Building Construction Understanding Construction Part Two Tom ...

clanmurderUrban and Civil

Nov 15, 2013 (4 years and 6 months ago)


In New York State, building construction, heating
plants, HVAC, etc., are regulated by the following;

The Building Code

The Existing Building Code

The Fire Code

The Fuel and Gas Code

The Mechanical Code

The Plumbing Code

The Residential Code

The Energy Conservation Code


also Reference Standards (NFPA, ANSI, ASME, etc..)

Additionally, we also have to comply with;

NYS approved “more restrictive” local codes (i.e.,
county, town, city, village)

These codes provide minimum requirements.

As with all codes, there are exceptions, such as, the
NYS Building Code does

apply to detached one
family dwellings and multiple single
family dwelling
(townhouses) not more than three stories in height with
separate means of egress. These buildings fall under the
Residential Code of New York State

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

All buildings in the US are constructed by one of the

construction categories;

Type “1”

Fire Resistive



Type “2”


Type “3”


Type “4”

Heavy Timber

Type “5”

Wood Frame




of the five types have subgroups “A” & “B”.

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.

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.


Type “3”



(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

Type “3”



(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

predominate and common construction type,

also know as “brick and joist” structure, (common
terms “Main Street, USA” or “Downtown, USA” and

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”



normally used for larger, sometimes multi
commercial or multi
family structures,

has also been used for one and two family

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 Construction

rarely protected by a sprinkler system,

many have been remodeled and altered,

roof often similar to floor construction,

hazards reduced by using fire

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”


typically will have two load
bearing walls (long
walls) and two curtain walls (short walls).

Type 3 Construction

Residential Type “3” building

One &

Type “3” Multiple Residence

Type “3” Commercial and Residential

Two story commercial Type “3” building

TYPE “3”


Type “3” buildings have been constructed in

distinct types;


late 19

and early 20

century and,




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,

TYPE “3”


floor joists commonly have a “fire cut” on each
end to keep floor joists from pushing the wall

1” to 1 ½” wooden planks commonly used in
the roof assembly.

TYPE “3”




flooring may consist of plywood, oriented
strand board (OSB),

laminated veneer lumber (LVL), and parallel
strand lumber (PSL), supported by

lightweight wooden trusses, and wooden I


these supports are more likely to collapse
sooner than larger solid lumber joists,

roof construction using lightweight materials.

Stability of masonry walls,

Stability of interior column, girder and beam

Void spaces,

Excessive fire loads, “dead” loads
(HVAC, Solar Arrays)

Bow string truss roof,

Alterations can have an effect on the building,

The largest concealed space is the “Cockloft”, an
open space for fire and smoke spread,

Braced Wall Spreaders


wall can be out
of alignment.

Solar Arrays and
HVAC Units


A basic sign that a wall is in distress

Braces of unprotected steel or cable will fail at fire

Arrows mark locations where star
shaped anchor plates were
located on the west
side of the theater building that was
adjacent to the fire building. The anchor plates appear to have
been attached to the ends of the heavy timber roof trusses
supporting the roof and also to some of the second
floor joists.

Photo shows star
shaped anchor plates located on the D
side wall in the area that collapsed.

Photo shows star
shaped anchor
plate attached to end of floor joist.

Photo shows star
anchor plate attached to end
of heavy timber roof truss.

Type “3” Bowstring truss

Collapse scene as viewed from building rear
facing building front. Note portion of bowstring
truss leaning against wall at right side of photo.

(Photo courtesy of fire department)


Photo shows the wall that supported western end of the bowstring truss roof.
The two arrows indicate the truss
end pockets in the brick masonry wall at
the top of the brick pilasters where the ends of the two bowstring trusses
rested. The roof was supported in the middle by the two bowstring trusses
while the north and south ends were supported by the front and rear non
bearing walls. The line indicates the approximate curvature of the roof.
photo F2010

21 Photo


Type “4”

Heavy Timber

(ISO Class 2)

(#2HH, NFPA 5000 “Building & Safety Code”)

structural frame, columns, etc.

heavy timber

exterior bearing walls

1 hour heavy timber

interior bearing walls

2 hour rated

floor construction, beams and joists

heavy timber

roof construction, beams and joists

heavy timber

2010 New York State Building Code


heavy timber construction is one of the oldest
types of buildings used in this country,

heavy timber buildings were originally designed
and used as multi
story industrial or storage

fire resistance is attained by placing limitations
of minimum sizes on wood structural members
and minimum thickness and composition of wood
floors and roofs,

will have four bearing exterior walls,

construction includes

not less than 8”
thick in any dimension,

beams and girders not less than 6” x 10”,

roof framing

is not less than 6” wide x 8” depth,

floors and roofs have thicker than normal
construction consisting of varying layers of
materials that build up to a deck of 3” thick to 4”

arches and trusses not less than 8” thick in any

usage of approved fastenings and adhesives,

lumber may be sawn or laminated,

usually found in very old mills, factories, and
warehouse, and in older churches,

exterior walls are noncombustible,

interior structures made of solid or laminated
wood with no concealed spaces,

does not have plaster walls & ceilings covering
interior framework,

TYPE “4”

Heavy Timber

wood has large dimensions, much heavier, more
difficult to ignite, can withstand fire for longer time

primary fire hazard

combustible contents of
structural members,

does not fail early in a fire,

because of massive amount of combustible
materials there will be serious heat given off and may
pose exposure protection problems,

TYPE “4”

Heavy Timber

Heavy Timber Frame building

Heavy Timber
columns, beams
& girders

Masonry walls

Large open spaces, lack of
hidden voids

Heavy fire loading,

Combustible finishes and furnishings,

Wooden floors/ceilings and coverings,

Large open spaces,

Unprotected openings

Heavy content loading;

combustibles stored in high piles next to each

usually found in commercial and storage facilities,

this may override sprinkler system and provide
access problems,

proper inspection and enforcement effective in
these types of facilities.

Combustible furnishings/finishes;

contribute to fire spread and smoke production.

Wooden floors and ceilings;

contribute to fire loading,

prolonged exposure may result in collapse,

Large open spaces;

contributes to spread,

warehouses, churches, large atriums, common
attics, and theaters.

Unprotected openings;

floor openings for stairwells, freight elevators or
conveyor devices


read a building to identify important

class of building construction,

resistance to fire, heat to critical structural

renovations that may have created void areas,

movement of heat, smoke and fire within the


areas around utility services should be suspected
as areas where fire can spread,

many older buildings have new plumbing and
electrical systems installed,

knowledge of potential building concerns can be
attained by performing inspections during new
construction or in existing buildings,

Lastly, information my be available through your
local fire inspector and/or building department.


Prepared by Thomas Bartsch

Chief Fire Inspector (ret)