Ducted fume cupboards:

Fumes go directly from source to the atmosphere via plastic extraction system. There is a choice of constant velocity or Variable velocity. The fan needs to be as close to the termination as possible it is preferred that most of the system us under negative pressure this will ensure that if there are any temporary breaks the fume will not escape. Siting of fume cupboards is essential, so build the Laboratory around the Fume Cupboard. Use the shortest route to get the duct out of the building, this will prevent unnecessary fire risk factors.

 

Recirculating fume cupboards:

These have limited use as the filters have restricted use for certain chemicals. In the modern school’s curriculum, they are generally fine. Filters are prone to failure and it is difficult to identify when this has happened. Any misuse will damage the filter and other break downs are possible allowing fumes to escape. There are some quality options but there are also a lot of copies on the market without the appropriate construction knowledge and appropriate design tests and certificates.

 

The modern fume cupboards:

With environmental challenges there is a challenge to create a ‘greener’ fume cupboard. Fume cupboards can run with a face velocity of 0.3 meters per second. These low velocity fume cupboards have unique design aspects not just any fume cupboard can contain and recover a fume quickly at low velocity. Some operations are better suited to higher velocities so consideration of the process is important. Risk assessments should be in place as to how you will control your airborne contaminants.

 

Variable air volume:

VAV can be problematic although essential as energy saving which has become crucial in this modern world and we need to consider effects on our environment. Fume Cupboard Doctor favours a British system which is less complicated than other models; we find this system more reliable than others. We recommend introducing VAV but would advise on a long warranty period. The after service arrangements are essential as some products require very expensive software to maintain. Some companies also struggle with providing after service.

 

Automatic sashes:

This facility takes the onus off the user to close the sash. The set up for these is critical as the closing times can cause problems and danger to users. Carefully consider the product and the set up before choosing; warranty and aftercare also need to be considered.

 

Gimmicks:

There are some new ideas being tried on fume cupboards. Fans that turn off or slow down when you walk away from cupboards – this only works if you stop what is going on in the fume cupboard. Fume cupboards are designed at a certain face velocity to contain the fume; any changes to fume cupboards must be type tested to prove they are efficient. The fume cupboard may be essential to keeping the area under negative pressure. Take as much advice as possible before changing anything. Design changes must be proven and certificated.