Illustrated Plumbing Code Study Notes

HISTORY OF PLUMBING PRACTICE IN THE PHILIPPINES

• 17th Century Origins: The plumbing profession began with the establishment of Intramuros (The Walled City) by the Spaniards. Friar Engineers incorporated European standards into government and residential buildings.

• 18th and 19th Centuries: Filipino plumbers maintained, repaired, and remodeled systems in "pueblos" (towns), including churches and convents. Skilled plumbers acted as consultants for the "ilustrados" (elite) in villas and mansions.

• 20th Century Transition: Plumbing advanced significantly with the arrival of American soldiers, engineers, and Thomasite teachers. Health and hygiene became a priority due to epidemics like cholera and leprosy.

• Recognition and Regulation (1902): Governor General Harrison issued instructions for waste disposal. John F. Hass became the first Chief of the Division of Plumbing Construction and Inspection in Manila.

• NAMPAP Foundation (1935): The National Master Plumbers Association of the Philippines was organized and registered with the SEC. Founding members included Francisco Geronimo, Mariano de Ocampo, Igmidio Suarez, Eusebio Mina, Jose Rivera, Raymundo Reyes, Sr., Roberto Feliciano, Gregorio Lazaro, Raymundo Gumapac, John Jones, Trinitario Ortiz, Valentin Casupanan, Catalino Casupanan, Crispin Francisco, Teodoro Pastor, Cornelio Odvina, and Jesus Tanghal Dera.

• Plumbing Law (R.A. 1378): Initiated by NAMPAP, House Bill No. 962 was approved and signed by President Ramon Magsaysay on June 18, 1955. This became the "Plumbing Law of the Philippines."

• Post-Law Developments:

  • January 28, 1959: National Plumbing Code of the Philippines promulgated.

  • 1966–1969: Curriculum for Plumbing Engineering introduced at Feati University.

  • November 28, 1967: First Amendment included "Asbestos Cement Pipe" as an approved material.

  • December 21, 1999: President Joseph Estrada approved the Revised National Plumbing Code, spearheaded by NAMPAP President Jaime M. Cabase and the Board of Master Plumbers chaired by Engr. Fortunato H. Amosco.

BASIC PRINCIPLES OF THE 1999 NATIONAL PLUMBING CODE

• Principle No. 1: All human habitations must have pure and wholesome water, disconnected from unsafe supplies and protected from backflow/back-siphonage.

• Principle No. 2: Fixtures must receive water in sufficient volume and pressure to function satisfactorily without undue noise.

• Principle No. 3: Plumbing must use the minimum quantity of water consistent with performance and cleaning.

• Principle No. 4: Water heating/storing devices must prevent explosion dangers from overheating.

• Principle No. 5: Buildings on premises abutting a public sewer must be connected to that sewer.

• Principle No. 6: Family dwellings on sewers must have at least one water closet, one kitchen sink, a lavatory, and a bathtub/shower.

• Principle No. 7: Fixtures must be made of smooth, non-absorbent material, free from concealed fouling surfaces, and located in ventilated enclosures.

• Principle No. 8: Drainage systems must prevent fouling/clogging and include adequate cleanouts.

• Principle No. 9: Piping must be NAMPAP-approved durable materials, constructed by Registered Master Plumbers.

• Principle No. 10: Fixtures directly connected to drainage must have a water-sealed trap.

• Principle No. 11: Systems must provide air circulation to prevent siphonage or forcing of trap seals.

• Principle No. 12: Vent terminals must extend to the outer air to prevent clogging and foul air return.

• Principle No. 13: Systems must be tested for leaks and workmanship defects.

• Principle No. 14: No substance that clogs pipes, causes explosions, or destroys joints shall enter the building drainage system.

• Principle No. 15: Protection against contamination of food/water by backflow of sewage must be provided.

• Principle No. 16: No water closet shall be in a room lacking proper light and ventilation.

• Principle No. 17: If no sewer is available, sewage must be disposed of via septic tank or other treatment.

• Principle No. 18: Systems subject to sewage backflow must have provisions to prevent overflow.

• Principle No. 19: Maintenance must be performed by Registered Master Plumbers.

• Principle No. 20: Fixtures shall be properly spaced and accessible.

• Principle No. 21: Installation must preserve structural strength and prevent damage to walls/surfaces.

• Principle No. 22: Sewage deleterious to waters shall not be discharged into ground or waterways without treatment.

MASTER PLUMBER’S CODE OF ETHICS

• Prohibited Acts: A Registered Master Plumber shall not:

  1. Act unprofessionally or demand remuneration beyond the contract.

  2. Supplant another plumber already commissioned for a contract.

  3. Underbid another plumber after learning their charged fee.

  4. Use a salaried government position to compete unfairly.

  5. Allow license use by an unlicensed person without personal supervision.

  6. Falsely injure the reputation of another plumber; work reviews are only allowed if the previous plumber's services are terminated and fees paid.

  7. Use self-laudatory advertising or engage in practices dishonoring the profession or NAMPAP.

CHAPTER 1: ADMINISTRATION

• Permit Requirements: It is unlawful to perform plumbing work without a permit from the Office of the Building Official. Permits are issued only to Registered and Licensed Master Plumbers.

• Application for Permit: Must include technical specifications, bills of materials, and six (6) sets of plans/specifications prepared, signed, and sealed by a Registered Master Plumber.

• Validity and Expiration: Permits expire if work does not commence within one (1) year of issuance or if work is suspended/abandoned for $120$ days.

• Renewal: Requires a fee equal to one-half the original permit fee.

• Inspections: No portion of the system shall be concealed until inspected. Request for inspection must be filed at least three (3) working days prior. Final inspection is mandatory upon completion.

• Standard Seal (Section 107): Round seal inscribed with name, registration number, and "Registered and Licensed Master Plumber."

CHAPTER 2: SELECTED DEFINITIONS

• Air Gap (Drainage): Unobstructed vertical distance through the atmosphere between the waste pipe opening and the flood level rim of the receptor.

• Backflow: Reverse flow of liquids into the distribution pipes of a potable water supply.

• Battery of Fixtures: Two or more similar adjacent fixtures discharging into a common horizontal soil or waste branch.

• Building Drain: Lowest horizontal piping receiving discharge from soil/waste pipes, conveying it to the building sewer beginning $0.6\,m$ outside the building wall.

• Fixture Unit: Arbitrary quantity where $1\,FU$ is equivalent to a rate of flow of $28.3\,L/min$ ($1\,cu.\,ft./min$).

• Potable Water: Water satisfactory for drinking and domestic use, meeting the Philippine National Standards for Drinking Water.

• Trap Seal: Vertical distance between the dip and crown weir of a trap, usually between $51$ and $102\,mm$.

• Wet Vent: A portion of a vent pipe through which wastewater also flows.

• Yoke Vent: A pipe connecting upward from a soil/waste stack to an adjacent vent stack to prevent pressure changes.

CHAPTER 3: GENERAL REGULATIONS

• Grade of Horizontal Piping:

  • Standard: $2\%\,slope$ ($20\,mm/m$).

  • Exception: For pipes $102\,mm$ or larger, a slope of $1\%\,slope$ ($10\,mm/m$) may be approved if $2\%$ is impracticable.

• Connections: Rainwater drains (roofs, inner courts) must discharge outside the building and shall not connect to soil/waste systems.

• Prohibited Practices:

  • Drilling/tapping of drainage/vent piping is forbidden.

  • No waste connection allowed to a closet bend or stub.

  • No structural member shall be weakened by cutting/notching.

• Support for Vertical Piping:

  • Cast Iron: Every storey.

  • Screwed Pipe (IPS): Every other storey.

  • Copper Tubing: Each storey or max $3\,m$ intervals.

  • Lead Pipe: Max $1.20\,m$ intervals.

  • Plastic Pipe: Every $1\,m$ interval.

• Trenching: Tunnels must have clear height of $0.6\,m$ above pipe; max length $2.4\,m$. Backfill must be in thin layers of $0.3\,m$ with clean earth.

CHAPTER 4: PLUMBING FIXTURES

• Materials: Must be dense, durable, and non-absorbent. Porcelain enamel must be acid-resistant. Water closets for public use must be elongated type with open-front seats.

• Installation Spacing:

  • Water closet/bidet: Min $0.375\,m$ from center to side wall; $0.75\,m$ center-to-center.

  • Urinal: Min $0.3\,m$ from center to wall; $0.6\,m$ center-to-center.

• Shower Compartments: Min interior area of $0.6\,sq.\,m$; must encompass a $762\,mm$ diameter circle. Finished dam/curb must be at least $25.4\,mm$ lower than outside floor (minimum depth $51\,mm$, max $228\,mm$).

• Floor Drains: Area of small holes in strainer must equivalent to the cross-sectional area of the tailpiece.

CHAPTER 5: INSPECTION AND TEST

• Water Test: Applied to drainage/vent system in entirety or sections. Min head for sections is $3\,m$. Water must remain for $15\,minutes$.

• Air Test: Uniform gauge pressure of $34.5\,kPa$ or enough to balance $254\,mm$ of mercury for $15\,minutes$.

• Water Piping Test: Hot/cold systems tested at working pressure plus $50\%$. A $344.5\,kPa$ air pressure may be substituted.

• Shower Receptor Test: Fill with water to the level of the rough threshold to ensure watertightness.

CHAPTER 6: WATER SUPPLY AND DISTRIBUTION

• Pressure Thresholds:

  • Min Pressure: $103\,kPa$ (after losses). If lower, use a booster pump/tank.

  • Max Pressure: If local pressure exceeds $551\,kPa$, an approved regulator must be installed to reduce building pressure.

• Cross-Connection Control: Potable water outlets with hose attachments must have a non-removable hosebibb-type backflow preventer or atmospheric vacuum breaker (AVB) $152\,mm$ above usage point.

• Air Gaps (Table 6-1):

  • Effective opening $≤ 13\,mm$: $25\,mm$ gap (unaffected by walls).

  • Effective opening $≤ 19\,mm$: $38\,mm$ gap.

  • Effective opening $≤ 25\,mm$: $51\,mm$ gap.

• Relief Valves: Must be set at max $1033\,kPa$. Drains must be $152\,mm$ to $0.6\,m$ above ground.

• Materials: Copper water supply piping must be at least Type "L". Lead content in pipes/fittings must not exceed $8\%$.

CHAPTER 7: EXCRETA DRAINAGE SYSTEM

• Materials: Cast iron, ductile iron, galvanized steel (above ground only; min $152\,mm$ above ground), PVC (Series 1000).

• Cleanouts: Required at upper terminal and every $15\,m$ of horizontal piping. Clearance required: $305\,mm$ for pipes $≤ 51\,mm$, and $0.45\,m$ for larger pipes.

• Backwater Valves: Required for fixtures with flood level rims below the nearby upstream manhole invert.

• Pumping/Ejecting: Min pump discharge for sumps with water closets is $50.8\,mm$ diameter.

CHAPTER 11: STORM DRAINAGE SYSTEM

• Sizing Methodology: Slashed vertical rainwater piping is based on rainfall depth in $mm/hr$ and roof area. Manila standard is often $102\,mm/hr$.

• Vertical Wall Areas (Adjustment):

  • One wall: Add $50\%$ of wall area to roof area.

  • Two adjacent walls: Add $35\%$ of total wall areas.

  • Walls on 3 sides: Add $50\%$ of inner wall below the lowest wall top.

• Roof Drains: Must have strainers extending $≥ 102\,mm$ above surface. Dome-type strainers need inlet area $1.5 \times$ the outlet pipe area.

CHAPTER 12: HOUSE DRAINS AND HOUSE SEWERS

• Sewer Availability: A public sewer is "available" if within $61\,m$ of the lot/building.

• Sizing Building Sewer: Min diameter $150\,mm$; never smaller than the building drain.

• Horizontal Distances (Table 12-1):

  • Sewer to Building: $0.6\,m$.

  • Sewer to Property Line: Clear.

  • Sewer to Water Wells: $15.2\,m$.

  • Sewer to Domestic Water Line: $0.3\,m$.

• Abandonment: Abandoned sewers/septic tanks must be removed of sewage and filled with earth/sand/gravel. Plugged/capped within $1.5\,m$ of property line.

CHAPTER 13: JOINTS AND CONNECTIONS

• Caulked Joints: Oakum/hemp packed and filled with molten pig lead to depth of $≥ 25.4\,mm$.

• Threaded Joints: Standard taper pipe threads. Plastic threads must be Schedule 80 min wall thickness.

• Solder/Sweat Joints: Flux must be noncorrosive. Solder lead content prohibited over $0.2\%$ for potable water.

• Wiped Joints: Surface on each side of joint must be $≥ 19\,mm$.

• Expansion Joints: Must be accessible; used in soil/waste stacks of high-rise buildings.

APPENDIX B: PRIVATE SEWAGE DISPOSAL SYSTEMS

• Septic Tank Capacity (Table B-2):

  • 1 or 2 Bedrooms: $750\,gallons$ ($2838\,L$).

  • 3 Bedrooms: $1000\,gallons$ ($3785\,L$).

  • Extra bedroom: Add $567.8\,L$.

• Construction Details:

  • Min compartments: Two (2).

  • Inlet compartment: $2/3$ of total capacity; min $2\,cu.\,m$ volume; min width $0.9\,m$, length $1.5\,m$.

  • Liquid depth: $0.6\,m$ to $1.8\,m$.

  • Secondary compartment: Min $1\,cu.\,m$; max $1/3$ total capacity.

• Percolation Test: Required for questionable soils to determine absorption qualities.

• Disposal Fields: Trench bottom calculation: Min $14\,sq.\,m$. No excavation within $1.5\,m$ of the water table.