6.1.11 Stopcock, glass, with double oblique bore of 3-mm
diameter.
6.1.12 Vacuum Source, vacuum pump or water pump powerful enough to ensure an air flow rate in the vacuum regulator
of 15 6 1 L/h for the duration of the test.
6.1.13 Vacuum Regulator, consisting of a glass bottle, at
least 350-mm high, not less than 5 L capacity, partially filled
with water. It shall be closed by a stopper with three holes of
convenient diameters for glass tubes. Two tubes shall be short
and shall not go below the water level. The third tube, with an
internal diameter of 10 6 1 mm, shall be long enough for one
end to be approximately 200 mm beneath the surface of the
water while the other end reaches a few centimetres above the
stopper. The depth of the immersed part shall then be adjusted
to obtain a depression of 200 6 1 mm of water (2 6 0.05 kPa)
on the manometer, which shall contain water. A second empty
5 L bottle shall be fitted in the line to serve as a vacuum
reservoir to ensure a constant depression. The arrangement is
shown in Fig. 1