diff --git a/schemas/BaseElements.xsd b/schemas/BaseElements.xsd
index 2743e723..93a81b05 100644
--- a/schemas/BaseElements.xsd
+++ b/schemas/BaseElements.xsd
@@ -2398,6 +2398,32 @@
 					</xs:sequence>
 				</xs:complexType>
 			</xs:element>
+			<xs:element minOccurs="0" name="Detectors">
+				<xs:complexType>
+					<xs:sequence>
+						<xs:group ref="SystemInfo"/>
+						<xs:element minOccurs="0" name="Smoke"
+							type="IntegerGreaterThanOrEqualToZero">
+							<xs:annotation>
+								<xs:documentation>Number of smoke detectors</xs:documentation>
+							</xs:annotation>
+						</xs:element>
+						<xs:element minOccurs="0" name="CarbonMonoxide"
+							type="IntegerGreaterThanOrEqualToZero">
+							<xs:annotation>
+								<xs:documentation>Number of Carbon Monoxide (CO) detectors</xs:documentation>
+							</xs:annotation>
+						</xs:element>
+						<xs:element minOccurs="0" name="Radon"
+							type="IntegerGreaterThanOrEqualToZero">
+							<xs:annotation>
+								<xs:documentation>Number of Radon detectors</xs:documentation>
+							</xs:annotation>
+						</xs:element>
+						<xs:element minOccurs="0" ref="extension"/>
+					</xs:sequence>
+				</xs:complexType>
+			</xs:element>
 			<xs:element minOccurs="0" name="Pests">
 				<xs:complexType>
 					<xs:sequence>