Ohalos6: 7
כֵּלִים שֶׁתַּחַת הַפֶּרַח טְהוֹרִים. רַבִּי יוֹחָנָן בֶּן נוּרִי מְטַמֵּא. הַטֻּמְאָה וְהַכֵּלִים שֶׁתַּחַת הַפֶּרַח, אִם יֶשׁ שָׁם פּוֹתֵחַ טֶפַח, טְמֵאִין; וְאִם לָאו, טְהוֹרִין. שְׁנֵי פַרְדַּסְקִים זֶה בְצַד זֶה אוֹ זֶה עַל גַּב זֶה. נִפְתַּח אֶחָד מֵהֶן, הוּא וְהַבַּיִת טָמֵא, וַחֲבֵרוֹ טָהוֹר. וְרוֹאִין אֶת הַפַּרְדַּסְקִין כְּאִלּוּ הוּא אֹטֶם, יִדּוֹן מֶחֱצָה לְמֶחֱצָה לְהָבִיא אֶת הַטֻּמְאָה לַבָּיִת.
Utensils that are beneath a capital remain tahor. R’ Yochanan ben Nuri declares [them] tamei. [In a case where] the tumah and the utensils are beneath the capital, if there is a space of a handbreadth, the [utensils] are tamei; if not, they remain tahor. Two wall closets are one beside the other or one above the other. One of [the closets] is opened; it becomes tamei and so does the house, while the other [closet] remains tahor. [However, if the door is closed,] the wall closets are treated as if there is no empty space inside them at all, and they are ruled half and half to make the house tamei.