Air-handling-units AT4 Hygienic Application According to Guideline VDI 6022
AT4 AHU for hygienic application The VDI guideline 6022, part 1 and 3 defines the hygienic requirements for AHU with regard to: I planning I design I operation I service I maintenance according to highest technical standard represents a qualified hygienic standard providing planning security and avoidance of problems AL-KO AHU comply to these requirements General requirements of VDI 6022 for manufacturers of AHU: I all materials must comply with health requirements and prevent microbiological growth I sandwich panel construction I low condensation tendency I smooth internal surfaces I grooves easily cleanable I bottom panel surface powder coated or made in stainless steel I all units and components are easily accessible and equipped with lighting where necessary and sight glasses (possible to darken) I continuous and complete condensate drainage I use of fans with access for cleaning I sealing materials must be closed-cell type and not absorb moisture, give out odours or form a nutritive medium for microorganisums I hygienically appropriate manufacture, transportation and intermediatestorage at the place of installation We recommend a design check (research institute for hygienic air) 2007-2010 2
AL-KO solutions: Construction I providing enough maintenance space I consideration of excellent air flow conditions for connections and air dampers I the outside air dampers have to be installed internally to avoid condensation I a drain pan under outside air filter ensure better cleaning I all relevant components are available either fully powder coated or in stainless steel I various design for all applications with AL-KO software Klima@Soft Not approved (e.g.): I place silencer immediately downstream the fan, eliminator always behind cooler. Alternative: Fan and cooler in the direction of air flow I the use of a direct driven fan or a fan with flat belt drive requires only filter class F7 for the supply air Examples: I filter or silencer downstream a humidifier I cooling coil without eliminator Housing construction I sandwich panels I no condensation tendency (category T3 / TB 3 or T2 / TB 2) I smooth internal surfaces without corners and edges I powder coated panels or internal panels in stainless steel I avoidance of corrosive tin-plated panel surfaces with unprotected cutting edges I door and panel seals are foamed seamlessly, have a high density, and are non-ageing I all sections are easily accessible, have the necessary lighting, access doors, and sight glasses I possibility of cabling mainly outside the casing: no additional dirty corners 3
AT4 AHU for hygienic application Sealing materials All used materials: I have been tested extensively I prevent microbacterial growth I are resistant to disinfectants I permit physical and chemical disinfection Filter Filter construction: I microbiological inert filter materials I only use of closed cell type sealing I mechanically sufficiently stable materials even during humidity I filter differential pressure control optically or electrically as standard I use of quality filters with test certificates Reduction of relative humidity at the outside air filter: I heating of outside air through preheater or heat recovery (run-around-coil) I providing warm air from heating coil to the outside air filter section I use of biostatic air filters I closing of outside air damper and heating of filter section Filter installation: I correct installation of filter to prevent mechanical stress on the filter medium I filter maintenance with easy access by using filter quick snap device I cleanable filter section optional with drain pan Fans Prevention of belt wear through: I use of direct driven fans (plug fans) I use of flat belts for belt driven fans Casing with water drainage and cleaning access (from size 400 onwards) 4
Air humidifier Heat exchanger I built-in automatic shut-off for humidifier to allow the humidifier to dry out I eliminator with stainless steel frame can be cleaned, pulled out and dismantled I exclusive use of humidifiers complying with VDI 6022 Sound absorber I sound absorber is usually located in the AHU, not in inaccessible air ducts Individual columns can be replaced I avoidance of loose fibres I columns can be removed easily without tools by using the installed handlevers I access panels on the front for easy access I all sections are easily accessible (can be pulled out) I frame of coolers are specially protected against corrosion I fin space are > 2.0 mm and can be cleaned up to the core by using a steam cleaner I drain tray made in stainless steel and guarantees continuous and complete drainage I installation of an eliminator with the cooler, can be pulled out and dismantled I complete insulation of pipes through the panel to avoid condensation I coil frame made out of aluminium, pipes and collector made out of copper 5
Checklist VDI 6022 Unit construction all materials meet health requirements sealing materials are closed cell type service space for maintenance to be foreseen all units and components are easily accessible, equipped with lighting and sight glasses (for filter, humidifier, fans with height > 1.3 m) continuous and complete drainage for wet componentsdrain tray and floor pan in stainless steel with sufficient gradient tray in outside air section pan with drainage (for external installation) air velocity through eliminator max. 3.5 m / s cleaning after manufacturing hygienically appropriate manufacture, transportation and intermediate storage at the place of installation bottom permanently non-corrosive with powder coating or in stainless steel filter with sight glass and lighting from height > 1.3 m onwards Fan prevention of belt wear: I filter F7 downstream fan with V-belt drive or I use of direct driven fans or I use of flat belt driven fans casing fan with water drainage and access (from size 400 onwards) Filter Casing for single stage filtering F7, for two-stage filtering sandwich panel construction from permanently corrosion-proof materials, e.g powder coated smooth internal surfaces without grooves surface can easily be cleaned wet sections are from non-corroding material F5 + F7 use of microbiological inert (biostatic) filter materials use of exclusively non-porous sealing profiles dust side filter maintenance with service chamber or fast filter release device 6
filter differential pressure monitoring optically or electrically for each filter stage correct air filter installation with low mechanical stress on filter medium filter section with drain pan (optional) low humidity at outside air filters through: I heating of outside air through preheater or heat recovery (KVS system) I return of partial air stream from the supply air side for preheating (optional or customer-fitted) I use of biostatic air filters I closing outside air damper and heating the filter section filter description fixed outside on the unit Humidifier sight glass (possible to darken) completely dryable flushing installation for circulating water automatic shut-off for humidifier drip eliminator can be cleaned, removed and dismantled Sound absorber use of materials harmless to health mechanically stable surfaces, easy to clean silencer columns positioned in AHU individual columns are easy to replace and service glass fiber surface to avoid loose fibres and for easier cleanability access panels at maintenance side Arrangement preferable in the AHU Heat exchanger fin space minimum 2,0 mm deep cleaning to the core possible all sections are easily accessibly (can be pulled out or accessed) frame protected against corrosion, for cooler made of aluminium or stainless steel condensate drain (cooler) for continuous and complete drainage removable and dismantable eliminator after cooler continuous insulation of pipe through the panel 7
AL-KO THERM GMBH Hauptstraße 248-250 89343 Jettingen-Scheppach Germany Fon +49 82 25 39-0 Fa x +49 82 25 39-113 klima.technik@al-ko.de w w w.al-ko.com