5. Positioning the CHCO
Ideally, a CHCO should be installed in every room containing a gas appliance. If this is not
practicable, the gas detector should be installed in the room where a gas escape is most likely to
occur; this would typically be the kitchen, due to the presence of a gas cooker and other gas
appliances.
The CHCO should be installed above the level of a possible gas escape and near the
ceiling (typically < 0.3m from the ceiling), in a place where air movements are not impeded by
furniture and furnishings.
The location should not be vulnerable to impact or splashing during normal routine operations such as
cleaning in the area. For further information see BS EN50292 and BS EN50244
Fuel Burning
Appliance
A
A
B
B
D
D
C
Flue or Extractor
Canopy
Key to Positioning Diagram
Fuel Burning Appliance: This could be a Fire, Cooker, Boiler, or any other gas fired appliance.
Flue or Extractor canopy: Used to remove the products of combustion from the room under normal cir-
cumstances.
Dimension A - 1m
Dimension B - 0.15m
Dimension C - Maximum distance from appliance - 3m CO and 5m Natural Gas.
Dimension D - For Natural Gas < 0.3m - For CO < the distance from the ceiling to the top edge of any open-
able window and any door.
The CHCO resets automatically however any connected devices such as Gas valves must be of a manual
reset type. See
Duomo EVRM Gas shut off valves
. https://duomo.co.uk/product/evrm-manual-reset-sole-
noid-gas-valve/
