CAGE PROCESSING in Animal Facilities - Felasa

4.6.2.1 Basic lock types for H 2O 2gassingFor gassing items with H 2O 2the following basic options are possible:• large, walk-in locks (gastight room or stainless steel chamber), common dimension: 2000 mm x 1000 mmx 2000 mm (hxwxd),• small pass-through locks, common dimension: 560 mm x 560 mm x 760 mm (hxwxd),• sterilisers or suitable rack washers that function as locks.When using sterilisers and rack washers for H 2O 2locks, the additionally required process time needs to beconsidered when calculating capacity and design of these machines. For all three options the H 2O 2generatorcan either be installed permanently or designed as an external, mobile unit that can be docked to the lock.4.6.2.2 Constructional requirementsConstructional requirements include the mechanical structure, procedural components, and electrical structureof H 2O 2locks.4.6.2.2.1 Mechanical structureThe mechanical structure of an H 2O 2lock must meet the following requirements:• Lock chambers must be designed of stainless steel.• With room locks, the material resistance and surface finish of walls and floors must be verified (H 2O 2-resistantepoxy resin).• Gastight doors with a suitable gasket system can be made of safety glass or stainless steel with an inspectionwindow.• Airtight connection between lock and building.• Gauge port or measuring line for leakage test.• A sampling port for determining the H 2O 2concentration is to be considered for installation inside the chamberor inside the gas return pipe.4.6.2.2.2 Procedural componentsThe following procedural components should be considered for H 2O 2locks:• HEPA filter for supply air and exhaust air (either inside the lock or on-site).• Air circulation system for gas distribution (in small chambers via the generator, in big chambers via a rotationsystem or pivoting fans inside the lock).• Automatic valves or shut-off dampers with repeater.• Exhaust air containing H 2O 2must only be discharged through the roof via separate exhaust air pipes.• Before being discharged, the exhaust air containing H 2O 2can be circulated through a catalyser in order toreduce the H 2O 2concentration inside the discharge air pipe or, where applicable, to avoid the extra pipecompletely.• Gastight shut-off dampers (in supply air and discharge air pipe).• The pipe works for the lock (internally) as well as for the generator connection should be made of stainlesssteel or plastics (e.g. PP, PVC-U). To ensure a universal use, the generator can be equipped with camlockcouplings (the dimensioning of the connection should be discussed with the manufacturer of the generator).• Galvanised sheet steel and copper pipes (catalytically effective) require special precautions in order toprevent material damage and to ensure process effectiveness.4.6.2.2.3 Electrical structureThe electrical structure of H 2O 2locks must meet the following requirements:• Control and communication (control via PLC or microprocessor controller, release, signal exchange, start/stop/abort signal, end of gassing, time control via validation) with the H 2O 2generator must be provided.Cage Processing in Animal Facilities · 4th issue · 2013 33