Hi group. With reference to UL 1950 3rd. Ed., Table 15 (size and spacing of holes in metal bottoms of fire enclosures) , I would like some opinions . . .
the largest size listed in the table is 1.00mm minimum metal thickness, 2.00mm maxhole dia., and 3.00mm minimum center-center hole spacing. If my metal thickness was greater (1.27mm), and my center-center hole spacing was 4.75mm, could I not go to a larger hole (3.175 - .125")? The reason I pose this question is that the dmensions I was thinking about using are for a 'standard' punch that a sheet metal fabricator would have. UL told me that what's they won't consider it because it's not listed on the chart. I am trying to tell my mechanical designer to use standard perforated stock which falls within the UL guidelines (there is stuff readily available) but he needs more airflow (without fans) . . . Has anyone been there? John Juhasz Fiber Options Bohemia, NY
