Part 2.
Applicable Codes and Standards
The installation of all plumbing fixtures, appurtenances, piping works and/or connection
and fittings shall strictly follow the Revised National Plumbing Code (NPC) of the
Philippines. High quality material shall be used and with due respect, shall passed the
quality standards of various institution such as, of that of PNS, ASTM, ANSI, UL, ISO
and other institution acknowledge by the NPC.
* PNS – Philippine National Standard
* ASTM – American Society of Testing and Materials
*ANSI – American National Standard Institute
*UL – Underwriter’s Laboratory, Incorporated
* ISO – International Standard Organization, organization for standardization
Part 3. General Regulations
All plumbing fixtures devices and appurtenance shall be supplied with water in sufficient
volume and at adequate pressure to enable them to function satisfactorily and without
undue noise under all normal condition of use.
3.1. Grade of Horizontal Drainage Piping. All horizontal drainage pipes shall be run in
practical alignment and at uniform grade of 20mm depression per 1 m length or 2% slope
towards the point of disposal. Where it is impractical to achieve a 2% slope due to
structural and/or geological constraint any piping of 102mm or larger in diameter may
have a slope of 10mm per 1 m or 1% provided that it is first approved by the
administrative authority.
3.2. Changes in Direction of Drainage Flow. Changes in direction of flow of
drainage piping shall be made by the use of code approved fittings and shall be of angles
22 ½ degree bend, 45 degree bend, 60 degree bend or other approved fittings with longer
sweeps.
3.2.1 Horizontal lines to Vertical stack shall enter through 45O or 60O wye
branches, combination wye and 1/8 bend branches, sanitary tee or other approved
fittings of longer sweeps.
3.2.2. Horizontal to Horizontal drainage lines shall enter through 45O wye
branches, combination wye and 1/8 bend branches or other approved fitting of
longer sweep.
3.2.3. Vertical stacks to Horizontal lines shall enter through 45O branches or
other approved fittings of longer sweeps. 60 O bend branches or offsets may be
used only when installed in a true vertical position
3.3. Workmanship. All designs, construction and workmanship shall be in conformity
with the accepted plumbing practice as guided by the National Plumbing Code of the
Philippines. Cracks, holes and other imperfection found in the pipes shall not be
concealed by use of any paints, tar, wax or other sealing agents and such pipes shall not
be installed. Burred ends of all pipes and tubing shall be reamed to full bore and all chips
left shall be removed.
3.4. Prohibited Fittings. No Double hub fitting for lead caulked joint in vertical
position, single or double tee/tapped tee branches, side inlet quarter bend, running thread,
band or saddle shall be used as a drainage fitting.
3.5. Hangers and Support. Vertical and horizontal pipe shall be secured and supported
at close interval. All vertical plastic pipes shall be supported at every one meter interval
and all horizontal pipes not laid on ground shall be supported by stiff metal or wooden
backing with hangers.
3.6. Trenching. All excavation shall be completely backfilled as soon as possible after
inspection. Trenches shall be backfilled in thin layers of 30 cm above the top of the pipe
with clean earth.
3.7. Supervising Master Plumber. All plumbing works for this project shall be in
accordance with the approved plans under direct supervision and control of a Registered
Master Plumber.
3.8. Testing. Upon completion of the installation, the plumbing system shall be tested
from any leaks that may arise from fixture connections, valves and fittings in accordance
with the standards of the National Plumbing Code of the Philippines. Any leakage in the
piping system shall be corrected and it shall be the responsibility of the Supervising
Master Plumber to conduct these inspections, testing and corrections deemed necessary
2
for the full operation of the Plumbing system and for the approval/acceptance of the
administrative authority.
Part 4. Plumbing Fixtures
4.1. Materials. Plumbing Fixtures to be installed shall be manufactured of high quality
made of dense, durable, non-absorbent material and must have smooth impervious
surface free from unnecessary concealed fouling surfaces. All porcelain enamel surfaces
on plumbing fixtures shall be acid resistant. Water closet having invisible seals or
unventilated space or having walls that are not thoroughly washed out per discharge shall
not be used. All fixtures to be installed shall be in accordance with the ANSI, ASTM,
PNS Standards.
Sinks made up of galvanize steel sheets shall not be less that Gauge no. 16 U.S. B&S or
16mm thick. All floor drains shall be provided with an approved type strainer plate.
Shower receptors shall be made up of vitrified china, ceramic tile, porcelain enamel metal
or other equivalent material. Finished floor of receptor shall have a slope of 2%. Shower
receptor shall have an approved type and should be constructed to have finished curb,
threshold of at least 25mm lower than the outside floor. Threshold shall not be less than
51mm or more than 228mm.
Part 5. Water Supply and Distribution System
5.1. Requirements. Each plumbing fixture shall be provided with an adequate supply of
potable running water so as to flush and keep same in clean and healthful condition.
Cross connection shall be avoided.
5.2. Valves. Valves up to and including 51mm in size shall be brass or other approved
material. Valves over 51 mm may have cast iron or brass bodies. All gate valves to be
installed shall be full-way nrs, Check valve shall be swing type Tong Yung, Jaman
Eurobrass or other equivalent material/brand.
5.3. Piping. All water pipes shall not be run or laid in the same trench as the building
sewer or storm drainage piping. In cases where water pipes crossing over or are laid
above the sewer line, the bottom of water pipes at all points shall be at least 30 cm above
the top of the soil/waste pipe.
Water lines including downfeeds and risers shall be Polypropylene (PP) pipes and
fittings, PN-20 minimum rating jointing shall be done by socket fusion
“unpipe”/”vesbo” or other approved equal.
3
Part 6. Excreta Drainage System, Vent, Storm Drainage
6.1. Materials. Soil/Waste pipes and fittings should be series 1000 Polyvinyl Chloride
(PVC) pipe, Neltex PVC or other approved material having smooth and uniform bore.
Vent pipe and fittings shall be of series 1000 Polyvinyl Chloride PVC, PVC series 1000
II, Neltex Brand PVC or other approved equal. Jointing shall be done by solvent
cementing conforming to ASTM D2564. Rainwater downspout and storm drains shall be
series 1000 Polyvinyl Chloride PVC. Roof Drain shall be equipped with strainers
extending not less than 102mm above the surface of the roof.
6.2. Soil, Waste and Drain Change of Direction. Changes in direction for all waste and
soil pipe shall be in accordance with section 3.2 of this specification.
6.3. Cleanouts. Each horizontal drainage pipe shall be provided with a cleanout at its
upper terminal and each run of piping more than 15m. Each cleanout shall be installed so
it opens in the direction of flow to allow cleaning of soil/waste line. All 90 degree
cleanout shall be extended using a wye type fitting, 1/8 bends or other approved fitting of
equivalent sweep.
Cleanout in piping 51mm or less shall be installed so that there is a clearance of
not less than 305mm in front and for piping larger than 51mm shall have a
clearance of 0.45m in front.
6.4. Traps. Each plumbing fixture should be separately trapped by an approved water
seal trap. An exposed and readily accessible trap (not including integral traps) shall be of
standard P-trap made of ABS, brass, PVC or other approved material.
6.5 Vent Grades and Connection. All horizontal vent branches shall be free from drops
and shall be graded and connected to drip back by gravity to the drainage line it serves.
Each vent shall raise vertically to a point not less than 152mm above the highest flood
level rim of the fixture/s it serve before offsetting horizontally to join the vent stack.
All vent pipes shall extend undiminished in size above the roof. Each vent pipe or
stack shall terminate vertically not less than 15cm above the roof or less than
0.3m from any structure nearby and 0.9m away from window opening.
