diff --git a/code/_helpers/game.dm b/code/_helpers/game.dm
index 6bd5c022dc2..c9727a8a98b 100644
--- a/code/_helpers/game.dm
+++ b/code/_helpers/game.dm
@@ -279,7 +279,7 @@
 		var/turf/U = GetBelow(O)
 		while(istype(U))
 			hearturfs |= U
-			if(istype(U, /turf/simulated/open))
+			if(isopenspace(U))
 				U = GetBelow(U)
 			else
 				U = null