Types Of Construction From Nfpa 13

Front 1

Obstructed Construction

Back 1

Panel construction and other construction where beams, trusses, or other members impede heat flow or water distribution in a manner that materially affects the ability of sprinklers to control or suppress a fire.

Front 2

Beam and Girder Construction

Back 2

- noncombustible and combustible roof or floor decks
o supported by wood beams of 4 in or greater nominal thickness
- or concrete or steel beams spaced 3 – 7.5 ft on center and either
o supported on girders or
o framed into girders
[Where supporting a wood plank deck, this includes semi-mill and panel construction, and where supporting (with steel framing) gypsum plank, steel deck, concrete, tile, or similar material, this includes much of the so-called noncombustible construction]

Front 3

Concrete Tee Construction

Back 3

- solid concrete members with stems (legs)
- having a nominal thickness less than the nominal height

Front 4

Composite Wood Joist Construction

Back 4

- wood beams of “I” cross section constructed of
o wood flanges and
o solid wood web
- supporting a floor or roof deck
- CWJs can
o vary in depth up to 48 in
o be spaced up to 48 in on centers
o span up to 60 ft between supports
- Joist channels should be firestopped to the full depth of the joists with material equivalent to the web construction so that individual channel areas do not exceed 300 ft²

Front 5

Panel Construction

Back 5

- ceiling panels formed by members
o capable of trapping heat to aid the operation of sprinklers
o and limited to a maximum of 300 ft² in area
- There should be no unfilled penetrations in the cross-sectional area of the bounding structural members, including the interface at the roof
- Beams qualify as panel construction if they are:
o spaced more than 7.5 feet apart and framed into girders
o and provided the 300 ft² area limitation is met

Front 6

Wood Joist Construction

Back 6

- solid wood members of rectangular cross section supporting a floor or roof deck which
o can vary from 2 to 4 in nominal width and
o can be up to 14 in nominal depth,
o spaced up to 3 ft on centers, and
o can span up to 40 ft between supports
- Also considered as wood joist construction are solid wood members
o less than 4 in nominal width
o up to 14 in nominal depth
o spaced more than 3 ft on centers

Front 7

Bar Joist Construction with Fireproofing

Back 7

- In order to meet building codes, bar joists are often covered with fireproofing materials
- In such an event, if greater than 30% of the area of the joist is obstructed, it should be considered obstructed construction

Front 8

Unobstructed Construction

Back 8

Construction where beams, trusses, or other members do not impede heat flow or water distribution in a manner that that materially affects the ability of sprinklers to control or suppress a fire.
Unobstructed construction
- has horizontal structural members
o that are not solid
o where the openings are at least 70% of the cross-section area, and
o the depth of the member does not exceed the least dimension of the openings
- or all construction types where the spacing of structural members exceeds 7.5 ft on center

Front 9

Bar Joist Construction

Back 9

- construction employing joists consisting of steel truss-shaped members
- Wood truss-shaped members are also defined as bar joists, which
o consist of wood top and bottom chord members
o not exceeding 4 in. in depth
o with steel tub or bar webs
- Bar joists include noncombustible or combustible roof or floor decks on bar joist construction

Front 10

Open-Grid Ceilings

Back 10

- the openings are ¼ in. or larger in the least dimension
- the thickness of the ceiling material does not exceed the least dimension of the openings, and
- the openings constitute at least 70% of the ceiling area

Front 11

Smooth Ceiling Construction

Back 11

- Flat slab, pan-type reinforced concrete
- Continuous smooth bays formed by wood, concrete, or steel beams
o spaced more than 7.5 ft on centers
o supported by columns, girders, or trusses
- Smooth roof or floor decks
o Supported directly on girders or trusses spaced more than 7.5 ft on center
- Smooth monolithic ceilings
o of at least ¾ in of plaster on metal lath
o or a combination of materials of equivalent fire-resistive rating
o attached to the underside of wood joists, wood trusses, and bar joists
- Open-web-type steel beams, regardless of spacing
- Smooth shell-type roofs, such as
o Folded plates
o Hyperbolic paraboloids
o Saddles
o Domes, and
o Long barrel shells
- Suspended ceilings of combustible or noncombustible construction
- Smooth monolithic ceilings with fire resistance less than that specified under item (Smooth monolithic ceilings) attached to the underside of wood joists, wood trusses, and bar joists
Combustible or noncombustible floor decks are permitted in the construction specified in A.3.7.2(3)(b) through (f). Item (b) would include standard mill.

Front 12

Wood Truss Construction

Back 12

- parallel or pitched wood chord members
o constructed by open wood members (webbing)
o supporting a roof or floor deck
- Trusses with steel webbing should also be considered wood truss construction, which
o are similar to bar joist construction, and
o have top and bottom wood chords exceeding 4 in. in depth