The proper name for it is "Asbestos-Cement", or simply "A-C" pipe, but it is also commonly called by its manufacturer JM's brand name - "Transite" pipe.

A-C pipe is present under most commercial and industrial sites.  Typically buried at a depth of 2 to 7 feet, A-C pipe was installed and used for a number of purposes:

1. Electrical and Telephone Conduit.  Typically 2"-6" O.D. (outer diameter), A-C conduit lines can typically be found embedded in large blocks of concrete, which can make excavation and disposal challenging.
2. High Pressure Fresh Water Line.  Sizes will range from 12" O.D. (main lines) to 4" O.D. (service lines).  Tees and elbows are often embedded in concrete thrust blocks.
3. Sewer Lines.  A-C pipe is a common way to move sewage from homes to the wastewater treatment plant, via 4" service lines connecting to a main line of 24" or more.

In southern California, the South Coast Air Quality Management District (AQMD) now requires that ALL A-C pipes must be excavated and removed in accordance with an approved "Procedure 5" (or simply "P5") application.  The P5 must be prepared by a California certified asbestos consultant (CAC) and must accurately describe a plan to excavate, expose, remove, wrap and dispose of A-C pipe wherever it is found.  Typically, this process will require approximately 3 weeks to complete, including the 2-week notification period to the AQMD.

Sometimes the A-C pipe must be removed or cut immediately, to repair a leak for example.  In such cases, the AQMD will consider an "emergency response" request. This can also be drafted by the CAC but must be submitted on the Owner's letterhead, along with Procedure 5 submittal and the Contractor's AQMD notification form. 

Although the "Procedure 5" request is required for any asbestos material that has been unintentionally disturbed, it is most commonly used to effect the excavation and removal of known A-C pipe.  Ellis typically prepares 3 - 5 A-C-pipe-related P5 requests each month.

On large grading or excavation projects, the AQMD will also consider extending a single, approved P5 notification for a maximum 6 months.