SHARED GAS FLUE AND VENTILATION SYSTEMS

General

Introduction:  Three shared flue systems designed to supply air to, and dispose of the products of combustion from gas fired appliances in multistorey buildings. All flue units are manufactured in refractory concrete.

Applications: Suitable for the ventilation of gas-fired appliances in low-rise and high rise housing developments. The Shunt system is also suitable for the ventilation of bathrooms and toilets.

Authority: All three systems comply with the Building Regulations and are approved by the Gas Council. Concrete components meet the requirements of BS 1289:1975 Precast concrete flue blocks for domestic gas appliances.

Composition, Manufacture

The flue units are precast in refractory concrete comprising of special cements and refractory aggregates.

The three systems are inclusive of the entries required by each installation.

Shape, Dimensions

The flues are pre-cast in lengths suitable for each installation, with cut lengths supplied to make up exact storey heights.

SE-DUCT SYSTEM

This system consists of one vertical duct open at each end to the atmosphere. The duct serves both to convey an air supply to each appliance and to disperse the products of combustion from each appliance. Dilution of gases in the duct ensures satisfactory operations of all approved appliances.

The system enables each flat in a multi-storey block to operate an independant heating system. Appliances should be of the room-sealed type and will offer the same advantages as balanced flue appliances, without needing to be sited on an external wall. The architect thereby has greater flexibility in planning and in interior design.

The air inlet to the duct can be varied to suit the particular installation. The simplest arrangement, suitable for a block of dwellings with an open ground floor, is an open open inlet on the underside of the floor of the first storey.

More usually, horizontal ducts are provided below ground level connecting to the base of the vertical duct. The entries are sited on opposite sides of the building to prevent to prevent the development of large variations in air pressure at the base of the vertical duct. Where appliances are not fitted to the system on the ground floor of the building (eg where shops occupy the ground floor), the horizontal ducts may be taken along the ceiling of the ground floor.

  
SHUNT SYSTEM

This is a shared flue system consisting of a main flue with subsidiary flues from each appliance connecting to the main at the correct height. It is designed for use with conventional type gas appliances and for use as a ventilation duct. It offers considerable savings in both space and cost as compared with the provision of separate flues to each appliance. the system operates smoothly under all weather conditions when designed with the correct terminal.

 

 

 

 

 

 

 

 

 

U-DUCT SYSTEM

This system is intended as an alternative to SE-Duct (described below) where an air supply at the bottom of the duct cannot conveniently be arranged. Two ventilation ducts are employed, one drawing air downwards from the roof of the building, the other conveying air upwards to the appliances. Continuous air flow under all weathger conditions is achieved by using a balanced terminal on the roof of the building, designed to give identical inlet and outlet exposure. Advantages of this system are as for the SE-Duct system described below.

COMMON INFORMATION

Handling and storage: Flue sections should be handled carefully to avoid damage during transit and storage. They are manufactured in convenient lengths for lifting by one man.

Installation: Sections of flue are jointed using refractory mortar that can be supplied by the manufacturer. Gas Board approval must be obtained.

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