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Specifications

Specification Value

Marley 

/

 

Sigma Steel 

Cooling Tower 

/

 

Specifications: Options

 

24

 

Convenience and Safety Options

 

Stairway: 

9.3

   Replace paragraph 9.3 with the fol-

lowing:

 A 30" wide, 45° steel stairway 

with 8" rise and run, shall be provided 

at the tower endwall rising from grade 

(roof) to the fan deck elevation. Stair 

treads shall be bar grating with checker 

plate nosing, and shall be through 

bolted to structural channel string-

ers. Stairway posts, guardrails and 

toeboards shall be as specified per 

Paragraph 9.2. Structural steel sup-

port columns for the stairway shall be 

provided by the cooling tower manu-

facturer. Stairway foundation shall be 

by others, designed in accordance with 

drawings provided by the cooling tower 

manufacturer. The entire stairway shall 

be hot-dip galvanized after fabrication 

and shall conform to OSHA standards.

 

 

Plenum Walkway: 

9.1

 

Add  the  following  to  the  end  of  this 

paragraph:

 Provide a 30" wide bar grat-

ing walkway extending from one endwall 

access door to the other in each cell. This 

walkway shall be supported by a galva-

nized steel framework, and the top of the 

grating shall be above the cold water basin 

overflow level. If the cold water basin is 

deeper than 4'-0", the walkway shall be 

equipped with guardrails.

 

Ladder Extension:

 

9.4

 

Add the following paragraph in the 

Access and Safety section:

 Provide 

a ladder extension for connection to 

the base of the ladder attached to 

the tower casing. This extension shall 

be long enough to rise from the roof 

(grade) level to the base of the tower. 

Anchorage and lateral bracing of the 

ladder extension shall be by others.

 

Ladder Safety Cage:

9.3

   Add the following to the end of this 

paragraph:

 A heavy gauge galvanized 

steel safety cage shall surround the 

ladder, extending from a point approxi-

mately 7'-0" above the base of the 

ladder to the top of the guardrail sur-

rounding the fan deck.

 

   Although they are not necessary for routine operation and mainte-

nance, stairways do provide a safe and comfortable means of access to 

the top of the tower that is often overlooked in the initial cooling tower 

purchase. They are designed in straight-run or double-back configura-

tions to accommodate your site requirements.

■ 

   This option permits freedom of movement for inspection or mainte-

nance within the tower without the need for wading boots or tower 

drainage. It also helps prevent maintenance personnel from damag-

ing submerged accessories in the cold water basin (such as screens, 

probes, basin heaters, etc.).

   Many towers are installed such that the base of the tower is 2'-0" or 

more above the roof or grade level. This makes it difficult to get up to 

the base of the attached ladder. The ladder extension alleviates this 

problem. Marley ladder extensions are available in standard 5'-0" and 

11'-0" lengths, and will be field-cut to fit.

    To meet OSHA guidelines, towers whose fan 

decks are 20'-0" or more above roof or grade, and 

which are equipped with ladders, are required to 

have safety cages surrounding the ladders.

Summary of Contents for Marley Sigma Marley Sigma Steel

Page 1: ...Marley Sigma Steel CoolingTower Engineering Data Specifications...

Page 2: ......

Page 3: ...m 18 Casing 18 Access 18 Cold Water Collection Basin 19 Scope of Work 19 Specifications Options Control Options Control System 20 Basin Heater 21 Fan Motor Variable Speed Drive 21 Marley Premium VFD S...

Page 4: ......

Page 5: ...rt of the continuing better ment of this Marley product line The Sigma Steel is a galvanized steel field erected general purpose crossflow cooling tower designed to serve normal air conditioning and r...

Page 6: ...model indicates number of cells Change as appropriate for your selection Primary engineering data is per cell 3 Height shown is from base of tower columns to top of fan cylinder 4 Pumping head shown i...

Page 7: ...ain at least 2 0 of clear space at tower endwalls for construction purposes Air inlet faces must have unobstructed air supply If obstructions exist nearby consult your Marley sales representative 4 Op...

Page 8: ...r Marley sales representative 4 Minimum basin depth is 1 6 Basin depth may vary to suit your storage requirements 5 All anchor bolts complete with nut and washer must be furnished by others Bolts must...

Page 9: ...required 4 Marley piping terminates at face of a cast iron flat face flange Bolt circle conforms to class 125 lb ANSI B 16 1 specifications 5 Supports on tower for crossover piping are part of the tow...

Page 10: ...esigner must take care to provide generous air inlet paths and the tower s fan cylinder discharge height should not be lower than the elevation of the top of the enclosure Obtain a copy of Marley Tech...

Page 11: ...u money in the long run both on operation and on maintenance Here are two of the more popular options Two Speed Motors Two speed motors improve operating flexibility by increas ing the number of poten...

Page 12: ...ection that fits your space allot ment and whose power usage is acceptable Limitations on physical size and total operating horsepower avoid the introduction of unfore seen operational and site relate...

Page 13: ...ase is incapable of performing as specified then you will not have received full value for your money Bear in mind that the size and cost of a cooling tower varies directly with its true thermal capab...

Page 14: ...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 galvan...

Page 15: ...surance that the tower can withstand long term operation in a hostile environment but that it will accept many years of inspection and maintenance traffic by your operating personnel Fiberglass reinfo...

Page 16: ...s a crossover pipe to deliver water to both sides of the tower 5 6 The mechanical equipment assembly shall be warranted for no less than five 5 years This warranty shall cover the fan s speed reducers...

Page 17: ...parate external louvers used by others permit water to escape the fill and form ice or produce an unsightly situation adjacent to the tower If you plan to use your tower in the wintertime particu larl...

Page 18: ...d steel shall also be provided 9 0 Access 9 1 There shall be a 33 wide by 61 high access door in each endwall casing to provide access to the interior of the tower Access doors shall be hinged and equ...

Page 19: ...be responsible for the design fabrica tion and delivery of materials to the project site and for the erection of the tower over supports provided by others Unless otherwise specified all external pipi...

Page 20: ...20VAC 50VA control power overload trip alarms and remote temperature control devices The temperature controller shall be adjustable for the required cold water temperature If a thermostatic controller...

Page 21: ...drive shafts The VFD shall catch a fan spinning in the reverse direction without tripping The panel shall include a main discon nect with short circuit protection and external operating handle lockabl...

Page 22: ...is no longer required The fluid cooler manu facturer shall supply VFD start up assis tance Tower vibration testing throughout the speed range is required to identify and lockout any natural frequency...

Page 23: ...assure proper gear box lubrication the VFD sys tem shall de energize the motor once 25 motor speed is reached and cool ing is no longer required The VFD shall include de icing logic with auto canceli...

Page 24: ...the ladder attached to the tower casing This extension shall be long enough to rise from the roof grade level to the base of the tower Anchorage and lateral bracing of the ladder extension shall be by...

Page 25: ...r Distribution System Section The distribution basins shall include galvanized steel covers These covers shall be designed for a uniform live load of 40 psf and shall be easily removable for maintenan...

Page 26: ...usually resolve these situations by using two speed motors in either 1800 900 or 1800 1200 RPM configuration and operating the fans at reduced speed without cycling after hours The natural nighttime r...

Page 27: ...n in the tower Refer to our Stainless Steel Sigma Series in which the use of stainless steel has been maximized Except for valve bodies and Geareducer every steel component of that product line is man...

Page 28: ...66213 UNITED STATES 913 664 7400 spxcooling spx com spxcooling com In the interest of technological progress all products are subject to design and or material change without notice 2008 SPX Cooling T...

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