diff --git a/admin/src/components/PhysicalEntityForm.vue b/admin/src/components/PhysicalEntityForm.vue
index b54c1dc..77aa3eb 100644
--- a/admin/src/components/PhysicalEntityForm.vue
+++ b/admin/src/components/PhysicalEntityForm.vue
@@ -3,7 +3,7 @@
     <div class="text-bold q-mb-sm">{{ $t('structural') }}</div>
     <div class="row q-col-gutter-lg">
       <div class="col">
-        <property-form-item
+        <property-form-number
           v-for="property in ['density', 'compressive_strength', 'tensile_strength']"
           :key="property"
           v-model="entity"
@@ -11,7 +11,7 @@
         />
       </div>
       <div class="col">
-        <property-form-item
+        <property-form-number
           v-for="property in ['youngs_modulus', 'shrinkage', 'settlement']"
           :key="property"
           v-model="entity"
@@ -22,7 +22,7 @@
     <div class="text-bold q-mb-sm">{{ $t('hygrothermal') }}</div>
     <div class="row q-col-gutter-lg">
       <div class="col">
-        <property-form-item
+        <property-form-number
           v-for="property in [
             'thermal_conductivity',
             'thermal_capacity',
@@ -35,7 +35,7 @@
         />
       </div>
       <div class="col">
-        <property-form-item
+        <property-form-number
           v-for="property in ['u', 'effusivity', 'diffusivity']"
           :key="property"
           v-model="entity"
@@ -46,7 +46,7 @@
     <div class="text-bold q-mb-sm">{{ $t('acoustic') }}</div>
     <div class="row q-col-gutter-lg">
       <div class="col">
-        <property-form-item
+        <property-form-number
           v-for="property in ['absorption_coefficient', 'sound_reduction_index']"
           :key="property"
           v-model="entity"
@@ -58,33 +58,26 @@
     <div class="text-bold q-mb-sm">{{ $t('fire') }}</div>
     <div class="row q-col-gutter-lg">
       <div class="col">
-        <property-form-item
-          v-for="property in ['reaction_to_fire']"
-          :key="property"
+        <property-form-suggest
           v-model="entity"
-          :property="property"
-          :options="reactionToFireClasses"
+          :property="'reaction_to_fire'"
+          :suggestions="reactionToFireClasses"
+          @suggest="onSuggest"
         />
       </div>
       <div class="col">
-        <property-form-item
-          v-for="property in ['fire_resistance_class']"
-          :key="property"
+        <property-form-suggest
           v-model="entity"
-          :property="property"
-          :options="fireResistanceClasses"
+          :property="'fire_resistance_class'"
+          :suggestions="fireResistanceClasses"
+          @suggest="onSuggest"
         />
       </div>
     </div>
     <div class="text-bold q-mb-sm">{{ $t('others') }}</div>
     <div class="row q-col-gutter-lg">
       <div class="col">
-        <property-form-item
-          v-for="property in ['air_tightness']"
-          :key="property"
-          v-model="entity"
-          :property="property"
-        />
+        <property-form-item v-model="entity" :property="'air_tightness'" />
       </div>
       <div class="col"></div>
     </div>
@@ -98,7 +91,9 @@ export default defineComponent({
 </script>
 <script setup lang="ts">
 import { PhysicalEntity } from 'src/models';
-import PropertyFormItem from 'src/components/PropertyFormItem.vue';
+import PropertyFormNumber from 'src/components/PropertyFormNumber.vue';
+import PropertyFormSuggest from 'src/components/PropertyFormSuggest.vue';
+import { Suggestions } from 'src/components/models';
 
 interface Props {
   modelValue: PhysicalEntity;
@@ -108,8 +103,8 @@ const props = defineProps<Props>();
 
 const entity = ref(props.modelValue);
 
-const reactionToFireClasses = ['A1', 'A2', 'B', 'C', 'D', 'E', 'F'];
-const fireResistanceClasses = ['R', 'RE', 'REI', 'EI'];
+const reactionToFireClasses = ref<Suggestions>({});
+const fireResistanceClasses = ref<Suggestions>({});
 
 watch(
   () => props.modelValue,
@@ -117,4 +112,50 @@ watch(
     entity.value = val;
   },
 );
+
+function onSuggest(property: string, key: string, value: string) {
+  let suggestions: string[] = [];
+  if (property === 'reaction_to_fire') {
+    // format suggested: <A1|A2|B|C|D|E|F>-<S1|S2|S3>-<D0|D1|D2>
+    const base = ['A1', 'A2', 'B', 'C', 'D', 'E', 'F'];
+    if (value && base.find((cls) => value.startsWith(cls))) {
+      const tokens = value.split('-');
+      const smoke = ['S1', 'S2', 'S3'];
+      const droplets = ['D0', 'D1', 'D2'];
+      // if value does not contain smoke
+      if (tokens.length > 1 && !smoke.find((cls) => tokens[1].trim().includes(cls))) {
+        suggestions = smoke.map((s) => `${tokens[0].trim()}-${s}`);
+      } else if (tokens.length > 2 && !droplets.find((cls) => tokens[2].trim().includes(cls))) {
+        suggestions = droplets.map((d) => `${tokens[0].trim()}-${tokens[1].trim()}-${d}`);
+      } else {
+        suggestions = base;
+      }
+    } else {
+      suggestions = base;
+    }
+    reactionToFireClasses.value = {
+      key,
+      options: suggestions,
+    };
+  }
+  if (property === 'fire_resistance_class') {
+    // format suggested: <R|RE|REI|EI>-<30|60|90|120>
+    const base = ['R', 'RE', 'REI', 'EI'];
+    if (value && base.find((cls) => value.startsWith(cls))) {
+      const tokens = value.split('-');
+      const time = ['30', '60', '90', '120'];
+      if (tokens.length > 1 && !time.find((cls) => tokens[1].trim().includes(cls))) {
+        suggestions = time.map((t) => `${tokens[0].trim()}-${t}`);
+      } else {
+        suggestions = base;
+      }
+    } else {
+      suggestions = base;
+    }
+    fireResistanceClasses.value = {
+      key,
+      options: suggestions,
+    };
+  }
+}
 </script>
diff --git a/admin/src/components/PropertyFormItem.vue b/admin/src/components/PropertyFormNumber.vue
similarity index 81%
rename from admin/src/components/PropertyFormItem.vue
rename to admin/src/components/PropertyFormNumber.vue
index fd1e0a7..955c137 100644
--- a/admin/src/components/PropertyFormItem.vue
+++ b/admin/src/components/PropertyFormNumber.vue
@@ -3,16 +3,7 @@
     <div class="q-mb-sm">
       {{ $t(property) }}
     </div>
-    <div v-if="options">
-      <q-select
-        filled
-        v-model="selected[property]"
-        :label="$t('class')"
-        :options="options"
-        @update:model-value="onUpdate(property)"
-      />
-    </div>
-    <div v-else class="row q-col-gutter-sm q-mb-sm">
+    <div class="row q-col-gutter-sm q-mb-sm">
       <div class="col">
         <q-input
           filled
@@ -49,7 +40,7 @@
 
 <script lang="ts">
 export default defineComponent({
-  name: 'PropertyFormItem',
+  name: 'PropertyFormNumber',
 });
 </script>
 <script setup lang="ts">
@@ -58,7 +49,6 @@ import { PhysicalEntity } from 'src/models';
 interface Props {
   modelValue: PhysicalEntity;
   property: string;
-  options?: string[];
 }
 
 const props = defineProps<Props>();
diff --git a/admin/src/components/PropertyFormSuggest.vue b/admin/src/components/PropertyFormSuggest.vue
new file mode 100644
index 0000000..ebe831b
--- /dev/null
+++ b/admin/src/components/PropertyFormSuggest.vue
@@ -0,0 +1,120 @@
+<template>
+  <div>
+    <div class="q-mb-sm">
+      {{ $t(property) }}
+    </div>
+
+    <div class="row q-col-gutter-sm q-mb-sm">
+      <div class="col">
+        <q-input
+          filled
+          v-model="selected[`${property}_low`]"
+          :label="$t('low')"
+          @update:model-value="onUpdate(`${property}_low`)"
+        >
+          <q-menu v-model="showLowSuggestions" no-parent-event no-focus auto-close>
+            <q-list style="min-width: 100px">
+              <q-item
+                clickable
+                v-close-popup
+                v-for="sugg in suggestions.options"
+                :key="sugg"
+                @click="selected[`${property}_low`] = sugg"
+              >
+                <q-item-section>{{ sugg }}</q-item-section>
+              </q-item>
+            </q-list>
+          </q-menu>
+        </q-input>
+      </div>
+      <div class="col">
+        <q-input filled v-model="selected[property]" :label="$t('std')" @update:model-value="onUpdate(property)">
+          <q-menu v-model="showStdSuggestions" no-parent-event no-focus auto-close>
+            <q-list style="min-width: 100px">
+              <q-item
+                clickable
+                v-close-popup
+                v-for="sugg in suggestions.options"
+                :key="sugg"
+                @click="selected[property] = sugg"
+              >
+                <q-item-section>{{ sugg }}</q-item-section>
+              </q-item>
+            </q-list>
+          </q-menu>
+        </q-input>
+      </div>
+      <div class="col">
+        <q-input
+          filled
+          v-model="selected[`${property}_high`]"
+          :label="$t('high')"
+          @update:model-value="onUpdate(`${property}_high`)"
+        >
+          <q-menu v-model="showHighSuggestions" no-parent-event no-focus auto-close>
+            <q-list style="min-width: 100px">
+              <q-item
+                clickable
+                v-close-popup
+                v-for="sugg in suggestions.options"
+                :key="sugg"
+                @click="selected[`${property}_high`] = sugg"
+              >
+                <q-item-section>{{ sugg }}</q-item-section>
+              </q-item>
+            </q-list>
+          </q-menu>
+        </q-input>
+      </div>
+    </div>
+    <div class="q-mb-md text-hint">
+      {{ $t(`${property}_hint`) }}
+    </div>
+  </div>
+</template>
+
+<script lang="ts">
+export default defineComponent({
+  name: 'PropertyFormSuggest',
+});
+</script>
+<script setup lang="ts">
+import { PhysicalEntity } from 'src/models';
+import { Suggestions } from 'src/components/models';
+
+interface Props {
+  modelValue: PhysicalEntity;
+  property: string;
+  suggestions?: Suggestions;
+}
+
+const props = defineProps<Props>();
+const emits = defineEmits(['suggest']);
+const showLowSuggestions = ref(false);
+const showStdSuggestions = ref(false);
+const showHighSuggestions = ref(false);
+
+const selected = ref(props.modelValue);
+
+watch(
+  () => props.suggestions,
+  (val) => {
+    if (val) {
+      showLowSuggestions.value = val.key.endsWith('_low');
+      showHighSuggestions.value = val.key.endsWith('_high');
+      showStdSuggestions.value = !showLowSuggestions.value && !showHighSuggestions.value;
+    } else {
+      showLowSuggestions.value = false;
+      showHighSuggestions.value = false;
+      showStdSuggestions.value = false;
+    }
+  },
+);
+
+function onUpdate(key: string) {
+  if (selected.value[key] === '') {
+    selected.value[key] = null;
+  }
+  emits('suggest', props.property, key, selected.value[key]);
+}
+</script>
diff --git a/admin/src/components/models.ts b/admin/src/components/models.ts
index 81ec165..3fac188 100644
--- a/admin/src/components/models.ts
+++ b/admin/src/components/models.ts
@@ -22,3 +22,8 @@ export interface Option {
   label: string;
   level?: number;
 }
+
+export interface Suggestions {
+  key: string;
+  options: string[];
+}
diff --git a/admin/src/models.ts b/admin/src/models.ts
index 54772d4..b1fab8d 100644
--- a/admin/src/models.ts
+++ b/admin/src/models.ts
@@ -79,6 +79,8 @@ export interface PhysicalEntity extends Entity {
   diffusivity_low?: number;
   absorption_coefficient_low?: number;
   sound_reduction_index_low?: number;
+  reaction_to_fire_low?: string;
+  fire_resistance_class_low?: string;
   air_tightness_low?: number;
 
   density_high?: number;
@@ -96,6 +98,8 @@ export interface PhysicalEntity extends Entity {
   diffusivity_high?: number;
   absorption_coefficient_high?: number;
   sound_reduction_index_high?: number;
+  reaction_to_fire_high?: string;
+  fire_resistance_class_high?: string;
   air_tightness_high?: number;
 }
 
diff --git a/backend/api/models/domain.py b/backend/api/models/domain.py
index e25a1f3..1b93569 100644
--- a/backend/api/models/domain.py
+++ b/backend/api/models/domain.py
@@ -65,6 +65,8 @@ class PhysicalEntity(Entity):
     diffusivity_low: Optional[float] = Field(default=None)
     absorption_coefficient_low: Optional[float] = Field(default=None)
     sound_reduction_index_low: Optional[float] = Field(default=None)
+    reaction_to_fire_low: Optional[str] = Field(default=None)
+    fire_resistance_class_low: Optional[str] = Field(default=None)
     air_tightness_low: Optional[float] = Field(default=None)
 
     density_high: Optional[float] = Field(default=None)
@@ -82,6 +84,8 @@ class PhysicalEntity(Entity):
     diffusivity_high: Optional[float] = Field(default=None)
     absorption_coefficient_high: Optional[float] = Field(default=None)
     sound_reduction_index_high: Optional[float] = Field(default=None)
+    reaction_to_fire_high: Optional[str] = Field(default=None)
+    fire_resistance_class_high: Optional[str] = Field(default=None)
     air_tightness_high: Optional[float] = Field(default=None)
 
 # Association tables
diff --git a/backend/migrations/versions/2024_12_18_0952-659fc00a69fa_fire_low_high.py b/backend/migrations/versions/2024_12_18_0952-659fc00a69fa_fire_low_high.py
new file mode 100644
index 0000000..fea0e3c
--- /dev/null
+++ b/backend/migrations/versions/2024_12_18_0952-659fc00a69fa_fire_low_high.py
@@ -0,0 +1,64 @@
+"""fire-low-high
+
+Revision ID: 659fc00a69fa
+Revises: 9dd17a356a73
+Create Date: 2024-12-18 09:52:55.635120
+
+"""
+from typing import Sequence, Union
+
+from alembic import op
+import sqlalchemy as sa
+import sqlmodel
+
+# revision identifiers, used by Alembic.
+revision: str = '659fc00a69fa'
+down_revision: Union[str, None] = '9dd17a356a73'
+branch_labels: Union[str, Sequence[str], None] = None
+depends_on: Union[str, Sequence[str], None] = None
+
+
+def upgrade() -> None:
+    # ### commands auto generated by Alembic - please adjust! ###
+    op.add_column('buildingmaterial', sa.Column(
+        'reaction_to_fire_low', sqlmodel.sql.sqltypes.AutoString(), nullable=True))
+    op.add_column('buildingmaterial', sa.Column(
+        'fire_resistance_class_low', sqlmodel.sql.sqltypes.AutoString(), nullable=True))
+    op.add_column('buildingmaterial', sa.Column(
+        'reaction_to_fire_high', sqlmodel.sql.sqltypes.AutoString(), nullable=True))
+    op.add_column('buildingmaterial', sa.Column(
+        'fire_resistance_class_high', sqlmodel.sql.sqltypes.AutoString(), nullable=True))
+    op.add_column('naturalresource', sa.Column(
+        'reaction_to_fire_low', sqlmodel.sql.sqltypes.AutoString(), nullable=True))
+    op.add_column('naturalresource', sa.Column(
+        'fire_resistance_class_low', sqlmodel.sql.sqltypes.AutoString(), nullable=True))
+    op.add_column('naturalresource', sa.Column(
+        'reaction_to_fire_high', sqlmodel.sql.sqltypes.AutoString(), nullable=True))
+    op.add_column('naturalresource', sa.Column(
+        'fire_resistance_class_high', sqlmodel.sql.sqltypes.AutoString(), nullable=True))
+    op.add_column('technicalconstruction', sa.Column(
+        'reaction_to_fire_low', sqlmodel.sql.sqltypes.AutoString(), nullable=True))
+    op.add_column('technicalconstruction', sa.Column(
+        'fire_resistance_class_low', sqlmodel.sql.sqltypes.AutoString(), nullable=True))
+    op.add_column('technicalconstruction', sa.Column(
+        'reaction_to_fire_high', sqlmodel.sql.sqltypes.AutoString(), nullable=True))
+    op.add_column('technicalconstruction', sa.Column(
+        'fire_resistance_class_high', sqlmodel.sql.sqltypes.AutoString(), nullable=True))
+    # ### end Alembic commands ###
+
+
+def downgrade() -> None:
+    # ### commands auto generated by Alembic - please adjust! ###
+    op.drop_column('technicalconstruction', 'fire_resistance_class_high')
+    op.drop_column('technicalconstruction', 'reaction_to_fire_high')
+    op.drop_column('technicalconstruction', 'fire_resistance_class_low')
+    op.drop_column('technicalconstruction', 'reaction_to_fire_low')
+    op.drop_column('naturalresource', 'fire_resistance_class_high')
+    op.drop_column('naturalresource', 'reaction_to_fire_high')
+    op.drop_column('naturalresource', 'fire_resistance_class_low')
+    op.drop_column('naturalresource', 'reaction_to_fire_low')
+    op.drop_column('buildingmaterial', 'fire_resistance_class_high')
+    op.drop_column('buildingmaterial', 'reaction_to_fire_high')
+    op.drop_column('buildingmaterial', 'fire_resistance_class_low')
+    op.drop_column('buildingmaterial', 'reaction_to_fire_low')
+    # ### end Alembic commands ###
diff --git a/frontend/src/models.ts b/frontend/src/models.ts
index 72fa77b..a255f64 100644
--- a/frontend/src/models.ts
+++ b/frontend/src/models.ts
@@ -80,6 +80,8 @@ export interface PhysicalEntity extends Entity {
   diffusivity_low?: number;
   absorption_coefficient_low?: number;
   sound_reduction_index_low?: number;
+  reaction_to_fire_low?: string;
+  fire_resistance_class_low?: string;
   air_tightness_low?: number;
 
   density_high?: number;
@@ -97,6 +99,8 @@ export interface PhysicalEntity extends Entity {
   diffusivity_high?: number;
   absorption_coefficient_high?: number;
   sound_reduction_index_high?: number;
+  reaction_to_fire_high?: string;
+  fire_resistance_class_high?: string;
   air_tightness_high?: number;
 }