Which approach to inherently safer design is being employed when the concentration of an alcohol in water solution used as a process solvent is lowered to ensure that the flash point is above the process operating temperature?

• A. Minimize
• B. Substitute
• C. Moderation
• D. Eliminate

Answer: (C)

Reducing the hazard by diluting a flammable solvent is an example of moderation. By lowering the concentration of the alcohol in the water, vapor generation and flammability decrease, which raises the solvent’s flash point above the process operating temperature. This makes ignition less likely during operation, improving safety without removing the solvent or replacing it. The other approaches would involve reducing the amount used, substituting a less hazardous material, or eliminating the hazard entirely, none of which describe the act of dilution to lower hazard.