Space Heating » Building Regulations South Africa
Nov 152011
 

Chimneys, Flues, Hearths and Fireplaces
Used for Space Heating

FireplaceBR1 Space Heating

A freestanding fireplace with a flue that goes through ceiling

Anyone searching through the National Building Regulations for information about chimneys and flues, hearths and fireplaces, might go straight to the part that deals with Fire Protection. The next step would probably to look through the part that deals with Walls – after all chimneys are often built with bricks and mortar and often extend from a wall. Or Roofs might seem to be a good place to look.

But no, you are not going to find the information you are looking for in any of these three sections of the NBR. The information you need is in Part V of the Act. This section is very short, and deals only with the design, construction and installation of fireplaces and hearths that have chimneys and/or flues.

 

 

 

 

 

 

 

The legislation states:

“(1)  Any system of space heating in any building shall be so designed, constructed and installed as to operate safely and any flue, flue pipe or chimney used in such system shall be so designed as to safely remove any smoke or noxious gases produced by such system.

“(2)  The requirements of sub-regulation (1) shall be deemed to be satisfied where the design and construction of any flue pipe, chimney, hearth or fireplace complies with SANS 10400-V.” That’s it.

SANS 10400-V: Space Heating

As with all the Standards that make up SANS 10400, if you ensure that your installations comply with the SANS it will be “deemed to satisfy” the law. But other Standards are often cross-referenced. This Part of SANS 10400 makes reference to:

  • SANS 10177-5, Fire testing of materials, components and elements used in buildings –– Part 5: Non- combustibility at 750 °C of building materials.
  • SANS 10400-A, The application of the National Building Regulations –– Part A: General principles and requirements.
  • SANS 10400-B, The application of the National Building Regulations –– Part B: Structural design.

Like all the published SANS, it has a list of useful definitions, some of which you will find in our Glossary of Terms.

Examples include:

  • chimney That part of a building which forms part of a flue, but does not include a flue pipe
  • flue Passage which conveys the discharge of a heat-generating appliance to the external air
  • flue pipe Pipe forming a flue, but does not include a pipe built as a lining into a chimney

Hearth and fireplace are not defined!

Chimneys

Chimneys must be designed and erected from materials that are non-combustible – which of course stands to reason. It is also important that they don’t become a fire hazard, particularly to those materials adjacent to the chimney structure. Further, chimneys should not reinstalled in shafts or ducts that might be affected by heat.

Timber is one of the combustible materials that we commonly use in our homes, and the regulation states that elements including joists for timber floors, trimmers or roof trusses may not be built within 200 mm of the inside of any chimney.

There are additional regs that relate to dimensions, for instance where the walls of a brick or block chimney are less than 190 mm-thick, it must be lined with a flue lining that is made of a material that will withstand the action of any flue gases and won’t crack or soften. The flue lining must also extend throughout the full height of the chimney.

There are also regulations that relate to the height of the outlet – this has not changed since the regulations were published previously in 1990 (and of course you can download these free). Below you can see the chimney positions.

Part V opening or adjacent structure Space Heating

Opening or adjacent structure

Part V roff pitch 10 deg or more  Space Heating

Position when the roof pitch is 10 degrees or more

Part V Roof pitch less than 10 deg Space Heating

Roof pitch less than 10º

Flue Pipes

This is all largely common sense. Flue pipes may not be designed or installed if they are going to become a fire hazard to adjacent material. They may also not be connected to shafts or ducts that form part of any ventilation system. And they may not be installed in shafts or ducts that are likely to be adversely affected by heat.

Hearths and Fireplaces

Any fireplace that is used for burning “solid fuel” MUST have a hearth that is make of a non-combustible material that is sufficiently thick. It must extend no less than 500 mm in front of the grate or fire basket and not less than 300 mm beyond each side of the grate or fire basket.

Timber floor joists and trimmers – or any other combustible material – may be built into a hearth.

 

 

  6 Responses to “Space Heating”

Comments (6)
  1. Please advise as the pictures & sub-titles on chimney installations on your website is turned-around if compared with the pictures in the 2010 government version on this section?

    Refer page 6 on the attached document compared to the website pictures under chimneys. Pictures for less than 10% roof pitch & opening adjacent structures are turned around compared to the original government file?

    • We are not aiming to replicate SANS 10400; rather we are presenting information taken from the regulations. It is totally irrelevant which order the drawings are presented in!

      • I think it does not refer to the actual order of the drawings but the descriptions/sub-titles of two of the pictures are different to the sub-titles used for the same pictures on the SANS document.

        • Hi Joe,
          I see now what you meant. Thanks for pointing that out. It is done and the correct caption is now in the right place. Thanks again :)

  2. HI CAN A SPLIT UNIT BE MOVED FROM ONE OFFICE AND REINSTALL INTO ANOTHER OFFICE

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