Hamer Fires 5 Series: Basset 5 / 5 Tall - Catalog - Page 20
CHIMNEY REQUIREMENTS
Chimney Requirements
This appliance is unsuitable for use in a shared 昀氀ue system. If elsewhere in the house another 昀椀replace
feeds into the same chimney, this must be sealed, otherwise 昀氀ue gases or air may be drawn into, or
escape from, the other chimney or 昀椀replace. This would contravene Building Regulations as it is
potentially very dangerous.
Chimney Height, Size, and Installation Requirements
The chimney plays a vital role in ensuring the safe and ef昀椀cient operation of your stove. Proper chimney
height, size, preparation, and lining are essential for maintaining adequate draught, ef昀椀cient combustion,
and venting of combustion gases to prevent smoke or fumes from entering the living space.
Chimney Height and Draught
The height of the chimney is critical to ensure suf昀椀cient natural draught. For satisfactory stove
performance, the chimney must:
•
Building regulation recommend a chimney height of 4.5 metres, measured vertically from the stove
outlet to the top of the chimney. Where an alternative approach is required to the design of the
chimney system a calculation in accordance to BS EN 13384-1 must be provided.
•
Provide a minimum 昀氀ue draught of 12 Pa to clear combustion gases effectively and prevent smoke
leakage into the room.
Chimneys shorter than this may result in poor draught, leading to smoke ingress and reduced stove
performance.
Existing Chimneys: Preparation and Lining
Before using an existing chimney, it must be thoroughly swept and examined for soundness.
Lining Requirements: If the chimney is not lined, it is strongly recommended to fully line it with a Class 1
Liner and insulate it before use. Partial lining should be avoided, as it creates issues where the lining
ends. Even small air breaks in the mortar can allow cold air to enter, cooling the 昀氀ue gases and causing
wood tar to precipitate on the chimney walls. Over time, this buildup can constrict the chimney, leading
to poor stove performance, chimney 昀椀res, and structural damage.
Importance of Lining and Insulation
Proper lining and insulation are essential to maintain 昀氀ue gas temperature and prevent tar buildup,
condensation issues, and structural damage to the chimney. Fully insulated liners improve draught and
ensure compliance with Building Regulations Approved Document J. Clay liners should be avoided unless
back-insulated, as they are prone to condensation. Insulation is especially important in cases where:
•
•
The chimney is located on an external wall, making it more susceptible to temperature drops.
The chimney is signi昀椀cantly tall, meaning that gases have a long way to travel before exiting, giving
them more time to cool down.
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SISB5 - REV1.7 / Issue Date 09-04-2025
