diff --git a/frb/dm/igm.py b/frb/dm/igm.py
index 1f8b19c1..3924e55f 100644
--- a/frb/dm/igm.py
+++ b/frb/dm/igm.py
@@ -13,7 +13,6 @@
 
 from astropy import units
 from astropy.table import Table
-from astropy.utils import isiterable
 from astropy import constants
 
 from frb.halos import hmf as frb_hmf
@@ -483,7 +482,7 @@ def z_to_array(z):
 
     """
     # float or ndarray?
-    if not isiterable(z):
+    if not np.iterable(z):
         z = np.array([z])
         flg_z = 0
     else:
diff --git a/frb/frb.py b/frb/frb.py
index 6cf7e464..0607326d 100644
--- a/frb/frb.py
+++ b/frb/frb.py
@@ -431,7 +431,11 @@ def by_name(cls, frb_name, **kwargs):
         Returns:
 
         """
-        json_file = importlib_resources.files('frb.data')/ f'FRBs/{frb_name}.json'
+        # searches for defined input directory. Otherwise uses default
+        if "ZDM_PATH_FRBDIR" in os.environ:
+            json_file = os.environ["ZDM_PATH_FRBDIR"]+f"/{frb_name}.json"
+        else:
+            json_file = importlib_resources.files('frb.data')/ f'FRBs/{frb_name}.json'
         slf = cls.from_json(str(json_file), **kwargs)
         return slf