【国外标准】 Standard Practice for Cleaning of Vitrified Clay Sanitary Sewer Pipelines

4.1 Hydraulic cleaning methods include equipment that uses water and water velocity to clean the invert and walls of the vitrified clay sewer pipe.4.2 The practice of high-velocity sewer cleaning is best described as a hydraulic cleaning method that uses water pressure to remove obstructions and deposits in sewers or storm drains.4.3 There are different configurations of high-velocity sewer cleaning machines. These units have the capability of generating variable water pressures up to 3500 psi (24 MPa) and variable flow rates of 50-125 gal per min (gpm) (180-473 L per min).4.4 The water tank capacity on these units varies from 1000-1500 gal (3785-5678 L).4.5 The hose lengths vary between 500 and 1000 ft (152 and 305 m) in length with a diameter of 3/4- 11/4 in. NPT.4.6 There are number of different nozzles and tools that may be used during the cleaning process.4.7 Some high-velocity sewer cleaners have a vacuum conveyance system that use large fans or positive displacement vacuum pumps for material removal capabilities. With this type of system, material can be vacuumed from the manhole into a debris tank as it is brought back with the jet or tool and taken to a disposal area. These systems can be either trailer or truck mounted and are generally known as combination machines.4.8 The Occupational Safety and Health Administration (OSHA) has set guidelines for the safe removal of hazardous and nonhazardous substances as stated in OSHA Section 5 of Public Law 91-596; OSHA 29 USC 654; 29 CFR 1910.120; as well as DOT CFR Parts 106-7, 171-180, and 390-397.1.1 This practice covers the personnel requirements, operator training, operating procedures, and recommended equipment performance/design for the proper operation of pressure water-jet cleaning and cutting equipment as normally used by municipalities and contractors tasked with operations, maintenance, cleaning, and pre-rehabilitation cleaning work of vitrified clay mainline sewer pipe.1.2 The term “high-pressure water jetting” covers all water jetting, including the use of jets and hydromechanical tooling at pressures above 2000 psig (0.69 MPa).1.3 This practice covers the “high-pressure water jetting” of vitrified clay pipe and should not be applied to other pipe and pipe lining materials without evaluating the recommended cleaning procedure from the manufacturer to avoid damage.1.4 Units—The values stated in inch-pound units are to be regarded as the standard. The values given in parentheses are mathematical conversions to SI units that are provided for information only and are not considered standard.1.5 This standard does not purport to address all of the safety concerns, if any, associated with its use. It is the responsibility of the user of this standard to establish appropriate safety, health, and environmental practices and determine the applicability of regulatory limitations prior to use.1.6 This international standard was developed in accordance with internationally recognized principles on standardization established in the Decision on Principles for the Development of International Standards, Guides and Recommendations issued by the World Trade Organization Technical Barriers to Trade (TBT) Committee.