Download Occupancy Classification

Occupancy Classifications
and Loads
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You must always determine the occupancy
classification and the occupancy load to
establish the parameters that are to be used
for your project.
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An occupancy classification is assigned to the
building or space. It is a broad classification.
(educational)
Building type is more specific. It is a specific
class or category within an occupancy. (high
school)
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The number of people or occupants for which
the code will require you to provide means of
egress or exiting in your design.
The occupant load sets the minimum level of
exiting that must be provided
 Number of exits
 Widths of corridors
 Distance to nearest exit
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The maximum number that can occupy the
space.
An older term used by the older codes.
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Must be assigned to the building or to a space
within the building
One of the most important steps in the code
process
Should be the first thing you determine when
designing an interior
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Will affect code requirement pertaining to:
 Occupant load
 Means of egress
 Egress capacities
 Finish selection
 Number of plumbing fixtures
 As well as other areas (shown in fig. 2.1, page 58)
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Existing buildings are already determined
Buildings with different types of tenants
require that occupancy classifications be
determined for each tenant.
Careful attention to renovation work (ie: a
warehouse converting to apartments)
Have a code official approve your decision if
you are unsure
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The ten most common occupancies are:
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Assembly
Business
Educational
Factory or Industrial
Hazardous
Institutional
Mercantile
Residential
Storage
Utility and Misc.
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You will need to know three things before you can
accurately determine the occupancy classification
 The type of activity occurring
 The expected number of occupants and
 If any unusual hazards are present
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These factors can affect the classification of a
building type. (ie: if a particular building is planned
to serve a large number of people, it may be
classified as an Assembly)
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Unusual hazards can either change an occupancy to
a stricter classification or simply require all or part of
a building to be classified as a Hazardous
occupancy…subject to tougher codes. (page 61)
 Large groups of people
 Night occupancies
 Mobility of occupants
 Familiarity of occupants
 Potential spread of fire
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Refer to pages 63-83
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Whether an occupancy is new or existing
becomes important when using the LSC.
An occupancy is considered new if it falls in
the following categories:
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New construction
Relocation into an existing building
New addition to an existing building
Occupancy is staying in existing space, but
changing size or use
Incidental Use (page 88) (hazardous areas that are
relatively small, storage, furnace rooms, boiler
rooms, laundry rooms etc.) Additional fire and
smoke protection may be required.
 Accessory Occupancy (page 89) A smaller
occupancy that is typically less than 10% of the total
area of the floor on which it is located. Mercantile
(M) with design center (B) can be considered as an
accessory and not have to design using two
occupancy requirements
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Mixed Occupancies: When two or more occupancies
occur in the same building - under one roof. (Hotels
with restaurants, ballrooms, exercise rooms will be
both Assembly and Business)
Trend for the future
Different codes will apply to each
Requires fire-walls between spaces
Treat as its own entity
 Office building with a childcare center
(Business/Educational)
 Hospitals with cafeterias (Institutional/Assembly)
 Malls with food courts (mercantile/assembly)
Certain occupancy classifications are also affected
by the ADA. (page 95)
 Federal building and 1 and 2 family dwelling are not
regulated by the ADA.
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Restaurants and Cafeterias (Assembly)
Libraries (business or educational)
Mercantile and many businesses
Medical (healthcare)
Transient lodging (residential and correctional/detention)
Childcare
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An occupant load is the second thing you
need to determine at the beginning of a
project.
It sets the minimum number of occupants for
which you must design the means of egress
from a building or specific area.
Each code set a predetermined amount of
space or sq. ft for each occupant. This figure
is called the load factor.
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The load factor is used to help you determine
the occupant load for a space or a building.
The load factor will help to determine the
number of people that will be using the
corridors, stairs and exits in the event of a fire
See table on page 101.
This factor indicates the amount of space or area it
is assumed each person present will require
 Although the sq foot figures may seem high for one
person, they allow for furniture and equipment and
in some cases corridors, closets and other
miscellaneous areas.
 It is always represented in sq. feet; however, it can
be a gross or a net figure.
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The gross area refers to the building as a whole and includes
all misc. spaces within the exterior walls.
 The net area refers to actual occupied spaces and does not
include accessory spaces such as corridors, restrooms, utility
closets etc.
 When net figures are required, it is assumed that the
occupants who are using an ancillary area would have left
the occupied space to do so. (ex: a student walking in a
hallway would already have been counted as a student in the
classroom)
 Note: a Load factor has nothing to do with individual space
allocation with planning a facility.
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Occupancy Load = Floor Area (sq. ft) / Occupant Factor
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Even if you know that your client will have
fewer occupants, you must plan the space
based on the determined load figures as
required by the codes.
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You must figure each occupant load
separately
Example: Multistory buildings may have
mercantile, business on one floor. Figure
each occupancy type for each floor and add
them together
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Example wasTemple Baptist Church prior to
construction of new sanctuary:
 Worship hall is also a basketball court
 Fellowship hall is also cafeteria
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Figure the occupancy load based on the
largest concentration of people.
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Common in Assembly occupancies
The seats are considered fixed if they do not easily
move.
 Theaters
 Churches
 Stadiums, bleachers
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Do not use standard formula
Count actual seats
For seats without arms, figure 18” for each occupant
12’ pew is 144” divided by 18 = 8 people
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The occupant load that you determine in the
beginning of a project will be used again later
in your code research to determine the
means of egress, such as
 The number of exits
 Width of exits
 Placement of exits
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Every assembly room or Assembly occupancy
usually requires the approved occupant load
to be permanently posted near the main exit
from the space.
A typical sign might read
 “Occupancy by more than 100 persons is
dangerous and unlawful.”