A flueless fire requested for a child's attic bedroom
A homeowner in a 1990s estate asks you to install a decorative flueless natural gas fire (catalytic, rated 2.6 kW input) in a converted attic bedroom. The room measures 4.2 m × 3.0 m × 2.4 m. Its only permanent opening is a 4,000 mm² trickle vent in the window frame, which the homeowner says was "put in for the old gas fire". The previous appliance was a 2 kW electric panel heater, now removed. Two young children sleep in the room every night. A battery-powered CO alarm is fitted in the hallway outside, not in the room itself. The quotation has been signed and the fire has been delivered to site. The homeowner will not consider a room-sealed appliance because, they say, "it would mean a flue through the new roof and I'm not paying for that". The builder who converted the attic has told them "a vent is all you need".
1. May the installation proceed? Justify your answer by reference to the room's use, the appliance type and the numbers given.
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No - the installation must not proceed, and the arithmetic does not rescue it.
- Room use is decisive. Flueless appliances discharge all products of combustion, including water vapour, into the room, and cannot be installed in rooms used for sleeping, or in bathrooms/shower rooms. The manufacturer's instructions will repeat this restriction. The reason is that the appliance's only safety barrier is room volume, adventitious air and the occupant noticing discomfort - none of which can be relied on in a room where two children are asleep.
- The volume and vent are secondary. 4.2 × 3.0 × 2.4 = 30.24 m³, and the 4,000 mm² vent would need to be checked against the manufacturer's table only if the location were permitted. Satisfying a ventilation table is not a substitute for the location prohibition.
- The CO alarm is not a control measure. A CO alarm is a last-resort warning device, not a substitute for safe flueing; a hallway alarm outside a closed bedroom door gives little protection to sleeping occupants.
- Contract does not override compliance. A signed quotation creates no duty to install a non-compliant appliance.
Decline the work in writing and offer compliant alternatives (room-sealed balanced-flue appliance or electric heating).
2. If the same appliance were proposed for a living room instead, what would you check before accepting, and how would combustion products and water vapour affect your advice?
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Location alone would no longer rule it out, so the checks become the substance of the decision:
- Manufacturer's instructions - minimum room volume, required permanent ventilation free area, clearances to combustible surfaces, and whether the model is approved for that room type at all.
- Combustion performance - set and verify per instructions, then confirm with a combustion analyser that the CO/CO₂ ratio is well below the 0.004 threshold used for natural gas, with a stable flame picture.
- Moisture load - at 2.6 kW input the gas rate is about 2.6 × 3.6 ÷ 39.0 = 0.24 m³/h. Each cubic metre of natural gas produces roughly 2 m³ of water vapour (about 1.6 kg), so the fire releases roughly 0.4 kg of water vapour per hour plus CO₂. In a cool, poorly ventilated or recently draught-proofed living room that shows up as condensation, mould and deteriorated decorations - a legitimate reason to advise against it even where it is technically permitted.
- Warning provision - a CO alarm to the relevant product standard in the same room as the appliance, plus the manufacturer's safety instructions explained to the user.
If any check fails, the correct answer remains a room-sealed alternative.
3. The customer insists you install it anyway and says "the last installer would have". What do you do, say and record?
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Refuse, and make the refusal evidential rather than conversational.
- Do not install. Fitting an appliance in a prohibited location is an unsafe situation you created, and no verbal instruction from a customer transfers that responsibility.
- Explain in plain language why: the appliance puts all products, including CO and about 0.4 kg/h of water vapour, into a room where children sleep, and that no ventilation size or alarm changes the prohibition.
- Put it in writing on the job documentation: the date, the appliance make/model, the room, the reason for refusal with the reference (manufacturer's instructions and IS 813 restrictions on flueless appliances in sleeping rooms), and the compliant alternatives offered.
- Handle the commercial side - the delivered appliance is not installed; any deposit or supply arrangement is settled per your terms, and the customer is given the refusal note so no one can claim later that the restriction was never raised.
- If the property is rented, the same advice goes to the landlord, since rented accommodation has additional minimum standards for heating appliances and their flueing.
If the customer says another installer will do it, your obligation is unchanged; your record is what protects the occupants and you.