Why Know Building Construction

WHY KNOW BUILDING CONSTRUCTION? To alert you to potential construction hazards, To enable a safe and effective fire attack, By knowing basic building construction types, we can approximate how fire will spread and allow us to extinguish it quickly, “The building is your enemy… know your enemy” Francis L. Brannigan.

There are TWO basic types of construction: “It either burns (combustible) or it does not burn (noncombustible)” All buildings in the US are constructed by one of the five construction categories; Type “1” - Fire Resistive – Least Combustible Type “2” - Non-Combustible Type “3” - Ordinary Type “4” - Heavy Timber Type “5” - Wood Frame – Most Combustible Four of the five types have subgroups “A” & “B”.

Subgroups

Subgroup “A” Means Protected; all structural members have an additional fire rated coating or cover by means of sheetrock, spray on, or other approved method, the additional fire rated coating or cover extends the fire resistance of the structural members by at least 1 hour.

Subgroup "B" Means Unprotected; all structural members have no additional fire rated coating or cover, exposed members are only fire resistant according to their natural ability, characteristics, and fire rating.

STRUCTURAL CHARACTERISTICS AND HAZARDS TYPE “3” - Ordinary

STRUCTURAL CHARACTERISTICS AND HAZARDS Type “3”- (A) (protected) – Ordinary (ISO Class 2) (#211, NFPA 5000 “Building & Safety Code”) structural frame, columns, etc. - 1 hour rating exterior bearing walls – 2 hour rated interior bearing walls – 1 hour rated floor construction, beams and joists – 1 hour rated roof construction, beams and joists – 1 hour rated 2010 New York State Building Code

STRUCTURAL CHARACTERISTICS AND HAZARDS Type “3”- (B) (unprotected) – Ordinary (ISO Class 2) (#200, NFPA 5000 “Building & Safety Code”) structural frame, columns, etc. - 0 hour rating exterior bearing walls – 2 hour rated interior bearing walls – 0 hour rated floor construction, beams and joists – 0 hour rated roof construction, beams and joists – 0 hour rated 2010 New York State Building Code

TYPE “3” - Ordinary Characteristics; predominate and common construction type, also know as “brick and joist” structure, (common terms “Main Street, USA” or “Downtown, USA” and “Taxpayer” exterior load bearing walls are of masonry and some or all other structural components are combustible (wood), masonry walls can be brick, stone, or concrete block and terra cotta block in some older buildings, interior structural members almost all wood, wood used has smaller dimensions than Type “IV”.

Type 3 Construction normally used for larger, sometimes multi-story, commercial or multi-family structures, has also been used for one and two family buildings, if floor and roof construction and their supports and all openings through floors (stairwells) are enclosed with one-hour fire resistive materials, the construction is classified as “Protected”, generally built no higher than 6 to 8 stories, most are 2 to 4 stories high, typically wall thickness range from 6” to 30”,

TYPE “3” - Ordinary rarely protected by a sprinkler system, many have been remodeled and altered, roof often similar to floor construction, hazards reduced by using fire-stops, unstable under fire conditions, highly damageable buildings, primary fire hazard - fire and smoke spread through concealed spaces, fire load – construction materials and contents,

TYPE “3” - Ordinary Type “3” buildings have been constructed in two distinct types; Older – late 19th and early 20th century and, Newer. “Older” buildings; tongue and grove floor boards, solid lumber joists and rafters ( can be 3” x 10”), columns could be added for additional support room size limited by span of supporting element,