Protocols_SOP_BiosafetyCabinets_V1.0 draft - BackmanLab/BackmanLab.github.io GitHub Wiki

Procedure: Biosafety Cabinets (BSC) Operation and Maintenance Protocol

SOP Prepared by: Maria Proença Version: 1.0

1. Scope

Biological safety cabinets (BSCs) must be used for all activities/experiments that demand a microbe-free work environment necessary for cell culture propagation and handling of any infectious organisms. All users of BSCs shall be familiar with the procedures described below.

The biological safety cabinet (BSC) is a fragile, precision piece of equipment intended for protecting the user from airborne aerosols that may cause infection and the cells/infectious organisms from being contaminated.

This SOP describes the procedures be followed properly by all who work in a biological safety cabinet as well as preventive maintenance and certification requirements.

IMPORTANT NOTE:

This SOP doesn't not supersede the requirement of reading the BSC manuals. Copy of the manuals are available in the shared lab's NU Box folder as well as in the Equipment Manuals & Spare Parts drawer next to the system. Before using any of the BSC, you must read the operating manual carefully and familiarize yourself with the device's mode of operation and required maintenance.

2. Description

A biological safety cabinet (BSC) is the primary barrier protection for individuals working with biohazardous materials. BSCs is a ventilated cabinet that uses a variety of combinations of HEPA filtration, laminar air flow and containment to provide personnel, product and/or environmental protection against biohazardous agents. It is distinguished from a chemical fume hood by the presence of HEPA filtration and the laminar nature of the airflow (Figure 1.).

Laboratory procedures that could create airborne biohazards should always be performed in a BSC as it protects laboratory workers and the environment from aerosols or droplets that could spread biohazardous material.

Biological safety cabinets must NOT be used for procedures with hazardous chemicals unless verified by Occupational Health and Safety.

There are 3 classes of BSCs:

Class I:

These cabinets have unrecirculated airflow directed away from the user that is discharged through a HEPA filter.

Class 1 cabinets provide protection to the user and protection of the environment but no protection to the work. Class 1 cabinets are suitable for some work procedures at Containment level 1 and 2 if no protection of the work is required.

Class II types:

Class II cabinets provide a high degree of protection to the worker, the work and the environment. They are suitable for work at Containment Level 1, 2, 3 and 4 and are divided into two types (A and B) on the basis of construction type, airflow velocities and patterns and exhaust systems.

• Class II, Type A1

Cabinet air may be recirculated back into the laboratory or ducted out of the building. It is able to maintain a minimum average face velocity of 0.38 m/s (75 ft/min) and may have positive pressure contaminated ducts and air flow. This type is not suitable for work with low levels of volatile toxic chemicals and volatile radioisotopes.

• Class II, Type A2

{width="4.095138888888889in" height="3.6875in"}Cabinet air may be recirculated back into the laboratory or ducted out of the building by thimble connection. It is able to maintain a minimum average face velocity of 0.5 m/s (100 ft/min) and has ducts and air flows under negative pressure. This type of cabinets are suitable for work with biological agents treated with minute quantities of volatile toxic chemicals and tracer quantities of radionuclides that will not interfere with the work if recirculated in the downflow air.

• Class II, Type B1

The cabinet is hard-ducted through a dedicated duct exhausted to the atmosphere after passage through a HEP A filter. It contains negative pressure air flow and 30% of the air is recirculated within the cabinet. It is able to maintain a minimum average face velocity of 0.5 m/s (100 ft/min). This type is suitable for work with low levels of volatile toxic chemicals and trace amounts of radionuclide.

• Class II, Type B2

The cabinet is hard-ducted through a dedicated duct exhausted to the atmosphere to which 100% of the cabinet air travels to after passage through a HEPA filter. The cabinet contains negative pressure air flow and maintains a minimum average face velocity of 0.5 m/s (100 ft/min). It is suitable for work with volatile toxic chemicals and radioisotopes.

An alarm should be provided that is audible at the cabinet to indicate loss of exhaust flow from the building exhaust system. The cabinet internal fan should also be interlocked to shut down when the building exhaust system fan fails, to prevent pressurization of the cabinet.

• Class III:

These are totally enclosed, gas-tight cabinets with HEPA filtered supply and exhaust air. The cabinet is kept under negative pressure of at least 120Pa and airflow is maintained by an exterior exhaust system. The work surface is accessed only through glove ports or sealed air locks. These cabinets provide a totally contained area to protect the worker, the work and the environment and are suitable for work at Containment Level 4. Removal of material from the cabinet must be through a dunk tank, double door autoclave or air-lock pass-through for decontamination. Interlock or protocols must be used for the autoclave and pass-through doors to prevent both doors from being open at the same time.

This SOP covers the two BSCs in the Backman lab. Both cabinets are Class II, Type A2, and as mentioned above, provide protection of the product (specimens, strain cultures), the worker, the work and the environment against contamination by recirculating part of the HEPA-filtered air in a laminar vertical flow inside the cabinet so that a "curtain" of clean air descends across the whole working surface and is vented through a thimble:

• Thermo Scientific 1300 Series Class II, Type A2 Biological Safety

  cabinet (TS1300) (EIBS room# B-745)

• Labconco Purifier Delta Series Class II Type A2 Biological Safety

  Cabinet double trap liquid aspiration system setup (DeltaS) (cell culture room# B-749)

This Procedure provides the basic guidelines for daily operation, routine (user) maintenance, decontamination/ cleaning, and emergency procedures for the Backman Lab's BSCs described above. Staff should not use any of the systems unless properly trained.

3. Personal Protective Equipment

• Lab coat;

• Disposable gloves;

• Hair tied back if long

• Proper enclosed footwear;

NOTE 1.: Additional Personal Protective Equipment, or PPE, may be required depending on the findings obtained from the biological risk assessment.

4. Potential Hazards & Safety Precautions

The BSC should be located away from sources of air disturbance such as doors, windows, air-conditioning, ventilation supply or return outlets, exhaust fans, etc. Personnel traffic in front of the BSC should be minimized to avoid disrupting the airflow.

The overall health and safety risk for use of BSCs in accordance with the procedure and protocol in the following sections is considered LOW .

• Exposure hazards:

Spills:

It's the user's responsibility to take any additional safety measure based on the reagents/materials being handled. When aspiring toxic, or pathogenic materials, be aware of potential hazards associated with them in case of a spill. If exposure occurs to toxic or pathogenic materials all necessary precautions and appropriate decontamination procedures should be used.

When using pathogenic, toxic, or radioactive materials, be aware of potential hazards associated with them. It is recommended that additional precautions be taken to prevent exposure (see lab safety procedures for toxic/pathogenic and Radiation Safety Handbook for radioactive).

Aerosols:

You may be exposed to aerosols dispersed in the air during procedures involving sample spraying, shaking, stirring, centrifuging. Reduce risk by placing all aerosol generating equipment and materials as far back in the cabinet, towards the rear edge of the work surface, as practical without blocking the rear grill.

Ultraviolet Light:

Possibility of burns to eyes or skin from UV light in cabinet. Ensure UV is turned off before using the cabinet. Ultraviolet lights are not required in BSCs. Ultraviolet lights must be turned off while the room is occupied, to protect eyes and skin from inadvertent exposure.

• For safe use of the BSCs:

  • Lab coats must be buttoned.

  • Gloves should be pulled over the wrists of lab coats, not worn

    inside the sleeve.

  • Minimize external airflow disturbances

  • Manipulation of materials inside the cabinet should be delayed

    for 1 minute after placing hands/arms inside the cabinet to allow the air to stabilize and to "air sweep" arms.

  • Do not rest arms on front grille (unless the BSC is specifically

    equipped with armrests that permit this action). Instead, work with both arms raised slightly

  • Do not block the front grille with papers or other materials.

  • Perform all operations on the work surface and at least 5 inches

    from the front grille.

  • Allow cabinet blowers to operate for at least 5 to 10 minutes

    before beginning work to allow the BSC to "purge" particulates.

  • Make sure that active work flows from the clean to contaminated

    area across the work surface.

  • When removing arms from cabinet move them slowly in a direction

    perpendicular to plane of work zone opening.

  • To minimize frequent in/out arm movement and maintain the air

    barrier, do not tape autoclavable biohazard collection bags to the outside of the BSC; upright pipette collection containers should not be used in the BSC and/or placed on the floor outside the BSC (instead, horizontal discard trays containing an appropriate chemical disinfectant should be used).

  • Use the aseptic techniques below to reduce splatter and aerosol

    generation:

    • Opened bottles or tubes should not be held in a vertical

      position.

    • Hold the lid above open sterile surfaces to minimize direct

      impact of downward air.

    • Open flames should not be used because they create

      turbulence that disrupts the pattern of air supplied to the work surface.

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• Aspirator bottles or suction flasks should be connected to an overflow collection flask containing an appropriate disinfectant, and to an in-line HEPA filter (see Liquid Aspirator Systems (LAS) SOP for details).

• If spilled liquid enters through the front or rear grilles, close the drain valves and pour decontaminating solution into the drain pans. Use the appropriate decontamination solution and contact time for the pathogens used in the BSC.

• Carefully handle the paper towels used for cleanup, as any materials present in the catch basin that are caught in the exhaust plenum may require BSC decontamination and the cabinet body being opened to remove the object.

• Immediately following the manipulation of infectious agents in the BSC, decontaminate surfaces and the BSC contents with the appropriate solution and contact time necessary for the infectious agents being used. Do not allow any potential contamination on the interior surfaces to remain until the end of the work shift as this will reduce the efficiency of decontamination procedures.

• When work is finished, remove and discard all waste and surface decontaminate all items that are to be brought out of the BSC prior to their removal.

• At the end of the workday, surface decontaminate the BSC with 70 percent ethanol, dilute bleach or any appropriate disinfectant.

  • Be aware of potential hazards associated with aspiring toxic, or

    pathogenic materials.

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  • Dispose of all waste solutions according to NU's procedures for

    Proper Segregation & Disposal of Laboratory Waste guidelines.

  • Do not circumvent any of the safety features (such as the low

    flow alarm, UV light on, etc.). They are there to protect you.

  • Do not mix incompatible disinfectants and/or reagents / solvents

    or any unknown substances.

5. Materials and Reagents

   5.1. Equipment

   {width="2.1944444444444446in" height="2.432638888888889in"}a){width="1.0770833333333334in" height="2.25625in"}

{width="3.888888888888889in" height="3.4340277777777777in"}b)

{width="3.1486111111111112in" height="1.9222222222222223in"}

Figure 2. Main components of the laboratory's Class II, Type A2 Biosafety cabinets. a) Labconco Purifier DeltaS (Cell culture room, B-749) and b) ThermoScientific 1300 Series Class II, Type A2 cabinet (EIBS room, B-745), (1) keys, (2) Status indicators shows window work position; airflow; reduced blower speed and Smart Flow Indicator. The Display with it's 5-digit panel shows filter life time (during normal operation); downflow and inflow air velocities (during safe work mode) and remaining time of the UV disinfection routine (when UV light "On").

Labware

NOTE 2.: All labware to go inside the BSC must be sterile. Make sure to spray with 70% ethanol prior to moving them inside the chamber.

Labware specific to the BSC -- be used exclusively inside the BSC and should only be removed for BSC maintenance and/or disinfection or when replacement is required:

• 1 set of pipettes and pipette holder,

• 1 automatic pipettor for serologic pipettes,

• 1 vacuum aspirator gun/tube,

• 1 biohazard waste bag holder,

• Rack and marker,

• Tips,

To be removed at the end of the work:

• Waste containers,

• Flasks, petri dishes, plates,

Reagents and Solutions

NOTE 3.: It is the user's responsibility to take any additional precaution and safety measures based on the reagents/materials to be handled. Including prepare additional decontamination solutions.

• 70% Ethanol

  • 70 mL denatured Ethanol + 30 mL of RO water

• 10% (100 ml/L) Commercial bleach (a.k.a. sodium hypochlorite)

  • 10 mL denatured Ethanol + 90 mL of RO water or 200 ml for each 800 mL of liquid biohazard waste.

• Alconox™ Liquinox Critical Cleaning Liquid Detergent (1 gal. Thermo

  Sci. Cat # 16-000-126, Manufacturer # 1201

  • Dilute 1:100 (dilute 10mL in 1L of water)

ATTENTION: Alconox foams.

6. Procedure

NOTE 4.: This SOP doesn't not supersede the requirement of reading the BSC manuals for the Labconco Purifier DeltaS (Cell culture room, B-749) and ThermoScientific 1300 Series Class II, Type A2 cabinets (EIBS room, B-745*. Copy of the manuals are available in the lab's NU Box folder as well as in the Equipment Manuals & Spare Parts drawer next to the systems. Before using any of the BSCs, you must read the operating manual carefully and familiarize yourself with the device's mode of operation.*

6.1. Handling Procedures:

Reminders:

• To avoid accidents and injury, always follow manufacturer's

  operating instructions for the BSC being used.

• Always follow best practices for handling of Biohazardous samples

  and use aseptic technique.

• Clutter inside the BSC may impede proper airflow and the level of

  protection provided. Use wire racks to increase airflow around front and rear grills.

• Active work should flow from clean to contaminated areas across the

  work surface.

• Mouth pipetting is not allowed.

• Read the Safety Data Sheets, or SDS, for materials being used in a

  BSC. Note any precautions regarding the use of the chemical or microorganisms in the BSC.

Operation:

1. If the BSC is "Off" for the:

Delta Series TS1300

Turn switch "On" (Fig. 2. a). Blowers start, and an audible alarm sounds Press and hold the ON key until the blowers start (audible blower operation), status indicators (LEDs) illuminate, and an audible tone sounds (Fig. 2.b).

NOTE 5.: A delay of several seconds may occur between key actuation and unit response.

2. Lift the sash to the recommended height A dimple on BSCs exterior

   sidewall indicates the correct working position (Fig. 3 and 4.b.)

3. Clean and disinfect the sample chamber surfaces and wait for

   approximately 10 mins..

NOTE 6.: Do not work in a BSC while the LED is/are RED or alarm is signaling.

{width="3.59375in" height="1.2534722222222223in"}

Figure 3. BSC sash work position. a) Sash's working height; b) TS1300 working height indicator and c) TS1300 air flow indicator.

4. Check the air intake and exhaust grilles for obstructions, and check

   the pressure reading until airflow has stabilized:

Delta Series TS1300

Alarm Shuts down. green LED is steady in "Air flow", "Sash level" and "Smart flow" indicators (Fig. 3.b).

5. Decontaminate the cabinet surface and surface-decontaminate all

   materials to be placed inside the BSC with 70% ethanol --- refer to the Cleaning and Disinfection section for more details.

6. Bulky items, such as waste containers, pipettes, etc. should be

   placed to one side of the interior of the cabinet.

7. Place samples within the defined work area of the work tray.

8. Keep the work area of the BSC free of unnecessary equipment or

   supplies.

9. Maintain the forearms in a nearly horizontal position.

After Operation:

1. Remove all samples from the chamber, disinfect and store them

   properly.

2. Use 70% ethanol to clean and disinfect the chamber surfaces,

   including the work tray and the drain pan.

3. Clean and disinfect all accessories with 70% ethanol.

4. Let the unit run for 5-10 mins to allow the surfaces to dry.

5. Turn the unit to standby mode by closing the window.

6. To turn "Off", press the "On" key until the indicators are off.

6.2. Cleaning and Maintenance:

Additionally to the routine cleaning performed after operation (see above). The BSC should be deep cleaned and disinfected at least bi-weekly.

NOTE 8.: The presence of any liquid or solid that remains in contact with the stainless steel for a prolonged time promotes corrosion, this includes cleaners and disinfectants containing chlorine, ammonia, iodine or other caustic agents. Never use abrasive cleaners, scouring pads or steel wool.

Several procedures can be used and the procedure selected, depends on the potential risk imminent in the agents used, and/or the degree of cleanliness required by an experiment or work process:

1. Standard cleaning/disinfection procedure:

Interior Surfaces:

i. Remove all samples and materials from the chamber. Disinfect with > 70% ethanol and store them properly.

ii. Do not remove the UV lamp from the sockets. Clean lamp gently but > thoroughly with a damp cloth to prevent dust particle > accumulation. Do not saturate. Be sure to dry completely.

iii. Remove and disinfect the work tray with 10% commercial bleach or 1% > Alconox and running water.

iv. Clean all chamber surfaces with 10% commercial bleach or 1% Alconox > and pass at least twice with clean RO water.

v. Rinse all surfaces at least twice with RO water.

vi. Discard any liquid from the drain pan using the draining valve if > necessary. The valve is located under the chamber on the lower > front left corner.

vii. Dry all chamber surfaces completely using a paper towel or similar > soft cloth.

viii. Use 70% ethanol to disinfect the working tray as well as all other > materials and place them back.

ix. Close the front window sash and turn "On" the UV lamp for ≥10 > minutes.

Drain Pan and Arm rests:

i. Clean thoroughly with 1% Alconox or 10% bleach and tepid water.

ii. Remove any residues and/or deposits. Discard any liquid in the drain > pan.

iii. Wipe using a clean cloth and rinse using a solution of tepid water > and commercially available mild dishwashing agent.

iv. Rinse with plenty of clean water and dry thoroughly.

NOTE 9.: After cleaning, make sure that all cleaning product has been removed completely from the drain pan.

v. Reinstall the work tray

Exterior Surfaces:

i. Use a solution of tepid water and commercially available mild > dishwashing agent.

ii. Dry all surfaces well using a soft, clean cloth.

Window:

i. For cleaning, the window can be lowered beyond the closing position > (fig. 4.c). To access the upper portion of the window.

{width="2.0840277777777776in" height="1.7180555555555554in"}{width="2.0840277777777776in" height="1.7180555555555554in"}

{width="1.84375in" height="1.7186187664041994in"}

1. Autoclaving (sterilization with steam) - can be used for

   treating the removable stainless steel components. The work tray(s), armrests and paper catch grids are autoclavable components.

2. Formaldehyde or vaporized hydrogen peroxide disinfection is

   mandatory before filters are replaced, or before the unit is discarded and should be performed if a sterile sample chamber is required for the work procedure. Decontamination with formaldehyde or hydrogen peroxide must be performed must be performed by a certified technician.

6.3. Maintenance

The BSCs must be certified annually. A sticker in the front panel of the cabinet shows last certification date. NU's BSCs are certified at no-cost for the lab through a service agreement between Salus and NU's Safety Office.

For maintenance schedule, contact Salus at 630.694.0014 or [email protected] or [email protected])

NOTE 10.: On the TS1300 the "SmartFlow Performance Indicator" displays the status of the compensation reserve. Green indicators show the fan and filters have power and capacity in reserve to respond to additional demands. Yellow or red indicators show that while the cabinet is providing personnel and product protection, maintenance should be scheduled to restore the compensation reserve.

Sample Chamber Lights

The chamber is illuminated by a florescent lamp (XXXX for DeltaS and YYYY for TS1300). To replace the lamp:

1. Switch the unit off and disconnect it from the power source.

2. Move the window to the cleaning position (Fig. 4.c) to ensure a sufficient gap between the window and the light dome.

3. Rotate the lamp counterclockwise to disengage the latch from the rotating sockets and remove it from the sockets.

4. To install a new lamp, slide the lamp pins into the rotating socket grooves and rotate the lamp clockwise to latch the sockets.

Ultraviolet (UV) lights

The UV light should be replaced after 1500 operating hours.

The UV light is installed in each chamber's back wall.

NOTE 11.: Wear protective gloves to prevent skin oils from burning into the bulb.

1. Switch the unit off and disconnect it from the power source.

2. Move the window to the maximum opening position (Fig. 4.a).

3. Rotate the lamp counterclockwise to disengage the latch from the

   rotating sockets and remove it from the sockets.

4. To install a new lamp, slide the lamp pins into the rotating socket

   grooves and rotate the lamp clockwise to latch the sockets.

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7. Disposals | Spills | Incidents

   1. Waste (see waste segregations and collection SOP for complete information):

Dispose of all waste solutions according to NU's procedures for Proper Segregation & Disposal of Laboratory Waste guidelines including:

• All waste containers should be closed once ¾ 's full and placed into the appropriate location for pick up.

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• All waste containers to be picked up by the Safety Office (SO)

  should be properly labelled with the following information:

  • PI's name

  • User | Responsible person

  • Content and approximate amount in %

  • Waste class (e.g. chemical, biohazard, radioactive, etc.)

  • Waste type (e.g. sharps, plastic, glass, metal, etc.)

  • Waste "status" (e.g. liquid, solid, etc.)

[Protocol Specific Waste]{.ul}

• Dispose of all waste solutions according to appropriate health and

  safety guidelines.

• Plastic waste should be segregated by type, collected in [specific

  waste containers](https://researchsafety.northwestern.edu/biological-safety-manual/) and placed in the appropriate waste collection area for pickup.

• Empty any remaining liquids either on a

  chemical or biohazard liquid waste disposal container, and discard tubes in the respective solid waste container, depending on the class of materials being discarded.

1. Spills:

In event of a spillage:

1. Alert the other laboratory employees.

2. Leave the cabinet turned on.

3. While wearing gloves, spray or wipe cabinet walls, work surfaces and

   equipment with disinfectant equivalent to 1:10 bleach solution. If necessary, flood the work surface, as well as drain-pans and catch basins below the work surface, with disinfectant for a contact time of at least 20 minutes.

4. Report the spill to the laboratory's manager, who will report the

   spill to the Responsible Official if a select agent or toxin is involved.

5. Soak up disinfectant and spill with paper towels.

6. Drain catch basin into a container.

7. Lift front exhaust grill and tray and wipe all surfaces. Ensure that

   no paper towels or solid debris are blown into the area beneath the grill.

8. Dispose all cleanup materials in the biohazard waste container.

9. Wash hands and any exposed surfaces thoroughly after the clean-up

   procedure.

• If exposure occurs to toxic or pathogenic materials all

  necessary precautions and appropriate decontamination procedures should be used (follow safety procedures for toxic/pathogenic and/or Radiation Safety Handbook for radioactive).

• When applicable:

  • Notify others in laboratory and if appropriate, evacuate

  • Notify the lab supervisor

  • Notify the Office of Research Safety (ORS)

  • Refer to hazardous agent use protocol (if required)

7.3. Mechanical failure:

7.3.2. Sash Alarms -- signifies that the operator has moved the sash to an improper position. Return the sash to the proper position.

7.3.3. Air-flow Alarms - indicate a disruption in the cabinet's normal air-flow pattern and can be due to mechanical failure of the external blower, an obstruction or leak in the exhaust system or loading of the exhaust HEPA filter.

1. Immediately stop working.

2. Close the sash.

3. Identify and correct the problem.

4. Reset the alarm by pressing the "Alarm Silence" switch.

5. Wait approx. 5 mins. before resuming work.

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8. References

   1. Lab safety and Chemical Hygiene Plan, Northwestern University, 2019.

   2. Biological Safety Manual, Northwestern University, 2019.

   3. Radiation Safety Handbook, Northwestern University, 2019.

   4. 1300 Series A2 Class II, Type A2 Biological Safety Cabinet Operating Manual, 7021355 Rev. 13

   5. Biological Safety Cabinets, Enclosures & Clean Benches, Labconco, 2005.

   6. Laboratory Biosafety Manual, World Health Organization, 2^nd^. Edition, 2003.

   7. OSHA Laboratory Standard.

   8. Pathogen Safety Data (PSD) Guide, NIH, 2016.

   9. Patogenic Safety Data Sheet (PSDS), Government of Canada.

SUMMARY FLOWCHART OF EMERGENCY PROCEDURES TO CONSIDER IN CASE OF SPILLAGE OF PATHOGENIC OR TOXIC MATERIAL

**
**

// Protocol Summary//

NOTE: Reading of this Summary does not supersede the requirement of reading the complete SOP and the BSC's instruction manuals. This Summary should only be used as a quick reference and only once you're familiarized with the full SOP.

Biological Safety Cabinets:

Reminders:

• Clutter inside the BSC may impede proper airflow and the level of

  protection provided.

• Active work should flow from clean to contaminated areas across the

  work surface.

Operation:

1. Turn the BSC "On".

Delta Series TS1300

Turn switch "On" Press and hold the ON key until the blowers start.

2. Lift the sash to the working position (top dimple on BSCs exterior

   sidewall indicates the correct working position).

3. Clean and disinfect the sample chamber surfaces and wait for

   approximately 10 mins..

NOTE 1.: Do not work in a BSC while the LED is/are RED or alarm is signaling.

Delta Series TS1300

Alarm Shuts down. Green LED in "Sash level", "Air" and "Smart flow indicators.

4. Check the air intake and exhaust grilles for obstructions, and check

   the pressure reading until airflow has stabilized.

5. Decontaminate the cabinet surface and all materials to be placed

   inside the BSC with 70% ethanol.

6. Place samples within the defined work area of the work tray and

   maintain the forearms in a nearly horizontal position

After Operation:

7. Remove all samples from the chamber, disinfect and store them

   properly.

8. Use 70% ethanol to clean and disinfect the chamber surfaces and

   accessories.

9. Let the unit run for 5-10 mins to allow the surfaces to dry.

10. Close the window to place the unit in standby mode.

11. To turn "Off", press the "On" key until the indicators are off.