<a href="//commons.wikimedia.org/wiki/Mortar_(firestop)" title="Mortar (firestop)">Firestop mortar</a> installation in a <a href="//commons.wikimedia.org/wiki/Paper_mill" title="Paper mill">Paper mill</a> in Northern <a href="//commons.wikimedia.org/wiki/Ontario" title="Ontario">Ontario</a>, <a href="//commons.wikimedia.org/wiki/Canada" title="Canada">Canada</a>, in a <a href="//commons.wikimedia.org/wiki/Cable_tray" class="mw-redirect" title="Cable tray">cable tray</a> penetration, in a fire-resistance rated <a href="//commons.wikimedia.org/wiki/Concrete" title="Concrete">concrete</a> block wall assembly.
<a href="//commons.wikimedia.org/wiki/User:Achim_Hering" title="User:Achim Hering">Achim Hering</a>
CC BY 3.0
<span class="int-own-work" lang="en">Own work</span>