The purpose of an NBC system is to clear the air within a shelter or building of an NBC contamination and allow the occupants to function normally without using personal protection equipment. To be effective the NBC system must be designed in conjunction with the shelter, or building air-conditioning or ventilation system. The shelter must be air-tight during an NBC attack. This can be achieved by using gas-tight valves, doors and utility penetrations.

The NBC Filtration System will comprise:

• Filters & Air Filtration Unit (AFU)
• Ductwork
• Control System
• Fan

The NBC system will have two modes of operation, By-Pass and Filtration. The By-Pass mode is used when there is no danger of an NBC attack and air will be supplied by the shelters normal air-conditioning or ventilation system. During periods of danger the filtration mode is switched on. The shelter will be sealed and the NBC system will start to filter and circulate the cleaned air throughout the shelter. The air to be filtered can come either directly from outside the shelter, or the air-conditioning system can direct cooled, or heated air to the room housing the NBC filtration system. In this case the shelter can still maintain temperature control.

Depending on the size of the shelter will determine the number of AFU’s (Air Filtration Units) required. Multiple AFU’s can be mounted in steel frames for large shelters.

Peacetime operation with the NBC Filtration System OFF and the air-conditioning system using fresh air directly from the outside

Wartime operation with the NBC filtration system ON.

The air-conditioning system can continue to be used but the plant room will be sealed and the air to the rest of the shelter filtered through the NBC system.

Alternatively, the air-conditioning system can be shut down and only unconditioned air filtered by the NBC system feed into the shelter

NBC Filters

The NBC system composite NBC Filters provide the highest levels of protection from Nuclear, Biological and Chemical threats.
Each filter includes two filtration stages to remove the particulate and gaseous threats. Particulate contamination such as dust and biological agents is removed by the ultra-high efficiency particulate filter element before an activated charcoal bed absorbs chemical agents from the air passing through the filter.
The NBC Filters are 99.997% efficient to BS3928 in removing particulate contamination and exceed the requirements of the NATO Tripych relative to NBC protection.
All NBC Filters are fully tested for both particulate and gas efficiency using the company's state of the art airflow test rig which incorporates the latest Sodium Flame photometer and Halide gas detection equipment.

Peacetime Filters are used in place of carbon filled NBC Filters. This allows the carbon filled filters to be held in hermetically sealed storage containers until they are needed.

The Peacetime Filters provide high levels of dust filtration within the crew space of military vehicles where Collective NBC Protection Systems are fitted. Peacetime Filters compatible with the British Army No 1 Composite NBC Filter are available.

Peacetime Filter versions of other types of NBC Filter are also produced. These Filters offer a very effective way of reducing the lifecycle cost of fitting Collective NBC Protection Systems to military vehicles.

NB: All the information provided within this datasheet is for reference only. Product specifications are subject to change without notice.