**Table of contents**

[10 Workstation and Workplace design
10-1](#workstation-and-workplace-design)

[10.1 General 10-1](#general)

[10.2 Workstations and consoles 10-2](#workstations-and-consoles)

[10.2.1 Sit, sit-stand, and stand consoles
10-3](#sit-sit-stand-and-stand-consoles)

[10.2.2 Seated workstations 10-5](#seated-workstations)

[10.2.3 Horizontal wrap-around console alternatives
10-10](#horizontal-wrap-around-console-alternatives)

[10.2.4 Vertical stacked segments for consoles
10-11](#vertical-stacked-segments-for-consoles)

[10.2.5 Design and arrangement of multi-person consoles
10-12](#design-and-arrangement-of-multi-person-consoles)

[10.2.6 Standing workstations 10-16](#standing-workstations)

[10.2.7 Work surfaces 10-19](#work-surfaces)

[10.2.8 Storage 10-20](#storage)

[10.2.9 Workstations for maintenance repair
10-20](#workstations-for-maintenance-repair)

[10.2.10 Workspace for positions other than seated or standing
10-20](#workspace-for-positions-other-than-seated-or-standing)

[10.3 Workplace layout 10-22](#workplace-layout)

[10.3.1 Equipment and workstation layout
10-22](#equipment-and-workstation-layout)

[10.3.2 Work space features designed into equipment
10-24](#work-space-features-designed-into-equipment)

[10.4 Design of passageways 10-26](#design-of-passageways)

[10.4.1 Walkways and traffic areas 10-26](#walkways-and-traffic-areas)

[10.4.2 Wheelchair accessible routes
10-27](#wheelchair-accessible-routes)

[10.4.3 Ground and floor surfaces 10-29](#ground-and-floor-surfaces)

[10.4.4 Landings 10-30](#landings)

[10.4.5 Catwalks, tunnels, and crawl spaces
10-30](#catwalks-tunnels-and-crawl-spaces)

[10.4.6 Platforms, elevators, inclinators
10-30](#platforms-elevators-inclinators)

[10.4.6.1 Platforms 10-30](#platforms)

[10.4.6.2 Portable platforms 10-31](#portable-platforms)

[10.4.6.3 Platform guardrails, toeholds, screens, and handholds
10-31](#platform-guardrails-toeholds-screens-and-handholds)

[10.4.6.4 Elevators, and hydraulically operated platforms
10-33](#elevators-and-hydraulically-operated-platforms)

[10.4.7 Entrances and exits 10-33](#entrances-and-exits)

[10.4.7.1 General 10-33](#general-1)

[10.4.7.2 Doorways and hinged doors 10-34](#doorways-and-hinged-doors)

[10.4.7.3 Alternative door rules 10-35](#alternative-door-rules)

[10.4.7.4 Emergency doors 10-36](#emergency-doors)

[10.4.7.5 Hatches 10-37](#hatches)

[10.4.7.6 Whole body access 10-37](#whole-body-access)

[10.4.8 Ramps, ladders, and stairs 10-39](#ramps-ladders-and-stairs)

[10.4.8.1 General 10-39](#general-2)

[10.4.8.2 Pedestrian ramps 10-43](#pedestrian-ramps)

[10.4.8.3 Stairs 10-44](#stairs)

[10.4.8.4 Stair ladders 10-46](#stair-ladders)

[10.4.8.5 Fixed ladders 10-48](#fixed-ladders)

[10.4.8.6 Portable ladders 10-50](#portable-ladders)

[Glossary 10-53](#__RefHeading___Toc26946082)

[References 10-54](#__RefHeading___Toc26946083)

[Index 10-55](#__RefHeading___Toc26946084)

**List of exhibits**

[**Exhibit 10.2.1.1 (a) Standard console dimensions
10-3**](#__RefHeading___Toc30386400)

[Exhibit 10.2.1.1 (b) Standard console illustration and dimension key
10-4](#__RefHeading___Toc30386401)

[Exhibit 10.2.2.2 Seated workspace dimensions and illustrations
10-7](#__RefHeading___Toc30386402)

[Exhibit 10.2.2.13 Swing-away seat for short-term use
10-9](#__RefHeading___Toc30386403)

[Exhibit 10.2.3 Example of horizontal wrap-around console
10-10](#__RefHeading___Toc30386404)

[Exhibit 10.2.4 Examples of vertical stacked segments
10-11](#__RefHeading___Toc30386405)

[Exhibit 10.2.5.1 Basic and variations of multi-person console
arrangements with an example control room arrangement
10-14](#__RefHeading___Toc30386406)

[Exhibit 10.2.5.2 Concepts of functional reach arc and equidistant
visual arc for a stand console 10-15](#__RefHeading___Toc30386407)

[Exhibit 10.2.6.1 Standing workstation illustration and dimensions
10-17](#__RefHeading___Toc30386408)

[Exhibit 10.2.6.2 Control and display placement limits for vertical and
stand consoles where see over capabilities are not required.
10-18](#__RefHeading___Toc30386409)

[Exhibit 10.2.10.1 Dimensions and illustrations for workspaces other
than seated or standing 10-21](#__RefHeading___Toc30386410)

[Exhibit 10.3.2.4 Access space through integral design.
10-25](#__RefHeading___Toc30386411)

[Exhibit 10.4.1.2 Walkway and passageway
10-27](#__RefHeading___Toc30386412)

[Exhibit 10.4.2.6 Minimum clearance point for a single wheelchair.
10-28](#__RefHeading___Toc30386413)

[Exhibit 10.4.2.7 Dimensions for making a U-turn in a wheelchair.
10-29](#__RefHeading___Toc30386414)

[Exhibit 10.4.7.2.1 Door dimensions 10-34](#__RefHeading___Toc30386415)

[Exhibit 10.4.7.6.1 Whole body access dimensions
10-38](#__RefHeading___Toc30386416)

[Exhibit 10.4.8.1.2 Type of structure in relation to angle of ascent
10-39](#__RefHeading___Toc30386417)

[Exhibit 10.4.8.1.12 Critical dimensions for ramps.
10-41](#__RefHeading___Toc30386418)

[Exhibit 10.4.8.1.15 Combined ramp and stairs
10-43](#__RefHeading___Toc30386419)

[Exhibit 10.4.8.3.1 Design requirements for stair dimensions
10-44](#__RefHeading___Toc30386420)

[Exhibit 10.4.8.4.1 Design requirements for stair ladders
10-46](#__RefHeading___Toc30386421)

[Exhibit 10.4.8.5.1 Design requirements for fixed ladders
10-48](#__RefHeading___Toc30386422)

[Exhibit 10.4.8.5.3 Design requirements for fixed ladder cage dimensions
10-49](#__RefHeading___Toc30386423)

[Exhibit 10.4.8.6.1 (a) Design requirements for portable step ladders.
10-50](#__RefHeading___Toc30386424)

[Exhibit 10.4.8.6.1 (b) Design requirements for portable rung ladders.
10-51](#__RefHeading___Toc30386425)

#   {#section .unnumbered}

#  Workstation and Workplace design

This chapter deals with the design criteria associated with workstations
and workplaces. A **workstation** is a place designed for a specific
task or activity from where work is conducted or operations are
directed. Desks, offices, repair benches, tools, equipment, and computer
terminals are examples of these special accommodations and equipment.
Workstations are designed as areas for one or more workers to use in
accomplishing purposeful tasks or jobs. A **workplace** is defined as an
area room or establishment where work is done. The chapter is organized
so as to start from the design of a single workstation then broaden to
multiple workstations and workplaces.

The following design criteria affect systems, equipment, and facility
design. Compliance will help enhance the performance of FAA personnel.
Some of the rules address the interaction of maintenance and operational
activities.

## 10.1 General

-   **10.1.1** **Design for human activities.** Workplace and associated
    equipment designs shall systematically incorporate the effects of
    tasks, performance capabilities, physical dimensions, and viewing
    dimensions for maintainers and for operators. \[Source: National
    Aeronautics and Space Administration (NASA-STD-3000A), 1989\]

-   **10.1.2** **Physical accommodation.** The physical dimensions of
    workplaces and equipment shall conform to the anthropometric and
    biomechanical characteristics of the specific population of users
    for whom the system is being designed and to the characteristics of
    the tasks to be performed. Anthropometric and biomechanical data are
    found in Chapter 14. \[Source: NASA-STD-3000A, 1989\]

**Examples.** Those areas that deal with clearance dimensions that a
large portion of the user population could be expected to use frequently
or in a life threatening situation require as a minimum the 99th
percentile value for clearance. Heavy traffic passageways and normal
doorway clearances are examples. Similarly, the 1st percentile values
for reach and strength are used as limiting dimensions. These values
ensure that the smallest personnel can reach and open escape mechanisms.
In most other cases, the convention of designing for the 5th through 95
percentile is used for practical design related reasons. Male and female
personnel are included in the anthropometric data. The higher percentile
values are often dominated by male data and the lower values by female
data (see Chapter 14 and its references for treatments of anthropometric
practice).

-   **10.1.3** **Work space to permit access.** Space for maintenance
    access shall be designed into systems and equipment. \[Source:
    Department of the Air Force (AFSC DH 1-3), 1980\]

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-   **10.1.4** **Maintenance independence.** Workplaces, controls, and
    displays that are associated with maintenance activities should be
    separate from operator workplaces, controls, and displays. \[Source:
    NASA-STD-3000A, 1989\]

-   **10.1.5** **Maintenance and operations interference.** Maintenance
    activities should not interfere with ongoing operator tasks.
    \[Source: NASA-STD-3000A, 1989\]

-   **10.1.6 Redundant information.** Where maintenance activities would
    interfere and where simultaneous activities are necessary, redundant
    information should be provided to the operators for their ongoing
    diagnostic and emergency maintenance responsibilities. \[Source:
    NASA-STD-3000A, 1989\]

-   **10.1.7** **Visibility of displays and controls.** Controls and
    displays that are solely for maintenance should be readily
    accessible when needed by maintenance personnel without being
    visible to the operators. \[Source: NASA-STD-3000A, 1989\]

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-   **10.1.8** **Task and general illumination of work space.**
    Illumination for maintenance shall include general area illumination
    and task illumination. Refer to Chapter 13 for detailed illumination
    design criteria. \[Source: NASA-STD-3000A, 1989\]

-   **10.1.9** **Illumination for normal operations and maintenance.**
    Where simultaneous operations and maintenance activities are
    necessary, workplace illumination for maintenance activities shall
    be compatible with illumination requirements for operators\' visual
    tasks. \[Source: NASA-STD-3000A, 1989\]

-   **10.1.10** **Illumination for critical operations and
    maintenance.** Where it is critical, the design shall ensure that
    adequate maintenance illumination shall not interfere with operator
    visual tasks. \[Source: NASA-STD-3000A, 1989\]

-   **10.1.11** **Special information and communications interfaces.**
    Workspace and interfaces for accessing maintenance information
    systems and maintenance communications systems shall be provided
    where these special maintenance linkages are appropriate in the
    design of the system. \[Source: NASA-STD-3000A, 1989\]

**Example.** Remote maintenance subsystems that include computers,
terminals, modems, and networks provide special links to maintenance
information and communications systems.

## 10.2 Workstations and consoles 

Standard console designs are addressed in this section. Recommended
configurations for sit, sit-stand, and stand consoles are given, and
horizontal wrap-around and vertically stacked segment alternatives are
provided. Additional consoles for teams that monitor ongoing processes
are addressed in this section.

### 10.2.1 Sit, sit-stand, and stand consoles

The rules that follow are to be used to gain the benefits and potential
cost savings inherent in standard consoles, units, and racks. In some
cases, planned usage may necessitate unique design solutions.

**Discussion.** The task performance of a user working with consoles is
influenced by 1) the contours and slopes of the console panels, 2) the
parallax in viewing displays, 3) the location of displays and controls,
and 4) the adequacy of the space to support the console operator.

-   **10.2.1.1** **Dimensions for console configurations.** Exhibit
    10.2.1.1(a) lists five types of consoles for individuals and gives
    dimensions for alternative standard configurations. Selected
    configurations should conform to the dimensions listed and
    illustrated in Exhibit 10.2.1.1(b). \[Source: Department of Defense
    (MIL-HDBK-759B), 1992\]

[]{#__RefHeading___Toc30386400 .anchor}**Exhibit 10.2.1.1 (a)** Standard
console dimensions

> []{#__RefHeading___Toc30386401 .anchor}**Exhibit 10.2.1.1 (b)**
> Standard console illustration and dimension key

![](media/image1.wmf)

-   **10.2.1.2** **Selection of a standard console.** Each console
    configuration should be selected to accommodate the following
    task-related variables:

a.  visibility over the top of console,

b.  user mobility (e.g., sit, sit-stand, or stand requirements),

c.  control and display demand for panel space (for example, display
    legibility, control accessibility),

d.  volume of space necessary for leg room and essential equipment
    beneath the writing surface, and

e.  communications demands of the tasks. \[Source: Department of Defense
    (MIL-STD-1472D), 1989\]

### 10.2.2 Seated workstations

In this section, a discussion to help exploit the advantages of the
seated position is followed by general rules for ensuring seating
compatibility with tasks. The section includes rules for office seating
design and for seat cushion, armrest, and footrest design. Temporary
swing away seats are also treated. Vehicles and moving platform seats
are not addressed in this document.

Designers can exploit the following advantages of seated positions:

a.  Seated positions reduce workload by helping maintain the body
    position and carry body weight.

b.  Seats provide comfortable positions that promote long-term focused
    attention on activities and information in the nearby workspace.

c.  Seating can help establish stability to accommodate fine eye-hand
    coordination tasks.

d.  Seating can be designed to accommodate powerful exertions on pedals.

e.  Seated workers have more accessibility to equipment and are able to
    move about to reduce fatigue and boredom,

f.  Seating can be designed to swivel and move on rollers to extend
    visual, reach, and communications access. \[Source: MIL-HDBK-759B,
    1992\]

The main disadvantages of seated work positions are that seated workers
can apply less arm force and smaller arm movements than standing
workers. In addition, seating limits reach with both arms and hands.

-   **10.2.2.1** **Swivels and rollers.** For most jobs and tasks that
    do not require heavy work and where seated positions are
    appropriate, swivel capability and caster rollers should be provided
    for seat ingress and egress and task performance throughout the
    workplace. \[Source: MIL-HDBK-759B, 1992\]

-   **10.2.2.2** **Seating dimensions.** General seated workplace
    dimensions are given and illustrated in Exhibit 10.2.2.2. Seat
    designs and selections should meet or exceed minimum values, provide
    adjustment ranges and fixed and preferred values when these are
    compatible with the population and tasks to be performed. \[Source:
    MIL-HDBK-759B, 1992; MIL-STD-1472D, 1989\]

> []{#__RefHeading___Toc30386402 .anchor}**Exhibit 10.2.2.2** Seated
> workspace dimensions and illustrations

-   **10.2.2.3** **Knee space height.** The preferred knee space, as
    shown in Exhibit 10.2.2.2, should be 640 mm (25 in) in height.
    \[Source: MIL-HDBK-759B, 1992\]

**Discussion.** A footrest will increase the needed knee space.

-   **10.2.2.4** **Attaining knee space.** Where equipment packaging
    permits, knee space and associated leg space should be attained by
    sloping the console surface under the working or writing surface.
    \[Source: MIL-HDBK-759B, 1992\]

-   **10.2.2.5** **Seat cushioning.** Seats should be cushioned whenever
    workers must remain seated for more than an hour at a time, or for
    more than 20% of their working time. \[Source: MIL-HDBK-759B, 1992\]

-   **10.2.2.6** **Seat cushioning features.** Good seat cushioning
    should

a.  have flat, firm shape with enough softness to deform,

b.  have resilient material under the cushion to absorb shocks,

c.  support body weight, primarily around the two bony points of the
    pelvis,

d.  tilt backward 5-7 degrees so the seat (rather than the user\'s
    muscles) supports the back,

e.  be shaped to follow the inward curve of the lower back and provide
    adequate support for it to relieve strain of the back muscles,

f.  avoid applying pressure under the thighs,

g.  incorporate perforated or ventilated materials to prevent hotness or
    sweating, and

h.  allow the sitter to shift positions. \[Source: MIL-HDBK-759B, 1992\]

**Discussion.** Larger cushioned backrests are best because a larger
support area provides the user more opportunities to change position.

-   **10.2.2.7** **The use of armrests.** Workplace seating should
    provide armrests so that the elbows can support some upper body
    weight, unless the rests would be incompatible with the tasks.
    \[Source: MIL-HDBK-759B, 1992; MIL-STD-1472D, 1989\]

-   **10.2.2.8** **Undercut armrests.** Armrests should be undercut to
    allow space for the hips and thighs. Exhibit 10.2.2.2 provides fixed
    armrest dimensions. \[Source: MIL-HDBK-759B, 1992; MIL-STD-1472D,
    1989\]

-   **10.2.2.9** **Removable or adjustable armrests.** Removable or
    adjustable armrests should be considered when removal is necessary
    for some primary tasks. The preferred adjustable range is from 190
    to 280 mm (7.5 to 11 in) above the compressed seat surface and at
    least 200 mm (8 in) in length. \[Source: MIL-HDBK-759B, 1992;
    MIL-STD-1472D, 1989\]

-   **10.2.2.10** **Support arm for tracking control.** When seated
    tasks include the use of a tracking control for frequent or
    continuous control, the armrest should support the worker\'s arm in
    the same plane as the control. \[Source: MIL-HDBK-759B, 1992;
    MIL-STD-1472D, 1989\]

-   **10.2.2.11** **Footrests.** Whenever workers must sit for extended
    periods in seats higher than 460 mm (18 in) or work with work
    surfaces higher than 760 mm (30 in), they should have a footrest.
    \[Source: MIL-HDBK-759B, 1992\]

**Explanation.** Footrests can provide support and add to comfort for
seated jobs. They may be attached to the chair or separate items
positioned on the floor.

-   **10.2.2.12** **Separate footrests.** When footrests are separate
    items, they should not be allowed to interfere with traffic.
    \[Source: MIL-HDBK-759B, 1992\]

-   **10.2.2.13** **Temporary seats.** Where space limitations and task
    frequency warrant, a temporary swing away seat should be provided
    with preferred dimensions of 380 mm (15 in) diameter, 460 mm (18 in)
    floor to seat top dimension with an adjustability of plus or minus
    50 mm (2 in). Exhibit 10.2.2.13 illustrates a swing away seat.
    \[Source: MIL-HDBK-759B, 1992\]

[]{#__RefHeading___Toc30386403 .anchor}**Exhibit** **10.2.2.13**
Swing-away seat for short-term use

![](media/image3.png){width="6.329166666666667in"
height="1.9680555555555554in"}

### 10.2.3 Horizontal wrap-around console alternatives

Whenever the panel space required for a seated console user exceeds that
recommended in Exhibit 10.2.1.1 (a) providing standard console
dimensions, the special purpose horizontal wrap-around console presented
in this section may be used. The concept for this alternative is
illustrated in Exhibit 10.2.3.

> []{#__RefHeading___Toc30386404 .anchor}**Exhibit 10.2.3** Example of
> horizontal wrap-around console

![](media/image4.png){width="2.392361111111111in" height="1.24375in"}

-   **10.2.3.1.** **Panel width.** When requirements for preferred panel
    space for the user exceed a panel width of 1.12 m (44 in), a
    flat-surface, segmented, wrap-around console should be provided.
    \[Source: MIL-STD-1472D, 1989\]

**Discussion.** This panel facilitates placing controls within the reach
of the 5th percentile users.

-   **10.2.3.2** **Panel angles.** The left and right segments should be
    placed at an angle, measured from the frontal plane of the central
    segment, so that these segments can be reached by the 5th percentile
    stationary operator. \[Source: MIL-STD-1472D, 1989\]

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-   **10.2.3.3** **Central segment** **dimensions with vision over the
    top.** Where vision over the top is required (thereby limiting
    vertical panel space), the width of the central segment shall not
    exceed 1.12 m (44 in). \[Source: MIL-STD-1472D, 1989\]

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-   **10.2.3.4** **Left and right segment** **dimensions with vision
    over the top.** Where vision over the top is required (thereby
    limiting vertical panel space), the left and right segments should
    not exceed 610 mm (24 in). \[Source: MIL-STD-1472D, 1989\]

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-   **10.2.3.5** **Width dimensions without vision over the top.** Where
    vision over the top is not required (that is, where the total
    console height exceeds the seat height by more than 690 mm \[27
    in\]), the width of the central segment shall not exceed 860 mm (34
    in). \[Source: MIL-STD-1472D, 1989\]

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-   **10.2.3.6** **Left and right segment** **dimensions without vision
    over the top.** Where vision over the top is not required (that is,
    where the total console height exceeds the seat height by more than
    690 mm \[27 in\]), and that of the left and right segments should
    not exceed 610 mm (24 in). \[Source: MIL-STD-1472D, 1989\]

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-   **10.2.3.7** **Viewing angle.** The total required left-to-right
    viewing angle shall not exceed 190 degrees. \[Source: MIL-STD-1472D,
    1989\]

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-   **10.2.3.8** **Reduction of viewing angle.** The required
    left-to-right viewing angle should be reduced whenever possible
    through appropriate control-display layout. \[Source: MIL-STD-1472D,
    1989\]

### 10.2.4 Vertical stacked segments for consoles

Another alternative special-purpose console applies to the case where
seeing over the top is not required and lateral space is limited. The
concept for this individual seated user console is shown in Exhibit
10.2.4.

> []{#__RefHeading___Toc30386405 .anchor}**Exhibit** **10.2.4** Examples
> of vertical stacked
> segments![](media/image5.png){width="1.9104166666666667in"
> height="2.283333333333333in"}

-   **10.2.4.1** **Panel division.** Where direct forward vision over
    the top of the console is not required by a seated person and where
    lateral space is limited, the panel shall be divided into three
    vertical stacked segments whose surfaces are perpendicular to the
    operator\'s line of sight when the head is moved up or down
    slightly. \[Source: MIL-STD-1472D, 1989\]

**Discussion.** Locating screens above resting eye level can cause the
user to adopt uncomfortable or awkward positions, leading to pain. To
avoid this, only infrequently used information ought to be located in
the upper tiers segments of the consoles. For additional information on
display location, see Chapter 5, Displays and printers.

-   **10.2.4.2** **Height.** The center of the central segment should be
    800 mm (31.5 in) above the seat reference point and not exceed 530
    mm (21 in). \[Source: MIL-STD-1472D, 1989\]

### 10.2.5 Design and arrangement of multi-person consoles

When a team must monitor, diagnose, or control a large ongoing process
or operation, many arrangements of consoles are possible. Exhibit
10.2.5.1 shows several basic console arrangements, variations on the
basic arrangements, and an example of a multi-unit control room which
incorporates supervisory visual access. This section offers rules for
selecting among alternative console arrangements and console designs.

-   **10.2.5.1** **Selecting arrangements for team consoles.** Several
    primary and support factors shall be used in selecting among
    alternative team console arrangements (see Exhibit 10.2.5.1). The
    factors to be used are listed in (a) through (q).

**Discussion.** Primary factors for team console arrangements, (a)
through (l), are those that directly involve and impact the ongoing
process and mission of the system. Secondary or support factors, (m)
through (q), are off-line to the direct process monitoring or control
but may influence the layout and design of team consoles.

a.  functions and resultant tasks for personnel, hardware, and software
    components that are necessary for process monitoring and controlling
    (these functions and tasks must cover normal, degraded, and
    emergency modes of system operations),

b.  necessary team communication interactions and team links with
    external command and control components of the system,

c.  numbers of personnel necessary to handle the expected high workload
    levels,

d.  common viewing requirements and individual visual access
    requirements,

e.  maintenance access for control or processing subsystems,

f.  supervisory viewing requirements, ongoing supervisory process
    control responsibilities, supervisory space and access requirements,
    and supervisory information and communications requirements,

g.  management, maintenance, and operating concepts and policies,

h.  architectural and facility engineering constraints,

i.  requirements and space constraints associated with primary
    equipment, controls and displays, computer, printout or readout
    devices, and closed-circuit monitoring devices,

j.  illumination, acoustic, and environmental requirements associated
    with primary tasks,

k.  primary work surface areas for writing and reading,

l.  primary storage areas and surfaces for documents, procedures, tools,
    spares, and supplies,

m.  secondary supervisor office privacy requirements,

n.  security requirements,

o.  visitor provisions and traffic areas,

p.  personnel conveniences such as restrooms, kitchen, snack, drinking
    water, and personal belonging storage, and

q.  support storage for additional documentation and other housekeeping
    needs. \[Source: Electric Power Research Institute (EPRI NP-36591),
    1984\]

> []{#__RefHeading___Toc30386406 .anchor}**Exhibit 10.2.5.1** Basic and
> variations of multi-person console arrangements with an example
> control room arrangement

![](media/image6.png){width="3.9923611111111112in"
height="6.607638888888889in"}

-   **10.2.5.2** **Selecting team console types and designs.** Selection
    and design of individual team position consoles should be made among
    standard sit, sit-stand, and stand consoles (see Section 10.2.1),
    free standing consoles, built-in vertical wall consoles, and
    specially configured consoles based upon the factors that follow:

a.  functions and tasks allocated to the types of personnel and
    position(s) associated with the console,

b.  visual access required for common control display areas that may
    determine the required see-over characteristics,

c.  position communication requirements,

d.  personnel mobility requirements,

e.  reach and visual access areas for consoles (Exhibit 10.2.5.2 shows
    reach and visual legibility arcs for console design),

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f.  work surface area requirements,

g.  requirements to share information, displays, controls, or work
    surfaces with adjacent positions,

h.  the postures required for monitoring and controlling, as well as the
    durations that such postures must be maintained, and

i.  the need for consoles and information standardization across system
    functions and locations to reduce training and to facilitate
    interoperability. \[Source: EPRI NP-36591, 1984\]\]

> **Discussion.** In accomplishing the design layout, the designer needs
> to consider the criticality, durations, and frequency of control and
> display interactions, as well as the legibility and accuracies
> required.
>
> []{#__RefHeading___Toc30386407 .anchor}**Exhibit** **10.2.5.2**
> Concepts of functional reach arc and equidistant visual arc for a
> stand console

### 10.2.6 Standing workstations 

Standing workstations are used for routine, frequent, or short term jobs
or tasks for which the worker needs to be able to face different
directions or to move from one position to another. The designer can
exploit the following advantages of a standing position when they are
compatible with the tasks to be performed:

a.  When standing, workers can apply more muscular arm force and make
    larger arm movements than when seated. These forces may be applied
    to levers or valves.

b.  Standing workers can move to see and use components in areas that
    would be inaccessible to seated users.

c.  Standing workers can move about to reduce fatigue and boredom.

d.  Standing workers can use flat working surfaces without knee room,
    thus saving space.

e.  A standing workstation is not as dimensionally constrained as that
    of the seated operator. Equipment that standing operators view or
    adjust may be placed anywhere around them as long as it is at the
    proper height.

**Discussion.** If the worker is not free to move about, or if the task
and attention demands are concentrated so that the worker remains in one
position, the workstation should be designed so the worker can sit or
take a sit-stand position. The main disadvantage of the standing
position is that the worker\'s physical workload is increased because
one constantly has to carry one\'s own weight and stabilize and balance
one\'s body.

-   **10.2.6.1** **Standing workstation and workbench dimensions.** The
    dimensions of standing workstations and workbenches should meet the
    minimum and not exceed the maximum preferred values in Exhibit
    10.2.6.1 and, when required, provide for adjustments to accommodate
    the 5th through the 95th percentile of the worker population.
    \[Source: MIL-HDBK-759B, 1992\]

[]{#__RefHeading___Toc30386408 .anchor}**Exhibit 10.2.6.1** Standing
workstation illustration and dimensions

![](media/image8.png){width="2.126388888888889in"
height="2.8027777777777776in"}

-   **10.2.6.2** **Control and display placement on stand consoles.**
    Prime controls and displays on stand consoles (including CRT
    displays) should be located in the prime areas and within the
    boundaries noted in Exhibit 10.2.6.2, which illustrates control and
    display placement limits for those vertical and stand consoles where
    see-over capabilities are not required. \[Source: EPRI NP-36591,
    1984\]

[]{#__RefHeading___Toc30386409 .anchor}**Exhibit 10.2.6.2** Control and
display placement limits for vertical and stand consoles where see over
capabilities are not required.

![](media/image9.png)

-   **10.2.6.3** **Hardwired display placement.** Hardwired displays,
    including annunciator displays, should be located horizontally
    within 45 degrees of the operator\'s eye reference point with CRT
    displays restricted to within 35 degrees. \[Source: EPRI NP-36591,
    1984\]

-   **10.2.6.4** **Control and display placement on stand consoles.** On
    consoles where a discrete task sequence of display and control
    actions is appropriate for a single user\'s actuation, the sequenced
    displays and controls should not exceed 1.8 m (72 in) in width so
    reach and visual access can be accommodated. \[Source: EPRI
    NP-36591, 1984\]

**Explanation.** The actual display limits on the console will depend
upon the distance from which the worker views the console displays. The
illustration at the bottom of Exhibit 10.2.6.2 shows a 1.8 m (72 in)
dimension as the maximum lateral spread for a discrete task at normal
viewing distance.

-   **10.2.6.5 Special team sit-stand console minimum vertical height.**
    When a sit-stand console requires a see-over capability, the
    vertical height of the console should be no higher than 1.40 m (55
    in). \[Source: EPRI NP-36591, 1984\]

**Explanation.** Where a sit-stand desk surface of at least 410 mm (16
in) deep and 610 mm (24 in) wide is provided, 760 mm (30 in) is
preferred.

-   **10.2.6.6 Special team sit-stand console minimum vertical height.**
    Desk height should be 910 to 960 mm (36 to 38 in) high so that the
    seated eye height can be about the same as the standing eye height.
    \[Source: EPRI NP-36591, 1984\]

-   **10.2.6.7 Special team sit-stand console seat dimensions.** The
    seat should be adjustable up to 760 mm (30 in) in seat cushion
    height and have a 460 mm (18 in) diameter footrest located at a
    constant 460 mm (18 in) below the seat cushion. \[Source: EPRI
    NP-36591, 1984\]

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-   **10.2.6.8 Kickspace.** All cabinets, consoles, and work surfaces
    that require an operator or maintainer to stand or sit close to
    their front surfaces shall contain a kick space at the base of the
    front surfaces of at least 100 mm (4 in) deep and 100 mm (4 in)
    high. \[Source: MIL-STD-1472D, 1989\]

### 10.2.7 Work surfaces

-   **10.2.7.1** **Work surfaces for standing positions.** Work surfaces
    shall be consistent with the needs of jobs and tasks. Surfaces for
    standing work shall be 915 mm plus or minus 15 mm (36 in plus or
    minus .6 in) from the floor. Where machine parts or equipment are
    manipulated, the surface shall be at least 760 mm (30 in) wide. In
    all cases, the work surface shall be at least 407 mm (16 in) deep.
    This lateral depth may be increased based upon the demands of the
    job. \[Source: MIL-STD-1800A, 1990\]

-   **10.2.7.2** **Work surfaces for seated positions.** Surfaces for
    seated operations shall be 740 - 790 mm (29 - 31 inches) above the
    floor. Width and depth shall be the same as in Paragraph 10.2.2.3.1.
    \[Source: MIL-STD-1800A, 1990\]

**Discussion.** For light precision work, work surface height can be
increased within the above limits. For work requiring increased force,
the work surface height can be lower.

-   **10.2.7.3** **Writing surfaces.** Writing surfaces shall be at
    least 610 mm (24 in) wide and 407 mm (16 in) deep. \[Source:
    MIL-STD-1800A, 1990\]

-   **10.2.7.4** **Task sizing of work surfaces.** When a work surface
    is used for more than one task, the surface dimensions for tasks
    requiring the most space shall be used. \[Source: MIL-STD-1800A,
    1990\]

### 10.2.8 Storage

-   **10.2.8.1** **Storage space.** Adequate space for storage of
    manuals, worksheets, test equipment, tools, and other materials that
    are required for use by operational or maintenance personnel shall
    be provided on consoles and, where appropriate, on equipment.
    \[Source: MIL-STD-1472D, 1989\]

### 10.2.9 Workstations for maintenance repair

-   **10.2.9.1** **Sizing.** Maintenance repair workstations shall be
    large enough to handle the largest equipment or component that will
    require repair. \[Source: NASA-STD-3000A, 1989\]

-   **10.2.9.2 Special equipment.** Maintenance repair workstations
    shall be designed to accommodate general purpose, specific purpose,
    and automated diagnostic and test equipment appropriate to the
    expected maintenance tasks. \[Source: NASA-STD-3000A, 1989\]

### 10.2.10 Workspace for positions other than seated or standing

Maintenance work requiring unusual working positions is to be avoided
through design. Dimensions for workspace other than seated or standing
are illustrated in this section.

-   **10.2.10.1** **Workspace clearance dimensions.** When personnel
    must work in or pass through limited spaces, the clearances shall
    meet or exceed the minimum values given and illustrated in Exhibit
    10.2.10.1. \[Source: MIL-HDBK-759B, 1992\]

[]{#__RefHeading___Toc30386410 .anchor}**Exhibit 10.2.10.1** Dimensions
and illustrations for workspaces other than seated or standing

  ----------------------------------------------------- --- --------------- ------------- --------------- -----------
  ![](media/image10.png){width="2.136111111111111in"        **Supine**      **Minimum**   **Preferred**   **Artic
  height="5.966666666666667in"}                             **workspace**                                 clothed**

                                                        A   Height          510mm (20in)  610mm (24in)    660mm
                                                                                                          (26in)

                                                        B   Length          1860mm (73in) 1910mm (75in)   1980mm
                                                                                                          (78in)

                                                            **Squatting**   **Minimum**   **Preferred**   **Artic
                                                            **workspace**                                 clothed**

                                                        C   Height          1220mm (48in) \--             1290mm
                                                                                                          (51in)

                                                        D   Width           685mm (27in)  910mm (36in)    \--

                                                            Optimum display 685mm (27in)  1090mm (43in)   \--
                                                            area                                          

                                                            Optimum control 485mm (19 in) 865mm (34in)    
                                                            area                                          

                                                            **Stooping      **Minimum**   **Preferred**   **Artic
                                                            workspace**                                   clothed**

                                                        E   Width           660mm (26in)  1020mm (40in)   1120mm
                                                                                                          (44in)

                                                            Optimum display 810mm (32in)  1220mm (48in)   
                                                            area                                          

                                                            Optimum control 601mm (24in)  990 mm (39in)   
                                                            area                                          

                                                            **Kneeling**    **Minimum**   **Preferred**   **Artic
                                                            **workspace**                                 clothed**

                                                        F   Width           1060mm (42in) 1220mm (48in)   1270mm
                                                                                                          (50in)

                                                        G   Height          1420mm (56in) \--             1500mm
                                                                                                          (59in)

                                                        H   Optimum work    \--           685mm (27in)    \--
                                                            point                                         

                                                            Optimum display 510mm (20in)  890mm (35in)    \--
                                                            area                                          

                                                            Optimum control 510mm (20in)  890mm (35in)    \--
                                                            area                                          

  ![](media/image11.png){width="2.2215277777777778in"       **Kneeling      **Minimum**   **Preferred**   **Artic
  height="1.9277777777777778in"}                            crawl space**                                 clothed**

                                                        I   Height          785mm (31in)  910mm (36in)    965mm
                                                                                                          (38in)

                                                        J   Length          1500mm (59in) \--             1760mm
                                                                                                          (69in)

                                                            **Prone work or **Minimum**   **Preferred**   **Artic
                                                            crawl space**                                 clothed**

                                                        K   Height          430mm (17in)  510mm (20in)    610mm
                                                                                                          (24in)

                                                        L   Length          2860mm        \--             \--
                                                                            (113in)                       
  ----------------------------------------------------- --- --------------- ------------- --------------- -----------

## 10.3 Workplace layout

### 10.3.1 Equipment and workstation layout 

-   **10.3.1.1 Traffic areas.** Traffic area and traffic flow design
    should be based upon

a.  a consideration of task-based activities in and around workstations,

b.  location of workstations and traffic areas so that they interfere
    minimally with each other,

c.  a consideration of the necessary movements of equipment in the work
    and traffic areas,

d.  a consideration of normal traffic conditions, worst cases, and
    emergency conditions, and

e.  a consideration of means by which to avoid collisions and to
    maximize traffic efficiency. \[Source: NASA-STD-3000A, 1989\]

-   **10.3.1.2** **Layout to minimize traffic and congestion.**
    Equipment and workstations shall be located so as to minimize
    congestion in workflow or worker movement and to minimize
    interference with and from personnel traffic areas. \[Source:
    NASA-STD-3000A, 1989\]

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-   **10.3.1.3** **Equipment grouping by maintenance needs.** Equipment
    and components maintained by the same technician should be grouped
    together so the technician will not have to move around in checking
    or working on the equipment. \[Source: MIL-STD-1472D, 1989;
    MIL-HDBK-759B, 1992; AFSC DH 1-3, 1980\]

-   **10.3.1.4** **Equipment grouping.** Equipment should be grouped so
    that no other type of technician has to remove equipment or
    components before the proper technician can obtain access to make
    replacements or repairs. \[Source: MIL-STD-1472D, 1989;
    MIL-HDBK-759B, 1992; AFSC DH 1-3, 1980\]

**Example.** Components that require frequent visual inspection of check
points, adjustment points, cable-end connection, and labels should be
located in positions that can be seen easily.

-   **10.3.1.5** **Equipment arrangements for groups of workers.** When
    groups of two or more people need to be located within a work space,
    the groups and their equipment shall be arranged so that equipment
    can be shared, communications requirements can be minimized,
    necessary face-to-face communications and coordination are
    facilitated, mutual interference is minimized, and supervision is
    simplified. \[Source: MIL-STD-1472D, 1989\]

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-   **10.3.1.6** **Layout for safety.** All equipment and components
    should be located to minimize the possibility of equipment damage,
    personnel injury, or inadvertent actuation. \[Source: MIL-HDBK-759B,
    1992; AFSC DH 1-3, 1980\]

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-   **10.3.1.7** **Criticality.** The most critical units (based on
    mission, functions, and tasks) shall be located so as to be most
    accessible. \[Source: MIL-STD-1472D, 1989; NASA-STD-3000A, 1989\]

-   **10.3.1.8** **Frequency.** Where criticality is not a factor, units
    expected to require more total use (either more frequent and longer
    durations of use) shall be more accessible. \[Source: MIL-STD-1472D,
    1989; NASA-STD-3000A, 1989\]

-   **10.3.1.9** **Floor space for work and passage.** Floor space shall
    be planned and designed to ensure the following: (a-f are required
    by 29 CFR 1910.22)

a.  floor space for work areas and for aisle space do not occupy the
    same space and, thus, the work and passage do not interfere,

b.  material and equipment handling tasks are to be used in sizing work
    and aisle spaces; necessary turning space for materials and
    equipment is included,

c.  the work and aisle space can be kept clean,

d.  storage space for material and equipment does not interfere with
    work or passage,

e.  floor work and aisle space are free of protruding nails, splinters,
    holes, loose boards, or other loose materials,

f.  permanent aisles and passageways are appropriately marked,

g.  floor loading limits are conspicuously displayed to prevent
    structural overloading,

h.  floor space around electrical utilization equipments is provided in
    accordance with Paragraph 12.4.1.18, (Design and location of
    electrical installations and electrical utilization equipment), and

i.  free floor space of at least 1.2m (4 ft) is to be provided in front
    of each equipment rack. \[Source: MIL-STD-1472D, 1989;
    MIL-STD-1800A, 1990\]

-   **10.3.1.10** **Spacing in front of racks and cabinets.** Clearance
    from the front of a rack to the nearest facing surface or obstacle
    shall be at least 1.07 m (42 in). \[Source: MIL-STD-1472D, 1989\]

-   **10.3.1.11** **Spacing between racks and cabinets.** The minimum
    space between rows of cabinets containing drawers shall be 200 mm (8
    in) greater than the depth of the deepest drawer. \[Source:
    MIL-STD-1472D, 1989\]

-   **10.3.1.12** **Lateral work space.** The minimum lateral work space
    for racks having drawers or removable equipment shall be as follows
    (measured from the drawers or equipment in the extended position):

a.  For racks having drawers of removable items weighing less than 20 kg
    (44 lb), allow 460 mm (18 in) on one side and 100 mm (4 in) on the
    other, and

b.  For racks having drawers or removable items weighing over 20 kg (44
    lb), allow for two person access (one on each side): 460 mm (18 in)
    on each side. \[Source: MIL-STD-1472D, 1989; MIL-STD-1800A, 1990\]

-   **10.3.1.13** **Rear access space.** When a maintainer is to have
    access to the back of an entire rack or panel-mounted unit, the unit
    shall be installed with sufficient clearance to permit the
    maintainer to perform all required maintenance tasks, including the
    removal of the rear panel(s). \[Source: AFSC DH 1-3, 1980\]

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-   **10.3.1.14** **Maintenance independence.** Workplaces, controls,
    and displays that are associated with maintenance activities should
    be separate from operator workplaces, controls, and displays.
    \[Source: NASA-STD-3000A, 1989; MIL-STD-1472D, 1989\]

**Discussion.** Controls and displays that are solely for maintenance
should not be visible to operators but should be readily accessible when
needed by maintenance personnel.

### 10.3.2 Work space features designed into equipment

-   **10.3.2.1** **Work space to permit access.** Space for maintenance
    access shall be designed into the systems and equipment. \[Source:
    AFSC DH 1-3, 1980\]

**Discussion.** Accessibility is influenced by system maintenance
concepts, procedures, and tasks. \[Source: AFSC DH 1-3, 1980

-   **10.3.2.2** **Access space for effective maintenance.** Equipment
    shall be designed to allow effective maintenance by providing
    sufficient space for maintenance personnel to access the equipment
    and components permitting maintainers with 95th percentile values on
    task related dimensions to have sufficient access and space to
    perform the maintenance tasks and to use the tools necessary for the
    tasks. \[Source: AFSC DH 1-3, 1980\]

**Example.** Where maintenance is to be performed at the equipment
location, equipment design can include techniques that use the chassis
as an integral part of the structure of the equipment, for example, pull
out drawers or shelves. These techniques ensure that all components can
be reached with a minimum of access space. (See also Chapter 4,
Designing equipment for maintenance.

-   **10.3.2.3** **Reach limits.** Reach limits shall permit the 5th
    percentile maintainer access to perform the tasks with the
    appropriate tools. \[Source: AFSC DH 1-3, 1980\]

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-   **10.3.2.4** **Access openings.** Access openings should be provided
    on at least three sides of equipment as illustrated in Exhibit
    10.3.2.4, which illustrates the space required for three-sided
    access with hinged doors versus that required for integral pullout
    drawers. \[Source: AFSC DH 1-3, 1980\]

**Discussion.** Equipment with panels or hinged access doors may need to
be removed before the equipment can be maintained or serviced. Less room
is generally required to work on equipment with pull out shelves or
drawers than on equipment with access doors or panels. Built in pullout
shelves and drawers are preferred to hinged doors or removable panels.

> **Exhibit 10.3.2.4** Access space through integral design.
>
> \[Source: AFSC DH 1-3, 1980\]

![](media/image12.png){width="2.3333333333333335in" height="1.96875in"}

-   **10.3.2.5** **Component locations for access.** Components to be
    serviced, replaced, or repaired on the equipment should be placed in
    a plane parallel to and within 150 mm (6 in) of the access openings
    when hinged doors or removable panels are used. \[Source: AFSC DH
    1-3, 1980\]

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-   **10.3.2.6** **Ease of replacement.** Each unit of equipment and its
    components shall be designed and installed to ensure ease of
    replacement. \[Source: AFSC DH 1-3, 1980\]

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-   **10.3.2.7** **Access interference.** Each unit should be located so
    that no other units or equipment need to be removed to reach it.
    \[Source: AFSC DH 1-3, 1980\]

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-   **10.3.2.8** **Equipment location to reduce access interference.**
    Units of equipment shall not be located in recesses, behind, or
    under structural members or other equipment components where access
    or removal is difficult. \[Source: AFSC DH 1-3, 1980\]

-   **10.3.2.9** **Access to equipment covers.** Technicians shall be
    able to open unit covers without interference from bulkheads,
    brackets, or other equipment. \[Source: AFSC DH 1-3, 1980\]

-   **10.3.2.10** **Visual access.** Units shall be located so that
    check points, adjustment points, connectors, and labels face the
    technician and are not hidden by other units. \[Source: AFSC DH 1-3,
    1980\]

-   **10.3.2.11** **Clear visual inspection.** Units and components that
    require frequent visual inspection shall be located so that items
    being inspected (for example, desiccators or fuses) can be seen
    easily without removal of panels, covers, or other units. \[Source:
    AFSC DH 1-3, 1980\]

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-   **10.3.2.12** **Front removal.** Units of equipment should be
    designed for removal of components and, if applicable, subordinate
    units, through the front rather than the back of the equipment.
    \[Source: AFSC DH 1-3, 1980\]

## 10.4 Design of passageways

In complex systems and facilities, passageways are necessary for
personnel to be able to get to equipment areas and works stations. These
personnel may be required to carry tools and to move equipment through
passageways including over steps and through entrances. This subsection
covers traffic area walkways; special spaces such as catwalks (to be
avoided when possible); platforms and elevators; entrances and exits;
and ramps, stairs, and ladders.

**Definitions. Passageways** for the purpose of this document are areas
across which people must pass for work purposes. **Walkways** are areas
designated for walking; **corridors** are walkways that are physically
restricted by walls or the like.

### 10.4.1 Walkways and traffic areas

-   **10.4.1.1** **Corridor width.** Corridor widths shall be designed
    for the peak traffic load expected, for traffic directions, and for
    the number of entrances and exits in the area. \[Source:
    MIL-HDBK-759B, 1992\]

-   **10.4.1.2** **Corridors.** To allow personnel to move with
    tolerable restrictions, the widths of corridors shall equal or
    exceed those given in Exhibit 10.4.1.2 (see Paragraph 10.4.7.4.1 for
    OSHA implications when a corridor is designated as part of an
    emergency egress). \[Source: MIL-HDBK-759B, 1992\]

> []{#__RefHeading___Toc30386412 .anchor}**Exhibit** **10.4.1.2**
> Walkway and passageway

![](media/image13.png){width="3.301388888888889in"
height="3.2909722222222224in"}

-   **10.4.1.3** **Added clearance.** Adequate clearance should be
    allowed for personnel wearing bulky clothing and carrying equipment.
    \[Source: MIL-HDBK-759B, 1992\]

**Example.** A person can move through a corridor 510 mm (20 in) wide
with some difficulty; however, a one-person corridor for bulky clothes
and comfortable travel should be at least 760 mm (30 in) wide (see
Exhibit 10.4.1.2). The dimensions of equipment to be carried or
transported may add width to these minimum and preferred values.

-   **10.4.1.4** **Floors.** Passageway floors shall be stable, firm and
    slip resistant. \[Source: Uniform Federal Accessibility Standard
    (UFAS), 1988\]

### 10.4.2 Wheelchair accessible routes

-   **10.4.2.1 Minimum accessible routes.** At least one accessible
    route within the boundary of the site shall be provided from public
    transportation stops, accessible parking, accessible passenger
    loading zones, and public streets or sidewalks to the accessible
    building entrance they serve. \[Source: UFAS, 1988\]

-   **10.4.2.2** **Protruding objects.** Protruding objects shall not
    reduce the clear width of an accessible route or maneuvering space.
    \[Source: UFAS, 1988\]

-   **10.4.2.3 Connecting routes to other areas.** At least one
    accessible route shall connect accessible buildings, facilities,
    elements, and spaces that are on the same site. \[Source: UFAS,
    1988\]

-   **10.4.2.4 Connecting entrances to other areas.** At least one
    accessible route shall connect accessible building or facility
    entrances with all accessible spaces and elements and with all
    accessible units within the building or facility. \[Source: UFAS,
    1988\]

-   **10.4.2.5 Width.** The minimum clear width of an accessible route
    for a single wheelchair shall be 32 in (815mm) at a point and 36 in
    (915 mm) continuously. \[Source: UFAS, 1988\]

-   **10.4.2.6 Making a 90 degree turn around an obstruction.** When a
    person in a wheelchair must make a 90 degree turn around an
    obstruction, the minimum clear width of the accessible route shall
    be a 36 in (915 mm) wide passage into another 36 inch (915 mm)
    passage if the depth of each leg is a minimum of 48 inches (1220 mm)
    on the inside dimensions of the turn, as shown in
    [Exhibit](http://www.access-board.gov/adaag/html/fig7a.html)
    10.4.2.6. \[Source: UFAS,1988\]

> []{#__RefHeading___Toc30386413 .anchor}**Exhibit 10.4.2.6** Minimum
> clearance point for a single wheelchair. \[Source: UFAS, 1988\]

[]{.mark}

![](media/image14.png){width="2.123611111111111in"
height="3.009027777777778in"}

[]{.mark}

-   **10.4.2.7 Making a U-turn in a wheelchair.** When a person in a
    wheelchair must make a U-turn, the space provided should at minimum
    be 1965 mm (78 in) by 1525 mm (60 in) as shown in Exhibit 10.4.2.7.
    \[Source: ADAAG, 1998\]

    []{.mark}

    []{.mark}

    []{.mark}

    []{.mark}

    []{.mark}

> []{#__RefHeading___Toc30386414 .anchor}**Exhibit 10.4.2.7** Dimensions
> for making a U-turn in a wheelchair. \[Source: UFAS, 1988\]

[]{.mark}

![](media/image15.png){width="2.2916666666666665in"
height="1.6979166666666667in"}

-   **10.4.2.8 Passing Space.** When an accessible route has less than
    60 in (1525 mm) clear width, then passing spaces at least 60 in by
    60 in (1525 mm by 1525 mm) shall be located at reasonable intervals
    not to exceed 200 ft (61 m). \[Source: UFAS, 1988\]

**Discussion.** A T-intersection of two corridors or walks is an
acceptable passing place. \[Source: UFAS, 1988\]

-   **10.4.2.9 Slope.** An accessible route with a running slope greater
    than 1:20 is a ramp and shall comply with Section 10.4.8 (Ramps,
    ladders, and stairs). \[Source: UFAS, 1988\]

-   **10.4.2.10 Maximum slope.** Nowhere shall the cross slope of an
    accessible route exceed 1:50. \[Source: UFAS, 1988\]

-   **10.4.2.11** **Exclusion of stairs, steps, and escalators.** An
    accessible route shall not include stairs, steps, or escalators.
    \[Source UFAS, 1988\]

-   **10.4.2.12 Egress.** Accessible routes serving any accessible space
    or element shall also serve as a means of egress for emergencies or
    connect to an accessible area of rescue assistance. \[Source: UFAS,
    1988\]

### 10.4.3 Ground and floor surfaces

-   **10.4.3.1** **Floors.** Passageway floors shall be provided with
    nonskid or other high friction surfaces. \[Source: MIL-HDBK-759B,
    1992\]

### 10.4.4 Landings

-   **10.4.4.1 Level landings.** Ramps shall have level landings at
    bottom and top of each ramp and each ramp run. \[Source:
    MIL-HDBK-759B, 1992\]

-   **10.4.4.2 Width.** The landing shall be at least as wide as the
    ramp run leading to it. \[Source: MIL-HDBK-759B, 1992; UFAS, 1988\]

-   **10.4.4.3 Length.** The landing length shall be a minimum of 60 in
    (1525 mm) clear. \[Source: MIL-HDBK-759B, 1992; UFAS, 1988\]

-   **10.4.4.4 Ramp changes directions.** If ramps change direction at
    landings, the minimum landing size shall be 60 in by 60 in (1525 mm
    by 1525 mm). \[Source: MIL-HDBK-759B, 1992; UFAS, 1988\]

### 10.4.5 Catwalks, tunnels, and crawl spaces

Catwalks, tunnels, and crawl spaces are specialized facility features
used to accommodate unique space or environmental limitations that
preclude normal corridors or walkways.

-   **10.4.5.1** **Minimum catwalk width.** The minimum catwalk floor
    width shall be 460 mm (18 inches) to accommodate walking one foot in
    front of the other and carrying tools or equipment. \[Source:
    VanCott & Kinkade, 1972\]

-   **10.4.5.2** **Enclosed space ventilation.** Enclosed catwalks,
    tunnels, and crawl spaces shall have adequate air ventilation to
    sustain their maximum permissible personnel numbers for an
    indefinite period. \[Source: NASA-STD-3000A, 1989\]

**Discussion.** Consider both temperature and air quality when
determining adequate air ventilation. \[Source: NASA-STD-3000A, 1989\]

-   **10.4.5.3** **Movement or work without mechanical aid.** When
    special passageways require bending, stooping, or crawling,
    personnel with 99th percentile dimensions shall be able to
    accomplish the movement and, where applicable, work without the
    assistance of other people or of mechanical aids. \[Source:
    NASA-STD-3000A, 1989\]

### 10.4.6 Platforms, elevators, inclinators

#### 10.4.6.1 Platforms

-   **10.4.6.1.1** **Hands free work area.** Platform design shall
    permit both of the users hands to be free for work. \[Source:
    MIL-HDBK-759B, 1992\]

-   **10.4.6.1.2** **Guardrails.** Guardrails shall be provided in
    accordance with Section 10.4.6.3 (Platform guardrails, toeholds,
    screens, and handholds). \[Source: MIL-HDBK-759B, 1992\]

-   **10.4.6.1.3** **Permissible gaps with equipment.** Platform design
    shall provide a continuous closure between the equipment and the
    platform with average conformation within 50 mm (2 in); avoiding
    gaps greater than 150 mm (6 in). \[Source: MIL-HDBK-759B, 1992\]

-   **10.4.6.1.4** **Protect equipment surface.** Contact plates,
    cushions, bumpers, or pads shall be used, as necessary, to protect
    the equipment surfaces. \[Source: MIL-HDBK-759B, 1992\]

-   **10.4.6.1.5** **Platform strength.** The platform shall have
    sufficient strength to hold the worker(s) in addition to the
    heaviest tools and equipment expected plus a safety factor
    consistent with design practice for the structural materials.
    \[Source: MIL-HDBK-759B, 1992\]

**Discussion.** Assume 113.4 kg (250 lb) for each person. \[Source:
MIL-HDBK-759B, 1992\]

-   **10.4.6.1.6 Test equipment support.** When test equipment will be
    used, the design shall provide support for test equipment at the
    appropriate height for its use. \[Source: MIL-HDBK-759B, 1992\]

-   **10.4.6.1.7** **Open metal grating for exterior platforms and work
    area surfaces.** Exterior platforms and similar work areas shall be
    constructed of open metal grating. \[Source: MIL-STD-1472D, 1989;
    MIL-STD-1800A, 1990; MIL-W-5044, 1998; MIL-W-5050, 1998\]

-   **10.4.6.1.8** **Alternate surfaces for platforms and work area
    surfaces.** Where grating is impractical and for alternatively
    constructed interior platforms and work passageways, floor surfaces
    shall be treated with non-skid material that conforms to MIL-W-5044
    and that is applied in accordance with MIL-W-5050. \[Source:
    MIL-STD-1472D, 1989; MIL-STD-1800A, 1990; MIL-W-5044, 1998;
    MIL-W-5050, 1998\]

#### 10.4.6.2 Portable platforms

-   **10.4.6.2.1** **Portable platforms.** Portable platforms should be
    lightweight in their material and fully collapsible. \[Source:
    MIL-HDBK-759B, 1992\]

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-   **10.4.6.2.2** **Platform wheels and brakes.** Any platform on
    wheels shall have brakes and wheel locks. \[Source: MIL-HDBK-759B,
    1992\]

#### 10.4.6.3 Platform guardrails, toeholds, screens, and handholds

-   **10.4.6.3.1** **Open sides of personnel platforms.** All open sides
    of personnel platforms shall be equipped with guardrails, which have
    at least two rails (an intermediate rail and top rail). \[Source:
    MIL-STD-1472D, 1989\]

-   **10.4.6.3.2** **Guardrails.** The open area of personnel platforms
    where work is to be done shall be guarded without interfering with
    work tasks. \[Source: MIL-STD-1472D, 1989\]

-   **10.4.6.3.3 Guardrail dimensions.** Guardrail dimensions shall be
    as follows:

a.  top rail height at least 1.1 m (42 in)

b.  distance between the platform edge and the centerline of the railing
    not to exceed 65 mm (2.5 inches)

c.  rail diameter between 37 mm (1.5 in) and 75 mm (3 in). \[Source: 29
    CFR 1910.23, 1985; MIL-STD-1472D, 1989\]

**Discussion.** In accordance with OSHA 29 CFR 1910.23 (e), this railing
height and diameter range describe the OSHA standard guard railing for
platforms, ramps, floor openings, hatches, and wall openings (that a
person could fall into). \[Source: 29 CFR 1910.23, 1985; MIL-STD-1472D,
1989\]

-   **10.4.6.3.4** **Toe board or guard screen.** A toe board of 10 cm
    (4 in) to 15 cm (6 in) or a guard screen that extends from the floor
    base to the intermediate rail shall be used to guard floor openings.
    \[Source: MIL-STD-1472D, 1989; MIL-HDBK-759B, 1992\]

**Note.** OSHA 29 CFR 1910.23 (e) permits a 102 mm (4 in) toe board as a
minimum.

**Discussion.** The guard screen is used to prevent a person who falls
on the platform from falling from the platform. It can also prevent most
tools, parts, and equipment from falling from the platform. Toe boards
are intended to prevent tools, parts, and equipment from falling as well
as to prevent the worker\'s foot from slipping off the edge of the
platform.

-   **10.4.6.3.5** **Handholds.** Handholds shall be furnished where
    needed to assist in climbing onto a platform or as aids in
    performing the intended maintenance tasks from the platform.
    \[Source: MIL-STD-1472D, 1989\]

-   **10.4.6.3.6** **Handholds, guardrails for adverse conditions or
    motion.** Handholds and guardrails shall be provided where personnel
    must stabilize themselves because of high winds, ice, fog or other
    hazards and when working in moving vehicles. \[Source:
    MIL-HDBK-759B, 1992\]

#### 10.4.6.4 Elevators, and hydraulically operated platforms

-   **10.4.6.4.1** **Elevators, inclinators, and hydraulic work
    platforms.** Where these passage or work aids are needed, the
    following operating safety features shall be included:

a.  Maximum load signs located where they can be easily seen.

b.  Guards used to prevent accidental operations of the lift.

c.  An easily reachable capability for manually lowering the platform or
    elevator provided when feasible.

d.  Floor surface treatment in accordance with the treatment of open
    platforms in Paragraph 10.4.6.1.8 (Alternate surfaces for platforms
    and work area surfaces). \[Source: MIL-STD-1472D, 1989;
    MIL-STD-1800A, 1990\]

-   **10.4.6.4.2** **Designed-in safety features.** The following
    designed-in features shall be provided:

a.  limit stops to prevent injury to personnel and damage to equipment,
    and

> **Definition.** **Limit stops** are mechanical mechanisms designed to
> restrict a moving object or part by stopping it at predetermined
> (limit) positions.

b.  an automatic fail-safe brake or other self-locking device in case of
    lift mechanism failure. \[Source: MIL-STD-1472D, 1989\]

### 10.4.7 Entrances and exits

This section covers general rules for entrances and exits. Doorways and
normal hinged doors for individual and multi-person entry, alternatives
to normal hinged doors, emergency doors, hatches, and emergency escape
hatches are treated.

#### 10.4.7.1 General

-   **10.4.7.1.1** **Entrances for enclosed work areas.** Enclosed work
    areas should have conventional entrances and exits for routine
    access and to permit unrestricted flow for all anticipated traffic
    and movements of equipment. \[Source: MIL-HDBK-759B, 1992\]

-   **10.4.7.1.2** **Routine.** Conventional entrances and exits for
    enclosed work areas should be located so that personnel who are
    entering or leaving will not inadvertently operate or block access
    to controls or displays or otherwise interfere with ongoing work in
    the area. \[Source: MIL-HDBK-759B, 1992\]

#### 10.4.7.2 Doorways and hinged doors

-   **10.4.7.2.1** **Door dimensions.** Hinged doors that allow the
    passage of one person shall have at least the dimensions shown in
    Exhibit 10.4.7.2.1. \[Source: MIL-STD-1800A, 1990\]

**Note.** If the depicted area is a means of exit, OSHA 29 CFR 1910.37
(h)(2)(i) requires that the floor to ceiling dimension be at least 2.29
m (7.5 ft) and any protrusions from the ceiling be no less than 2.04 m
(6.7 ft).

> []{#__RefHeading___Toc30386415 .anchor}**Exhibit** **10.4.7.2.1** Door
> dimensions. \[Source: MIL-HDBK-759B, 1992\]

![](media/image16.png){width="4.236111111111111in"
height="2.6979166666666665in"}

-   **10.4.7.2.2** **Perpendicular wall door clearances.** When a door
    opens inward next to a perpendicular wall, a clearance of at least
    100 mm (4 in) between the door at the hinge and the plane of the
    wall shall be provided (see Exhibit 10.4.7.2.1). \[Source:
    MIL-STD-1800A, 1990\]

-   **10.4.7.2.3** **Equipment or furniture door clearances.** Equipment
    or furniture shall not be positioned within 2.9 inches of the swing
    path of a door that opens inward (see Exhibit 10.4.7.2.1). \[Source:
    MIL-STD-1800A, 1990\]

-   **10.4.7.2.4** **Door opening direction for normal density
    traffic.** When the normal traffic density and the exiting personnel
    traffic in emergency conditions are expected to be low, then hinged
    doors shall open inward rather than outward into a corridor.
    \[Source: MIL-STD-1800A, 1990\]

**Discussion.** Opening inward will prevent injury to personnel using
the corridor. \[Source: MIL-STD-1800A, 1990\]

-   **10.4.7.2.5** **Door opening direction for high density traffic.**
    When exiting traffic volume is expected to be high, the door shall
    have a see-through window and open outward to ensure the feasibility
    of exiting in an emergency. \[Source: MIL-STD-1800A, 1990\]

#### 10.4.7.3 Alternative door rules

-   **10.4.7.3.1** **Sliding and folding doors.** When horizontal or
    vertical sliding or folding doors are used to allow large pieces of
    equipment or vehicles to pass through, alternative personnel exits
    should be available. \[Source: MIL-STD-1800A, 1990; MIL-HDBK-759B,
    1992\]

**Discussion.** Because large doors may jam, provide a hinged door for
personnel entrance and exit. If horizontal or vertical sliding or
folding doors are the only exits available for personnel to egress the
building, provide a hinged door built into the sliding or folding door.
\[Source: MIL-STD-1800A, 1990; MIL-HDBK-759B, 1992\]

-   **10.4.7.3.2** **Swinging doors.** Swinging doors should be used in
    pairs, one for each direction of traffic, with the hinges attached
    to a center post that separates the doors. \[Source: MIL-STD-1800A,
    1990; MIL-HDBK-759B, 1992\]

-   **10.4.7.3.3** **Visual access on swinging doors.** Swinging doors
    should have openings or windows for visual access to oncoming
    traffic. \[Source: MIL-STD-1800A, 1990; MIL-HDBK-759B, 1992\]

-   **10.4.7.3.4** **Spring mechanisms on swinging doors.** A spring
    mechanism should only be used when the door size or weight prevents
    manual opening and closing. \[Source: MIL-STD-1800A, 1990;
    MIL-HDBK-759B, 1992\]

**Discussion.** Avoid spring closure mechanisms with a light door as
this closing arrangement can be hazardous. \[Source: MIL-STD-1800A,
1990; MIL-HDBK-759B, 1992\]

-   **10.4.7.3.5** **Revolving doors.** Revolving doors are hazardous
    and should not be used. \[Source: MIL-STD-1800A, 1990;
    MIL-HDBK-759B, 1992\]

-   **10.4.7.3.6** **Floor to ceiling glass doors or windows.** Where
    floor to ceiling doors or windows are used, the glass area should be
    patterned or labeled so that users will not mistake it for an
    unobstructed passageway. \[Source: MIL-STD-1800A, 1990;
    MIL-HDBK-759B, 1992\]

#### 10.4.7.4 Emergency doors

-   **10.4.7.4.1** **Space for exit.** Emergency exits shall allow
    enough space for rapid exit of all occupants, including any who must
    carry essential equipment or wear bulky clothing without danger of
    personnel injury or damage to the equipment being carried. \[Source:
    29 CFR 1910.36-37, 1985; MIL-HDBK-759B, 1992\]

**Discussion.** OSHA 1910.36-37 and National Fire Protection Association
codes specify the design requirements for \"ways of exit\" from
buildings and facilities. A designated means of emergency egress
requires a minimum of 18 inches of unobstructed \"way of exit\" travel
from any point in a structure to an exterior safe public way. Design
requirements for any unobstructed \"way of exit\" are functions of the
nature of the building construction and contents, the maximum occupancy
capacities of its components, and the arrangement of designated \"ways
of exit.\"

-   **10.4.7.4.2** **Emergency door and exit design and construction.**
    Emergency doors and exits shall be designed and constructed so that
    they

a.  are simple to operate,

b.  are readily accessible,

c.  are clearly designated,

d.  are unobstructed,

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e.  are simple to locate and operate in the dark,

f.  are capable of being opened in 3 sec or less,

g.  require 44 and 133 N (10 to 30 lbs) of operating force to open,

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h.  permit exit by one person in 5 sec or less, and

i.  do not in themselves, or in their operation, constitute a safety
    hazard. \[Source: MIL-STD-1472D, 1989\]

**Discussion.** A door that is not blocked in the direction of exiting
travel is not considered an obstruction. An inside door under low
occupancy conditions cannot be less than 71 cm (28 in) in width. For
occupancy capacities of 60 to 100 people, the unobstructed minimum
widths would range between 76 to 112 cm (30 to 44 in), respectively.
When other conditions are considered these minimal dimensions could be
larger. If the depicted corridors in Exhibit 10.4.1.2 are designated
parts of an emergency \"way of exit\", the minimal width of the
unobstructed way would exclude the swing areas where doors open into the
\"way of exit.\"

-   **10.4.7.4.3** **Ceiling areas along a means of egress.** According
    to OSHA 29 CFR 1910.37 (h)(2)(i), ceiling areas along a means of
    egress (including exterior escape paths) shall be at least 2.29 m
    (7.5 ft) above the floor and protrusions not be lower than 2.04 m
    (6.7 ft). \[Source: 29 CFR 1910.37, 1985\]

#### 10.4.7.5 Hatches

-   **10.4.7.5.1** **Flush with surfaces.** Where structural
    considerations permit, hatches shall be flush with the floor or wall
    surfaces. \[Source: MIL-STD-1800A, 1990\]

-   **10.4.7.5.2** **Hatch opening motion.** Hatches shall open with a
    single motion of the hand or foot. \[Source: MIL-STD-1800A, 1990\]

-   **10.4.7.5.3** **Hatch opening and closing forces.** When a handle
    is used, the unlocking force shall not exceed 90 N (20 pounds).
    \[Source: MIL-STD-1800A, 1990\]

-   **10.4.7.5.4** **Hatch opening and closing forces.** Overhead
    hatches shall require no more than 220 N (50 pounds) for opening and
    closing or not exceed the fifth percentile arm and hand strength of
    the user population, whichever is less. \[Source: MIL-STD-1800A,
    1990; MIL-STD-1472D, 1989\]

-   **10.4.7.5.5** **Clearance dimensions for hatches.** Clearance
    dimensions for size and passage shall be based upon the 99^th^
    percentile values for the expected population and accommodate
    suitably clothed and equipped maintainers together with any
    equipment they are expected to carry. \[Source: MIL-STD-1472D,
    1989\]

-   **10.4.7.5.6** **Limiting dimensions for hatches.** Limiting
    dimensions for location and operability shall be based upon the 1st
    percentile values for females in the expected user population.
    \[Source: MIL-STD-1800A, 1990\]

**Discussion.** Clearance dimensions influence the size for access,
accommodation, and entrance by the larger people in the user population.
Limiting dimensions permit the smaller people in the user population to
reach or view controls and displays and to manipulate latches, handles
or accesses.

-   **10.4.7.5.7** **Rescue requirements.** Where rescue of personnel
    may be required, openings shall be large enough to accommodate two
    suitably clothed rescuers. \[Source: MIL-STD-1800A, 1990\]

-   **10.4.7.5.8** **Rectangular hatch minimums.** When rectangular
    hatches are used, they shall meet or exceed the minimal whole body
    dimensions of Exhibit 10.4.7.6.1. \[Source: MIL-STD-1800A, 1990\]

#### 10.4.7.6 Whole body access

-   **10.4.7.6.1** **Whole body access.** Dimensions for whole body
    access shall meet or exceed those shown in Exhibit 10.4.7.6.1.
    \[Source: MIL-STD-1472D, 1989; MIL-STD-1800A, 1990\]

> []{#__RefHeading___Toc30386416 .anchor}**Exhibit 10.4.7.6.1** Whole
> body access dimensions. \[Source: MIL-STD-1472D, 1989; MIL-STD-1800A,
> 1990\]![](media/image17.png){width="2.95625in"
> height="2.5208333333333335in"}

-   **10.4.7.6.2** **Whole body access with a step down.** Where there
    is a need to step down through an access and the step distance
    exceeds 690 mm (27 in), foot rests or steps shall be provided.
    \[Source: MIL-STD-1472D, 1989; MIL-STD-1800A, 1990\]

-   **10.4.7.6.3** **Emergency escape hatches.** Emergency escape
    hatches shall accommodate the equipment and clothing that escaping
    personnel will be carrying and wearing, be clear of all external
    obstructions, and located to avoid external hazards. \[Source:
    MIL-HDBK-759B, 1992\]

-   **10.4.7.6.4** **Emergency escape hatch dimensions.** The minimum
    and preferred dimensions for special emergency escape hatches shall
    be (1) rectangular minimum: 405 mm by 610 mm (16 in by 24 in),
    preferred 510 mm by 710 mm (20 in by 30 in); (2) square minimum: 460
    mm (18 in), preferred 560 mm (22 in); (3) circular minimum 560 mm
    (22 in), preferred 710 mm (30 in). \[Source: MIL-HDBK-759B, 1992\]

### 10.4.8 Ramps, ladders, and stairs 

#### 10.4.8.1 General

Rules are provided below for selecting and using structures for making
changes in elevation of ramps, stairs, and ladders. Common design
criteria for these structures are provided as are detailed rules for
ramps, stairs, stair ladders, fixed ladders and portable ladders. Stair
ladders have steps rather than rungs.

-   **10.4.8.1.1 Selection of safest.** The structure that gives the
    safest and most efficient passage shall be selected. \[Source:
    MIL-STD-1800A, 1990; MIL-STD-1472D, 1989; MIL-HDBK-759B, 1992;
    Department of Energy (UCRL-15673), 1985\]

**Note.** The rules for ramps specified in this section apply to
\"working\" ramps (for example, ramps for forklifts from a dock down to
the ground) or those used for purposes other than for wheelchair
accesses.

-   **10.4.8.1.2 Selection based on angle.** The selection of ramps,
    stairs, stair-ladders, or fixed ladders for specific applications
    shall be based on the angle of ascent required and the critical
    criteria levels in Exhibit 10.4.8.1.2. \[Source: MIL-STD-1800A,
    1990; MIL-STD-1472D, 1989; MIL-HDBK-759B, 1992; UCRL-15673, 1985\]

![](media/image18.png){width="3.8854166666666665in"
height="3.6326388888888888in"}

> []{#__RefHeading___Toc30386417 .anchor}**Exhibit 10.4.8.1.2** Type of
> structure in relation to angle of ascent.

-   **10.4.8.1.3** **For heavy carrying.** The following guidance should
    be followed when selecting structures over which equipment or tools
    must be carried:

a.  Provide ramps, elevators, or equivalent means when maintainers must
    carry or transport heavy or bulky equipment.

b.  Do not use stairs and steps where the user or maintainer must carry
    bulky loads or loads in excess of 13 kg (29 lbs).

c.  Do not use ladders when users or maintainers carry equipment because
    both hands should be free to grasp and climb ladders.

**Exceptions.** Vehicular-boarding ladders are not considered to be
stair ladders or fixed ladders. Thus, the rules in Section 10.4.8 do not
apply. \[Source: MIL-HDBK-759B, 1992\]

-   **10.4.8.1.4 Material characteristics.** Ramps, stairs, and ladders
    shall be constructed of materials that are lightweight,
    nonconductive, splinter-proof, waterproof, weatherproof,
    humidity-resistant, and resistant to chemical action. \[Source:
    UCRL-15673, 1985\]

**Discussion.** Take into account the environmental conditions during
the design phase, including inclement weather (for example, snow, ice,
mud, sand, and wind), if applicable. If de-icing is applicable, design
them to be tolerant of hot water or steam de-icing. \[Source:
UCRL-15673, 1985\]

-   **10.4.8.1.5** **Carrying strength of the structures.** Ramps,
    stairs, and ladders shall be designed to withstand the total weight
    of the largest combination of personnel and carried equipment likely
    to be on them at one time. \[Source: UCRL-15673, 1985\]

**Note.** Multiply these estimates by a safety factor appropriate to the
materials used. Use 113.4 Kg (250 lb) per person to estimate personnel
weight. \[Source: UCRL-15673, 1985\]

-   **10.4.8.1.6** **Nonskid floor surfaces.** Ramps, stairs, and
    ladders shall be provided with nonskid surfaces on all areas where
    personnel are expected to walk or stand to work. \[Source:
    UCRL-15673, 1985\]

-   **10.4.8.1.7** **Warning labels.** Ramps, stairs, and ladders shall
    have symbols or placards that warn against any hazards associated
    with their use, (for example, low overhead obstructions, possible
    shock, and load limits). \[Source: UCRL-15673, 1985\]

-   **10.4.8.1.8** **Handrails.** Ramps, stairs, and ladders shall be
    equipped with a handrail on each side. \[Source: MIL-STD-1472D,
    1989\]

-   **10.4.8.1.9** **Guardrails.** Where personnel could fall into an
    open area under a ramp, stair, or ladder handrail, an intermediate
    level guardrail shall be provided. \[Source: MIL-STD-1472D, 1989\]

-   **10.4.8.1.10** **Proper illumination.** Ramps, stairs, and ladders
    shall be provided with appropriate illumination (see Chapter 13
    (Environment) for illumination criteria). \[Source: UCRL-15673,
    1985\]

-   **10.4.8.1.11** **Ramp landings.** Ramps shall have level landings
    at the top and bottom of each ramp and each ramp run that have the
    following features:

a.  the landing at least as wide as the ramp run leading to it,

b.  the landing with a minimum length of 1.53 m (60 in) clear,

c.  when ramps change direction at landings, a minimum landing size of
    1.53 m by 1.53 m (60 in by 60 in), and

d.  make the area in front of a doorway located at a landing comply with
    Section 10.4.7.2. \[Source: MIL-HDBK-759B, 1992\]

**Note.** The rules for ramps specified in this section, apply to
\"working\" ramps (for example, ramps for forklifts from a dock down to
the ground) or those used for purposes other than for wheelchair
accesses.

-   **10.4.8.1.12** **Optimum dimensions for ramps.** Dimensions for
    ramps should conform to the recommended best values for ramps given
    in Exhibit 10.4.8.1.12. \[Source: UCRL-15673, 1985\]

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-   **10.4.8.1.13** **Minimal and maximum dimensions for ramps.** In all
    cases, dimensions for ramps shall be within the specific minimum and
    maximum limits shown for ramps given in Exhibit 10.4.8.1.12.
    \[Source: UCRL-15673, 1985\]

**Note.** In Exhibit 10.4.8.1.12, the minimal and best handrail height,
diameter, and hand clearance comply with OSHA 29 CFR 1910.23 (e).

> **Exhibit 10.4.8.1.12** Critical dimensions for ramps.
>
> \[Source: UCRL-15673, 1985\]

![](media/image19.png){width="2.347916666666667in"
height="1.6076388888888888in"}

-   **10.4.8.1.14** **Ramps for pushing or pulling equipment on carts.**
    When ramps are used to push or pull carts, the designer shall stay
    within human strength capabilities in establishing the angle of
    inclination. \[Source: MIL-HDBK-759B, 1992\]

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-   **10.4.8.1.15** **Combined vehicular or cart and personnel
    traffic.** Stairs should be provided for personnel when vehicles and
    pedestrians share a ramp and the angle of ramp inclination exceeds 7
    degrees. Exhibit 10.4.8.1.15 illustrates a ramp and stairs
    combination with a pedestrian area on the right side. \[Source:
    MIL-HDBK-759B, 1992\]

> **Exhibit 10.4.8.1.15** Combined ramp and
> stairs.![](media/image20.png){width="2.0208333333333335in"
> height="1.84375in"}
>
> \[Source: MIL-HDBK-759B, 1992\]

-   **10.4.8.1.16** **Personnel traffic area placement.** Personnel
    traffic areas should be off to the side or on both sides of the
    vehicle areas. \[Source: MIL-HDBK-759B, 1992\]

-   **10.4.8.1.17** **Separation of vehicular and personnel traffic
    areas.** Vehicular traffic and walking traffic should be clearly
    separated by markings and handrails. \[Source: MIL-HDBK-759B, 1992\]

#### 10.4.8.2 Pedestrian ramps

The rules for ramps specified in this section apply to pedestrian ramps.
These ramps are intended for pedestrian traffic including those
individuals requiring wheelchair access.

-   **10.4.8.2.1** **Handrails for ramps.** Ramps for pedestrian traffic
    should have handrails. \[Source: MIL-STD-1472D, 1989\]

-   **10.4.8.2.2** **Nonskid materials for ramps.** Nonskid materials
    should be used on the floor area of ramps wherever pedestrian
    traffic is expected. \[Source: MIL-STD-1472D, 1989; MIL-HDBK-759B,
    1992\]

-   **10.4.8.2.3** **Cleating of ramps.** Where special environmental
    conditions require cleating of ramps, cleats should be spaced 360 mm
    (14 in) apart and run from handrail to handrail at right angles to
    traffic. \[Source: MIL-STD-1472D, 1989; MIL-HDBK-759B, 1992\]

**Discussion.** Cleating of ramps facilitates footing for walking and
rolling equipment on inclines.

#### 10.4.8.3 Stairs

-   **10.4.8.3.1** **Dimensions for stairs.** Stair dimensions shall be
    within the minimum and maximum values shown in the Exhibit
    10.4.8.3.1. \[Source: UCRL-15673, 1985\]

**Discussion.** It is recommended that stair dimensions conform to the
recommended best values provided in Exhibit 10.4.8.3.1.

> []{#__RefHeading___Toc30386420 .anchor}**Exhibit 10.4.8.3.1** Design
> requirements for stair dimensions. \[Source: UCRL-15673, 1985;
> MIL-STD-1472D, 1989; MIL-HDBK-759B, 1992; MIL-STD-1800A, 1990\]

  ------------------------ ------------------- --------------- --------------- -----------------
  ![](media/image21.emf)                                                       

                                               **Minimum**     **Maximum**     **Best**

  A                        Angle of rise       30              50              \--

  B                        Tread depth         24 cm (9.5 in)  30 cm (12 in)   28-30 cm (11-12
                                                                               in)

  C                        Riser height        13 cm (5 in)    20 cm (8 in)    17-18 cm (6.5-7
                                                                               in)

  D                        Depth of nosing     2 cm (.75 in)   4 cm (1.5 in)   3 cm (1 in)

  E                        Width (handrail to                                  
                           handrail)                                           

                           One-way stairs      56 cm (22 in)   \--             56 cm (22 in)

                           Two-way stairs      122 cm (48 in)  \--             130 cm (51 in)

  F                        Minimum overhead    2.1 m (7 ft)    \--             2.1 m (7 ft)
                           clearance                                           

  G                        Height of handrail  76 cm (30 in)   86 cm (34 in)   84 cm (33 in)

  H                        Diameter of         4 cm (1.5 in)   8 cm (3 in)     4 cm (1.5 in)
                           handrail                                            

  I                        Hand clearance      8 cm (3 in)     \--             8 cm (3 in)
  ------------------------ ------------------- --------------- --------------- -----------------

-   **10.4.8.3.2** **Landings.** There should at least be a landing for
    each floor level and other landings are recommended for each ten to
    twelve treads. \[Source: MIL-HDBK-759B, 1992\]

-   **10.4.8.3.3** **Riser uniformity.** Riser heights and the height to
    landings should be uniform. \[Source: MIL-HDBK-759B, 1992\]

-   **10.4.8.3.4** **Stair lengths.** Long flights of stairs should be
    avoided. \[Source: MIL-HDBK-759B, 1992\]

-   **10.4.8.3.5 Open tread and protection beneath.** Where practical,
    treads should be open with metal screens or kick plates fastened to
    the underside to avoid injuries from dropped articles. \[Source:
    UCRL-15673, 1985\]

-   **10.4.8.3.6** **Stair design for load carrying.** When people are
    going to carry loads of more than 9 kg (20 lb) or where stairs are
    more than two stories high, deep treads, 300 mm (12 in), and low
    risers 125 mm (5 in) should be used. \[Source: UCRL-15673, 1985\]

**Note.** The following criteria are suggested by Building Officials and
Code Administrators (BOCA): minimum tread depth, 280 mm (11 in); minimum
riser height, 100 mm (4 in); and maximum riser height, 180 mm (7 in).
OSHA 29 CFR 1910.23 (e)(6) requires a minimum hand clearance of 75 mm (3
in). Stair railings (hand railings) are a minimum of 76 cm (30 in) and a
maximum of 86 cm (34 in) above the leading edge of step treads. OSHA 29
CFR 1910.24 (d) requires that a fixed stairs be a minimum stair rail
(handrail) to stair rail distance of 56 cm (22 in) and have a minimum
overhead clearance of 2.1 m (7 ft).

#### 10.4.8.4 Stair ladders

-   **10.4.8.4.1** **Dimensions for stair ladders.** Stair ladder
    dimensions shall be within the minimum and maximum best values
    recommended in Exhibit 10.4.8.4.1. \[Source: UCRL-15673, 1985\]

> []{#__RefHeading___Toc30386421 .anchor}**Exhibit 10.4.8.4.1** Design
> requirements for stair
> ladders.![](media/image22.png){width="4.688194444444444in"
> height="6.747222222222222in"}

**Note.** OSHA 29 CFR 1910.28 requires a standard stair railing and not
a handrail if the fall distance is greater than 1.2 m (48 in). Also,
Exhibit 10.4.8.4.1 shows a drawing of open stairs where OSHA requires
stairs to be closed.

-   **10.4.8.4.2** **Two way traffic with stair ladders.** When
    simultaneous two way traffic is desired, separate up and down
    ladders should be provided, located side by side with double center
    handrails and a minimum separation of 150 mm (6 in) (200 mm (8 in
    preferred separation)) between these rails. \[Source: UCRL-15673,
    1985\]

**Note.** Stair ladders are intended for one person at a time either
coming up or down.

-   **10.4.8.4.3** **Open treads and protection.** Treads should be open
    (without risers boards) and have screens or kick plates fastened to
    the underside to prevent injury to personnel or damage to equipment
    if objects are dropped. \[Source: UCRL-15673, 1985\]

#### 10.4.8.5 Fixed ladders

-   **10.4.8.5.1** **Dimensions for fixed ladders.** Fixed ladder
    dimensions shall be within the minimum and maximum values in the
    Exhibit 10.4.8.5.1, preferably conforming to the recommended best
    values \[Source: UCRL-15673, 1985\]

**Note.** OSHA 29 CFR 1910.27 recommends a maximum rung spacing of 305
cm (12 in) and recommends a minimum clearance of back of the ladder of
18 cm (7 in). OSHA 29 CFR 1910.27 covers many more varieties and
dimensions for fixed ladders.

[]{#__RefHeading___Toc30386422 .anchor}**Exhibit 10.4.8.5.1** Design
requirements for fixed ladders.

+-------+-------------------+-------------+-------------+-------------+
| !     |                   |             |             |             |
| [](me |                   |             |             |             |
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| th="2 |                   |             |             |             |
| .4402 |                   |             |             |             |
| 77777 |                   |             |             |             |
| 77777 |                   |             |             |             |
| 78in" |                   |             |             |             |
| heig  |                   |             |             |             |
| ht="2 |                   |             |             |             |
| .1673 |                   |             |             |             |
| 61111 |                   |             |             |             |
| 11111 |                   |             |             |             |
| 1in"} |                   |             |             |             |
+-------+-------------------+-------------+-------------+-------------+
|       |                   | **Minimum** | **Maximum** | **Best**    |
+-------+-------------------+-------------+-------------+-------------+
| A     | Angle of rise     | 60          | 90          | 75-90       |
+-------+-------------------+-------------+-------------+-------------+
| B     | Rung or cleat     |             |             |             |
|       | diameter          |             |             |             |
+-------+-------------------+-------------+-------------+-------------+
|       | wood              | 3 cm (1.18  | 4 cm (1.5   | 4 cm (1.5   |
|       |                   | in)         | in)         | in)         |
+-------+-------------------+-------------+-------------+-------------+
|       | protected metal   | 2 cm (.75   | 4 cm (1.5   | 4 cm (1.5   |
|       |                   | in)         | in)         | in)         |
+-------+-------------------+-------------+-------------+-------------+
|       | metal that may    | 3 cm (1.18  | 4 cm (1.5   | 4 cm (1.5   |
|       | rust              | in)         | in)         | in)         |
+-------+-------------------+-------------+-------------+-------------+
| C     | Rung spacing      | 23 cm (9    | 30 cm (12   | 28-30 cm    |
|       |                   | in)         | in)         | (11-12 in)  |
+-------+-------------------+-------------+-------------+-------------+
| D     | Height, rung to   | 15 cm (6    | 30 cm (12   | 28-30 cm    |
|       | landing           | in)         | in)         | (11-12 in)  |
+-------+-------------------+-------------+-------------+-------------+
| E     | Width between     | 30 cm (12   | \--         | 46-53 cm    |
|       | stringers         | in)         |             | (18-21 in)  |
+-------+-------------------+-------------+-------------+-------------+
| F     | Climbing          | 76 cm (30   | \--         | \--         |
|       | clearance width   | in)         |             |             |
+-------+-------------------+-------------+-------------+-------------+
| G     | Minimum clearance |             |             |             |
|       | depth             |             |             |             |
+-------+-------------------+-------------+-------------+-------------+
|       | in back of ladder | 18 cm (7    | \--         | 20 cm (8    |
|       |                   | in)         |             | in)         |
+-------+-------------------+-------------+-------------+-------------+
|       | on climbing side  | 91 cm for   |             |             |
|       |                   | 76          |             |             |
|       |                   |             |             |             |
|       |                   | (36 in for  |             |             |
|       |                   | 76)         |             |             |
+-------+-------------------+-------------+-------------+-------------+
|       |                   | 76 cm for   |             |             |
|       |                   | 90          |             |             |
|       |                   |             |             |             |
|       |                   | (30 in for  |             |             |
|       |                   | 90)         |             |             |
+-------+-------------------+-------------+-------------+-------------+
| H     | Height of string  | \--         | \--         | 91cm (36in) |
|       | above landing     |             |             |             |
+-------+-------------------+-------------+-------------+-------------+
| I     | Maximum height of | \--         | 3m (10ft)   | 2.4m (8ft)  |
|       | climb             |             |             |             |
+-------+-------------------+-------------+-------------+-------------+

-   **10.4.8.5.2** **Guarded landings, entrances.** When fixed ladders
    are used between several floors, the landings and entrances should
    be guarded, especially if the ladder well is open. \[Source: 29 CFR
    1910.27, 1985; UCRL-15673, 1985; MIL-STD-1800A, 1990\]

-   **10.4.8.5.3** **Cages and safety devices.** Cages or ladder safety
    devices complying with Exhibit 10.4.8.5.3 should be provided for
    fixed ladders over 6.1 m (20 ft) long. \[Source: 29 CFR 1910.27,
    1985; UCRL-15673, 1985; MIL-STD-1800A, 1990\]

> []{#__RefHeading___Toc30386423 .anchor}**Exhibit 10.4.8.5.3** Design
> requirements for fixed ladder cage dimensions.

![](media/image24.png){width="3.6951388888888888in" height="2.09375in"}

-   **10.4.8.5.4** **Obstruction free cages.** The inside of fixed
    ladder cages shall be free of all obstructions. \[Source: 29 CFR
    1910.27, 1985; UCRL-15673, 1985; MIL-STD-1800A, 1990\]

```{=html}
<!-- -->
```
-   **10.4.8.5.5** **Rungs versus level steps.** Rungs provide better
    hand holds than steps, but when handrails are provided on both sides
    of the ladder, level steps 75 to 100 mm (3 - 4 in) wide should be
    used. \[Source: UCRL-15673, 1985\]

-   **10.4.8.5.6** **Nonskid surfaces on rungs.** All rungs should have
    nonskid surfaces. \[Source: UCRL-15673, 1985\]

-   **10.4.8.5.7** **Tread and tread rise.** Tread rise should be open
    in the rear. \[Source: MIL-STD-1472D, 1989\]

-   **10.4.8.5.8** **Exterior stair ladders.** The surface of treads on
    exterior stair ladders should be constructed of open grating
    material or be treated with nonskid material. \[Source:
    MIL-STD-1472D, 1989\]

#### 10.4.8.6 Portable ladders

-   **10.4.8.6.1** **Dimensions for portable ladders.** Portable ladder
    dimensions shall be within the minimum and maximum values
    (preferably conform to the recommended best values) in Exhibits
    10.4.8.6.1 (a) for stepladders and Exhibit 10.4.8.6.1 (b) for
    portable rung ladders. \[Source: 29 CFR 1910.25-26, 1985;
    UCRL-15673, 1985; MIL-HDBK-759B, 1992\]

**Note.** OSHA 29 CFR 1910.25-26 provides guidance for the design and
use of ladders. \[Source: 29 CFR 1910.25-26, 1985; UCRL-15673, 1985;
MIL-HDBK-759B, 1992\]

![](media/image25.png){width="3.2423611111111112in"
height="2.3756944444444446in"}

> []{#__RefHeading___Toc30386424 .anchor}**Exhibit 10.4.8.6.1** **(a)**
> Design requirements for portable step ladders.
>
> []{#__RefHeading___Toc30386425 .anchor}**Exhibit 10.4.8.6.1** **(b)**
> Design requirements for portable rung
> ladders.![](media/image26.png){width="4.750694444444444in"
> height="6.102777777777778in"}

-   **10.4.8.6.2** **Lifting ladders.** Where one person is to lift
    ladders and store them by hand, ladder weights shall not exceed 9.0
    kg (20 lb) for a lift distance of 1.83 m (6 ft) or 11.3 kg (25 lb)
    for a lift distance of 1.52 m (5 ft.). \[Source: UCRL-15673, 1985;
    MIL-HDBK-759B, 1992\]

```{=html}
<!-- -->
```
-   **10.4.8.6.3** **Ladder hinges and locks.** Permanent hinges and
    locks should be used in preference to bolts and nuts for assembly of
    two-section extension ladders. \[Source: UCRL-15673, 1985;
    MIL-HDBK-759B, 1992\]

-   **10.4.8.6.4** **Weather implications for portable ladders.**
    Ladders should be provided with rubber-cleated, pivoted feet for use
    in nonfreezing weather, and steel cleats for use in ice and snow.
    \[Source: UCRL-15673, 1985; MIL-HDBK-759B, 1992\]

**Note.** OSHA 29 CFR 1910.26-29 treats additional details for design
and use of a variety of ladders and scaffolding.

[]{#__RefHeading___Toc26946082 .anchor}Glossary

**Corridors** - Walkways that are physically restricted by walls or the
like.

**Limit stops** - mechanical mechanisms designed to restrict a moving
object or part by stopping it at predetermined (limit) positions.

**N** - A metric term for the force measure called a Newton**.**

**Newton** - A one pound force in the English measurement system is
equal to 4.4482 Newton (1 lbf = 4.4482 N).

**Passageways** - Areas across which people must pass for work purposes.

**Public entrances** - any entrances that are not loading or service
entrances.

**Walkways** - Areas designated for walking.

**Workplaces** - An area room or establishment where work is done.

**Workstations** - A place designed for a specific task or activity from
where work is conducted or operations are directed. Desks, offices,
repair benches, tools, equipment, and computer terminals are examples of
these special accommodations and equipment. Workstations are designed as
areas for one or more workers to use in accomplishing purposeful tasks
or jobs.

[]{#__RefHeading___Toc26946083 .anchor}References

Department of Defense. (1989). *Human engineering design criteria for
military systems, equipment and facilities* (MIL-STD-1472D).
Philadelphia, PA: Navy Publishing and Printing Office.

Department of Defense. (1990). *Human engineering performance
requirements for systems* (MIL-STD-1800A). Philadelphia, PA: Navy
Publishing and Printing Office.

Department of Defense. (1992). *Human factors engineering design for
Army materiel* (MIL-HDBK-759B). Philadelphia, PA: Navy Publishing and
Printing Office.

Department of Defense. (1998). *Aircraft application of nonslip walkway,
coating and matting* (MIL-W-5050). Philadelphia, PA: Navy Publishing and
Printing Office.

Department of Defense. (1998). *Nonslip walkway compound and nonslip
walkway matting* (MIL-W-5044). Philadelphia, PA: Navy Publishing and
Printing Office.

Department of Energy. (1985). *Human factors design guidelines for
maintainability of Department of Energy nuclear facilities*
(UCRL-15673). Washington, DC: United States Department of Energy.

Department of the Air Force. (1980). *Human factors engineering* (AFSC
DH 1-3). Wright-Patterson AFB, OH: ASD/ENESS.

Electric Power Research Institute. (1984). *Human factors guide for
nuclear power plant control room development* (EPRI NP-36591). Palo
Alto, CA: Research Reports Center.

National Aeronautics and Space Administration. (1989). *Man-systems
integration standards* (NASA-STD-3000A). Houston, TX: National
Aeronautics and Space Administration.

Title 29. *Occupational health and safety standards* (OSHA 29 C.F.R.).
Rehabilitation Act of 1973, 29 U.S.C. § 794 et seq. (amended 1974). Part
1910. Occupational Health and Safety Standards (29 CFR 1910).
Washington, DC.

Uniform Federal Accessibility Standard (UFAS). (1988). 41 CFR Ch101
subpart 101-19.6 Appendix A. Available online from
[www.access-board.gov]{.underline}

VanCott, H. P., & Kinkade, R.G. (1972). *Human engineering guide to
equipment design*. Washington, DC: United States Government Printing
Office.

[]{#__RefHeading___Toc26946084 .anchor}Index

A

Access 10-37

Access openings 10-25

Access space 10-24

Accessible route

slope 10-29

Armrests 10-8

C

Cages 10-49

Caster rollers 10-6

Catwalks 10-30

Ceiling areas 10-36

Clearance dimensions 10-1

Component locations 10-25

Connecting entrances 10-28

Connecting routes 10-28

Console design 10-2

Console dimensions 10-3

Corridors 10-26

Crawl spaces 10-30

D

Door clearances 10-34

Door opening 10-34

Doorways and hinged doors 10-34

E

Elevators 10-30

Elevators, inclinators, and hydraulic work platforms 10-33

Emergency door design 10-36

Emergency escape hatches 10-38

Emergency exits 10-35

Entrances and exits 10-33

doorways 10-34

hatches 10-36

whole body access 10-37

Equipment clearances 10-34

Equipment grouping 10-22

Equipment layout 10-22

Exit design 10-36

Exterior platforms 10-31

F

Floor space 10-23

Floors 10-27, 10-29

Folding doors 10-35

Footrests 10-9

Furniture clearances 10-34

G

Glass doors 10-35

Ground and floor surfaces 10-29

Guard screen 10-32

Guardrails 10-30, 10-31, 10-40

H

Handholds 10-31, 10-32

Handrails 10-40

Hatches 10-36

I

Illumination 10-2, 10-41

Inclinators 10-30

K

Kickspace 10-19

Knee space height 10-8

Kneeling 10-21

L

Ladders 10-39

fixed ladders 10-48

portable ladders 10-50

stair ladders 10-46

Landings 10-30, 10-44

Lateral work space 10-24

Lifting ladders 10-51

M

Maintenance 10-2

Maintenance workstations 10-20

Multi-person consoles 10-12

N

Nonskid floor surfaces 10-40

Non-skid material 10-31

P

Passageways 10-26

Physical accommodation 10-1

Platform strength 10-31

Platforms 10-30

Portable platforms 10-31

Prone 10-21

R

Ramp cleating 10-43

Ramp dimensions 10-41

Ramp landings 10-41

Ramps 10-39, 10-42

landings 10-30

Reach limits 10-25

Rear access space 10-24

Redundant information 10-2

Repair 10-20

Rescue requirements, hatches 10-37

Revolving doors 10-35

S

Screens 10-31

Seat cushioning 10-8

Seated workplaces 10-5

Seating dimensions 10-6

Sliding doors 10-35

Spacing 10-23

Squatting 10-21

Stacked consoles 10-11

Stair design 10-45

Stairs 10-39, 10-44

Standing workstations 10-16

Stooping 10-21

Storage 10-20

Supine 10-21

Swinging doors 10-35

Swivel capability 10-6

T

Team console types 10-15

Toe board 10-32

Toeholds 10-31

Traffic areas 10-22

Tunnels 10-30

U

Unusual working positions 10-20

V

Vehicular traffic 10-42

Vertical stacked consoles 10-11

Visibility of controls 10-2

Visibility of displays 10-2

Visual access 10-26

W

Walking traffic 10-42

Walkways 10-26

Warning labels 10-40

Wheelchair accessibility 10-28

Work space to permit access 10-24

Work surfaces 10-19

Workplace design 10-1

layout 10-22

Workspace clearance dimensions 10-20

Workstation 10-1

Wrap-around console 10-10