BS/EN 1366-13-2019 pdf download.Fire resistance tests for service installations Part 13 : Chimneys.
6.3.2 Distances to the test furnace and between each other
There is no limit to the number of test specimen that may be tested simultaneously in the same test furnace, provided that there is sufficient space to do so, in accordance with the dimensions shown in the corresponding figures.
The maximum separation intended to use in practice shall be provided between the horizontal test specimen and the floor, and if this Is not possible, the distance between the horizontal test specimen and the floor shall be at least 500 mm. The distance between the horizontal test chimney and the furnace ceiling shall be at least 500 mm.
There shall be a minimum separation of at least 500 mm between the sides of the horizontal or vertical test chimneys and the test furnace walls. The clearance between single specimens in the test shall be at least 200 mm.
6.3.3 Openings in test specimen
6.3.3.1 Test specimen A
Test specimen A does not have any opening inside the test furnace. Cleaning and inspection doors and draught regulators, if part of the system, have to be part of the test specimen inside and outside the test furnace. During the test they are closed.
6.3.3.2 Test specimen B
One opening into each flue shall be provided for a test specimen B. For horizontal test specimens the centre of the opening(s) shall be positioned (500 i 25) mm from the end of the specimen opposite to the penetrated test furnace wall. For vertical test specimens the centre of the opening(s) shall be positioned ata distance of (1200 ± 200) mm above the floor.
In both vertical and horizontal chimneys the openings shall have the same width to height ratio as the connected flue of the test specimen and the same opening area as the connected flue. Cleaning and inspection doors and draught regulators, if part of the system, may not be taken into consideration inside the test furnace.
If cleaning and inspection doors for an inspection opening or draught regulators on different levels are part of the system chimney they have to be tested mounted according to the manufacturers instruction outside of the furnace. If the system has already shown the resistance against soot fire the cleaning and inspection doors for an inspection opening or draught regulators outside the furnace can be omitted.
6.3.4 Joints in horizontal test specimens including connecting flue pipes
The test configuration for test specimen A and test specimen B shall include at least one joint inside and at least one joint outside the test furnace (see the corresponding Figure 1).
There shall be at least one joint in every layer of the components as in practice, at least one inside and one outside the test furnace.
Outside the furnace, the joint in the outer layer of the lire protection material shall be not farther away than 700 mm from the supporting construction and not closer than 100 mm to thermocouples T2.
Inside the furnace, the joint in the outer layer of the tire protection material shall be located at approximately midspan if only one joint is inside.
If more than one joint is relevant joints should be at least ≥ 500mm below the ceiling and  500 mm above ground of the furnace except that the parts are smaller than 500 mm.
The distance between joints and supports shall not be less than declared, lithe minimum distance has not been specified, supports shall be arranged so that the joint at midspan lies midway between the supports. Distances between the centres of the supports shall be specified by the manufacturer and shall be representative of practice.
6.3.5 Joints in vertical test specimen
The test configuration shall include at least one joint inside and one joint outside the test furnace (see the corresponding Figure 2). There shall be at least one joint for every layer of components as in practice, at least one inside and one outside the furnace.
Outside the furnace, the joint in the outer layer(s) of the components shall be no further than 700 mm from the supporting construction and not closer than 100 mm to thermocouples T2. Inside the furnace, the joint in the outer layer of fire protection material shall be located at approximately midspan if only one joint is inside.BS/EN 1366-13-2019 pdf download.