Unflued Heater in a Childcare Sleep Room
A childcare centre wants to install a 25 MJ/h unflued gas convection heater in a 4 m × 3 m × 2.4 m sleep room with eight cots. The room has one openable window (900 mm × 600 mm) and a door to a corridor. The centre argues the window provides adequate ventilation and that the heater has an oxygen depletion sensor. The heater's instructions state it must not be installed in rooms used for sleeping and require a permanent ventilation opening of at least 100 cm². The centre's maintenance officer plans to fit a 100 cm² wall vent and proceed. The room is on the first floor of a two-storey building with bedrooms above.
1. Assess whether this installation can proceed, identifying every barrier.
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Several independent barriers each stop the installation.
- Manufacturer's instructions: the heater must not be installed in rooms used for sleeping. A sleep room with eight cots is unambiguously a sleeping room. Manufacturer's instructions are mandatory; this alone prevents installation.
- Room volume and ventilation: the room is 4 × 3 × 2.4 = 28.8 m³. The required permanent opening is 100 cm², but the maintenance officer's proposed vent only meets the minimum on paper. The openable window does not count as permanent ventilation because it can be closed. Even with a compliant vent, the sleeping-room prohibition remains.
- Oxygen depletion sensor: an ODS is a backup safety device, not a substitute for correct installation. It does not authorise use in a prohibited location.
- Occupancy: eight children in a small room with an unflued appliance means combustion products, moisture and CO are released directly into the breathing zone. The risk is unacceptable regardless of vent size.
- Building context: the room is on the first floor with bedrooms above; flue options and structural penetrations would need separate assessment if a flued appliance were considered.
Conclusion: the installation cannot proceed. The correct advice is a flued or electric heating solution, with the flue termination assessed for clearances to windows and the upper floor.
2. What would you tell the centre in writing, and what alternative would you recommend?
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Written advice should be clear, cite the basis, and offer a path forward.
Content of the advice:
- State that the proposed unflued heater cannot be installed in the sleep room because the manufacturer's instructions prohibit installation in sleeping rooms, and that this prohibition is binding.
- Note that the ODS does not change this, and that a 100 cm² vent, even if fitted, would not make the location acceptable.
- Explain the risk in plain terms: combustion products and moisture released into a room occupied by sleeping children.
- Confirm you will not certify the installation and that proceeding would leave the centre with a non-compliant installation and invalid compliance documentation.
Alternative recommendation:
- A room-sealed or flued appliance with the flue terminating clear of openable windows, the upper-floor bedrooms and the boundary, sized for the room and the centre's load.
- Or electric heating, which avoids combustion products entirely and is often the simplest solution for a small sleep room.
- If a flued option is chosen, provide the flue route, termination clearances and ventilation calculation in the written advice so the centre can obtain approval.
Offer to assess the alternative and issue a compliance certificate once a compliant design is agreed.