HVAC GLOSSARY - N

---

National Institute for Occupational Safety and Health: (NIOSH) The US government agency authorized to research and develop exposure criteria for toxic substances and recommend these standards to OSHA. NIOSH is also authorized to investigate unsafe working conditions.

Natural Ventilation: The supply of outdoor air through passive flow from windows, chimneys, doors, and other infiltration.

Negative Ion Generator: An air cleaning device that uses static charges to remove particulates from indoor air.

Negative Pressure: Condition that exists when less air is supplied to a space than is exhausted from the space, so the air pressure within that space is less than that in surrounding areas. Under this condition, if an opening exists, air will flow from surrounding areas into the negatively pressurized space.

NESHAP: National Emissions Standard for Hazardous Pollutants.

New Construction: Energy efficiency program promotion to encourage the building of new homes, buildings, and plants to exceed standard government-mandated energy efficiency codes; it may include major renovations of existing facilities.

Nitrogen dioxide: (N02) A pollutant associated with combustion; a deep lung irritant. The two most prevalent oxides of nitrogen are nitrogen dioxide (NO2) and nitric oxide (NO). Both are toxic gases with NO2 being a highly reactive oxidant, and corrosive. NO gradually reacts with the oxygen in the air to form NO2.

Nozzle: An air terminal device designed to generate a low energy loss and thus produce a maximum throw by minimum entertainment.