I have a "silly" question regarding the allowable for the API 661 air cooler. We ask the vendor for increased factor for allowable nozzle loads on several air coolers, they will agree for 3 times factor according API 661.
The question is, this factor should apply for all three paragraph 7.1.10.1 (individual nozzle), 7.1.10.2(header combination) and 7.1.10.3(multi-bay combination)?
Or this factor should apply only for paragraph 7.1.10.1, individual nozzle loads and for the rest the allowable should be " 1x API661 ".

When we apply a factor to API 661 allowables (3X is not unusual), it applies to all of the nozzle load allowables in API 661. If it were only meant to apply to some of the allowables, this would be specified.