How many people do you cater for

Sizing on your braai will determine not only for how many people you would be able to braai for, but also what accessories can be used and in what combination they can be used. Various accessories are available, and you should consider what you would like to do with the braai before choosing the correct product. Standard sizes that are available are 800 mm, 1000 mm, 1200 mm & 1500 mm.

Wood or gas or a combination

Most South Africans prefer to braai with wood or charcoal, but that is now changing over to gas. Often it is required to do a quick steak in the middle of the week—this is where the gas option comes in handy. Making wood fires and waiting for coal takes up much time. We have a special range of Combo Built-In Braai’s which houses both a wood and a gas section which all works on one chimney and can be used individually or as a unit.

Chimney principles

The terms Flue and Chimney are often used interchangeably. The Flue is the working part of the Chimney, conveying the products of combustion safely to the atmosphere. The Chimney includes the shaft within which the Flue is housed. A Flue works under negative pressure, drawing the product of combustion from the appliance.
A successful “Chimney Draw” is dependent on the following principles:

• The difference in air pressure between the appliance and the top of the Chimney. (created by the height of the chimney)
• The difference in temperature between the appliance’s exhaust gas and the outside temperature.
• The quality of insulation along the length of the Chimney.
• The route of the Chimney. (The straighter and more vertical the Chimney, the better).

It is essential to choose a Flue diameter that matches the output from the appliance. An adequate air supply is also required for the appliance to operate safely and efficiently.

Chimney position

The ideal location for a Chimney is on the inside of the building. Chimneys situated outside the building can be affected by cold weather causing poor “up draught” and condensation, particularly if they are uninsulated. It is therefore important that a cavity wall is continued around a lined masonry Chimney or a factory made insulated Chimney system is used for external applications.

Connection to the chimney

For open fires a suitable throated front lintel must be installed above the fire opening so that the front, back and sides slope up smoothly into the Flue opening in the chimney at an angle no greater than 45° from the vertical. Flat surfaces or shelves must be avoided as these can cause turbulence and smokey fires. Most Flue and Chimney manufacturers provide standard gather fireplace components. Precast fire chambers or fire chests are also available for standard and larger fire openings.

Bends in the chimney

Both the Regulations and the Standards recommend that bends in the Chimney be avoided, as a straight vertical chimney performs better. If bends are necessary, there must be no more than four in the length of the Chimney. The angle of the bend should be no greater than 45° from the vertical, with the exception that 90° factory made bends or tees may be treated as being equal to two 45° bends. Where System Chimneys are used, always use the standard offset components which are available from the Chimney manufacturer. For Stainless Steel Chimneys, the distance between bends must be no greater than 20% of the total Chimney length. It is recommended that a vertical rise of 600 mm should be allowed immediately above the appliance before any change of direction. An inspection hatch is required between each offset.

Chimney heights and termination

The minimum Chimney height recommended for minimum performance of wood burning and multi fuel appliances is 4.5 m from the top of the appliance to the top of the Chimney. It is best to position the Chimney so that it goes straight up, as near to the roof ridge as possible.

Fuel burning

A Chimney operates on the principle of having a natural “up draught”. One factor in creating the “up draught” is maintaining a warm flue gas temperature, of between 150°C and 450°C. Burning wood or multi fuel slowly with insufficient air supply, particularly on stoves or closed appliances, must be avoided. Low flue gas temperatures will cause condensation and greatly increases the risk of producing excessive tar and corrosive soot deposits.

This is a common problem, particularly when burning wet wood or coal, and should be avoided. If soot and condensate deposits are allowed to accumulate in a flue, the deposits can ignite, causing a Chimney fire. These deposits can also be very corrosive and if they are not regularly removed can cause corrosion of the metal parts of both the Chimney and the appliance. When burning wood, it is important to ensure that it is dry and well-seasoned.

Regular inspection

The Chimney should be swept regularly to remove soot and tar. At the very least, the Chimney should be swept at the start of the heating season. It is not recommended that the appliance is over fired, (allowed to burn fiercely and out of control), or Chimney fires be started in an attempt to clean the Chimney. Deposits of soot and tar will be greatly increased if unseasoned wood is burnt. Should a Chimney fire occur, the Chimney and appliance should be checked for damage before using it again. It is also good practise to check at least every year or two that the exposed parts of a Chimney, Flashings, and Terminals for signs of damage. Just like the outside of a house, Chimneys can suffer from the wear and tear of extreme weathering. If at any time smoke or fumes are apparent or suspected from the appliance, Chimney or Flue, seek advice immediately from the installer or Chimney expert in case there is a blockage or failure. Do not use the appliance or Chimney until they have been thoroughly checked for safety and soundness.