Sanitary Sewer Pipe LayOut and Design Guidelines

This article is about technical specification, design notes of Sanitary Sewer Pipe LayOut and Design Guidelines of Plumbing System as per international codes and standards for plants and refinery projects.

Sanitary Sewer Pipe Layout and Design Guidelines

1. Acceptable material for gravity sewer piping :
   1. Underground (Hydrocarbon Handling areas)
      a) 80FEOD – RTR (fiberglass) Sewer Pipe and fittings – 01-SAMSS-029
      c) Resin-impregnated Tube (Cured-In-Place Pipe) – ASTM F1216 (For repair of existing system only).
   2. Acceptable pipe joints for underground gravity sewer in all areas other than Hydrocarbon Handling Areas and above ground sanitary sewers for all areas except as prohibited by other Saudi Aramco Engineering Standards:
      a) Materials as listed in A1.1 above.
      b) 80PVOD – PVC Pipe SASO SSA/14, Class 3.(300 mm ɸ or less)
      c) 80PVOD1 – PVC Pipe Schedule 40, ASTM D2665 & D3311
      d) High Density Polyethylene (HDPE) pipe liner – ASTM D3350
2. Acceptable pipe joints for underground gravity sewer in all areas other than Hydrocarbon Handling Areas and above ground sanitary sewers for all areas except as prohibited by other Saudi Aramco Engineering Standards:
   a) 80PVOD – PVC Pipe SASO SSA/14, Class 3.(300 mm ɸ or less) – Joints shall be solvent cemented per ASTM D2855 (cement as per ASTM D2564) or elastomeric ring gasket conforming to ASTM D3212.
   b) 80PVOD1 – PVC Pipe Schedule 40, ASTM D2665 & D3311 – Joints shall be solvent cemented per ASTM D2855 (cement as per ASTM D2564) or elastomeric ring gasket conforming to ASTM D3212.
   c) High Density Polyethylene (HDPE) pipe liner – ASTM D3350 – joints shall be butt fusion welded or socket fusion welded.
3. Sanitary sewers shall be continuously down hill, without low points or high points.
   Note: Slope shall be in accordance with Issued for Construction Drawings “
4. The minimum size of a Public Sewer shall be 200 mm nominal diameter.
5. Public Sewers shall be laid in straight lines between manholes
6. Pipes shall not reduce in the direction of flow
7. Only DWV (Drain, Waste & Vent) type fittings shall be used in gravity flow sewer systems
8. No elbows, wyes, or other fittings that change the direction of sewers between manholes shall be permitted.
9. The maximum distance between manholes for public sewers shall be 90 meters (295 ft)
10. There shall be no physical connection between a potable water supply system and a sewer or a junction that would permit the passage of any wastewater into the potable water supply
11. No portion of a sewer system and no discharge from a sewer system shall be located within 15 meters of any well, spring, or other source of potable water supply
12. Public sewers that are parallel to potable water lines shall be separated from such lines by a minimum distance of 3m and shall be located below the potable water lines.
13. A sewer crossing a potable water line shall be orientated such that the sewer crosses under the potable water line with a minimum vertical surface clearance of 300mm. Also see item below.
14. Minimum Horizontal separation distance between sewer lines and water system shall be as shown in the Table-1 below: ê
    .
15. Any one of the following requirements must apply to sewer piping that, due to existing conditions must cross over a potable water line regardless of vertical separation; and must have less than 300 mm clear separation even though running beneath the potable water line.
    a) The sewer piping crossing a potable water line shall be one continuous joint of pipe and both ends of that sewer pipe shall be at least 3 meters beyond the point of crossing.
    c) The sewer line shall be encased in a sealed casing of either steel sleeve, PVC or RTR pipe for a minimum distance of 3 meters, in both directions beyond the point of crossing.
16. Identification: Color coding of Sanitary Sewer Pipes
    1. Outside Sewage Treatment Plants
       1. All underground Sanitary Sewer Piping, shall be identified through the manhole covers. Color coding of the Manhole covers shall be as instructed / directed by the Utilities or Operations Department which ever has the jurisdiction.
       2. All above ground sanitary sewer piping shall have color identification band to designate the liquid being conveyed in accordance with Table 3 of SAES-A-104, SAES-B-067 and Saudi Aramco Sanitary Code, GI-0151.006 and the direction of normal flow shall be clearly shown at every 20 ft (6096 mm) intervals. Minimum length of color field and size of letter shall be in accordance with the table shown below:

          

    2. Within Sewage Treatment Plants
       All above and below ground sanitary sewer piping within the sewage treatment plant shall be color coded in accordance with the requirements of SAES-A-104, SAES-B-067 and Saudi Aramco Sanitary Code, GI-0151.006. Piping system shall be fully painted of the color coding.

       

International Codes and Standard References for Sanitary Sewer Pipe LayOut and Design

SAES-S-010 – Sanitary Sewers