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<br />FIRE RESISTANCE .TINGS
<br />
<br />e
<br />
<br />e
<br />
<br />FIRE .SISTANCE
<br />
<br />BEAM, GIRDER AND TRUSS PROTECTIONS-Continued
<br />Estimated Ratings
<br />
<br />.
<br />
<br />.
<br />
<br />RATINGS
<br />
<br />"Group 2: Granite, quartzite, siliceous gravel, sandstone, gneiss, cinders
<br />containing more than 25%, but not more than 400/0 of combustible material
<br />and not more than 5% of volatile material and other materials meeting the
<br />requirements of these specifications, and containing more than 300/0 of quartz,
<br />chert, flint, and similar materials."
<br />
<br />Concrete, Group 1 coarse aggre-
<br />gatesk ; metal ties bent around
<br />beam flanges and other projecting
<br />
<br />parts. ."",..,......".............".,..."...""......
<br />Concrete, Group 2 coarse aggre-
<br />gatesk; with 3 in. or finer metal
<br />mesh placed 1 in. from the fin-
<br />
<br />ished surface. .............,".,..,....'..',.......'
<br />Brick, hollow or solid (clay, con-
<br />crete or sand-lime). ..n...........,.........,
<br />Gypsum blocks, hollow; plastered
<br />with ~ in. gypsum plaster. ....,....,..
<br />G>:p~um blocks, hollow; unplastered;
<br />J omts grouted. ""....,.........',..........,...
<br />Gypsum blocks, solid; plastered with
<br />~ in. gypsum plaster. "...",........,...,.
<br />G>:p~um blocks, solid; unplastered;
<br />J omts grouted. """......"."",."..",......
<br />Gypsum poured; plastered with ~
<br />in. gypsum plaster. ..,.....""...
<br />Gypsum, poured; unplastered.
<br />
<br />hr.
<br />
<br />Minimum Thickness.
<br />Inches, for Rating of
<br />
<br />2 hro.
<br />
<br />3 hrs.
<br />
<br />4 hrs.
<br />
<br />Protection
<br />
<br />of
<br />
<br />Details
<br />
<br />Type
<br />
<br />";.
<br />
<br />i\
<br />~.
<br />
<br />. Thicknesses given are of the protection around the outside of the steel
<br />column, beam, girder or truss, or cast iron column, and outside of the reinforcing
<br />steel ,in reinforced concrete columns, beams, girders and trusses. They do not
<br />include thickness of plaster except where the protection consists only of metal
<br />lath and plaster.
<br />
<br />1
<br />
<br />~
<br />2~
<br />2
<br />
<br />1~
<br />
<br />2
<br />2~
<br />2
<br />
<br />2
<br />
<br />2~
<br />3~
<br />3
<br />
<br />2
<br />
<br />2~
<br />3~
<br />3
<br />
<br />Steel
<br />Beams,
<br />Girders
<br />and
<br />Trusses
<br />individually
<br />protected
<br />
<br />m The fire resistance of columns varies with the area of solid material
<br />in the cross section of the column-the larger the column the greater the fire
<br />resistance, for a given thickness of protection around the structural or reinforcing
<br />steel. The column dimensions given are the outer cross sectional dimensions of
<br />the steel or cast iron columns and the outside cross sectional dimensions of rein-
<br />forced concrete columns. Columns smaller than those listed may require greater
<br />thicknesses of protection for the same degree of fire resistance. For columns which
<br />are not square the protection should correspond to that for the square column
<br />having the same or next smaller cross sectional area.
<br />
<br />n
<br />
<br />2
<br />
<br />2
<br />
<br />2
<br />
<br />2
<br />
<br />3
<br />
<br />2
<br />
<br />2
<br />
<br />100/0
<br />
<br />wire
<br />
<br />Calcareous aggregate containing a combined total
<br />chert and flint for the coarse aggregate.
<br />
<br />Cinders contained not over 10% unburned coal and not over 5% ash,
<br />
<br />P Wire ties consisted of No. 5 B. & S. gauge (0.18 in. diam.) steel
<br />wound spirally around the steel columfl on a pitch of 8 in.
<br />
<br />q Outside wire ties consisted of No. 12 B. & S. gauge (0.08 in. diam.)
<br />wire tied around the outside of each course of tile at the middle.
<br />
<br />in. and
<br />
<br />than
<br />
<br />more
<br />
<br />not
<br />
<br />of
<br />
<br />quartz,
<br />o
<br />
<br />2
<br />
<br />2
<br />
<br />steel
<br />
<br />~
<br />1
<br />
<br />1
<br />1~
<br />
<br />1~
<br />2
<br />
<br />1~
<br />2
<br />
<br />.
<br />
<br />Rating
<br />
<br />2~ hrs.
<br />
<br />2 hrs.
<br />1 hr.
<br />
<br />Any ceiling construction described under Floor and
<br />Ceiling Constructions, provided there are no com-
<br />bustible materials above the ceiling. ..___,___,__
<br />
<br />Note. The fire resistance rating of the ceiling con-
<br />structions described under Floor and Ceiling Con-
<br />structions is the time in hours the ceiling will
<br />protect the structural members above it. Where
<br />there is combustible material above the ceiling
<br />the fire resistance rating of the ceiling construc-
<br />tion will be considerably less than the rating
<br />of the floor construction employing the same ceil-
<br />ing protection,
<br />
<br />hr.
<br />
<br />Rating
<br />Same as
<br />Floor
<br />Rating
<br />
<br />Protection
<br />
<br />Two ~ in. layers of 1:3 gypsum and sand plaster
<br />metal lath, with ~ in. air space between. """..,...,..,
<br />Two ~ in. layers 1 :2~ portland cement and sand
<br />plaster on metal lath, with ~ in. air space between. ...."
<br />~ in. 1:3 gypsum and sand plaster on metal lath. .'""..,.
<br />1 in. 1 :2~ portland cement and sand plaster on metal
<br />lath
<br />
<br />1
<br />
<br />CEILING CONSTRUCTIONS
<br />
<br />-\
<br />i
<br />I
<br />1
<br />
<br />,
<br />
<br />l
<br />,.~
<br />.r
<br />.
<br />II
<br />".1
<br />:1
<br />
<br />~I
<br />
<br />I
<br />
<br />the
<br />
<br />which
<br />
<br />on
<br />
<br />sand plaster,
<br />
<br />gypsum
<br />
<br />~
<br />
<br />covering of
<br />
<br />Tested with
<br />was 7 hours.
<br />
<br />r
<br />rating
<br />
<br />8
<br />
<br />--
<br />
<br />granite.
<br />which the
<br />
<br />or
<br />
<br />more of quartz, chert
<br />and sand plaster, on
<br />
<br />used contained 600/0 or
<br />in. gypsum
<br />
<br />The aggregates
<br />Tested with
<br />was' 6 hours.
<br />
<br />on
<br />
<br />of
<br />
<br />Details
<br />
<br />Type
<br />
<br />Steel
<br />Beams,
<br />Girders
<br />and
<br />Trusses
<br />individually
<br />protected
<br />
<br />~
<br />
<br />U The "Standard Methods of Fire Tests of Building Construction and Ma-
<br />terials" fix a temperature limit for wood members such as sleepers set into the
<br />top slab of a floor construction. Except where test data are available to show
<br />that wood members may be embedded in the top slab a certain depth without
<br />developing temperatures higher than the standard specifies, or except as other-
<br />wise specifically indicated, the rating of floor and ceiling constructions are based
<br />on the assumption that no wood sleepers or other combustible members will be
<br />embedded in the specified top covering of concrete or gypsum. Such members
<br />may rest on top of the specified thickness of concrete or gypsum with additional
<br />concrete or gypsum fill between sleepers.
<br />
<br />covering of
<br />
<br />t
<br />rating
<br />
<br />v The thickness of concrete floor slab given is the minimum thickness over
<br />the joists. Between joists the thickness will be greater due to sagging of the metal
<br />lath. Tests at the National Bureau of Standards have indicated that this addi-
<br />tional thickness between joists is necessary if the specified fire resistance is to be
<br />assured. If the n,ormal sag between joists is not present the average thickness
<br />of slab should be Y-i in. greater. Concrete plank may be used for the top slab if
<br />joints are thoroughly grouted and the plank is at least Y-i in. thicker than the
<br />specified thickness for the top' slab.
<br />
<br />page 47.
<br />
<br />to notes,
<br />
<br />Letter superscripts refer
<br />9
<br />
<br />-
<br />
<br />It
<br />
<br />slab maJt
<br />
<br />clear quartz.
<br />
<br />y These ratings apply to columns with standard ties or spirals, and to col-
<br />umns without spirals if designed on the basis that the protective concrete covering
<br />carries no load. If the design load is based on the gross column area and the
<br />column does not have adequate ties or spirals the actual fire resistance will be
<br />considerably lower.
<br />
<br />48
<br />
<br />top
<br />
<br />poured
<br />
<br />for
<br />
<br />form
<br />
<br />serving as
<br />
<br />100%
<br />
<br />weight
<br />
<br />'IF Metal lath of approved
<br />be considered as reinforcement.
<br />
<br />Siliceous contained
<br />
<br />gravel
<br />
<br />..
<br />
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