2.3 Interior Space Numbering

2.3.1            Introduction

Interior space numbers are unique codes that are used to identify individual interior spaces at BWI Marshall or Martin State Airports. These standards define space numbering conventions (i.e., how space numbers are formatted) and procedures (i.e., how spaces are assigned numbers) for BWI Marshall and Martin State Airports. The GETS office is responsible for maintaining and implementing the numbering standards at BWI Marshall and Martin State.

Each interior space is represented by a space polygon in the MDOT MAA GIS database. The attributes of these space polygons contain all components of the interior space number in separate fields, allowing interior space data to be queried, sorted, and analyzed according to any combination of those components, for example: querying the data for all spaces on a specific level of a specific building, or all spaces on all levels within a specific building section, etc.

2.3.2            Interior Space Numbering Coordination

The designers of Capital and Permitted projects shall contact GETS to request space number assignments during the design or construction process when one or more spaces are to be created, removed, or modified as part of the project. Designers shall contact GETS at the following times depending on the project type:

A.      Capital Projects: Prior to each design submittal, beginning with the 30% design phase, and prior to any field changes or addenda, and prior to any temporary construction which may modify existing or create new spaces

B.      Permitted Projects: As early as possible during design, prior to application for building permit.

GETS will assign space numbers for a project based on the following conventions and procedures described in Section 2.3.4 Space Number Assignment and will notify consultants via annotated plan and/or text document of the newly assigned space numbers.

Designers are required to coordinate with GETS to adjust space number assignments as a project evolves, to accommodate expected design changes which may add, remove, or modify interior spaces. Although such communication is mandated at each design phase, it is also encouraged in between design phases as well.

2.3.3            Interior Space Numbering Conventions

Interior space numbers are built from the components defined below. All components are required to form a completely unique space number. Components are joined by underscores to form the completed space number. By convention, space number components do not require leading zeros, e.g., 001, however those may be used at the discretion of GETS staff.

A.      Airport Campus: A code denoting the airport campus where the space is located.

B.      Building Number: The MDOT MAA-issued number of the building containing the space.

C.      Section Identifier: A code denoting subdivision of a building where the space is located.

D.      Level Number: A code denoting the level within a building where the space is located.

E.       Unit Identifier: An individual code assigned to each interior space.

F.       Function Designator (Optional): An optional single letter code denoting a specialty space’s function.

2.3.3.1            Space Numbering Examples

Table 2.3.3.1-1 Space numbering component examples

Table 2.3.3.1-2 Space numbering examples

In Figure 2.3.3.1-3 below, several rooms in the BWI Marshall B Terminal are shown with space identifiers for the primary spaces (in green) and identifiers for sub-rooms (in purple). All of these spaces will share many components in the space number, BWI_100_BT_2, but have a unique space number when all components are combined: BWI_100_BT_2_BT254A, BWI_100_BT_2_BT254A1, BWI_100_BT_2_BT254B, BWI_100_BT_2_BT254B1, etc. The purpose of the full space number (e.g., BWI_100_BT_2_BT254A) is to provide a unique value to represent the space in digital databases that contain features for all spaces at BWI Marshall and Martin State Airports.

In day to day operations, and on digital or printed plans, it is common to represent space numbers by using only the Unit Identifier component (e.g., BT254A) as highlighted in Figure 2.3.3.1-3.

Figure 2.3.3.1-3 Space numbering at BWI Marshall showing different space identifiers for rooms and sub-rooms

Unit Identifiers and door numbers are closely related and are typically assigned at the same time. In general, a door number will match the Unit Identifier of the space into which it opens. Further description of how door numbers are assigned is found in Section 2.4 Door Number Assignment.

2.3.4            Space Number Assignment

This section describes the space numbering process for all MDOT MAA Marshall buildings for designating the campus, building, section, level, and space identifier components of space numbers.

2.3.4.1            Airport Campus

All interior spaces at BWI Marshall are assigned the campus code BWI. All interior spaces at Martin State Airport are assigned the Airport Campus code MTN.

2.3.4.2            Building Number

All interior spaces are assigned the building number of their building. Building numbers are assigned as defined in Section 2.2.3 Assigning Building Numbers and are maintained by GETS in coordination with the Office of Planning, the Office of the Fire Marshal, the Office of Maintenance, and other MDOT MAA offices. Interior spaces at the BWI Marshall Terminal are assigned the building number 100.

2.3.4.3            Section Identifier

For buildings with multiple sections (e.g., wings, concourses, zones) interior spaces are assigned a Section Identifier based on their location within the building. Section Identifiers in the BWI Marshall Terminal are based on the building’s Terminals and Concourses (Table 2.3.4.3-1, Figure 2.3.4.3-2). Section Identifiers for buildings consisting of multiple hangars generally indicate the hangar number. Sections Identifiers in cargo buildings and warehouses are typically single letters. GETS will delineate building sections and assign Section Identifiers as needed. If a building has no delineated sections, all spaces within building shall be assigned the default Section Identifier “0” (the number zero).

Table 2.3.4.3-1 BWI Marshall Terminal Section Codes

Figure 2.3.4.3-2 BWI Terminal Orientation Map

2.3.4.4            Level Number

All interior spaces are assigned the level number of the level where they are located. This can be a number (e.g., 1, 2, 3) or an alphanumeric value (e.g., 1a, 2i) depending upon the layout of the building.

A.      BWI Marshall Terminal Level Numbers and Names

Terminal levels are divided by program at each level as defined in Table 2.3.4.4-1 below.

Table 2.3.4.4-1 BWI Marshall Terminal Levels

B.      Outbuildings

Buildings at BWI Marshall other than the Terminal, commonly referred to as Outbuildings, and all buildings at Martin State Airport, use a simplified numbering system for Level Numbers as defined in Table 2.3.4.4-2 below.

Table 2.3.4.4-2 Level Numbers in BWI Marshall Outbuildings and Martin State Buildings

2.3.4.5            Unit Identifier

Unit identifiers are the individualized code assigned to each interior space. They are typically two to eight characters in length, include the Section Identifier, an optional Function Designator, the Level Number, and may include alphanumeric suffixes in the case of sub-rooms. In buildings without delineated sections, the default Section Identifier “0” is omitted from the Unit Identifier and is only stored in the attributes of the building’s space polygons.

A.      Linear Buildings/Sections with a Central Corridor

For buildings or building sections whose rooms are arranged in a linear fashion along corridors, Unit Identifiers begin at the end or side closest to the main entrance and increment toward the opposite end or side, with spaces to the left of the corridor receiving sequential odd numbers, and spaces to the right of the corridor receiving sequential even numbers (e.g., 101, 103, 105 on the left and 102, 104, 106 on the right). If the corridor runs perpendicular to the face containing the main entrance, numbering shall begin at the end of the corridor to the left of the main entrance. Spaces along corridors are to be numbered sequentially whenever possible. Determination of the main entrance to a building or section for the purposes of assigning Unit Identifiers is by GETS staff.

B.      Non-Linear Buildings/Sections without a Central Corridor

For non-linear buildings or sections without a central corridor, such as hangars and warehouses, Unit Identifiers begin at the main entrance and increment in a clockwise spiral from the exterior of the building towards the interior. When possible, spaces along corridors are numbered sequentially. Determination of the main entrance to a building or section for the purposes of assigning Unit Identifiers is by GETS staff.

C.      Sub-rooms

Rooms may have one or more sub-rooms and on occasion there can be multiple levels of sub-rooms, such as in a suite containing open offices, private offices, and other rooms, or rooms wholly contained within another room, such as a closet. Sub-rooms are assigned Unit Identifiers that consist of the parent space’s Unit Identifier plus an alphabetical suffix, always starting with the letter A, increasing by a letter suffix clockwise from the main entrance of the space. Occasionally, sub-rooms will also have sub-rooms. In those circumstances, an additional numeric suffix is added: room 201A1 is a sub-room of 201A, which is a sub-room of 201.

D.      Ad Hoc Space Identifiers

GETS staff will assign Unit Identifiers that deviate from these procedures in cases where strictly following the procedures results in confusion in the field. For example, if the standard procedure would result in Unit Identifiers 124 and 146 being placed together, the second space may instead be assigned a Unit Identifier 124A to maintain a logical sequence along a corridor.

D.      Curbside Entry Vestibules

Curbside entry vestibules along the BWI Marshall Terminal roadway are numbered 1-19 on the Lower Level and 1-20 on the Upper Level, starting on the Terminal A-B side. The vestibules are assigned a Unit Identifier based on a prefix of either LL indicating Lower Level (Level 1), or UL indicating Upper Level (Level 2), and the entry number. For example: curbside entry vestibule #2 on the Lower Level is assigned Unit Identifier LL2.

E.       Holdrooms

Holdrooms are open public spaces at Gates where passengers wait to board their flights. Unit Identifiers for holdrooms include the prefix “HR” followed by the Gate number of the holdroom. For example, the Unit number HRE6 refers to the holdroom at Gate E6.

F.       Restrooms, Nursing Rooms, and Adult Changing Rooms

All projects involving renovation or reconstruction of restrooms at BWI Marshall and Martin State Airport shall include numbering of each restroom, as well as numbering of each stall within the restrooms. The stall numbers should be affixed to the outside and inside door of each stall. The positioning and esthetics of the signs affixed on the stall doors shall be at the discretion of the Director of the MDOT MAA Office of Architecture.

Public Restrooms, Nursing Rooms, and Adult Changing Rooms at BWI Marshall are each assigned a unique MDOT MAA Identifier. The Unit Identifier for these rooms and their sub-rooms will match the room’s MDOT MAA Identifier. The MDOT MAA Identifier includes the Section Identifier, a dash, the appropriate Function Designator (see 2.3.4.6 Function Designator for list), the Level Number, and an alphanumeric identifier assigned by GETS. For example: Family Assist Restroom C-F2A, Men’s Restroom C-M2A, and Women’s restroom C-W2A are located in the C Concourse on Level 2, resulting in Space Numbers BWI_100_C_2_C-F2A, BWI_100_C_2_C-M2A, BWI_100_C_2_C-W2A.

Non-public restrooms, such as those located within MDOT MAA occupied space or a tenants leased space, shall be issued standard Unit Identifiers.

Toilet stalls within a restroom are not represented in the MDOT MAA GIS by unique space polygons, but are incorporated as part of the parent restroom. However, each stall shall be assigned a sequential stall number, beginning with “1” at the first stall to the right of the entrance and counting up in a counter-clockwise direction, or beginning with the first stall to the left of the entrance and counting up in a clockwise direction.

G.      Escalators, Elevators, Open Stairs, Stairwells, Moving Walkways

Escalators, Elevators, Open Stairs, and Stairwells are features with spaces that span multiple levels and thus may have duplicate Unit Identifiers from level to level. Additionally, the Maryland Department of Labor, Licensing and Regulation issues each Elevator, Escalator, and Moving Walkway a unique identifier consisting of two letters representing the Maryland county, and a four-digit number. The letters in state-owned facilities, such as BWI Marshall and Martin State Airports, are always “ST”. This identifier is recorded the MDOT MAA GIS database for reference, but is not part of the space number or MDOT MAA Identifier.

1.       Escalators

Escalators have a space polygon on each level through which they pass. Escalators at BWI Marshall are each assigned a unique MDOT MAA Identifier. The Unit Identifier for an escalator’s two space polygons will match its MDOT MAA Identifier. The MDOT MAA Identifier includes the Section Identifier, the Function Designator “L”, the Level Number of the unit’s bottom level, and an alphanumeric identifier assigned by GETS. For example: Escalator DYL1A is located in the DY Concourse, spanning levels 1 and 2, resulting in two space polygons with the Space Numbers BWI_100_DY_1_DYL1A and BWI_100_2_DYL1A.

2.       Elevators

Elevators have a space polygon on each level through which they pass. Elevators at BWI Marshall are each assigned a unique MDOT MAA Identifier. The Unit Identifier for an elevator’s multiple space polygons will match its MDOT MAA Identifier. The MDOT MAA Identifier includes the Section Identifier and an alphanumeric identifier assigned by GETS. (NOTE: Elevators lack a Function Designator). Alphanumeric identifiers in the Concourses will generally correspond to the number of the nearest Gate. For example: Elevator B7 is located on Concourse B, nearest Gate B7, spanning Levels 1a and 2, resulting in two space polygons with the Space Numbers BWI_100_B_1a_B7 and BWI_100_B_2_B7.

3.       Enclosed Stairwells

Stairwells have a space polygon on each level through which they pass. Stairwells are enclosed by walls, unlike open stairs, and are typically restricted from public use except in case of emergency. Stairwells at BWI Marshall are each assigned a unique MDOT MAA Identifier. The Unit Identifier for a stairwell’s multiple space polygons will match its MDOT MAA Identifier. The MDOT MAA Identifier includes the Section Identifier, the Function Designator “S”, and an alphanumeric identifier assigned by GETS. Alphanumeric identifiers in the Concourses will generally correspond to the number of the nearest Gate. For example: Stairwell DYS21 is located at Gate D21, spanning Levels 1 and 2, resulting in two space polygons with the Space Numbers: BWI_100_DY_1_DYS21 and BWI_100_DY_2_DYS21.

4.       Open Stairs

Open Stairs have a space polygon on each level through which they pass. Open stairs are not enclosed by walls and are considered public spaces. Open stairs are not assigned unique MDOT MAA Identifiers, and so their Unit Identifiers will correspond to the standard format for interior spaces and will not match from level to level. Open stairs are given a Function Designator of “P”, as they are considered public spaces. For example: a stair in Concourse DY spanning Levels 1 and 2, resulting in two space polygons with the Space Numbers BWI_100_DY_1_DYP101 and BWI_100_DY_1_DYP244.

5.       Moving Walkways

Moving walkways are pieces of equipment having a single space polygon. Moving Walkways are each assigned a unique MDOT MAA Identifier. The Unit Identifier for a moving walkway’s space polygon will match the MDOT MAA Identifier. The MDOT MAA Identifier includes the Section Identifier, the Function Designator “V”, the Level Number, and an alphanumeric identifier assigned by GETS. For example: Walkway BV2A is located in the B Concourse on Level 2, resulting in Space Number BWI_100_B_2_BV2A.

2.3.4.6            Function Designator

For certain spaces with dedicated functions, a Function Designator code is included in the Unit Identifier immediately following the Section Identifier. Function Designators are assigned by GETS staff as part of the Unit Identifier.

Table 2.3.4.6-1 Function Designators

F.       Family Assist Restrooms: Unisex facilities designed to be more accommodating to families with small children or those with special physical needs who might find it uncomfortable or impractical to use standard restrooms. One Family Assist Restroom is typically provided at or near each grouping of public restrooms. Family Assist Restrooms are assigned the Function Designator “F” in their Unit Identifier.

G.      Adult Changing Rooms: Toilet and change facilities provided for those with high support needs and their caregivers, who may require more space, assistance, and specialized equipment than is available in a standard restroom. One Adult Changing Room is typically provided at or near each grouping of public restrooms. Adult Changing Rooms are assigned the Function Designator “G” in their Unit Identifier.

K.       Kiosks: Found throughout BWI Marshall Terminal. Kiosks represent leasable area of open space, typically contained within a larger public space, which may include information, ticketing, queueing, or concession areas. Kiosks are assigned the Function Designator “K” in their Unit Identifier.

L.       Escalators: Escalators may be found in public areas throughout the BWI Marshall Terminal. Escalators are assigned the Function Designator “L” in their Unit Identifier.

M.    Men’s Restrooms: Public Men’s Restrooms in the BWI Marshall Terminal are assigned the Function Designator of “M” in their Unit Identifier.

N.      Nursing Rooms: Facilities provided to allow mothers to nurse or pump in privacy and comfort. One Nursing Rooms is typically provided at or near each grouping of public restrooms. Nursing Rooms are assigned the Function Designator “N” in their Unit Identifier.

P.       Public Spaces: Typically open spaces (spaces not enclosed by walls) accessible to airport patrons, located in either the secured or non-secured areas. Public spaces typically include concourses, walkways, Open Stairs, and other terminal areas delineated by GETS based on structural features, usage, or occupancy. Public Spaces are assigned the Function Designator “P” in their Unit Identifier.

S.       Stairwells: Stairs enclosed by walls, typically not accessible to the public except in an emergency, when they provide emergency egress from the building. Stairwells are assigned the Function Indicator “S” in their Unit Identifier.

U.      Unleasable Spaces: Those spaces in a building that are not normally human-accessible, such as dead spaces, shafts, or “open to below” spaces. Unleasable Spaces are assigned the Function Indicator “U” in their Unit Identifier.

V.      Moving Walkways: Slow-moving conveyors within a public space, not enclosed by walls, that transport people across horizontal or inclined planes to shorten walking times. Moving Walkways are assigned the Function Indicator “V” in their Unit Identifier.

W.    Women’s Restrooms: Public Women’s Restrooms in the BWI Marshall Terminal are assigned the Function Designator of “W” in their Unit Identifier.

2.3.4.7            Construction and Renovation

Designers for both Capital and Permitted projects shall coordinate with GETS staff for the assignment of space numbers, beginning at the earliest possible time and continuing throughout the design phase of a project (see Section 2.3.2 Interior Space Numbering Coordination). Spaces may receive a completely new space number or an existing space number if the space layout is being rearranged, depending upon the nature of construction and as outlined below.

A.      Additions and New Spaces

When an addition is made to an existing building, GETS staff will assign numbers to the new spaces following these space numbering procedures. New numbers follow the sequence from the existing building, for example when an extension is added to the end of a concourse.

B.      Splitting of Spaces

When a space is split, and new spaces are created, GETS staff will review all new spaces to ensure a proper number is assigned in accordance with these space numbering procedures. The first space closest to the main entrance of the area will retain the original space number. For subsequent spaces created from the split, new numbers will be assigned based on availability to maintain logical sequencing, including alphanumeric suffixes as need, as defined in Section 2.3.4.5.C Sub Rooms.

C.      Combining or Merging of Spaces

When multiple spaces are combined or merged into a new single space, for example when several subdivisions in a suite are removed during construction, GETS staff will review current space numbers and reassign numbers so that the renovated space matches the numbering conventions. The space number of the new larger space is based on the primary space number prior to the merge or the lowest sequential space number. For example, an office is made up of three spaces: the main space from the entrance, AT200, and two subdivision offices, AT200A and AT200B. During a renovation, the subdivisions are removed, creating a single space, the new space has the number AT200 and the numbers AT200A and AT200B are no longer in use.

2.3.4.8            Updating Legacy Space Numbers

Many existing spaces in MDOT MAA buildings have legacy space numbers which do not comply with this standard. Un-numbered or non-compliant spaces will be numbered or re-numbered to comply with this standard when a space is to be modified by a Capital or Permitted project, or when a building is discovered to have been incorrectly or incompletely numbered and must be completely numbered to comply with this standard.

2.3.4.9            BWI Marshall Space Names and Additional Identifiers

Along with the above criteria for assigning space identifiers and space numbers, many spaces at BWI Marshall have additional identifying information including State of Maryland identifiers and common space names. For example, the mechanical room in Unit number NTE100 has the space number BWI_100_NTE_1_NTE100. This space is widely known by the name “MER #1”, which is displayed prominently on signs outside the room. Both the space number and the space name are recorded in the MDOT MAA GIS database.

2.3.4.10          Martin State Space Numbering

Space numbering at Martin State Airport follows the process outlined above, with the campus code MTN, and under the coordination of GETS staff and the Martin State Airport management.