diff --git a/hips/tiles/surveys.py b/hips/tiles/surveys.py
index 28bc65b..f5c462b 100644
--- a/hips/tiles/surveys.py
+++ b/hips/tiles/surveys.py
@@ -128,7 +128,10 @@ def hips_order(self) -> int:
     @property
     def tile_width(self) -> int:
         """HiPS tile width"""
-        return int(self.data['hips_tile_width']) or 512
+        try:
+            return int(self.data['hips_tile_width'])
+        except KeyError:
+            return 512
 
     @property
     def tile_format(self) -> str: