diff --git a/cara/apps/calculator/report_generator.py b/cara/apps/calculator/report_generator.py
index 7a11c1b0..917cacf5 100644
--- a/cara/apps/calculator/report_generator.py
+++ b/cara/apps/calculator/report_generator.py
@@ -110,16 +110,12 @@ def jet_origin_concentrations(model: models.ExposureModel) -> typing.List[float]
 
 
 def short_range_initial_concentrations(model: models.ExposureModel, time: float):
-    dilution = dilution_factor(np.linspace(0.1, 2., 1000))
+    dilution = dilution_factor(distance=np.linspace(0.1, 2., 1000))
     jet_origin_initial_concentrations = jet_origin_concentrations(model)
     for index, interaction in enumerate(model.concentration_model.infected.short_range_presence):
         start, finish = tuple(interaction.boundaries())
         if start <= time <= finish:
-            expiration = build_expiration(model.concentration_model.infected.short_range_activities[index])
-            single_exposure_model = dataclass_utils.nested_replace(
-                model, {'concentration_model.infected.expiration': expiration}
-            )
-            concentration = single_exposure_model.concentration_model._normed_concentration(float(time))
+            concentration = model.concentration_model.concentration(float(time))
             jet_origin_concentration = jet_origin_initial_concentrations[index] * model.concentration_model.infected.virus.viral_load_in_sputum
             return concentration + ((1/dilution)*(jet_origin_concentration - concentration))
 
diff --git a/cara/apps/calculator/static/js/form.js b/cara/apps/calculator/static/js/form.js
index 89dfeaeb..9b5d2f06 100644
--- a/cara/apps/calculator/static/js/form.js
+++ b/cara/apps/calculator/static/js/form.js
@@ -520,17 +520,39 @@ function validateLunchTime(obj) {
 }
 
 function overlapped_times(obj, start_time, finish_time) {
+    let simulation_start = parseTimeToMins($("#exposed_start").val())
+    let simulation_finish = parseTimeToMins($("#exposed_finish").val())
+    let simulation_lunch_start = parseTimeToMins($("#exposed_lunch_start").val())
+    let simulation_lunch_finish = parseTimeToMins($("#exposed_lunch_finish").val())
+    if (start_time < simulation_start || start_time > simulation_finish  ||
+        finish_time < simulation_start || finish_time > simulation_finish ||
+        start_time >= simulation_lunch_start && start_time <= simulation_lunch_finish ||
+        finish_time >= simulation_lunch_start && finish_time <= simulation_lunch_finish ) {//If start and finish inputs are out of the simulation period
+            let parameter = document.getElementById($(obj).attr('id'));
+            if (!$(obj).hasClass("red_border")) { //Adds the red border and error message.
+                $(parameter).addClass("red_border");
+            }
+            removeErrorFor($(obj));
+            insertErrorFor(parameter, "Short range interactions must be within the simulation time.")
+            return;
+    } else {
+        removeErrorFor($(obj));
+        $(obj).removeClass("red_border");
+    } 
     let current_interaction = $(obj).closest(".form_field_outer_row");
     $(".form_field_outer_row").not(current_interaction).each(function(index) {
         start_time_2 = parseTimeToMins($('#sr_start_no_' + String(index + 1)).val());
         finish_time_2 = start_time_2 + parseInt($('#sr_duration_no_' + String(index + 1)).val());
-        if ((start_time >= start_time_2 && start_time <= finish_time_2) || (finish_time >= start_time_2 && finish_time <= finish_time_2) || start_time == start_time_2 ||
-            (start_time <= start_time_2 && finish_time >= finish_time_2)) {
+        if ((start_time >= start_time_2 && start_time <= finish_time_2) || ( //If hour input is within other time range
+          finish_time >= start_time_2 && finish_time <= finish_time_2) || //If finish time input is within other time range
+            (start_time <= start_time_2 && finish_time >= finish_time_2) || //If start and finish inputs encompass other time range 
+            start_time == start_time_2) {
+            let parameter = document.getElementById($(obj).attr('id'));
             if (!$(obj).hasClass("red_border")) { //Adds the red border and error message.
-                var parameter = document.getElementById($(obj).attr('id'));
-                insertErrorFor(parameter, "Short range interactions must not overlap.")
                 $(parameter).addClass("red_border");
             }
+            removeErrorFor($(obj));
+            insertErrorFor(parameter, "Short range interactions must not overlap.")
             return false;
         } else {
             removeErrorFor($(obj));