diff --git a/Source/read.f90 b/Source/read.f90
index 862ff98f59..371242eaf0 100644
--- a/Source/read.f90
+++ b/Source/read.f90
@@ -6214,7 +6214,7 @@ SUBROUTINE READ_PART
          LPC%PERMEABILITY(1:3) = 3.44E-9_EB*LPC%FREE_AREA_FRACTION**1.6_EB
          LPC%DRAG_COEFFICIENT(1:3) = 4.30E-2_EB*LPC%FREE_AREA_FRACTION**2.13_EB
       CASE('POROUS MEDIA')
-         IF (ANY(DRAG_COEFFICIENT<TWO_EPSILON_EB) .OR. ANY(PERMEABILITY<TWO_EPSILON_EB)) THEN
+         IF (ANY(DRAG_COEFFICIENT < 0._EB) .OR. ANY(PERMEABILITY < TWO_EPSILON_EB)) THEN
             WRITE(MESSAGE,'(A,I0,A)') 'ERROR(222): PART ',N,'. Specify all compoents for DRAG_COEFFICIENT and PERMEABILTIY.'
             CALL SHUTDOWN(MESSAGE) ; RETURN
          ENDIF