diff --git a/rocket_twin/notebooks/test_sequences.ipynb b/rocket_twin/notebooks/test_sequences.ipynb
index 2c68ea2..baecd52 100644
--- a/rocket_twin/notebooks/test_sequences.ipynb
+++ b/rocket_twin/notebooks/test_sequences.ipynb
@@ -93,7 +93,8 @@
    "source": [
     "#Run fuelling sequence (transfers fuel from ground tank to rocket tank until it is full)\n",
     "\n",
-    "s2 = [{'name' : 'fuel', 'type' : 'transient', 'init' : {'g_tank.w_out_temp' : 1.}, 'dt' : 0.1, 'Tf' : 5., 'stop' : 'rocket.tank.weight_p == rocket.tank.weight_max'}]\n",
+    "s2 = [{'name' : 'fuel', 'type' : 'transient', 'init' : {'g_tank.w_out_temp' : 1., 'pipe.is_open' : True},\n",
+    "       'dt' : 0.1, 'Tf' : 5., 'stop' : 'rocket.tank.weight_p == rocket.tank.weight_max'}]\n",
     "run_sequences(sys, s2)"
    ]
   },
@@ -142,7 +143,7 @@
    "source": [
     "#Run flight sequence (turns rocket on and discards rocket tank fuel until it is empty)\n",
     "\n",
-    "s3 = [{'name' : 'flight', 'type' : 'transient', 'init' : {'rocket.tank.w_out_temp' : 0.5, 'g_tank.w_out_temp' : 0., 'rocket.dyn.switch' : True},\n",
+    "s3 = [{'name' : 'flight', 'type' : 'transient', 'init' : {'rocket.tank.w_out_temp' : 0.5, 'pipe.is_open' : False, 'rocket.dyn.switch' : True},\n",
     "       'dt' : 0.1, 'Tf' : 10., 'stop' : 'rocket.tank.weight_p == 0.'}]\n",
     "run_sequences(sys, s3)"
    ]
@@ -171,6 +172,16 @@
     "sys.rocket.dyn.inwards"
    ]
   },
+  {
+   "cell_type": "code",
+   "execution_count": null,
+   "id": "602b8d98-a7e8-4660-aaea-7a5a4f59ac63",
+   "metadata": {},
+   "outputs": [],
+   "source": [
+    "sys.g_tank.inwards"
+   ]
+  },
   {
    "cell_type": "code",
    "execution_count": null,
diff --git a/rocket_twin/systems/tank/pipe.py b/rocket_twin/systems/tank/pipe.py
index 59e6e1e..2b3597f 100644
--- a/rocket_twin/systems/tank/pipe.py
+++ b/rocket_twin/systems/tank/pipe.py
@@ -8,6 +8,8 @@ class Pipe(System):
     ------
     w_in [kg/s]: float,
         mass flow of fuel entering the pipe
+    is_open: boolean,
+        whether the pipe is open or closed
 
     Outputs
     ------
@@ -17,8 +19,13 @@ class Pipe(System):
 
     def setup(self):
 
+        self.add_inward("is_open", False, desc="Whether the pipe is open or not", unit='')
         self.add_inward("w_in", 0.0, desc="Fuel income rate", unit="kg/s")
+
         self.add_outward("w_out", 0.0, desc="Fuel exit rate", unit="kg/s")
 
     def compute(self):
-        self.w_out = self.w_in
+
+        if self.is_open == False:
+            self.parent.g_tank.w_out_temp = 0.
+        self.w_out = self.w_in
\ No newline at end of file