Planning MMcCann For projects that require an extensive ventilation system, hire a ventilation engineer experienced and trained in industrial ventilation. Input from both parties is required to design an effective system; you might not know which types of ventilation systems are appropriate, and the engineer might not be familiar with the chemicals and processes you are using. A common problem with designing ventilation systems for art spaces is pinpointing where hazardous activities might occur. Use of toxic materials should be limited to specific areas and fixed workstations to promote efficiency and economy. For example, if you are designing a printmaking studio that specializes in etching, it would be impractical to install slot hoods in every work area; rather, plan the space to restrict use of acids and other etching materials to certain locations. Your workspace’s hours of operation are also important. If your space is only open at certain times of the day, the ventilation system can usually be shut down during off-hours. If you are designing a space that will have multiple uses, make sure everyone understands how to operate the ventilation system. There are two types of ventilation systems used for hazardous substances: dilution ventilation and local exhaust ventilation. Dilution ventilation involves bringing in clean air from outside the workspace to dilute contaminated air. The contaminated air is then pushed to the outside, usually with exhaust fans. Local exhaust ventilation traps the contaminants near their source in the work area before they become more widely airborne, and then expels them into the outside air. The rest of this section discusses the ins and outs of dilution and local exhaust ventilation, and how to maintain these systems.