Neighbourhood considerations
If a room-sealed gas appliance is fitted on that boundary wall, the flue terminal may extend into the neighbouring
property. This may lead to a customer complaint, with allegations of trespassing and complaints of POC entering
the adjacent premises.
The situation is compounded if the gas appliance is room-sealed and POC are blown onto neighbouring doors and
windows. To add to the misery, in colder weather, the POC condense in the cold air to form a plume, which can be
particularly irritating for the neighbour.
Be aware that installing an appliance in such a position may contravene the Gas Safety (Installation and Use)
Regulations.
In addition, the neighbour may also have plans to develop or build an extension on their property, which may
ultimately obstruct the flue outlet. When you are requested to install a gas appliance in these positions, advise the
customer all the consequences. Such installations often offend neighbours who may contact local Planning or
Environmental Health Officers who in turn may have powers under the Environmental Health Act 1990 to shut down
an offending appliance. See also Exchanging Information with the gas user and planning - and Siting of flue
terminals in relation to boundaries - care needed in this part.
Carport or building extension
Where you site a flue terminal within a carport or building extension, it should have at least two completely open
and unobstructed sides. The distance between the lowest part of the roof and the top of the terminal should be at
least 600mm for balanced flue appliances.
Note: Do not treat a covered passageway (e.g. between terraced houses) as a carport and do not install new
appliances in this location.
Basements, light wells and retaining walls - points to note
Do not site flue terminals within the confines of a basement area, light well or external space formed by a retaining
wall, unless you take steps to ensure that the POC can disperse safely at all times. It may be possible to locate
room-sealed appliances in such a location provided that they are not sited lower than one metre from the top level
of that area to allow POC to disperse safely.
Light well - an area that may inhibit dispersal of POC
A light well can be best described to cover areas where for example, there are walls opposite and/or around the
wall on which a flue terminal is located, that may be inhibiting the free dispersal of POC. An illustration of this might
be the common Victorian urban terrace property, where the front door opens onto the street footpath across a
narrow well, which provides light and possibly access to a cellar. It may also be the small central area in a square
building designed to give light to the rooms on the inside of the building.
Be aware of the dangers of locating flue terminals where the POC cannot freely disperse. This could be
accentuated by the possible accumulation of POC caused by several flue terminals all discharging into a single
confined space.
Terminal guards - when to use
Fit a flue terminal guard over a terminal:
• if anybody could come into contact with that terminal
• it could be subject to damage
• where the terminal is less than 2m from the finished floor level
The appliance manufacturer will specify a suitable terminal guard. No part of the guard should be less than 50mm
from any part of the terminal when fitted in accordance with the manufacturer’s instructions. The guard should not
have any sharp edges, which could cause injury and any opening should be no larger than 16mm. Proprietary
guards are generally available.
Timber frame construction - ensure no adverse effect on weather proofing
Whilst it is possible to install both open-flued and room-sealed appliances in timber frame properties, take great
care to ensure that the chimney does not interfere with the weather proofing qualities of any outer wall it may
penetrate.
TERMINAL LOCATION
CONTINUED
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