If it is difficult to do leak-tightness test with a certain type of EEBD, the inward leakage shall be
tested instead of leak-tightness. The inward leakage shall not exceed 4% during the rated working duration.
The inward leakage test method depends on national standard or other standard.
|Leak-tightness test can not be done at hood parts of hood type EEBD. Therefore,
the inward leakage is tested instead of the leak-tightness. The inward leakage value of NIOSH is 2% (demand
type), 4% (hood type), 0.05% 〜 0.01% (pressure demand type). Value of EN standard is 0.05% for hood type,
demand type, 0.05% is very severe value to obtain.