S.I. No. 386/1953 - Standard Specification (Clayware Flue Liners For Open Fires) Order, 1953

S.I. No. 386 of 1953.


I, SEAN F. LEMASS, Minister for Industry and Commerce, in exercise of the power conferred on me by subsection (3) of section 20 of the Industrial Research and Standards Act, 1946 (No. 25 of 1946), hereby order as follows :

1. This Order may be cited as the Standard Specification (Clayware Flue Liners for Open Fires) Order, 1953.

2.—(1) The specification set forth in the Schedule to this Order is hereby declared to be the standard specification for Clayware Flue Liners for Open Fires.

(2) The said standard specification may be cited as Irish Standard 51 : 1953 or as I.S. 51 : 1953.



1. This specification covers the requirements of clayware flue liners of circular section suitable for use with open fires in dwelling houses.


2. Flue liners shall be manufactured from fireclay or other suitable clay that can be well burnt at a temperature of not less than 850° C.


3. Clayware flue liners shall consist of the same material throughout and shall not be glazed. When fractured for examination in different places they shall appear substantially uniform in structure. The surface shall be smooth and free from evidence of vitrification due to over-firing. The flue liners shall be free from cracks and reasonably free from blow holes, indentations and protuberances and shall have clean jointing ends. Flue liners when stood on end shall give a clear ring when tapped.


4. Clayware flue liners shall be of one of the three types :

straight flue liners,

curved flue liners, or

splayed flue liners.


5. The nominal internal diameter of flue liners shall be 8 in., 9 in., 10 in., or 12 in. The actual internal diameter throughout the length shall not deviate from the nominal internal diameter by more than 1/8 in.

The radial thickness of the walls of flue liners shall be ¾ in. ± 1/16 in.

The length of straight flue liners shall be 12 in. ±¼ in.

The centre line of curved flue liners shall be an arc of a circle subtending an angle of 37½°. The radius of the outside curve shall be 2 ft. 2 in.

The length on the convex side of curved flue liners, when measured as indicated in Fig. 1, shall be 157/8 in. The length, on the concave side shall be 10 1/16 in. for 8 in. flue liner, 9½ in. for 9 in. flue liner, 87/8 in. for 10 in. flue liner and 75/8 in. for 12 in. flue liner. The length on both sides shall be subject to a tolerance of ¼ in.

Splayed flue liners shall have one jointing end at an angle of 12½° from the horizontal, as shown in Fig. 2. The length of splayed flue liners measured as shown in Fig. 2 shall be 11¾ in. ± ¼ in.


6. The walls of straight flue liners shall not deviate from the straight by more than ¼ in. at any point.


7. The jointing ends of straight flue liners shall be at right angles to the axis. The deviation d, from a right angle when determined by placing a square with one edge along the side of the flue liner and the other edge in contact with the jointing end, as shown in Fig. 3 shall be not more than ¼ in.


8. Flue liners shall be clearly marked with the manufacturer's name or mark.


GIVEN under my Official Seal, this 7th day of December, 1953.


Minister for Industry and Commerce.