diff --git a/src/ifcopenshell-python/ifcopenshell/util/unit.py b/src/ifcopenshell-python/ifcopenshell/util/unit.py
index 329ccff281..a19594f1b5 100644
--- a/src/ifcopenshell-python/ifcopenshell/util/unit.py
+++ b/src/ifcopenshell-python/ifcopenshell/util/unit.py
@@ -289,15 +289,11 @@ unit_symbols = {
     "SECOND": "s",
     "SQUARE_METRE": "m2",
     "METRE": "m",
-    # non si units
-    "cubic inch": "in3",
-    "cubic foot": "ft3",
-    "cubic yard": "yd3",
-    "square inch": "in2",
-    "square foot": "ft2",
-    "square yard": "yd2",
-    "square mile": "mi2",
+    "NEWTON": "N",
+    "PASCAL": "Pa",
     # conversion based units
+    "pound-force": "lbf",
+    "pound-force per square inch": "psi",
     "thou": "th",
     "inch": "in",
     "foot": "ft",