SPX Cooling Technologies Marley Sigma Steel - Manual (Page 14)

Specifications Specification Value
Marley / Sigma Steel Cooling Tower / Specifications: Base
14
3.0 Construction:
3.1 The tower shall be capable of with-
standing water having a pH of 6.5 to
8.0; a chloride content (NaCl) up to 300
ppm; a sulfate content (SO4 ) up to
250 ppm; a calcium content (CaCO3)
up to 500 ppm; silica (SiO2) up to
150 ppm; and design hot water tem-
peratures up to 120°F. The circulating
water shall contain no oil, grease, fatty
acids, or organic solvents.
3.2 The structural framework of the tower,
as well as all basins and decking, shall
be of heavy gauge cold-formed steel
and/or mill shapes, hot-dip galvanized
after fabrication to a deposition of at
least 2.25 ounces of zinc per square
foot.
3.3 Column lines shall be on no greater
than 4' longitudinal centers, and the
base of all columns shall be firmly
anchored. Basic design criteria shall
be 30 psf wind load and 5%g seismic
load. Framing joints shall be made
with 1 ⁄
2
" diameter and larger Series 300
stainless steel machine bolts, nuts and
washers.
3.4 Towers of more than one cell shall
include galvanized internal partitions
to separate the fan plenums, and a
hinged access door shall be provided
in each partition for freedom of access
throughout the tower.
■ The limiting water quality values indicated are those which are accept-
able for the normal materials of construction specified. If water of more
aggressive quality is anticipated, consider specifying a stainless steel
Sigma tower. See page 27.
■ Hot-dip galvanizing after fabrication assures that all steel surfaces will
be heavily coated with zinc. All shearing, bending, drilling, punching,
etc. will have been completed prior to galvanization.
■ Multicell towers must have plenum partitions between cells. Otherwise,
air will be induced downward through an inoperative fan, bypassing
the fill entirely. Without these partitions, part-load or off-season opera-
tion of the tower would be completely unsatisfactory.