Wastewater Conveyance - Wastewater Operators - page 175

4.9.1.2.4.1 Safe Work Practices for a-C Pipe
1. When repairs or modifications are conducted that require cutting,
sanding, or grinding on cement pipe containing asbestos, USEPA-
trained asbestos workers or supervisors are to be called to the work
site immediately .
2. Excavation personnel will unearth buried pipe to the point neces-
sary to make repairs or modifications. The immediate work area
will then be cleared of personnel as directed by the asbestos-trained
super visor.
3. The on-scene supervisor will direct the asbestos-trained workers
as required to accomplish the work task.
4. The work area will be barricaded 20 feet in all directions to prevent
unauthorized personnel from entering.
5. Asbestos-trained personnel will wear all required personal pro-
tective equipment (PPE). Required PPE includes Tyvek ® totally
enclosed suits, half-face respirators equipped with HEPA filters,
rubber boots, goggles, gloves, and hard hats.
6. Supervisors will perform the required air sampling before entry.
7. Air sampling must be conducted using the NIOSH 7400 protocol.
8. A portable decontamination station will be set up as directed by the
supervisors.
9. Workers will enter the restricted area only when directed by the
supervisors and, using wet methods only , will either perform pipe
cutting using a rotary cutter assembly or inspect the broken area
to be covered with a repair saddle device.
10. After performing the required repair or modifications, workers will
encapsulate bitter ends and fragmented sections.
11. After encapsulation, the supervisor can authorize entry into the
restricted area for other personnel.
12. Broken ACM pipe pieces must be properly disposed of following
EPA, state, and local guidelines.
Note: Although exposure to asbestos fibers is dangerous, it is important
to note that studies by the USEPA, AWWA, and other groups have con-
cluded that the asbestos in water mains does not generally constitute a
health threat to the public (AWWA, 1996).
Because A-C pipe is strong and corrosion resistant, it is widely
used for carrying water and wastewater. Standard sizes range from 3
to 36 inches. Although highly resistant to corrosion, A-C pipe should
not be used for carrying highly acid solutions or unusually soft water,
unless its inner and outer surface walls are specially treated. A-C pipe
is preferred for use in many outlying areas because of its light weight,
which offers greater ease of handling. An asbestos-cement sleeve joins
A-C pipe. The inside diameter (I.D.) of the sleeve is larger than the out-
side diameter (O.D.) of the pipe. The ends of the pipes fit snugly into the
sleeve and are sealed with a natural or synthetic rubber seal or gasket,
which acts as an expansion joint.