the handrail shall be 26 inches (660 mm).

Spiral stairways are generally constructed with a fixed center pole that serves as either the primary or the only means of support from which pie-shaped treads radiate to form a winding stairway.

The commentary to Section 1009.4.3 regarding the possible event of nonconcentric movement on stairways with winders also applies to spiral stairways. The nature of stairway construction is such that it does not serve well when used in emergencies that require immediate evacuation, nor does a spiral stairway configuration permit the handling of a large occupant load in an efficient and safe manner. Furthermore, it is impossible for fire service personnel to use a spiral stairway at the same time and in a direction opposite that being used by occupants to exit the premises, possibly causing a serious delay in fire-fighting operations. Therefore, this section allows only very limited use of spiral stairways when part of a required means of egress. Spiral stairways may be used in any occupancy as long as such stairways are not a component of a required means of egress.

Spiral stairways are required to have dimensional uniformity. The stairway must have a clear width of at least 26 inches (660 mm) at and below the handrail. The depth of the treads must not be less than 71/2 inches (191 mm) measured at a point that is 12 inches (305 mm) out from the narrow edge (see Figure 1009.9). Riser heights are required to be the same throughout the stairway, but are not to exceed 91/2inches (241 mm). Minimum headroom of 6 feet, 6 inches (1981 mm) is required.

There is a picture::: see figure 1009.9

http://publicecodes.cyberregs.com/icod/ibc/2009f2cc/icod_ibc_2009f2cc_10_par107.htm?bu2=undefined
 
This might be the one and better;;

1009.3 Walkline. The walkline across winder treads shall be concentric to the direction of travel through the turn and located 12 inches (305 mm) from the side where the winders are narrower. The 12-inch (305 mm) dimension shall be measured from the widest point of the clear stair width at the walking surface of the winder. If winders are adjacent within the flight, the point of the widest clear stair width of the adjacent winders shall be used.

This requirement is essential for smooth, consistent travel on stairs that turn with winder treads. It provides a standard location for the regulation of the uniform tread depth of winders. Due to the wide range of anthropometrics of stairway users, there is no one line that all persons will travel on stairs; however, the code recognizes a standard location of a walkline is essential to design and enforcement. Each footfall of the user through the turn can be associated with an arc to describe the path traveled. As a user ascends or descends the flight, the turning at each step should be consistent through the turn. The walkline is established concentric, or having the same center (approximately parallel) as the arc of travel of the user. The tread depth dimension at the walkline is one of two tread depths across the width of the stair at which winder tread depth is regulated, cited in Section 1009.4.2. The second is the minimum tread depth. Regulation at these two points controls the angularity of the turn and the configuration of the flight. In order to establish consistently shaped winders, tread depths must always be measured concentric to the arc of travel. The walkline is unique as the only line or path of travel where winder tread depth is controlled by the same minimum tread depth as rectangular treads. However, Exception 2 of Section 1009.4.4 recognizes winder tread depth need not be compared to rectangular tread depths for dimensional uniformity in the same flight because the location of the walkline is chosen for the purpose of providing a standard and cannot be specific to the variety of actual paths followed by all users. This specific line location is determined by measuring along each nosing edge 12 inches (305 mm) from the extreme of the clear width of the stair at the surface of the winder tread or the limit of where the foot might be placed in use of the stair. If adjacent winders are present, the point of the widest clear stair width at the surface of the tread in the group of adjacent consecutive winders is used to provide the reference from which the 12-inch (305 mm) dimension will be measured along each nosing. The tread depth may be determined by measuring between adjacent nosings at these determined intersections of the nosings with the walkline. It is important to note that the clear stair width is only that portion of the stair width that is clear for passage. Portions of the stair beyond the clear width are not consequential to use of the stair, consistent travel or location of the walkline.
 
Welcome SUNTHAR!

From the 2012 IBC;

1009.7.4 Dimensional uniformity.

Stair treads and risers shall be of uniform size and shape. The tolerance between the largest and smallest riser height or between the largest and smallest tread depth shall not exceed 3/8 inch (9.5 mm) in any flight of stairs. The greatest winder tread depth at the walkline within any flight of stairs shall not exceed the smallest by more than 3/8 inch (9.5 mm).

Exceptions: 1. Nonuniform riser dimensions of aisle stairs complying with Section 1028.11.2.2. Consistently shaped winders, complying with Section 1009.7, differing from rectangular treads in the same stairway flight.

Where the bottom or top riser adjoins a sloping public way, walkway or driveway having an established grade and serving as a landing, the bottom or top riser is permitted to be reduced along the slope to less than 4 inches (102 mm) in height, with the variation in height of the bottom or top riser not to exceed one unit vertical in 12 units horizontal (8-percent slope) of stairway width. The nosings or leading edges of treads at such nonuniform height risers shall have a distinctive marking stripe, different from any other nosing marking provided on the stair flight. The distinctive marking stripe shall be visible in descent of the stair and shall have a slip-resistant surface. Marking stripes shall have a width of at least 1 inch (25 mm) but not more than 2 inches (51 mm).
 
fatboy said:
Welcome SUNTHAR!From the 2012 IBC;

1009.7.4 Dimensional uniformity.

Stair treads and risers shall be of uniform size and shape. The tolerance between the largest and smallest riser height or between the largest and smallest tread depth shall not exceed 3/8 inch (9.5 mm) in any flight of stairs. The greatest winder tread depth at the walkline within any flight of stairs shall not exceed the smallest by more than 3/8 inch (9.5 mm).

Exceptions: 1. Nonuniform riser dimensions of aisle stairs complying with Section 1028.11.2.2. Consistently shaped winders, complying with Section 1009.7, differing from rectangular treads in the same stairway flight.

Where the bottom or top riser adjoins a sloping public way, walkway or driveway having an established grade and serving as a landing, the bottom or top riser is permitted to be reduced along the slope to less than 4 inches (102 mm) in height, with the variation in height of the bottom or top riser not to exceed one unit vertical in 12 units horizontal (8-percent slope) of stairway width. The nosings or leading edges of treads at such nonuniform height risers shall have a distinctive marking stripe, different from any other nosing marking provided on the stair flight. The distinctive marking stripe shall be visible in descent of the stair and shall have a slip-resistant surface. Marking stripes shall have a width of at least 1 inch (25 mm) but not more than 2 inches (51 mm).
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Interesting note, it states you must be a minimum of 4 inches in height, no more than a 1:12 slope, but nowhere does it give a maximum riser height if you are using this exception...... If my stairway is eight feet wide, does this mean that the minimum riser would be 4 inches one side and 12 inches on the other end? of the bottom riser.

Common sense would dictate a maximum riser of 7 inches as outlined in 1009.7.2.
 
I'm reading it as this section allows you to reduce to less than four inches, as an exception to the riser heights called out in 1009.7.2.
 
If my stairway is eight feet wide, does this mean that the minimum riser would be 4 inches one side and 12 inches on the other end? of the bottom riser.
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No

1/12 slope 8 ft long would run into the second riser on the stairs with a maximum 7" rise per code
 
cda said:
Well welcome!!!How did you find us???

I think you may be the farthest away ??
Click to expand...
An overseas guest tripped on

the stairway and fractured her arm and the insurer has denied liability stating the stairway is hazard free and the hospital is demanding payment for the treatment from us.

therefore I am seeking the opinion of professionals via the internet and luckily came across your site.The sloped landing is not fully planar is composed two inclined surfaces.

The post by members were helpful and educative

Regards

sunthar
 
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