Fume cupboards and bio-safety cabinets
Fume cupboards and bio-safety cabinets are in widespread use within the pharmaceutical industry, and play an important role in protecting users from hazardous substances. However many are poorly designed from an ergonomic perspective, making them difficult and inefficient to use and giving rise to awkward and uncomfortable working postures.
This document provides a compendium of poor design features found in some cabinets and good features found on others.
Operator needs to sit high to see and reach the items on shelves at the back of the cabinet. This results in his thighs being squashed up against the underside of the cabinet.
Note also the lack of a footrest on the cabinet, resulting in the use of the chair ring and an acutely flexed knee posture.
The apertures for the sleeves and gloves do not extend high enough to enable him to easily reach the top shelf. His arms are pressed hard up against the top of the aperture.
When the operator stands upright at this cabinet his eyes are level with the control panel. This completely obscures his line of sight to the work.
This operator is of average height. Only the shortest 5% of the adult male population would have an un-obscured view.
To see what he is doing the operator needs to adopt and maintain this very awkward posture.
He is prevented from sitting by obstructions in the leg well - a deep sink and a plug socket with sharp edges.
Here the sliding screen gives good access, but the cupboards under the work surface prevent sitting at this type of cabinet.
There is no foot recess meaning that the operator either needs to stand with splayed feet or is forced to stand back. In addition, the relatively deep stainless steel aerofoil on the front edge of the work-surface means that the operators spend much of their time reaching or stooping forward.
The sliding screens are also stiff and heavy to move.
The position and depth of this sink produces a very thick front edge to this cabinet. This obstructs the knee space thus obliging the operator to sit too low and too far back, and to work with elevated and outstretched arms.
This could be avoided by standing rather than sitting, but this cabinet is too low for a standing workstation and would result in a stooped posture.
This fume cupboard is clearly much too low for a comfortable working posture whilst standing. The working surface is too low and the sliding screen does not extend high enough.
The lack of leg space under the work-surface prevents a comfortable seated posture, although the safe working practices in this particular laboratory require the technicians to stand and not sit when handling harmful substances. This is to enable them to step away quickly in the event of a spillage.
Poor working postures at this fume cupboard are therefore inevitable.
This is an example of a well-designed fume cupboard. Access is made easier by the provision of doors that swing open between floor and mid-height. The equipment inside is situated on trolleys on lockable wheels that can be easily moved. From mid-height upwards is a screen that can be pushed up out of the way, leaving unimpeded access within the cupboard for maintenance, repair or general activities.
In this cabinet the high aerofoil also acts as a convenient armrest, reducing fatigue and helping to steady the arms during the precision weighing operation.
This cabinet has a built-in foot platform at the appropriate height for most users. It extends the full width and depth of the foot-well providing support and postural variety for the legs.
This isolator has height adjustable legs to accommodate a wide range of users.
The arm apertures are large and well positioned to facilitate reach and manual tasks within the isolator.
Indicative dimensions for arm apertures in glove-boxes and bio-safety cabinets based on anthropometric data. Account must always be taken of the nature of the tasks to be performed and characteristics of the user population when determining the appropriate dimensions.