Topside of <a href="//commons.wikimedia.org/wiki/Firestop" title="Firestop">firestop</a> with <a href="//commons.wikimedia.org/w/index.php?title=Penetrant&amp;action=edit&amp;redlink=1" class="new" title="Penetrant (page does not exist)">penetrants</a> consisting of electrical conduit on the left and a bus duct on the right. The firestop consists of <a href="//commons.wikimedia.org/wiki/Mortar_(firestop)" title="Mortar (firestop)">firestop mortar</a> on top and rockwool on the bottom, for a 2 hour <a href="//commons.wikimedia.org/w/index.php?title=Fire-resistance_rating&amp;action=edit&amp;redlink=1" class="new" title="Fire-resistance rating (page does not exist)">fire-resistance rating</a>
<a href="//commons.wikimedia.org/wiki/User:Achim_Hering" title="User:Achim Hering">Achim Hering</a>
2006-11-10
<span class="int-own-work" lang="en">Own work</span>