Heraeus HS 12, Руководство по обслуживанию, Страница: 192 / 282

Testing Safety Cabinet Class II according to EN 12 469
Testing HS / HSP Ingo Nierobisch 14.06.02
HS / HSP
Visual check
•
Labels, warnings
•
Scratches
•
Exhaust connection
•
Options
Electrical safety test ( VDE )
•
Ground conductor ( Schutzleiter )
•
Insulation resistance ( Isolationswiderstand )
•
Leakage current ( Ableitstrom )
Air direction test
•
Adjust front window to working position ( 200 mm )
•
Slide along the window opening with smoke tube
•
Air flow direction from outside to inside
( no refluxing, no visible turbulence )
Inflow air velocity test
Inflow air speed (method 1)
•
Adjust front window to an opening of 5 cm
•
Measuring air velocity in the middle in steps of
10 cm (start with 5 cm) __
•
Inflow air can be calculated: v
2
= v
2
/ 4
Exhaust air speed (method 2)
•
Place the measuring frame over the exhaust
filter opening and seal with adhesive tape
•
Measure air velocity according to 5-position
method
•
Inflow air can be calculated: v
2
= v
1
x A
1
/A
2
Laminar air flow test
•
Cabinet in operation ( at least 20 min.)
•
Adjust anemometer 5 cm above front window
opening
•
Measuring grid: of the edge 15 cm,
between measure point 30 cm
•
Measure air velocity (wait 1 min.)
•
Mean value of air velocity: 0,25 - 0,5 m/s + 20 %
If air velocity is too low, test the following:
•
Voltage of the fans
•
Exhaust connection
•
Ducting system
Filter leakage test (DEHS- test)
Main filter and exhaust filter
•
Turn cabinet on
•
Calibrate particle counter
•
Place aerosol generator in the cabinet
•
Connect rarefaction between particle counter and
test connection (under working plate)
•
Only HSP: Remove rubber seal from bypass opening
•
Switch on aerosol generator
•
Measure particles at the dirty side of main or exhaust
filter, 5 measurements (each for 1 min)
•
Required value: 30 mil. particles of size 0.3 µm
•
Disconnect the particle counter from the rarefaction
and connect to the measuring-head
•
Scan the seat of the sealing an the clean side of the
main filter. Speed of scanning < 5 cm/sec, distance
max. 1 cm.
•
Limit value of particles > 300 St./ 0.3 µm
•
If max. number of particles is exceeded change filter.
Monitoring equipment, acoustic and visual alarm
•
Cabinet in operation
•
Measure fan voltage
•
Perform test for laminar air ( mean value 0,40 m/s )
Adjust lower limit pressure switch
•
Find out point with lowest air velocity
•
Set anemometer in this point, measure air
velocity
•
Set fan voltage so that at this measuring point air
velocity is mean value -20 % ( 0,32 m/s )
•
Change adjustment of lower pressure switch it
just turns on. Visual and acoustic alarm goes on
Adjust upper limit pressure switch
•
Find out point with highest air velocity
•
Set anemometer in this point, measure air
velocity
•
Set fan voltage so that at this measuring point air
velocity is mean value +20 % ( 0,48 m/s )
•
Change adjustment of upper pressure switch it
just turns on. Visual and acoustic alarm goes on
•
Return fan voltage to the measured value
•
Turn cabinet off and on, check operation
Fill out test protocol and paste up inspection sticker
Additional: KI-Discus test (personnel protection test)
•
Cabinet in operation (at least 20 min)
•
Reduce air movements in laboratory ( close doors,
windows, air condition, ... )
•
Install KI-Discus equipment according to its operating
instruction
•
Do measurement 5 times according to instruction
•
Count potassium iodide particles on filter paper
•
Calculate protection factor
•
Limit < 60 particles
•
For deviations: repeat measurement 2 times
•
Check air flow in laboratory, check filter sealing