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The Regs: Part J

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As the new Building Regs are just days away, Geoff Wilkinson rounds up Part J

Part J has been pretty much overlooked by the technical press in the run up to the October changes to the building regulations, yet, while the carbon reduction in Part L may save the planet in the long run, the changes to Part J should have more immediate results.

Concealed flues

The first change follows the investigation into the death of Elouise Littlewood, 26, who died of carbon monoxide (CO) poisoning in 2008 in a newly built flat in Bedfont, Middlesex. The subsequent investigation showed that homes had been built with gas flues without appropriate access for inspection.

This led to defects in the installation being missed, and the release of carbon monoxide that led to Elouise’s death. The changes to the approved document are designed to prevent this happening again and to incorporate the key elements of CORGI Technical Guidance Bulletin 200. Concealed flues should be avoided, but if they are to be routed within a void, access hatches (a minimum of 300 x 300mm) will now need to be provided to enable the building inspector to check that the flue is continuous, with all joints correctly assembled and sealed. It is also necessary to demonstrate that the flue is supported and any required backfall and other drain points have been provided.

Room-sealed fanned-draught flues should not pass through other properties since access for inspection will not always be available.

CO detectors

There is also a new requirement to install CO detectors, but surprisingly this is only where a new or replacement solid fuel appliance is installed. This is despite the majority of CO poisoning deaths occurring due to faulty gas appliances. Communities and Local Government’s (CLG) reasoning for this is that incidences of poisoning are more common with solid fuel, and the number of deaths is a product of the larger number of gas installations.

CO alarms should be located on the ceiling at least 300mm from any wall or, if it located on a wall, as high as possible but not within 150mm of the ceiling; and between 1m and 3m horizontally from the appliance.

Open-flued appliances

The previous guidance on requirements for combustion air assumed that there was a certain level of ventilation through leaks from cracks and holes in the building fabric. As Part L now requires improved levels of air-tightness, there is a need to increase the area of permanent ventilation openings required for open-flued appliances where an air permeability of less than 5.0 m³/(h.m²)@50 Pa is achieved.

Biomass boilers

Guidance has been added on the size of flues for biomass boilers which now permits flue sizes of 100mm instead of 125mm.

Bunding of oil appliances

The last major change is that additional requirements have been introduced requiring bunding where the tank has a capacity of more than 2,500 litres or is located within 10m of inland fresh water or coastal water. The same applies if it is located where spillage could run into an open drain or manhole cover, or is located within 50m of sources of potable water. Changes also apply if it is positioned where oil spilled from the installation could reach the waters listed above by running across hard ground; or is located where tank vent pipe outlets cannot be seen from the intended filling point.

Plume management

Although not strictly an issue for Building Regs, pluming from boilers often results in neighbour disputes and health concerns. Outlets from flues should allow the dispersal of products of combustion and, in the case of balanced flues, the intake of air.

Designers can now refer to the snappily-titled Guide to Condensing Boiler Installation Assessment Procedure for Dwellings.

Note that the old rules apply to any application registered before 1 October 2010, so there is still time to apply

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