Plumbing Dictionary


Plumbing termonalogy.

Browse the glossary using this index

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M

MAIN

The principal pipe artery to which branches are connected.

MAIN BURNER

A device or group of devices essentially forming an integral unit for the final conveyance of gas or a mixture of gas and air to the combustion zone, and on which combustion takes place to accomplish the function for which the appliance is designed.

MAIN VENT

The principal artery of the venting system, to which the vent branches may be connected.

MANIFOLD

See "Plumbing appurtenance."

MEASURED GAS

Gas which has passed through and the volume of which has been measured by a meter, or gas which has been otherwise measured such as by weight or volume.

MECHANICAL DRAFT VENTING SYSTEM

A venting system designed to remove flue or vent gases by mechanical means, which may consist of an induced draft portion under nonpositive static pressure and/or a forced draft portion under positive static pressure.   a. Induced draft venting system. A portion of a venting system using a fan or other mechanical means to cause the removal of flue or vent gases under nonpositive static vent pressure. b. Forced draft venting system. A portion of a venting system using a fan or other mechanical means to cause the removal of flue or vent gases under positive static vent pressure. c. Power venting system. See FORCED DRAFT VENTING SYSTEM.

MECHANICAL JOINT

A connection between pipes, fittings, or pipes and fittings is not screwed, caulked, threaded, soldered, solvent cemented, brazed or welded. A joint in which compression is applied along the centerline of the pieces being joined. In some applications, the joint is part of a coupling, fitting or adapter.

MEDICAL GAS SYSTEM

The complete system to convey medical gases for direct patient application from central supply systems (bulk tanks, manifolds and medical air compressors) through piping networks with pressure and operating controls, alarm warning systems, and related components, and extending to station outlet valves at patient use points.

MEDICAL VACUUM SYSTEMS

A system consisting of central-vacuum-producing equipment with pressure and operating controls, shutoff valves, alarm- warning systems, gauges and a network of piping extending to and terminating with suitable station inlets at locations where patient suction may be required.

METER

The instrument installed to measure the volume of gas delivered through it.

MOBILE HOME

A vehicular, portable structure built on a chassis and designed to be used without a permanent foundation as a dwelling when connected to indicated utilities.

MODULATING

Modulating or throttling is the action of a control from its maximum to minimum position in either predetermined steps or increments of movement as caused by its actuating medium.