Guidelines for the use of Fume Hoods and Point suction

Fume Hoods in the Life Sciences Building

The Life Sciences Building has several types of fume hoods, compliant with NS-EN 14175:

1. Zystm Ergo Safe 83 (height-adjustable), made of high-pressure laminate with a ceramic worktop
2. Zystm Walk-in 88, made of high-pressure laminate
3. Zystm Zafe 82, made of high-pressure laminate with a ceramic worktop
4. Kavica (height-adjustable), made of steel
5. Zystem cupboards made of laminate and polypropylene for use with hydrofluoric acid

The fume hoods are configured with either a straight or angled front, electricity, gas, water, sink, etc., according to user requirements.

All fume hoods use the same control system: Lindinvent Flowcheck V.

To ensure that the fume hoods operate and provide protection optimally, it is important that users familiarise themselves with the fume hoods and follow the instructions for use and guidelines for fume hoods described above.

The fume hoods are integrated into the laboratories’ ventilation system and interact with the extract air and supply air systems. It is therefore important to keep laboratory doors closed in order to maintain the correct pressure and balanced ventilation.

The air velocity in the fume hoods is regulated automatically, so that it remains approximately 0.5 m/s when the sash opening is between 5 and 35 cm. This can be checked on the Flowcheck V control panel.

The exceptions are walk-in hoods and hoods for use with hydrofluoric acid. These have a fixed extract airflow, resulting in a higher air velocity at a 5 cm sash opening than at a 35 cm sash opening.

Zone Alarm

Some laboratories in the Life Sciences Building have a zone alarm. Laboratories within the same zone cannot operate all fume hoods simultaneously with a sash opening of 35 cm. If the ventilation in the zone becomes unbalanced, the zone alarm is activated. This consists of a small white box by the door which emits an audible alarm and displays a red light.

The alarm can be stopped by lowering the sash opening on one or more fume hoods. In laboratories with a zone alarm, it is particularly important to keep the sash lowered when not actively working in the fume hood, and to ensure that point suctions are closed when not in use.

Laboratory Ventilation Control – Flowcheck V

• Flowcheck V is a panel for monitoring the air velocity in fume hood. The display shows the current status and operating mode in plain text and by means of LEDs. The air velocity should always be approximately 0.5 m/s, regardless of how far the sash is open.
• A green LED indicates normal operation. In the event of a deviation, such as air velocity that is too low or too high, an alarm is activated, with a red LED and an audible signal.
• The fume hood can be manually set to emergency mode (*Nödlage*), which increases the air velocity to 0.8 m/s and activates an alarm. This may, for example, be relevant if air appears to be flowing out of the fume cupboard.
• When cleaning or setting up equipment in a fume hood, provided that no chemicals are present, the air velocity may be temporarily reduced (*Rigglage*). This mode is activated and deactivated using the panel.
• Important: In the event of faults or deviations, contact the Estate Department. This also applies if a light is not working or if there is no electricity in the fume hood.
• Walk-in fume hoods and fume hoods for use with hydrofluoric acid have a constant extract airflow, meaning that the air velocity decreases when the sash is opened. These fume hoods therefore do not have Flowcheck V.

Worktop Properties

Zystm fume hoods have ceramic worktops, whereas Kavica fume hoods have steel worktops. Steel is less resistant to acids and high temperatures. It is recommended that very hot equipment is not placed directly on the steel worktop.

Maintenance

• Any chemical spillages must be removed immediately to prevent permanent damage.
• Surfaces must be cleaned regularly using warm water and detergent. Use non-abrasive cleaning products and cloths.
• Clean at least once a month, and more frequently where the fume hood is used daily.

When the fume hood is not in use, the sash must be kept closed. In general, the fume hoods are programmed as follows:

• When the fume hood is not in use and the sash is closed, it is in energy-saving mode (a steady blue “Energy” light).
• When someone is standing in front of the fume hood and/or working with the sash open, the fume hood is in normal operating mode (a steady green “OK” light). The air velocity is 0.5 m/s. If the air velocity falls below this level, the visual and audible alarms will be activated. Action: lower the sash.
• When the sash is opened to the maximum permitted height, the audible alarm and warning light will be activated (flashing “Emergency” and “Close” lights). The same applies if the extract ventilation is operating inadequately.
• If no one is standing in front of the fume hood for 10 minutes, the light inside the fume hood switches off and it automatically enters energy-saving mode. In fume hoods fitted with a sash motor, the sash will also lower automatically.

For a full understanding of the control functions, the manufacturer’s user manual must be consulted. As not all fume hoods have a functioning sash motor, the sash must always be lowered when you leave the fume hood or the laboratory.

Fume Cupboards with a Sash Motor

Do not force the sash open or closed; always open and close it slowly. During the final centimetres of closing, and when opening to the maximum position, the sash is controlled by the sash motor. Keep the first 10 cm of the fume hood opening clear of equipment. Otherwise, equipment and the sash motor may be damaged as the sash is lowered.

Airfoil

The airfoil must not be removed. Correct airflow can only be maintained when the airfoil is in place. It also protects you in the event of a spill.

Maintenance

The work surfaces must be cleaned regularly, at least once a month, using warm water and detergent. Use non-abrasive cleaning products and cloths. After cleaning, dry the fume hood with a dry cloth.

Several buildings have older wooden fume hood controlled by a switch and a red warning light.

Before working in the fume hood, set the switch to MAX to increase the air velocity. When you have finished working in the fume hood, return the switch to MIN, which reduces the air velocity.

Before starting work, test the warning light by pressing the test button for 3–4 seconds. The warning light should illuminate. If it does not, contact the Estate Department to have the bulb replaced. Please note that there is a small number of fume hoods for which the light cannot be tested. It is not recommended to start work if the warning light is not functioning.

While you are working, a red light indicates low air velocity. First, reduce the sash height. If the light remains red, stop work and contact the HSE coordinator or laboratory manager. Please note that this red warning light is not entirely reliable. This must therefore be taken into account in your risk assessment of the planned work. Consider what action to take if the fume hoods fails, and how the work can be stopped safely if the fume hood ceases to operate. Attach a lightweight piece of paper inside the fume hood to make the airflow visible.

Correct Sash Height

The maximum working height is 30 cm, usually marked by stickers on both sides of the fume cupboard.

Note: The sash must be closed manually when you have finished working, and whenever you leave the fume hood or the laboratory.

Point Suction is used for work carried out outside a fume hood where extraction is required. It is most commonly used above instruments used with solvents and other chemicals.

The point suction must be positioned as close to the source of contamination as possible. The point suction must be opened before use and closed when not in use. If you cannot feel air being extracted, check the airflow using a lightweight piece of paper.