From: Hans Berger
To: Jim Buckley
Subject: Rumford in Norway
Date: Tue, 29 Jan 2008
it's been very hectic here so I haven't been able to finished translating the brick chimney section yet. However, I am forwarding a draft of the translation and a scanned version of the code. The code is a scan of a copy I made at the library. You can get a clean pdf version at the link below for about $25 (I just recently found out). Would appreciate if you do not post the code on the web site as it is copyrighted. However, a link to the brochure I forwarded which basicall says the same should be ok.
I have some other reference as well which I can forward later.
Would be interesting to hear your opinion on the code.
Yes, I would be interested in the section on brick chimneys, particularly if the Norweigian code allows the chimney to be in contact with combustibles. How thick must the walls be, etc.?
It would also be useful to have the text of the code in Norwegian. You sent me a technical brochure in October but I don't think it was the code itself.
I apologize for taking my time to translate the code as promised. Have been trying to find some time to build the fireplace, but have made much progress there either. However, here is a translation of masonry fireplace part of the 2005 version of the Norwegian code called "Fireplaces and Chimneys". The figures that are referred to in the translation are the same that are called 11.5 b and c (page 32) in the brochure I sent you. There is an old (1960s) test that was conducted to verify the clearances to combustibles. What is different between the Norwegian code and other is that in norway we typically have the combustible material up against the masonry without any clearance. I have considered getting a copy of the test report, but haven't made up my mind yet since it costs $100.
The translation of the section covering masonry fireplaces is as follows:
18 Load Bearing Capacity for Fireplace
The floor shall be able to withstand actual load. Dedicated foundation or reiforcement of floor may be required to avoid cracking due to floor subsidance. See also Byggdetaljer 522.353. Kakkelovner and masonry fireplace must, due to their weight, be installed on a supported foundation suited for the given load.
30 Masonry Fireplaces
Masonry fireplaces is constructed using brick of normal size accoridng to NS3000, crushing strength 350 (35 N/mm2). The firebox shall be lined with firebrick of minimum 65 mm thickness.
32 Foundation and Masonry Thickness
Masonry fireplace must be built on a self supported masonry or concrete foundation, see fig 32, or alternately on concrete floor or light weight concrete elements, see sect 18. Where the masonry is in contact with combustible material a minimum thickness of 470 mm is required from the inside of the firebox to the combustible material, see fig 32b. This thickness can be reduced to 350 mm if a non-combustible plate with a minimum heat resistance of 0,04 m2K/m is installed between the masonry surface and the combustible material. Some types of fibrous-cement plates are suited and meet this requirement.
33 Floor in Front of Fireplace
Floor of combustible material must be covered with steel plate or other suitable non combustible material. The plate must:
Cover the floor at lease 300 mm from the front of the heart and at lease 800 mm from the firebox inner corner or edge, see fig 33a. Have a witdt which at least is equal to the firebox and the fireplace width
The plate on the floor can be eliminated if the heart is at least 800 mm deep and extend at least 300 mm in front of the firebox, see fig 33b.
A fireplace should be equipped with a screen for sparks.
When the hearth is raised more than 470 mm, the plate on the floor has to extended equal to the increase in height, see fig 33c.
34 Dimensioning of Fireplace Opening
The vertical area of the fireplace opening (radiation opening) must take into account the room volume, and should be between 0.005 Č*„ 0.008 m2 per m3 of room volume. In large room which is above 50 m2 this guidance will have to be considered individually.
Let me know if you are interersted in the section regarding brick chimneys as well.
(Scanned code off line in jpg format.)
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