GLOSSARY OF PLUMBING TERMS | N

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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 NOM Comp. Fitting is actually 5/8″ because  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

NPSP (Discharge) – Non Point Source Pollution. Nutrients, sediments, toxic substances, and pathogens that degrade waterways. NPS occurs mainly through storm water runoff.

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Source: “Plumbing Terms” Standard Plumbing Supply. 11 Sept. 2008