- Natural Gas:
- A colorless, odorless fuel derived from the earth, consisting primarily of Methane. Odors are added to aid in leak detection.
- Negative Pressure:
- Less than atmospheric pressure.
- National Electrical Manufacturers Association.
- Term used to describe shower receptor or bathtub that fits into a corner. Two corner walls butt up against the fixture.
- Net Usable BTU:
- The portion of a fuel's heat energy actually transferred into the water by a heater.
- No Hub.
- A short length of pipe installed between coupling or other fittings.
- Nipple Extractor:
- A tool used to unscrew sections of pipe.
- National Kitchen and Bath Association.
- No-Hub Connector:
- A connector for no-hub iron pipe consisting of a rubber sleeve and a stainless steel band secured by hose clamps. A variation, a neoprene sleeve with two
adjustable steel bands, is used for connecting dissimilar materials, as when connecting new plastic pipe to an existing cast-iron drainpipe.
- Nominal. Usually refers to the inside diameter of trade sizes of copper pipe and some CPVC pipes. Not for iron pipe connections. For example, a 1/2" Nom comp.
fitting is actually 5/8" because 1/2" pipe has an OD of 5/8".
- Nominal Size:
- Size used for identification only; not literal dimensions.
- Foam insulation that minimizes the use of Chlorofluorocarbons.
- Not containing iron.
- Not suitable for drinking.
- National Pipe Straight threads standard, same as IPS.
- NPS (Discharge):
- Nonpoint Source pollution: nutrients, sediments, toxic substances, and pathogens that degrade waterways. NPS occurs mainly through storm water runoff.
- Net Positive Suction Head Available to prevent cavitation of the pump. It is defined as atmospheric pressure + gas pressure + static pressure - vapor pressure -
friction loss in the suction piping.
- Net Positive Suction Head Required to stop a pump from cavitating. This number is usually provided by the pump manufacturer.
- National Pipe Tapered thread standard. Same as IPS.
- Natural Resources Defense Council - A non-profit environmental advocacy organization that seeks to protect the encironment and the nations natural resources.
- National Sanitation Foundation.