| NH |
 |
No Hub |
| NOM |
|
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 ½" NOM Comp. Fitting is actually 5/8" because ½" pipe has an OD of 5/8". |
| NPS |
|
National Pipe Straight threads standard, Same as IPS. |
| NPSP (Discharge) |
|
Non Point Source Pollution. Nutrients, sediments, toxic substances, and pathogens that degrade waterways. NPS occurs mainly through storm water runoff. |
| NPSHA |
|
Net Positive Suction Head Available to prevent cavitation of the pump. It is defined as:
Atmospheric pressure + gage pressure + static pressure - vapor pressure - friction loss in the suction piping. |
NPSHR |
|
Net Positive Suction Head Required to stop a pump from cavitating. This number is provided by the pump manufacturer. |
| NPT |
|
National Pipe Tapered thread standard. The same as IPS. |
| NSF |
|
National Sanitation Foundation |
| Natural Gas |
|
A colorless, odorless fuel derived from the earth, consisting primarily of Methane (CH4). Odors are added to aid in leak detection. |
| Neo Angle Base |
|
A shower base designed to allow the shower to fit into a corner using minimal floor space while maintaining an elegant look. |
| Negative Pressure |
|
Less than atmospheric pressure. |
| Net Usable BTU |
|
That portion of a fuel's heat energy actually transferred into the water by a heater. |
| Nipple |
|
A short length of pipe installed between couplings or other fittings. |
| Nipple Extractor |
|
A tool used to unscrew sections of pipe. |
| 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. |
| Non-CFC Foam |
|
Insulation that minimizes the use of Chlorofluorocarbons. |
| Non-Ferrous |
|
Not containing iron |
| Non-Portable |
|
Not suitable for drinking |
