BS/EN 14175-3-2019 pdf download.Fume cupboards Part 3 : Type test methods.
The sampling probe grid shall be positioned on the inner measurement plane with its centre probe at points formed by the intersection of lines with a tolerance of ±5 mm as follows:
c) A series of equally spaced lines between the vertical side boundaries of the inner measurement plane with the two outermost lines 130 mm from the vertical side boundaries. Any lines In between shall be at a distance of 600 mm or less from the outermost lines and to each other.
d) A series of equally spaced lines between the horizontal boundaries of the inner measurement plane with the two outermost lines 130 mm from the horizontal boundaries. Any lines in between shall be at a distance of 600 mm or less from the outermost lines and to each other.
5.3.4 Positioning of test equipment for outer measurement plane
5.3.4.1 Injector grid
Nine test gas injectors shall be arranged inside the workspace of the fume cupboard on a plane (200 ± 5) mm away from the plane of sash. They shall be positioned with horizontal axis, the test gas flow direction towards the sash and in a grid formed by the intersection of the following lines:
a) Three equally spaced vertical lines between the two extreme side boundaries of the sash opening with the two outermost lines (100 ± 5) mm from the two extreme side boundaries.
b) Three horizontal lines with the bottom line (100 ± 5) mm. the middle line (250 ± 5) mm and the top
line (650 ± 5) mm above the bottom horizontal boundary of the sash opening. 5.3.4.2 Sampling probe grid
The sampling probes (see 5.3.1.6) shall be positioned at grid points formed by the intersection of lines on the outer measurement plane with a tolerance of ±5 mm as follows:
a) A series of equally spaced vertical lines between the side boundaries of the outer measurement plane with the two outermost lines on the side boundaries. Any lines in between shall be at a distance of 400 mm or less from the outermost lines and from each other.
b) A series of horizontal lines between the horizontal boundaries of the outer measurement plane with the two outermost lines on the horizontal boundaries and the penultimate lines 200 mm from the horizontal boundaries. Any lines in between shall be equally spaced at a distance of 200 mm or less for vertical sashes respectively 400 mm or less for horizontal sashes from the penultimate lines and from each other.
Figure 3 shows examples of the positioning of the outer measurement plane for four different designs of fume cupboards.
Where the plane of the sash does not meet the work surface, the lowest row of sampling probes shall be positIoned (50 ± 5) mm in front of the vertical plane through the front edge of the work surface. If the handle of the sash is such that it prevents the movement of the sash with the sampling probes in this position, the sampling probes shall be placed further away but as close as possible to the outer measurement plane. The position of each sampling probe shall be recorded in the test report.
When low level fume cupboards or walk-in fume cupboards are tested, the test report shall record the height of positioning of the injector grid and the sample grid. When the test opening exceeds 1 000 mm, the distance between horizontal lines [see b)] may be 400 mm instead of 200 mm.
5.3.5 Test procedure
5.3.5.1 Preparation
Switch on all supply and extract air systems and adjust controls to give specilled volume how rates. Connect the cylinder of test gas to the test gas flow regulator and to the test gas injector(s). Connect the sampling probes to the collecting and analysing system. Switch on suction pumps, the gas analyser and the data recording/storage system and allow ample time for the instruments to stabilize.
5.3.5.2 Inner measurement plane test procedure
Set the sash to the test sash opening.
Position the sampling probe grid at one of the test positions.
Turn on the test gas, adjust the volume flow rate to 2.0 1/mm and allow it to stabilize.
Measure and record the tracer gas concentration as volume fraction for 360 s.
Stop the injection of the test gas and analyse the data according to 5.3.6.1.
Repeat the test at the same test position for two further times if the mean tracer gas
concentrationexceeds a volume fraction of 108 during the test period described in 5.3.6.1.
Repeat the test procedure above for other test positions at the same test opening.
Repeat the test procedure above for other test sash openings according to 4.4.2.BS/EN 14175-3-2019 pdf download.
BS/EN 14175-3-2019 pdf download
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