This article is about Indirect Waste Piping Installation Requirement in commercial buildings, plants and refinery projects related to Plumbing Engineering System as per international codes and standards.
Indirect Waste Piping Installation Requirement
- The following piping material shall be used for Indirect waste:
1-Schedule 40 PVC DWV
2-Copper with DWV fittings
3-Cast iron with DWV fittings (UPC Para 701.1)
Note: See item No. A17 in this SAIC for pipes receiving corrosive chemical and acids. - Copper tube shall not be used for chemical or industrial waste. (UPC Para 811.1).
- All indirect waste piping shall discharge into the building drainage system through an air gap or air break. (UPC Para 801.1)
- Minimum vertical distance (air gap) as measured from the lowest point of the indirect waste pipe or the fixture outlet to the flood level rim of the receptor shall be less than 1 inch. (UPC Para 801.1)
- The minimum size of the indirect waste pipe shall not be smaller than the drain of on the unit, but shall not be smaller than one inch and the maximum develop length shall not exceed 15 feet (4572 mm). (UPC 801.2.1)
Exception: Refrigeration coils. Also see item No. 6 in this checklist. - Indirect waste pipe for ice making machine, shall not be less than the drain of the unit, but shall not be less than 3/4″. (UPC 801.2.1)
- For Walk-in coolers, floor drain may be connected to a separate drainage line discharging into an outside receptor.
- The flood level rim of the receptor shall be a minimum of six (6) inches (152 mm) lower than the lowest floor drain.
- Such floor drain shall be trapped and individually vented.
- Clean-outs shall be provided at every 90° turn and shall be accesibly located.
- Drains, overflow or relief pipes from potable water pressure tanks, water heaters, boilers, and other similar equipment connected to a water distribution system shall have an indirect waste connection by means of an airgap or airbreak into an approved receptor.
- No vent from indirect waste piping shall combine with any sewer connected vent. (UPC Section 803.0)
- Vent from indirect waste drain shall not combined with any sewer connected vent but shall extend separately to the outside air. (UPC Section 803.0).
- Indirect waste pipe exceeding five feet but less than fifteen feet in length shall be directly trapped, but such traps need not to be vented. (UPC Section 803)
- “Indirect waste pipe less than fifteen (15) feet in length shall not be less than the diameter of the drain outlet or tailpiece of the fixture, appliance, or equipment served, and in no case less than one-half (1/2) inch in size (UPC Section 803) . Also see item No. A15 in this SAIC.
- No portion of the drainage system underground or below a floor slab, basement or cellar shall be less than 2 in (50 mm OD) nominal diameter.
- Angles and changes of direction in indirect waste pipes shall be provided with cleanouts. (UPC Section 803)
- Drain piping for condensate waste from air conditioning cooling coils shall be indirectly connected to a floor drain, or shall be indirectly connected into the inlet side of a P-trap
- Drinking Fountains that are not manufactured with an integral air gap drain shall be installed with an indirect wastes.
- Pipes from boilers shall discharge by means of indirect waste. (UPC Para 810.1)
- Every indirect waste interceptor receiving discharge containing particles that would clog the receptor drain shall have a readily removable beehive strainer. (UPC Para 810.4)
- Each waste pipe and fitting receiving, or intended to receive, any acid or corrosive chemical shall be constructed of the following chemical resistant material:
a) Chemical resistant Borosilicate Glass pipe and fittings DWV, ASTM C1053 – 90,
b) Corrosion Resistant High Silicon Iron pipe and fittings DWV, ASTM A861 and ASTM A518 (for example Duriron Silicon Pipe),
c) Other corrosion resistant materials such as Schedule 40 PVC DWV, where no hydrocarbon or solvent wastes are present, and the temperature of the waste does not exceed 50°C (120°F) and Schedule 40 Polypropylene DWV, where temperature of the waste does not exceed 50°C (120°F) may be used upon written approval of the Chairman of Plumbing and Utilities Standards Committee prior to purchase of the material in question” - No chemical vent shall intersect vents for other services. (UPC Para 811.6)
- No acid or chemical wastes shall be discharged into the ground or local sewer without approval of the Chairman of Plumbing and Utilities Standards Committee.
- In remote areas where no sewer or drainage lines are close by, the waste system shall have primed traps and piped to a dry sump. The system shall be vented.
International Codes and Standard References for Indirect Waste Piping
1- SAES-S-060 – Saudi Aramco Plumbing Code.
2- Uniform Plumbing Code (UPC).
Hangers and Supports Selection & Material Inspection Checklist
Control Wire Installation with mainline pipe for Plumbing System
Electric Water Heater Installation & Piping Connection