The "Bag-in/Bag-out" (BIBO) HEPA filter housing system is designed for exhaust air treatment. It has high requirements as regards to tightness and contamination free changing (bag-in bag-out) of filter elements such as medical, pharmaceutical and nuclear facilities, BSL 3 & 4 laboratories, etc.

The whole housing is designed to withstand an admissable design pressure of ±6000 Pa. H13 or H14 high efficiency filter together with M6 prefilter elements are equipped inside each housing. Bubble tight dampers on the inlet and outlet form an integral part of each housing.

Clamping of the HEPA filter elements is a self-adjusting spring system, ensuring the tightness requirements for the seat of filter elements as according to DIN 25 496. 

Quick release of the clamping device by means of single acting pneumatic cylinders. For initial filter element fitting and subsequent filter element changes only a portable supply of compressed air at 6 bar is required. This is via a fast acting coupling positioned on the front of filter housing.

Prior to dispatch, Factory Accpetance Test (FAT) according to DIN/ASME standard is conducted. These tests includes the HEPA filter scan test, the filter seat tightness of each filter, the tightness of the whole filter holding frame and the tightness of the whole housing including the bubble tight dampers.

Fast acting air tight couplings are pre-installed on the outside of the housing to test the airt ightness of each filter seat on site. Manual or automatic built-in scanner can be incorporated in each housing.

The Krantz "Bag-in/Bag-out" HEPA filter housing system with bubble tight dampers was first installed at the Public Health Laboratory in 2000. This system is now commonly used in Hong Kong for exhaust air treatment for BSL 3/4 laboratories, infectious isolation wards and indoor shooting ranges.

In Hong Kong, there are currently more than 25 project references that have been realized and under operation since 2000.