04_sanitary drainage system

7/28/2019 04_sanitary Drainage System

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1BUILDING UTILITIES 1: PLUMBING

SANITARY DRAINAGE SYSTEM

GENERAL RULES IN DESIGNING THE SANITARY SYSTEM

The pipes should take the shortest possible route to the house sewer or the terminating point ofthe sanitary system

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

SUBSYSTEMS OF SANITARY DRAINAGE SYSTEM

1.Waste Collection System2. Ventilation System

ESSENTIAL PARTS

WASTE PIPE

Conveys only wastewater or liquid waste free of fecal matter.

VENT PIPE

used for ensuring the circulation of air in a plumbing system and for relieving the negative pressure

exerted on trap seals.

TRAP

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.

STACK

The vertical main of a system of soil, waste or vent pipings extending through one or more stories and

extended thru the roof.

BRANCH

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

HOUSE/ BUILDING DRAIN

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 SEWER

Extends from the house drain at a point 0.60 meters from the outside face of the foundation wall of a

building to the junction with the street sewer or to any point of discharge, and conveying the drainage

of one building site.

CHANGES IN DIRECTION IN SANITARY DRAINAGE LINES

Horizontal to horizontal change

use 45 wye branches, combination wye 1/8 bend branches, or other approved fittings ofequivalent sweep

Vertical to horizontal change

45 wye branches or other approved fittings of equivalent sweepHorizontal to vertical change of direction

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

No fitting having more than one inlet at the same level shall be used (i.e., sanitary cross) Double sanitary tees may be used when the barrel of the fitting is at least two pipe (2) sizes

larger than the largest inlet, (pipe sizes recognized for this purpose are 51, 64, 76, 89, 102, 114,

127, & 152 mm dia.)


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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 0.47 liters/sec or 28.3 liters/min (7.5 gallons per min or 1 cu ft per min), which is

equivalent to the Fixture Unit (F.U.)

The F.U. rating of plumbing fixtures is based on the size of required trap.

Minimum slope of sanitary drainage lines

Minimum slope or pitch of horizontal drainage pipe 2% or 20mm/m ( 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 1% or

10mm/m (1/8 per foot), approved by the Administrative Authority


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TRAPS REQUIRED

Each plumbing fixture, except those with integral traps, shall be separately trapped with anapproved-type water seal trap.

Only one trap shall be permitted on a trap arm (portion of a fixture drain between a trap andthe vent)

One trap, centrally located, may serve three single compartment sinks or laundry tubs orlavatories, adjacent to each other and in the same room, where their waste outlets are not

more than 0.75 m apart.

The trap shall be the same size as the trap arm to which it is connected. Each fixture trap shall have a trap seal of water of not less than 51 mm and not more than 102

mm (except where a deeper seal is found necessary by the Administrative Authority for special

conditions.

04_sanitary drainage system

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