Revision: May 9, 2014
This design standard provides typical design data for air fin piping design. The notes with the figures are:
General
1.1 - Forced draft air coolers are defined as those coolers whose fans are located below the tube bundle and push the air through the tubes.
1.2 - Induced draft air coolers are defined as those coolers whose fans are located above the tube bundle and draw the air through the tubes.
Location
2.1 - Care should be exercised in locating air cooler to prevent starvation of air flow. Intake of hot exhaust gases (from whatever source) and recycling of air flow from the air coolers themselves (see examples for correct and incorrect air cooler arrangements)
2.2 - Air coolers are to be located as close as possible to their related equipment and within available space above overhead pipeways or other elevated structure
2.3 - Air coolers may be mounted at grade if process requirements can be met and adequate space is available
2.4 - Multiple air cooler units should be grouped together whenever possible to enable supporting of a common location and the sharing of common platforms
2.5 - Whenever air coolers are mounted above pipeways, consideration must be given to provide ample clearances between fan drives and access platforms. These considerations will normally determine the elevations of coolers.
Ladders and Platforming
3.1 - Air coolers located above pipeways or elevated structures are to be provided with ladders from grade and platforms for the purpose of servicing gearing, fan drives and motors, these consist of main walkways, at or near center of the coolers, with auxiliary platforms to each drive mechanism. The width of the auxiliary platform should be of sufficient size to permit the removal of the driver gear and the transporting of same, by portable means to a convenient dropout area to grade.
3.2 - Platforms are also required at cooler header boxes for access to inlet and outlet connections. These platforms are often provided by the air cooler vendor. Access to the above platforms can be either by ladder or stairways or a combination of both depending on individual job requirements.
3.3 - Air coolers located at grade shall be provided with ladders from grade and platforming for access to header boxes only, as fan drives are normally accessible from grade
3.4 - Provide escape ladder only when walking distance from main access ladder or stairway exceeds 15 meters
Piping
4.1 - Pocketing of inlet piping to the air cooler is not permitted
4.2 - When inlet or outlet valves at the coolers are required, they must be accessible from and clear of platforming
4.3 - These piping configurations to be used only when flexibility requirements dictate. If these configurations are use, the resultant total forces and loading on the equipment shall be transmitted to the vendor, so that he may incorporate the required pipe support on the equipment. If vendor's requirement cannot tolerate this additional loading, consideration must be given to the possibility of spreading apart adjacent coolers, (if present) so that column extensions may be provided to support the piping.
4.4 - Close liaison must be maintained between the piping design, pipe support and stress analysis group during the layout phase to ensure that the allowable forces and moments on the nozzles as specified by the vendor, are not exceeded. If impractical to meet specified loading, consult vendor to develop a satisfactory solution
