Operation of safety cabinets

It is recommended that the safety cabinet be connected to a permanent exhaust system.If the cabinet is not connected to a technical exhaust system, the specific area in front of and around the cabinet is considered a zone 2 hazardous area.If the safety cabinet is connected to a 24-hour technical exhaust system,the hazardous area is limited to the inside of the safety cabinet.To prevent corrosion damage to the cabinets, no acids or alkalis shall be stored in such cabinets:TRbF Annex L: Storage devices in work areas (safety cabinets) /points 4.1 and 4.2 and BGR 104 2.2.8).Solvent cabinets and safety cabinets can be technically vented with recirculating air filter units if connection to an exhaust system is not possible on site.These units filter cabinet exhaust air through activated carbon filters,capturing harmful vapors and returning clean air to the work environment.

Function 

In the event of a fire and the ambient temperature reaches 50 °C (+0/−10 °C), the drawer (if fitted) must first be retracted and the door must close automatically.These actions are usually activated by bimetal strips or fusible links. in approx.When the temperature is 70°C, the fire damper at the connection point between the fresh air inlet and the exhaust outlet is automatically closed. from ambient temperature at approx.At 160 °C, the intumescent seal foams and expands to seal the seam at the door.The cabinet is thus hermetically sealed.Safety cabinets with automatic door closures provide additional security. After a defined time interval,the cabinet closes automatically, minimizing exposure to stored chemicals and reducing the risk of escaping harmful vapors.In modern safety cabinets,there are visual and audible warning signals when the door is closed.Compressed gas cylinder safety cabinets do not have automatic door closing, as the doors of these cabinets must always be closed during operation.

Performance

Depending on the fire rating, a safety cabinet prevents stored goods from heating up for a specified length of time For example, a Type 30 BS EN cabinet will guarantee safety for 30 minutes before the internal temperature reaches critical temperature.Type 90 BS EN cabinets provide maximum safety and protection for 90 minutes.For flammable liquids and solids this temperature rise is 180 °C (K) and for pressurized gas cylinders a temperature rise of 50 °C (K) is permitted.The tests are carried out as a freestanding single cabinet in a suitable fire compartment.The entire cabinet must be exposed to the same heating conditions.The temperature rise is measured inside the cabinet according to the unit temperature curve (ETK)).

Inspection and service

According to BS EN 14470, the safety cabinet must be inspected regularly by a qualified person. This inspection should include:

• Condition of fuses/fire dampers

• Condition of fire insulation

• Condition of fire seals (intumescent)

• Hinge condition

• Door closing function

• Door interlock function

• Body condition (corrosion)

• Compatible with hazardous areas

• Measurement of exhaust volume flow (for technical ventilation)

• Health and Safety Act also requires regular cleaning or maintenance of equipment used at work.