Methods of Source Contaminant Control
In contaminant control, the main focus should be placed on control of the source. Stellman (1998) noted that in the planning stage of an industrial procedure or during the monitoring stage, control should begin at the source and continue with the workers. Occupational Safety and Health Administration (1998) indicated that contaminant control strategies should be implemented following the standard hierarchy of controls that OSHA emphasizes as a matter of policy and enforcement. There are seven methods of source contaminant control, which include elimination, substitution, and isolation, sealing the source, general ventilation, local exhaust ventilation, and process and equipment design changes.
The primary approach of controlling contamination at the source is elimination. This approach entails the removal dangerous material from the industrial process. This eliminates the hazard once and for all and offers complete protection for the worker (Robson & Toscano, 2007). Eliminating the source of contamination is the ideal method for control, because it requires no substitution for contaminating agents. This method is stable and does not require any further repair procedure. It is applied when the source of contamination is known, for example, radioactivity in nuclear power stations.
Substitution is the method that is used to minimize the contamination by replacing dangerous substance with lesser contaminant substances or revamp the procedure to eradicate substance release. Stellman (1998) says that alternate compound can be dangerous or the intended design can entirely dispose of substance exposure. It is important to note that intense caution should be put in place to ensure that the substituted substances do not become more dangerous in the long run. Brauer (2006) noted that by replacing a hazardous material with a nonhazardous one, the danger of exposure to a hazardous one can be eliminated. Research shows that less hazardous material may form a desirable control by substitution (Plog & Quinlan, 2012).
This method seeks to reduce the danger by unraveling the procedure releasing the toxin in the workplace. This is achieved by totally enfolding the procedure or positioning it in a secure place far from the people. Brauer (2006) indicated that enclosing the process equipment that generates a contaminant provides the barrier. The enclosure usually involves an exhaust ventilation system. Placing workers in an enclosure may not be desirable if the workers must enter the contaminated process area frequently (Brauer, 2006). Isolation method is significant for the type of work that involves small number of employees and in instances where the use of other methods can not be achieved. The application of isolation methods in some instances does not completely remove the levels of contamination but reduces the number of people facing exposure.
Sealing the Source
This approach entails the use substances that release nominal levels of contamination. Stellman (1998) noted that this method is proposed as a way to restrain the removal loose equipments of insulation and, at the same time, hinder the emanation of formaldehyde in the surfaces that are treated with resin. In structures that are polluted with harmful gases, this approach fastens residue wedge and cracks in surface walls. Polymers are helpful, since they avert the release of harmful gases.
General ventilation is used as a source of contaminant control. In general ventilation, one moves fresh outside air into the general work space to dilute or displace source contaminants. Burgess, Ellenbecker, & Treitman (2004) noted that “general ventilation consists of an exhaust system which continuously removes contaminated air out of the working area to the outside” (p. 4). This type of ventilation structure involves a substitute air structure, a mechanism of reducing air, and air purifying system. Plog & Quinlan (2012) indicated that general ventilation is widely used in cases where there is multiple cause of contamination that is distributed in the entire place such as fork lifting machines in an industry.
Local Exhaust Ventilation (LEV)
Local exhaust ventilation means an effort to eliminate the toxin at the position of discharge and, thus, reduce the chances of the contaminant entering the workplace (Burgess, Ellenbecker, & Treitman, 2004). The capability of a local exhaust ventilation mechanism of achieving this is based on the good design of contaminant control mechanism. Local exhaust ventilation requires much smaller volumes of air than general ventilation (Brauer, 2006). Local exhaust systems capture contaminants at or near their source, before hazardous substances reach the breathing zone of people, and move the air to locations where people will not be present. Plog & Quinlan (2012) noted that exhaust systems can be designed with capture efficiencies approaching 100% for small areas.
Process and Equipment Change
Process and equipment change is a method of source control of contaminant. Roelofs (2007) noted that process change includes changes in temperature or speed of chemical reactions, fastening alternatives to soldering, and shifting from manual batch charging to hopper or automatic charging to reduce source contamination. Process changes like automated mechanical cleaning and pre-coating prevent polymer build-up and control source contaminants. Roelofs (2007) indicated that change from batch to continuous operations controls contaminants due to the reduction in frequency and duration of potential contact between workers and materials. Equipment changes to low pressure-low volume, high volume-low pressure, and the use of liquid bubbler generation system for compressed gas volumetric dispensing helps to control source contaminants.