Every evening, Wilmington daily commercial., 1906-01-27
BOOKCASES

end or Intel constructed floors shall not
exceed feur-ffths of the limits given in
division lA).
CO. Intel concrete The depth or
thickness Of concrete shall never be less
than four inches, nor shall the span eX-
ceed twenty times the thickness of the
Intel or exceed fourteen feet.
tD.l Slab concrete shall never be less
than four inches thick nor shall the span
exceed twenty-five times the thickness OF
the slab or exceed sixteen feet.
(E) Roof concrete and tie-Hollow
book tile in short spans and concrete in
iireproof construction shall never be less
than three inches thick. II the roof is of
Intel or slab concrete construction their
respective spans shall not exceed thirty
and thirty-fve times the thickness Of the
plate.
The dimensions given in the proposed
law viii be regarded as the maximum
limit of the span between the beams or
girders when carrying live loads not eX
ceeding sixty pounds per square foot.
| When the floor loading is over sixty but
not over one hundred pounds per square
foot and the load is quiescent or the
| building contains machines requiring
]
/ foot. the spans must be reduced twenty
and thirty-three per cent for all buildings
! designed TO carry live loads over one hun
dred pounds per square foot OF vibratory
machinery requiring a live load of over
/ fifty pounds per square foot, or II It IS TO
be used as a warehouse, store or sales
room. workshop or factory for inilam-
mable. easily ignited or hazardous risks,
l 9 of
fective thickness of any tireproof floor
construction may be increased instead OF
the spans being decreased, If the ratio Of
span TO thickness shall be decreased
twenty and thirty-three per cent, re-
spectiYely, for the conditions as prescrib-
ed.
All skew backs must be Of such form
ana section as TO properly receive the
thrust of the arches. Arches and filling
of any Kind between floor beams, which
are likely to be injured by frost during
freezing weather, shall be temporarily
covered with suitable material Tor pro
lection from freezing. On top Of any
arch Intel OF other device, which. does
NOT extend 10 and form a horizontal line
with the top Of the floor beam, cindel
concrete or other suitable hollow or solid
hreproof material shall be placed to hl
nm the space to a level with the top OF
the floor beams and shall be carried 70
the under side Of the wood door boards
in case such be used. If the finished nool
is of concrete, tile OF other ineombusn
bic material the bed Of concrete hlling C
receive such finished floors shall eNtenc
al least one and three-quarter inches
above the top Of the ilanges OF beam'
and qirders, but no such concrete nillns
For aoor shall be regarded as part Of tn'
e effective thickness of any hreprooi noo
construction. :.
Temporary centering, when used il
placing freproof systems between noo
p beams, shall not be removed within lou
s davs or until such time as the mortar o
material has set and the floor system
safe for ordinary working loads
P The bottom hanges of all wrought irol
, or rolled steel floor and fiat root beams
d and all exposed portions of such beam
G below the abutments Of the hoor arehes
o irrespective of their form, shall be en-
tire,v encased in hard-burnt clay, porou
I or semi porous terra Gotta or other fre
Z nroof material allowed 10 be used for tn
g anino between the beams in accordane
= with the provisions of the law; such en-
o casing material TO be no less than wv
d inches thick and to be properly molde
and secured to the beams, and II the en-
a CASING material of such members Is q
Il concrete il shall be armored concrete. Ih
s exposed sides and bottom plates or iiange
d M wrought iron or rolled steel girder
It supporting iron or steel floor beams, Q
u supporting floor arches or toofs' shai 2
e entirely encased in the same manner
s In all cases the covering Of beams II q
e hollow tile OF porous or semi-porous TERI
y Gotta. shall be so applied as TO be suppol
e ed entirely by the beams or girders pre-
tectod and shall be held in place entirel
"a bv the support of the ilanges o. sue
: beams or girders and by the mortar use
in setting Wire binding and anchor
/ saall not be used as tastenings ol sue
Y freproof covering.
? An cast iron, wrought iron or role
A steel columns, including the lugs an
y braekets. used in the interior OF any mr.
Z nroof building, or used to support an
q freproof floor, shall be protected with ne
t less than two inches Of freproof matters
securely applied. The extreme outer edi
8 NJ lucs and brackets and similar supper
x inc material may project TO WIN
q seven-cighths of an inch OF the surface
y the iircproofng.
n Plastcrine on metal lath or wire WI
\ NOT he considered as p trepr0ohng j
II steel OF iron structural members, III
n used ns a substitute for armored co
Y crete in a 6reproof building, but may