House drain part of the lowest horizontal piping of a

HOUSE DRAIN - part of the lowest horizontal piping of a plumbing system
which receives the discharge from soil, waste, and other drainage pipes
inside of a buildings conveys it to the house sewer.
HOUSE STORM SEWER - A house storm sewer is the pipeline from the
building to the public storm sewer system.
INDIRECT WASTE PIPE - A waste pipe that does not connect directly with
the building drainage system but discharges into is through a properly
trapped fixture or receptacle.
INDIVIDUAL VENT - See back vent.
INDUSTRIAL WASTES - Industrial waste are liquid waste resulting from the
processes employed in industrial establishments and are free from fecal
matter.
INSANITARY - Contrary to sanitary principles or injurious to health.
INTERCEPTOR - A receptacle designed and constructed to intercept or
separate, and prevent the passage of oil, grease, sand, or other materials
into the drainage system to which it is directly or indirectly connected.
INVERT - The lowest portion of the inside of any pipe conduit that is not
vertical.
LATERAL - In plumbing, a secondary pipe line. In average, a common
sewer to which no other common sewer is tributary, receives sewage only
from building sewers.

LATRINE - A water closet consisting of a continuous though containing
water. The
trough extends under two (2) or more adjacent seats. Prohibited by most
authorities
for permanent installations.
LAVATORY - A fixture designed for the washing of the hands or face.
Sometimes called a wash basin.
LEACHING CESSPOOL - A cesspool that is not watertight.
LEADER - See conductor.
LENGTH OF PIPE - The length as measured along.
LOCAL VENT - A pipe or shaft serving to convey foul air from a plumbing
fixture or a room to the outer air.
LOOP OR CIRCUIT VENT - A continuation of a horizontal soil or waste pipe
beyond the connection at which liquid wastes from a fixture or fixtures
enter the waste or soil pipe. The extension is usually vertical immediately
beyond its connection to the soil or waste pipe. The base of the vertical
portion of the vent may be connected to the horizontal portion of the soil
or waste stack between fixtures connected thereto.
MAIN - The main of any system of continuous piping is the principal artery
of the system, to which branches may be connected.
MAIN VENT - See vent stack.
MANHOLE - An opening constructed in a sewer or any part of a plumbing
system of sufficient size for a man to gain access thereto.
MASTERPLUMBER - A person with knowledge of and experience in
plumbing who employs journeymen plumbers or who conducts a plumbing
business.
OAKUM - Hemp or old hemp rope soaked in oil to make it waterproof.
OCCUPANCY - Occupancy is the purpose for which a building is used or
intended to be used. The term shall also include the building or room
housing such use. Change of Occupancy is not intended to include change
of tenants or proprietors.