Lesson 11 : Sanitary Piping Layout

General Rules in designing

the Sanitary system:

The pipes should take the shortest possible route to the house sewer or the terminating point of the Sanitary system

Control components such as clean-outs, traps, and vents, should be located strategically so as to ensure efficient circulation

Subsystems of the Sanitary System:

Waste Collection System

Ventilation System

conveys only wastewater or liquid waste free of fecal matter.

Waste Pipe

used for ensuring the circulation of air in a plumbing system and for relieving the negative pressure exerted on trap seals.

Vent Pipe

a fitting or device designed and constructed to provide, when properly vented, a liquid seal which prevents the backflow of foul air or methane gas without materially affecting the flow of sewage or wastewater through it.

Trap

the vertical main of a system of soil, waste or vent pipings extending through one or more stories and extended thru the roof.

Stack

any part of the piping system other than a main, riser or stack.

Branch

part of the lowest horizontal piping of a plumbing system which receives the discharges from the soil, waste and other drainage pipes inside of a building and conveys it to the house sewer outside of the building.

House/Building Drain

__________________ extends from the house drain at a point ____meters from the ___________________________ to the junction with the street sewer or to any point of discharge, and conveying the drainage of one building site.

House/Building Sewer

0.60meters

outside face of the foundation wall of a building

use 45° wye branches, combination wye - 1/8 bend branches, or other approved fittings of equivalent sweep

Horizontal to Horizontal change in direction

45° wye branches or other approved fittings of equivalent sweep

Vertical to Horizontal change in direction

use 45° or 60° wye branches, combination wye -1/8 bend branches, sanitary tee or sanitary tapped tee branches, or other approved fittings of equivalent sweeps.

Horizontal to vertical change in direction

Horizontal to vertical change in direction

No fitting having more than _______________ shall be used (i.e., sanitary cross)

one inlet at the same level

Horizontal to vertical change in direction

Double sanitary tees may be used when the barrel of the fitting is at least ___________________________, (pipe sizes recognized for this purpose are 51, 64, 76, 89, 102, 114, 127, & 152 mm dia.)

at least two pipe (2) sizes larger than the largest inlet

UNIT OF MEASUREMENT OF SIZES OF SANITARY DRAINAGE LINES

The size of waste pipes or soil pipes depend on the amount of waste it carries.

A lavatory discharges _____ liters/sec or _____ liters/min (____

gallons per min or __ cu ft per min), which is equivalent to the Fixture Unit (F.U.)

0.47 liters/sec

28.3 liters/min

(7.5 gallons per min or 1 cu ft per min),

The F.U. rating of plumbing fixtures is based on ______________________________

the size of required trap.

Minimum slope or pitch of horizontal drainage pipe is

2% or 20mm/m (¼" per foot).

Exception: Where it is impracticable due to depth of street sewer, adverse structural features and irregular building plans, pipes 102 mm dia or larger may have a slope of not less than _________________________, approved by the Administrative Authority

1% or 10mm/m (1/8" per foot)

Fixture unit is equal to ____ cu.ft (____ cu.m) of water drained in a _____ inches diameter pipe over one minute.

1 cu.ft./0.028cu.m.

1 1/4 inches (32mm)

1 cu.ft = ____ US gallons ( ___ L/min)

7.48 US gallons (28.3L/min)

Also called drain fixture unit (DFU), a unit of meausre based on the rate of discharge, time of operations and frequency of use of a fixture that expresses the hydraulic load imposed by that fixture on the sanitary plumbing installation.; Not a flow rate but a design factor for both water supply and waste water

Fixture Unit