A dry steam-type humidifier is proposed for local humidity control in a patient room. The designer wishes to install it in the supply air duct downstream of the final filter bank (Filter Bank No. 3). According to CMC Section 408.1.5, is this installation compliant?

• Yes, dry steam humidifiers are always permitted downstream of the final filter.
• No, all humidification equipment must be upstream of all filter banks.
• Yes, but only if the design is specifically approved by the enforcing agency.
• No, humidifiers are not permitted in ductwork serving patient rooms.