Trap and Interceptors / Separators Installation Requirements

This article is about Trap and Interceptors / Separators Installation Requirements in commercial buildings, plants and refinery projects related to Plumbing Engineering System as per international codes and standards.

Trap and Interceptors / Separators Installation Requirements

Traps

1. Each plumbing fixtures trap, shall be protected against siphonage and backpressure and air circulation assured throughout all parts of the drainage system by means of vent pipes.
2. Each Plumbing fixtures, except those having integral traps shall be separately trapped by an approved type water seal trap. (UPC Para1001.1)
   Note: 1-Not more than one trap shall be permitted on a trap arm
   2- See item No. A3 in this SAIC for exception.
3. One trap may serve a set of not more than three single compartment sinks or laundry tubs of the same depth or three lavatories immediately adjacent to each other and in the same room if the waste outlets are not more than thirty inches apart and the trap is centrally located when three compartments are installed (UPC Para1001.2)
4. The vertical distance between a fixture outlet and the trap weir shall be as short as practicable, but in no case shall the tailpiece from any fixture exceed twenty-four (24) inches. (UPC Para 1001.4)
5. Each fixture trap, except shall have a protecting vent so located that the developed length of the trap arm from the trap weir to the inner edge of the vent shall be within the distance given in Table 10-1 as shown below ê, but in no case less than two times the diameter of the trap arm.
   Note: Slope one-fourth (1/4) inch per foot.

Table 10-1 – Horizontal Distance of Trap arms (Except four water closets and similar fixtures)

* The developed length between the trap of a water closet or similar fixture (measured from that top of the closet ring to the inner edge of the vent) and its vent shall not exceed six (6) feet.

1. The vent pipe opening from a soil or waste pipe, except for water closets and similar fixtures, shall not be below weir of the trap. (UPC Para 1002.4)
2. The size (nominal Diameter) of the trap for a given fixture shall be sufficient to drain the fixture, but in no case less than nor more than one pipe size larger than given in Table 7-3. See attachment No. 1 (UPC Para 1003.3).
3. The trap shall be the same size as the trap arm which it is connected to. (UPC Para 1003.3)
4. Each fixture trap shall have a water seal of not less than two (2) inches and not more than four (4) inches.
   Exception: Deeper seal shall be provided if found necessary by the Chairman of Plumbing and Utilities standards Committee for special conditions or for special design relating to handicapped accessible fixtures (UPC Para 1005.0).
5. Trap used in pressurized buildings shall have a minimum trap seal of 4 inches
6. Floor drains or similar traps directly connected to the drainage system and subject to infrequent use shall be provided with an approved (acceptable to the Authority Having Jurisdiction) automatic means of maintaining their water seal, except where not deemed necessary by Chairman of Plumbing and Utilities standards Committee (UPC Para1007.0).
7. When Automatic trap priming are installed, they shall be accessible for maintenance (UPC Para1007.0)
8. No tubing trap shall be installed without a listed tubing trap. (UPC Para 1003.2)
9. Drawn brass tubing traps shall not be used for urinals. (UPC Para 1003.1)
10. No traps which has concealed interior partitions, except those of plastic, glass, or similar corrosion resistant material, shall be used (UPC Para 1004.0).
11. No plumbing fixture shall be double trapped.
12. No trap shall be installed without vent.
13. S-traps, bell traps, and crown vented traps shall be prohibited. (UPC Para 1004.0)
    Note: Drum & Bottle traps may be use only when permitted and approved for special conditions by the Chairman of the Plumbing & Utilities Standard Committee.
14. Building traps shall not be installed except where required and approved by the Chairman of the Plumbing & Utilities Standard Committee. Each building Trap when installed shall be provided with a cleanout and with a relieving vent or fresh air intake on the inlet side of the trap which need not be larger than one-half the diameter of the drain to which it connects. Such relieving vent or fresh air intake shall be carried above grade and terminate in a screened outlet located outside the building.

Interceptors (Clarifiers) and Separators

1. Interceptors (Clarifiers) including grease, oil and sand interceptors shall be provided when they are deemed necessary for the proper handling of liquid wastes, containing grease, flammable waste, sand, solids, acid or alkaline substances or other ingredients harmful to the building drainage system.
2. The size, type and location of the interceptor or separator shall have prior approval from the Chairman of the Plumbing & Utilities Standard Committee except where otherwise specifically permitted, no waste other than those requiring treatment or separation shall be discharge into any interceptor (clarifier).
3. Interceptors (clarifiers) shall be properly vented.
4. “Interceptors (clarifiers) covers shall be readily accessible for servicing and maintaining the interceptor (clarifier) in working and operating condition.
   Note: Use of ladders or the removal of bulky equipment in order to maintain or service the interceptors (clarifiers) shall constitute a violation of accessibility.

International Codes and Standard References for Trap and Interceptors / Separators Installation

1-SAES-S-060 – Saudi Aramco Plumbing Code.
2-Uniform Plumbing Code (UPC).

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