MI Plumber key terms

The complete assembly of pipes, fixtures, fittings, traps, and appurtenances that supplies water, removes waste, and vents gases inside or near a building. In Michigan, supply, drainage, venting, and special wastes are regulated as one connected system.

The official body that enforces the plumbing code, interprets its rules, issues permits, and approves materials and methods. In Michigan this is usually the state department or a local enforcing agency acting for it.

A unit of measure expressing the approximate waste-flow rate of a fixture, used to size drainage piping. One fixture unit equals roughly 1 cubic foot per minute, or about 7.5 gallons per minute.

A vertical pipe that carries the discharge of water closets and may also receive waste from other fixtures. It runs at least one story and connects at its base to the building drain.

The lowest piping of a drainage system that receives waste from inside the building and carries it to the building sewer. It ends at the exterior wall or foundation line.

The pipe that carries sewage from the building drain to the public sewer, private disposal system, or other point of disposal. It begins outside the building foundation and is usually the owner's responsibility.

An accessible fitting with a removable plug or cap that allows a drain to be opened for rodding and clearing stoppages. It is required at the base of stacks, at changes in direction, and at intervals along horizontal runs.

The downward pitch of horizontal drainage piping stated as fall per unit of run, such as one-quarter inch per foot. Proper slope lets solids travel with the flow and keeps the pipe scoured.

A device installed in a drain that stops sewage from flowing backward into a building when the public sewer surcharges. It stays open for normal flow and closes automatically when flow reverses.

A vertical vent pipe that supplies air to a soil or waste stack so trap seals are not siphoned out. It runs from the highest branch connection through the roof to open air.

The extension of a soil or waste stack above the highest fixture branch, carried through the roof to open air. It vents that stack only and is not a separate vent pipe.

A pipe that serves as both a drain for fixtures and a vent for other fixtures, such as a lavatory drain venting a nearby water closet. It must be sized and arranged within code limits.

A one-way mechanical device that admits air into a drainage system when negative pressure develops and seals shut to keep sewer gas inside the pipe. It must be listed and installed only where the code permits.

A single vent pipe connected to two fixture drains or traps on the same floor level. It must be sized for the combined fixture units of everything it serves.

A unit that estimates a fixture's probable demand on the water distribution system. Units are totaled and converted to gallons per minute when sizing pipe and meters.

The pipe that carries potable water from the water main, meter, or other source to the building. It ends where the building water distribution piping begins.

A device or assembly that keeps contaminated water from reversing into the potable supply. Common types include air gaps, reduced-pressure zone assemblies, and double check valve assemblies.

The unobstructed vertical distance between the lowest point of a water outlet and the flood level rim of the fixture it discharges into. It is the most reliable form of backflow protection.

A device containing an air or mechanical cushion, installed near a quick-closing valve, that absorbs the pressure surge causing banging and strain in piping.

A valve that lowers incoming water pressure to a safe value for the building distribution system and holds it fairly steady as supply pressure changes.

A safety valve on a water heater that opens when temperature or pressure exceeds its rating, releasing hot water or steam to prevent tank rupture. Its discharge must terminate in a safe, observable location.

A fixture set into the floor that collects spills and wash-down water and drains through a trap. It normally has a strainer and must keep a water seal between uses.

The depth of water held in a trap that blocks sewer gas from entering the building. It is measured from the crown weir of the trap to the top of the dip.

The pipe running from a trap outlet weir to its connection at a vent or stack. It must be limited in length and properly sloped so the trap can be cleared and the seal protected.

A device or piping arrangement that delivers a small amount of water to a floor drain trap to replace evaporation and keep the seal intact.

A plumbing appurtenance that separates and holds fats, oils, and grease from kitchen waste so they do not clog the drainage system. Clarified liquid flows out while grease floats and is pumped out.

Waste piping that discharges into a receptor through an air gap or air break instead of a direct connection, protecting potable water and food products from contamination.

The edge of a fixture or receptor from which water would overflow onto the floor. Air gaps, indirect waste connections, and fixture openings are all measured from this level.

A fitting set into a roof to collect rainwater and lead it into a leader or storm drain. It usually has a strainer and may include a flashing flange or overflow feature.

A pipe that carries rainwater, roof drainage, and surface water to a point of disposal. Sanitary or industrial waste may not be connected to it.

A pump, usually set in a pit, that lifts collected water from a low point and discharges it outside or to a storm drain so the space does not flood.

The measured distance along the actual centerline of a pipe run, including offsets, risers, and turns. It is used with slope and friction calculations to size piping correctly.

The length of straight pipe that produces the same friction loss as a given fitting or valve. Adding it to the developed length gives the total effective length used in sizing.

A pictorial plumbing drawing with the system shown in three dimensions on angled axes. It makes risers, offsets, and branch connections easier to read than a flat floor plan.

The safety gear a worker wears to prevent injury, such as safety glasses, gloves, hearing protection, hard hats, and respirators. It is the last line of defense after engineering controls.

A space large enough to enter that has limited access and is not meant for continuous occupancy, and that may contain a hazardous atmosphere. Entry may require testing, ventilation, an attendant, and a permit.

A test in which piping is filled with water and held under pressure while joints are checked for leaks. It is commonly required for drainage and water distribution systems before they are covered or placed in service.

A short capped pipe leg installed at thelowest point of gas piping near an appliance to catch dirt, scale, and pipe dope before they reach the burner controls.

The air a gas appliance needs to burn fuel safely. It must come from outdoors or from spaces sized by the code so burners do not starve, misfire, or produce carbon monoxide.

The passage or pipe that carries combustion gases from an appliance to the outdoors. It must be listed for the appliance, properly sized and sloped, and terminated where gases cannot re-enter the building.