The filtered flow from the impulsion unit passes through a perforated plated constructed from anodised aluminium (stainless steel or PLF screen as option) which protects the filter surface from physical damage and promotes a downward laminar flow over the working zone. The working zone is typically enclosed with transparent plastic strip curtains to provide easy access and excellent process visibility. The zone is illuminated by fluorescent lamps with protective covers. The frame can be made from epoxy powder coated zinctec steel or from stainless steel AISI 404L/316L for high resistance and durability. The equipment is fitted with two stages of filtration: • G-3 synthetic fibre pre-filters of efficiency equivalent to ≤80% (EN779: 2012). • H-14 high-efficiency absolute HEPA 99.995% MPPS (99.999% DOP) to readily enable a clean flow area to ISO 5 (EN ISO 14644-1). The HEPA filters are arranged across the lower portion of the air flow modules, which constitute the ceiling of the working zone. Below the filters is a micro-perforated plate that protects them from physical damage and promotes a homogeneous air velocity across the entire laminar flow area. The high-efficiency EC (electronically commutated) fans, Green Tech and eco-friendly, are statically and dynamically balanced to provide low levels of noise and vibration. A fan speed controller is also included in order to maintain a constant flow rate. The control panel can be placed in the module or installed remotely to provide local access. It includes a differential pressure gauge, time counter, HEPA filter clogging alarm, lighting controls and flow switches.