Het belang van effectieve stofbeheersing op de farmaceutische werkplek

The questions that need answering when analysing the potential risks associated with dusts generated in the workplace include the following:

• Are the dusts potentially harmful to human health and the environment?
• Do they have the potential to cause explosions or fires?
• Do they have the potential to interfere with moving parts of machinery and electrical components?
• Is there the potential for cross-contamination of products?

If you are uncertain or don´t have all the relevant data, it´s recommended to evaluate the properties of the processed material. Besides analysing the dust characteristic, it also makes sense to perform a dust hazard analysis to evaluate the risk for employee exposure and a dust explosion & flammability test, which can be required according to ATEX-directives.

Combustion risk and dust explosions
In pharmaceutical manufacturing, it is common to extract process air containing combustible dusts, flammable gases, mists and vapors, a mixture of some or all of these. Containing such an explosive atmosphere in a sealed environment (such as a dust collector) with an ignition source and you have all the necessary constituent parts for an explosion to occur.

There is a growing trend for pharmaceutical ingredients, particularly Active Pharmaceutical Ingredients (APIs), to consist of smaller molecules to provide faster reactions and greater potency. Solvents are often used in the processing phases. Whilst providing significant benefits in terms of drug delivery and performance, it creates a number of challenges for pharma manufacturers and their production processes:

• The API’s create very fine dusts and often high solvent concentrations during the product handling and manufacturing processes. The finer the dust, the greater explosive potential due to increased surface area and greater concentration.
• The fine dusts also pose the greatest risk to the worker’s health, with harmful particles being retained in the lungs.

Containment:
Another critical consideration and one which is often overlooked, involves effective containment of potent dusts. Once the airborne dust is captured at source, it needs to be contained at every stage of the extraction process. Containment is also essential during maintenance of the dust collector unit. Especially for potent dusts there should be a specific and integral safe change operation for both the dust discharge system and the filter cartridge change-out. The so called Bag-In/Bag-Out (BIBO) technology is used to prevent operator exposure and the collected material from escaping when performing filter change-outs. The continuous liner technology is used at the discharge system to contain the dust released from the cartridges to the hopper during automatic pulse-cleaning of the system.

Explosion Protection:
If the dust is considered to be combustible or explosive, there are certain values that need to be determined in order to  select the correct and ATEX-certified explosion protection system for each dust collector. The goal of these systems are to control an explosion, to keep employees safe, and minimise plant and equipment damage.

• Passive Systems: This systems utilise passive components such as vent panels and mechanical flat valves. Passive systems are very reliable but also have limitations in there usage.
• Active Systems: Active systems involve much more costly technology but allow a greater flexibility in installation.