Ramp, Stair, and Elevator Drawings 21€¦ · To prevent dropping off the ramp edge, a curb or barrier must be provided at the floor or ground surface of the ramp and landing. The

464

21Ramp, Stair, and Elevator Drawings

Changes in floor elevation are accomplished by using a ramp, stairs, elevator, escalators, or a combination of each. Although the architect is responsible for the design, a CAD technician should be familiar with the code requirements and vendor drawings associated with each method of changing floor levels. This chapter will introduce the drawings required for:

Ramps. ●

Stairs. ●

Major stair materials. ●

Drawing representation. ●

Elevator drawings. ●

Escalator drawings. ●

RAMPS

A ramp is an inclined surface that connects two different floor levels. Design and construction are regulated by both the building code and Americans with Disabilities Act (ADA) requirements. (See Chapter 5 for a review of ADA requirements.) Chapter 16 introduced ramp representation on the floor plan. This chapter addresses code requirements, methods of representation on draw-ings, and common sections and details that a drafter is required to work with.

Code Requirements

Ramps are classified by International Building Code (IBC) based on usage. Ramps that are used in an aisle for an exit from a structure must also meet the exit requirements that were presented in Chapter 12. This chapter focuses on code requirements for ramps that are used to achieve a change in floor levels.

Minimum Ramp SizesThe IBC requires ramps to have a minimum width equal to the required width for the corridor and a minimum clear width of 36" (900 mm) for the ramp and clear width between the handrails. Handrails are allowed to project into the required ramp width a maximum of

4 1/2" (114 mm) on each side provided the minimum clear width of 36" (914 mm) is maintained. Any deco-rative trim or other features may project a maximum of 1 1/2" (40 mm) on each side. The rise of ramps is restricted to 30" (762 mm) total with a maximum slope of 1 vertical unit per each 8 horizontal units, or a 12.5% slope. Ramps used as a means of egress are restricted to a maximum slope of 1 vertical unit per each 12 horizontal units, or an 8% slope. The cross-slope of a ramp, measured perpendicular to the direction of travel, cannot be greater than 1 vertical unit per each 48 hori-zontal units (2% slope). If a door swings over an egress ramp, the door when opened in any position cannot reduce the width of the ramp to less than 42" (1067 mm). A minimum of 80" (2032 mm) headroom must be provided above a ramp.

LandingsExcept in non-accessible Group R-2 and R-3 units, a landing with a length of 60" (1525 mm) measured in the direction of the ramp is required at the top and bottom, points of turning, doors, and the entrance and exit of all ramps. Group R-2 and R-3 units can have a landing with a minimum length of 36" (914 mm). The landing width must be as wide as the widest ramp that connects to the ramp. The slope of a landing cannot be greater than 1 vertical unit per each 48 horizontal units (2% slope).

Railings, Handrails, and CurbsWith the exception of ramps in aisles that serve seating, ramps with a rise greater than 6 inches (152 mm) must have a handrail on both sides of the ramp. The hand-rail must be between 34" and 38" (864 and 965 mm)in height. The rail must extend horizontally 12" (305 mm) past the top and bottom of the ramp. For round rails, the handgrip portion of the rail must be between 1 1/4" and 2" (32 and 51 mm) wide and must be smooth with no sharp corners. Rails must project 1 1/2" (38 mm) clear from walls to provide hand space. To prevent dropping off the ramp edge, a curb or barrier must be provided at the floor or ground surface of the ramp and landing. The

Chapter 21: Ramp, Stair, and Elevator Drawings 465

curb must be constructed to prevent the passage of a 4" diameter sphere. Guards must be provided in accordance with IBC section 1013.

Ramp Representation

The width and length of a ramp can be represented on the floor plan using thin lines. The angle can be repre-sented by listing either the slope or the elevation of each end, as seen in Figure 21-1. The slope and construction method must be represented by means of a section or

detail that is referenced to the floor plan. Figure 21-2 shows an example of a ramp detail.

STAIRS

Stairs are a primary method of changing floor levels in a multilevel structure. To effectively work with the architect’s stair drawings, the CAD drafter must be familiar with common terms, layout methods, and code requirements.

Stair Terminology

The exact terminology for stair construction may vary in different parts of the country. Figure 21-3 shows each of the common components of a stair that must be represented by a drafter. The layout of a stair is dictated by the rise and run.

The ● rise is the vertical distance from one floor level to the next.

The ● run is the total length required to form the stairs.

The total rise is made up of individual ● risers, which are the vertical portion of a step. The height of a riser is measured from one step to the next.

The ● tread is the horizontal portion of a step. The length of a tread is measured from the face of the riser at the rear of the tread to the nosing at the front-end of a tread.

The ● nose is the front edge of a step. Nosing is mate-rial that is added to the nose of the tread for decora-tion and to provide a slip-resistant surface. The type and design of nosing varies depending on the mate-rial used to build the stair. Nosings usually project approximately 1 1/8" (28 mm) past the riser.

FIGURE 21-1 A ramp is an inclined floor surface used to con-nect two different floor elevations that are often represented on the floor and site plans. Courtesy Michael & Kuhns Architects, P.C.

FIGURE 21-2 Sections or details should be drawn to explain ramp angle, construction methods, and railings. Courtesy Michael & Kuhns

Architects, P.C.

466 Commercial Drafting and Detailing

A ● stringer provides support for the tread and riser. In some areas of the country, it is referred to as a car-riage or stair jack. The stringer may be placed below or beside the risers.

The ● headroom for stairs is the vertical distance above the stair measured from the tread nosing to any obstruction above the stair.

Figure 21-4 shows the relationship of the stringer to the tread for various materials. The stringer termi-nates at a floor level or at an intermediate platform called a landing. Landings are inserted into long stair runs to provide users with a resting point, or as a means of changing the direction of the run. In multi-level structures, stair landings are often stacked above each other.

To provide stability to the user, a handrail must extend 12" (300 mm) past the upper riser. The lower end of the rail must continue to slope for the depth of one tread beyond the bottom riser. The number of handrails required is based on the width of the stairs and is discussed later in this chapter. The handrail on the open side of a stair terminates at a newel post.

A ● newel post is a large, fancy post used to provide sup-port at the end of a railing. The handrail is connected to the open side of the stair by a vertical baluster.

A ● guardrail is the railing that is placed around stairs to protect people from falling from the floor into the stairwell.

A ● stairwell is the vertical shaft where the stairs are to be placed. The design of the baluster connection to the stair and floor systems is of great importance for the safety of the stair users.

Depending on the height of the structure, the occu-pancy, and fire-resistive construction used, stairs may need to be separated from the balance of the structure by an enclosed stairwell. To control the spread of smoke and flames throughout a structure, access to stairwells is restricted by doors that must have a minimum 1-hour fire rating. Review Chapter 12 for fireproofing of stairwells.

Stair Types

Depending on the material used, stairs may either be open or enclosed. Stairs framed with wood, steel, or

TOTAL RUN

RISER

TREAD

GYPSUM BOARDFIRE RETARDANT

UNDER STAIR

TOTA

L R

ISE

( FIN

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FLO

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RA

IL H

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(36"

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IND

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UA

LR

ISE(TYPE 'X') @ ALL

FIGURE 21-3 Common stair terms.

FIGURE 21-4 Depending on the occupancy and the type of construction, stair treads may be directly supported by the stringer, placed between the stringers, or be above the stringer and supported by metal brackets.


precast concrete risers on a steel stringer can be framed as open stairs with no riser. Each of these materials can also be used to form enclosed stairs. Stairways that serve as the only access to another floor cannot be open because of ADA restrictions. The method of framing is not represented in plan view but is shown in sections and details. In addition to the type of riser construction, the configuration of the run can also be altered to meet design needs.

Straight stair runs are the most economical to build. ●

If space for the run is limited, a landing can be inserted into the run and the direction of the run can be altered. L- and U-shaped stairs are two common variations to a straight run.

An L-shaped stair contains a 90° bend in the total ●

run. The change in direction occurs at a landing, which may be placed in any portion of the run. A U-shaped stair causes the user to make a 180° turn at a landing. The landing can be placed at any point of the run, but it is usually placed at the midpoint so that each run is of equal length.

A curved or circular stairwell can be used to enhance ●

the design of an entry. Curved stairways are formed by using one or more radii to form the stair. Curved stairs have wedge-shaped treads.

A ● spiral stair is a stair that has a circular form in plan view with treads that radiate about a central support column. Spiral stairs can be used only within an individual unit or an apartment that serves an area less than 250 square feet (23 m2) and serves less than five occupants.

Figure 21-5 shows an example of how each type of stair is represented on a floor plan.

Minimum Code Design Requirements

Any stairs having two or more risers (except stairs used exclusively to service mechanical equipment) are regulated by the IBC and the ADA. A drafter must be familiar with these codes so that drawings and details are accurate.

Required Sizes for Straight-Run StairsThe IBC specifies minimum sizes for the width, height, individual rise and run, and the headroom for stair construction.

Required Width—Stairways serving an occupant load of less than 50 can be a minimum of 36" (914 mm) wide. Stairs serving 50 or more occupants must be a minimum of 44" (1118 mm) wide.

Required Riser Height—4" (102 mm) minimum and 7" (178 mm) maximum measured vertically between the leading edges of adjacent treads. For dwelling units in Group R-2 and R-3 occupancies, and for Group U occupancies that are accessory to a Group R-3 occupancy, or accessory to individual units in Group R-2 occupancies, the maximum rise can be increased to 7 3/4" (197 mm).

Maximum Stair Rise—A landing must be provided for every 12' (3658 mm) of vertical rise.

Required Tread Depth—11" (279 mm) minimum measured horizontally between the vertical planes of the foremost projection of adjacent treads and at right angles to the tread’s leading edge. For dwelling units in Group R-2 and R-3 occupancies, and for Group U occupancies that are accessory to a Group R-3 occupancy, or accessory to individual units in Group R-2 occupancies, the minimum tread depth can be reduced to 10" (254 mm).

Landing—A landing equal in length and width to the width of the stair must be provided at the top and bottom of a stairway. If a landing is provided in the stair span, the length of the landing measured in the direction of travel must be equal to the width of the stair run but is not required to exceed 48" (1219 mm).

Tread and Landing Slope—The walking surface of a tread or ramp cannot be greater than 1 vertical unit per each 48 horizontal units (2% slope) in any direction.

(a ) (b)

(c) (d)

FIGURE 21-5 Common stair types include: (a) straight, (b) L-shaped with a landing at any point of the run, (c) U-shaped with a landing at any point of the run, and (d) spiral. The occupancy load and the type of construction limit the use of spiral stairs.


Required Headroom—Stairways must be designed so that a minimum height of 80" (2032 mm) is pro-vided. The minimum allowable headroom is to be measured vertically from a plane parallel and tangent to the stairway nosing to any obstruction.

Circular, spiral, and winding stairs must meet other code requirements in addition to the requirements for straight stairways.

Curved StairsCurved stairs can be used for an exit as long as the minimum tread run is 11" (279 mm) when measured at a point 12" (305 mm) from the narrow end of the tread (6" [152 mm] for dwelling units in Group R-2). The minimum tread depth shall not be less than 10" (254 mm) at the narrow end. The smallest radius used to lay out the stairway curve cannot be less than twice the width of the stair. Curved stairs that do not have a uniform radius are considered winders by the building code.

WindersWinders can be used as a means of egress only within dwelling units unless they comply with the dimensional criteria and requirements of curved stairs. When used, a required width for the run of 11" (279 mm) is pro-vided at a point 12" (305 mm) from the narrowest portion of the stair. Winders also must be a minimum of 6" (152 mm) at the narrowest portion of the tread. Required tread sizes are shown in Figure 21-6.

Spiral StairsThe tread of a spiral stair must provide a clear walk-ing area of 26" (660 mm) from the outer edge of the supporting column to the inner edge of the handrail. A minimum run of 7 1/2" (191 mm) must be provided at a point 12" (305 mm) from the narrowest portion of the tread. The maximum rise for spiral stairs cannot exceed 9 1/2" (241 mm) and minimum headroom of 78" (1981 mm) must be provided. Figure 21-7 shows the mini-mum tread requirements for a spiral stair.

Rail Design

The placement of handrails and guardrails must be con-sidered as stair drawings are completed.

HandrailsHandrails must be provided on each side of the stair run. Common exceptions include stairs in aisles used to serve seating areas, stairways within dwelling units, and spiral stairs. An intermediate handrail must be provided for wide stairs so that no portion of the width required for egress is more than 30" (762 mm) of a handrail. Handrails must be between 34" and 38" (864 and 965 mm) high above the nosing of treads or land-ings. Handrails are required to extend horizontally 12" (305 mm) past the top riser and continue to slope for the depth of one tread beyond the bottom riser. The guidelines used for placing handrails by ramps also apply for stairs.

GuardrailsGuardrails are required at non-enclosed floor areas that are 30" (762 mm) above the ground or another floor level. Guardrails are not required on the load-ing side of loading docks, on the auditorium side of stages, or around service pits that are not accessible to

REQUIREDWIDTH

12"305mm

FIGURE 21-6 Tread requirements for a curved stair.

7 1/2" MIN.190mm

26" CLEAR660mm

12" CLEAR305mm

FIGURE 21-7 Tread requirements for a spiral stair.


the public. Guardrails must be 42" (1067 mm) high, except for rails serving occupancies in Group R-3, and within individual dwelling units in group R-2. Guards on the open side of stairways in these two occu-pancies are allowed to be between 34" to 38" (864 to 965 mm) high. Intermediate railings in a guardrail must be designed so that a 4" (102 mm) diameter sphere cannot pass through any openings up to a height of 34" (864 mm). Openings in the railing above 34" to 42" (864 to 1067 mm) can be designed using a 4 3/8" (111 mm) sphere. The triangular opening formed by the riser, tread, and the bottom rail at the open side of the stairway must be designed so that a 6" (533 mm) diameter sphere cannot pass through the opening. Railings for industrial occupancies that are not open to the public can be designed so that a 21" (533 mm) sphere will not pass through the railing.

Lateral Load Design for Railings Railings must be able to withstand the pressure of people pushing or pulling on the rail. The IBC requires rails to resist a lateral load of 50 plf (0.73 kN/m2) applied in any direction. Rails are also required to resist a single con-centrated load of 200 pounds (0.89 kN) applied from any direction to any portion of the railing. For Group I-3, F, H, and S occupancies that are not accessible to the general public and have an occupant load of less than 50, the minimum load the rail is required to resist can be reduced to 20 plf (0.29 kN/m2). For guardrails in one- and two-family dwellings, the rail is required to resist only the concentrated load. These loads must be transferred down through balusters into the floor or stair system. Both the connectors used to attach bal-usters and the material they are connected to must be strong enough to resist the loads to be supported and to resist the tendency to twist as the loads are applied. Figure 21-8 shows an example of a detail used to show the connection of a railing to the floor system.

Determining Required Rise and Run

The total rise and run of a stair is based on the legal requirements for the rise and run of each tread. If the floor-to-floor height is 9'–6" and a rise of 7" is used, 17 risers will be required. This is determined by divid-ing 114" (the total height) by 7" (the maximum rise). Although the answer is 16.28, this must be rounded up to 17 risers. The actual riser height of 6.70" can be determined by dividing 114 inches by 17. The number of treads is always one less than the number of risers. This stair would require 17 risers and 16 treads. If a run of 11 inches is used, the total run would be 176 inches (16 treads × 11").

STAIR MATERIAL

The occupancy and type of construction dictate the material used to form the stairs. Wood, timber, steel, concrete, or a combination of steel and concrete is used to form the stairs.

Wood

Wood stairs are made by using 2 × 12 or 2 × 14 (50 × 300 or 50 × 350) stringers. One-inch (25 mm) tread

FIGURE 21-8 Details must be drawn to show how the handrail and guardrail will be constructed. This railing is designed for use in an industrial area that is not open to public use. Courtesy

Scott R. Beck, Architect.


material or 3/4" (19.1 mm) plywood can be used to form the treads. Nonslip surfacing material must be used for both the treads and the risers. If carpet is used as the finish material, the riser should be set on an angle. Figure 21-9 shows a detail of a stair made of wood. The stringer is supported by a metal hanger, which is connected to a header in the floor system. Where the stringer rests on the floor platform, a metal angle or a kicker block is used to keep the stringer from sliding across the floor. A block of 2× (50×) material is placed between the stringers at midspan to minimize stringer vibrations and to reduce the spread of fire through the chase formed between the stringers. Figure 21-10 shows an example of a wood-framed stair.

Timber

Timber can be used to form open stairs. A 3 × 12 (75 × 300) or larger is used for the stringer. The size of the stringer must be determined based on the span and load to be supported. Stringers are attached to the floor plat-form by use of a metal angle at each end of the stringer. Treads are generally made of 2" or 3" (50 or 75 mm) material and are attached to the stringer by use of a metal angle or let into the stringer. Figure 21-11 shows examples of each method of attachment. Figure 21-12 shows an example of a stair using timber construction.

Steel

Steel stairs are found in many types of commercial and light industrial construction because of the need for

noncombustible construction. Steel stairs can be built similar to wood stairs, using a channel as the stringer and steel plates for the risers and treads. Stringers are attached to each floor system by the use of a steel angle. Handrails are generally made of 1 1/4" diam-eter metal pipe and are supported on metal uprights called balusters. Balusters are welded to the channel stringer. Figure 21-13 shows a portion of a steel stair. As shown in Figure 21-14, steel treads can be made in several configurations. For exterior applications, plates forming a grating or made from extruded metal are used to shed water. Metal is also used to form a pan to support concrete steps. The combination of a metal frame and concrete steps is quite common in many

FIGURE 21-9 Although typically drawn as a vertical riser in a small-scale section, a riser covered with carpet is generally inclined and must be represented in detail. Courtesy Architects

Barrentine, Bates & Lee, A.I.A.

FIGURE 21-10 A wood-framed stair in section for a multilevel office complex. Courtesy Architects Barrentine, Bates & Lee, A.I.A.

FIGURE 21-11 Timber treads may be supported by a metal angle or let into the stringer.


office structures. Figure 21-15 shows an example of a stair framed with steel and concrete. Figure 21-16 shows examples of details required to supplement the section.

Concrete

Because of their high cost, concrete stairs are used in only the most restrictive fire rating situations. When used, the stairs are designed as an inclined one-way slab with an irregular upper surface. Concrete stairs can be cast after the wall and floor systems have been cast, or at the same time. Drawings for concrete stairs are generally done by CAD drafters working for the engi-neering team. Figure 21-17 shows an example of a stair formed using concrete. Reinforcing details can be seen in Figure 21-18. Concrete stairs similar to Figure 21-19 are formed at grade.

DRAWING REPRESENTATION

The CAD technician will generally be required to work with stairs in plan views, sections, and details.

Plan Views

Stairs and the line work used to represent them were first introduced in Chapter 16. The stairway must be shown on the floor plan before details and sections can be started. The sections must be planned however, before the floor plan can be drawn. Using directions from earlier in this chapter, the number of risers and treads must be determined. When drawing a stair that goes to another level on the same floor, the entire run of the stair is shown. Figure 21-20 shows an example of a stair going up to an intermediate floor level. For a stair that extends between two full floors, the lower portion of the stair is shown on the main floor plan, and the upper end is shown on the second floor plan, as shown in Figure 21-21.

In planning the layout of the stairs on the floor plan, the required width, tread length, and number of risers must be known. Using a height of 9'–6" from floor to floor, it is determined that 17 risers and 16 treads are required with an overall run of 176". The layout of the stair on the floor plan can be completed by using the following steps:

1. Draw a line to represent the width of the stair.

2. Start at the upper floor landing, and place a line to represent the ending point. The length of the run can be determined as illustrated in Figure 21-22.

STEEL PLATE TREAD

STEEL STRINGERS

STEEL SUPPORT

FIGURE 21-13 A steel plate stair.

FIGURE 21-12 A stair section for a timber stair in a Group R-3 occupancy.

(a ) (b)

(c) (d)

FIGURE 21-14 Steel treads can be made from (a) bar grating, (b) steel plates with a textured surface, (c) concrete treads sup-ported by a steel pan, and (d) precast concrete treads with a steel mounting plate.


FIGURE 21-15 A stair section for a multilevel steel stair. The plan view is shown in Figure 21-23. Courtesy Peck, Smiley, Ettlin Architects.


FIGURE 21-16 Details for construction of a steel stair. Courtesy Dean Smith, Kenneth D. Smith Architect & Associates, Inc.

3. Use either OFFSET or ARRAY to show enough treads to establish the pattern. The run should be terminated with a short break line at the end of the run.

4. Represent the handrail by a line offset into the stairs approximately 1". There is no need to accurately rep-resent the actual rail offset on the floor plan because it will be included in the stair details.

5. Label the rails, floor above, the direction of travel, and the number of risers per flight. Figure 21-21 shows the completed lower floor plan. A similar pro-cess can be used to draw the upper portion of the run on the upper floor plan.

For structures with U-shaped or other shaped stairs, the layout process is similar. Remember, on multilevel stairs the highest and lowest floor levels show only one


run. Middle floors show runs going both up and down. Figure 21-23 shows how multilevel stairs would be represented. Notice that the stair going up is always on the same side of the stair and the upper run is opposite the lowest run.

Drawing Stair Sections

Stair sections are typically drawn at a scale of 1/4" = 1'–0", 3/8" = 1'–0", or 1/2" = 1'–0". The space available, the detail to be shown, and the amount of related details

to be used affect the selection of the scale. If the stair is to be premanufactured, only drawings required to attach the stair are supplied. Straight steel, concrete, and com-bination stairways are drawn using similar methods and should represent the following items in section:

Draw the stair section so that it is referenced to a ●

reference grid whenever possible.

When drawing enlarged plan views of stairs, place ●

the lowest floor level at the sheet, with each upper level placed vertically above it in order.

FIGURE 21-17 Sections showing the construction of a concrete stairway. Background information is often shown to help the print reader relate the section to the structure. Courtesy G. Williamson Archer, A.I.A., Archer & Archer, P.A.


FIGURE 21-18 The details for the stair shown in Figure 21-17. Courtesy G. Williamson Archer, A.I.A., Archer & Archer, P.A.

FIGURE 21-19 A concrete stairway formed at grade. Courtesy

Scott R. Beck, Architect.

FIGURE 21-20 When a stair serves two different levels of the same floor, both ends of the stair run are shown in the plan view.


Place stair sections adjacent to the corresponding ●

enlarged plan view whenever possible.

Show and dimension the size and number of treads, ●

risers, and headroom.

Show details of handrail and guardrail construction. ●

Show details showing the construction of each tread, ●

riser, and landing.

Show and dimension the location of fire hose cabi- ●

nets that are located in stairwells.

Show and specify the space below the stairs and the ●

first landing to indicate fire protection.

Indicate a ladder and roof hatch if located in the ●

stairwell. If the roof access is through a pent-house, include the penthouse in the stair section and show a curb at the access door to the adja-cent roof.

The section for the stair shown in Figure 21-21 can be completed by using the following steps:

1. Draw a line to represent each floor level.

2. Establish a line to represent the edge of the upper floor.

3. Establish a line to represent the total run.

4. Draw lines to represent the required number of treads and risers.

5. Draw a line to represent where each tread and riser will be placed.

6. Draw a line through the nose of the lowest tread to the nose of the highest tread.

7. Offset the line just drawn to represent the bottom side of the stringer. The drawing should now resem-ble Figure 21-24.

8. Use the line drawn in step 7 to determine where the stringer intersects the floor framing. Use this point to locate the stair support. In this example, (2)-2 × 12 floor joists are used with metal hangers to the floor joist and the stringer.

9. Using the grid that was established in step 4, draw a tread and a riser similar to Figure 21-25.

10. Using the COPY command with a running OSNAP of INT, copy the tread and riser to reproduce the required number of treads.

11. Eliminate all layout lines.

12. Provide a 2× kick block at the toe of the stair and blocking at the midspan of the stringer.

13. Show required finish material on the bottom side of the stringer and floor system so that the stair resembles Figure 21-26.

14. Locate required guardrails and handrails.

15. Provide dimensions to represent the following sizes:

Total rise and run ●

Individual rise and runs ●

Required headroom ●

Handrail and guardrail heights ●

FIGURE 21-21 When a stair serves two different floors, only one end of the run is shown on each floor plan.

44"

14'-8" = TOTAL RUN(16 x 11" = 176)

FIGURE 21-22 The stair plan is started by determining and representing the limits and width of the stair.


16. Use leaders to label each size and component used to make the stair. Material represented in a detail does not have to be completely specified.

Notice the lack of notes in each of the professional examples throughout this chapter and the dependence on details for a clear explanation of construction.

17. Place a title and scale below the drawing.

18. Place required detail tags to locate related details to the section.

The completed stair section should resemble Figure 21-27.

Drawing Stair Details

Stair details should be drawn at a scale appropriate tothe detail that must be shown. Scales ranging from 3/4" = 1'–0" to 3" = 1'–0" (1:20 to 1:5) are typically used for stair details. Material typically shown in detail includes:

Stringer-to-upper-floor-system connection. ●

Stringer-to-lower-floor-system connection. ●

Baluster-to-stringer connection. ●

Stringer-to-tread connection. ●

FIGURE 21-23 When a stair serves more than two levels, the drafter must coordinate each run so that it does not interfere with the headroom of other stairs in the run. Courtesy Peck, Smiley, Ettlin Architects.


Figure 21-18 shows several of the supplemental details for the stair drawn in Figure 21-15. Each is a stock detail edited to meet the specific needs of this stair. Because of the scale used for details, it is important to use varied lineweights and appropriate hatch patterns to accent each material used.

ELEVATOR DRAWINGS

The elevator manufacturer provides the bulk of the drawings required to install elevators. The responsi-bility of CAD drafters working with the architectural team is to accurately represent the shaft size and loca-tion on each plan view based on the design of the architect. Figure 21-28 shows how an elevator can be represented on enlarged floor plans. Sections and

FIGURE 21-24 A stair section is started by defining the limits and representing each finished floor level. The distance from floor to floor is divided by the number of risers. The distance representing the run is divided by the number of treads.

FIGURE 21-25 Once a grid for the stair has been determined, individual treads and risers can be drawn.

FIGURE 21-26 The layout is completed by adding rails, sup-port walls, and required supports.

FIGURE 21-27 A completed stair section. The absence of notation is allowed because of the use of four details to further explain construction.

Documents

Ramp, Stair, and Elevator Drawings 21€¦ · To prevent dropping off the ramp edge, a curb or barrier must be provided at the floor or ground surface of the ramp and landing. The