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Solvent based inks in different
colors and patterns are applied to paper, plastic, film and foil
substrates. Finished products include all sorts of wrapping paper,
wall covering, candy wrappers, flexible food packages, shrink
labels, high quality magazines and many, many more. These industries
employ ovens or dryers to remove the solvents from the finished
product.
The key hazard is an explosion from the buildup of solvent vapors in
the oven or dryer atmosphere. This buildup could occur by a
malfunction in the production process such as: a sudden or improper
amount of coating, a change in ventilation controls or excessive
speed. In any of these cases, the concentration of flammable vapor
has an opportunity to rise above safe levels, creating a potentially
explosive mixture of vapor in air.
The design specification for safe operation of a solvent oven or
dryer is outlined in safety and fire codes. The codes limit the
maximum solvent concentration allowable to 25% of the LFL under
worst case operation. However if a flammable vapor analyzer is
installed as a safety control the maximum allowable concentration is
50% LFL. Our PrevEx analyzers are the only analyzers that meet all
the requirements of the NFPA standards.
Examples of solvent-based printing applications including: Pressure sensitive labels,
shrink labels, heatset web offset printing, flexible packaging, wall coverings,
gravure printing, fexographic printing, and decorated paper. |
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