diff --git a/src/ifcopenshell-python/ifcopenshell/express/rule_compiler.py b/src/ifcopenshell-python/ifcopenshell/express/rule_compiler.py
index 990608d792..bbc66674fd 100644
--- a/src/ifcopenshell-python/ifcopenshell/express/rule_compiler.py
+++ b/src/ifcopenshell-python/ifcopenshell/express/rule_compiler.py
@@ -8,6 +8,7 @@ import functools
 import itertools
 
 import ifcopenshell.express
+import ifcopenshell.express.express_parser
 
 import networkx as nx
 
@@ -331,7 +332,7 @@ def calc_{class_name}_{str(derived_attr.attribute_decl.redeclared_attribute.qual
 
 def process_domain_rule(context):
     return f"""
-assert {context.expression}
+assert ({context.expression}) is not False
 """
 
 def process_expression(context):
diff --git a/src/ifcopenshell-python/ifcopenshell/express/rule_executor.py b/src/ifcopenshell-python/ifcopenshell/express/rule_executor.py
index 8b0f282608..5579d3cf41 100644
--- a/src/ifcopenshell-python/ifcopenshell/express/rule_executor.py
+++ b/src/ifcopenshell-python/ifcopenshell/express/rule_executor.py
@@ -7,7 +7,7 @@ from codegen import indent
 
 
 def reverse_compile(s):
-    return s.strip().replace("len(", "SIZEOF(").replace("assert ", "")
+    return s.strip().replace("len(", "SIZEOF(").replace("assert ", "").replace(" is not False", "")
 
 
 @dataclass