Ohalos13: 3
הַחוֹר שֶׁבַּדֶּלֶת — שִׁעוּרוֹ מְלֹא אֶגְרוֹף, דִּבְרֵי רַבִּי עֲקִיבָא; רַבִּי טַרְפוֹן אוֹמֵר: בְּפוֹתֵחַ טֶפַח. שִׁיֵּר בָּהּ הֶחָרָשׁ מִלְּמַטָּן אוֹ מִלְמַעְלָן, הֱגִיפָהּ וְלֹא מֵרְקָהּ, אוֹ שֶׁפְּתָחַתּוּ הָרוּחַ — שִׁעוּרוֹ מְלֹא אֶגְרוֹף.
A hole in the door should be measured with the size of a fist; these are the words of R’ Akiva. R’ Tarfon says: [This hole is measured] with a square handbreadth. [If] the carpenter left a space at the bottom or top, or he did not complete [the door], or the wind opened [the door], [the hole] is measured with the size of a fist.