Anyone in the trenchless industry knows that cleaning a sewer pipe requires significant knowledge and expert safety skills. Without these ingredients, serious accidents can occur.
That’s why in 2006, the National Association of Sewer Service Companies (NASSCO) published the Jetter Code of Practice manual, a guideline for the safe and efficient use of sewer cleaning and jetting equipment. Now in its second edition, the manual helps users understand cleaning techniques, equipment selection, and general sewer and storm water operational practices.
The 58-page manual is designed for those who operate jetters and trains or supervises people who do. Authors include Barry Howell, vice president and general manager of KEG Technologies, Brad Dutruch of Compliance EnviroSystems, and Gerry Muenchmeyer, P.E., NASSCO technical director. A peer group of industry professionals reviewed it before publication.
Before NASSCO published the manual, jetter operators and cleaning crews learned about the equipment and cleaning techniques from truck, trailer and nozzle manufacturers and from in-house training. Crew members learned from supervisors, and information passed by word-of-mouth. While this approach to training is effective, NASSCO saw a need to augment it with written documentation beyond the operating manuals supplied by jetter manufacturers.
The manual is the first formal document for jetting and cleaning that standardizes terms and helps correct common misconceptions. It adds to the industry knowledge base and gives operators a quick guide to safe and efficient jetter operation.
“I have guys tell me all the time how valuable the Jetter Code of Practice has been for their job,” says Irvin Gemora, NASSCO executive director. “From what I hear, this manual has led to many success stories and probably saved some lives, too.”
Divided into ten sections, the manual begins with an introduction and definitions of the jetting machines, nozzles, hoses, cutters and other equipment used in jetting. The other sections include:
Pipelines and conduits. This section describes the various types of collection systems, combined sewers, detention facilities and highway drains used in North America, and the types of piping material, including corrugated steel, high density polyethylene, and vitrified clay.
Guidance on pipeline installation and repair. Many internal and external conditions can cause a pipe to malfunction and need repair. Examples include pipe material defects, soil conditions, installation problems, joint failures, and materials flowing in the pipes. This section identifies some common causes and effects and possible solutions for remediating these problems. Sewer equipment operators must be aware of the problems before cleaning so as to avoid making problems worse or losing or damaging cleaning tools, cameras, or other equipment. These techniques are also useful when a project requires point repairs or pipe replacement.
Maintenance and line cleaning. This section identifies debris found in pipelines, how it gets there, and techniques for removing it. Roots and vegetation are found in pipes where a joint has separated or a crack appears in an access point or other opening. Grease, sand and debris are common in pipes. Operators must carefully monitor and manage the amount of debris removed from a pipeline. Large amounts of backfill material or pipe fragments can indicate a looming pipe failure and could mean the cleaning process should be stopped and a video inspection performed.
Operating procedures for jetter trucks. This section outlines practical issues to consider before and after blockage removal and during sewer cleaning. Jetter operators must understand the maximum working pressures to use to avoid damaging the pipe. The pressure should be based on the pipe’s structural condition, material and diameter, and the jetting equipment being used. Whenever possible, operators should ask the customer for complete information about the pipe location, size, material, condition and repair history before starting work on the line.
Topics in this section include jetting machine selection, types of nozzles, blockage removal, working from the downstream manhole, working from the upstream manhole, sewer cleaning, recommended pressures, hold time, operation of jetting equipment, recording and reporting, jetter water usage, and disposal of debris.
Explanations on various types of jetting equipment. Just as a carpenter can’t build a house with one tool, pipe cleaners need different tools for various functions. Jetting operators must look at the relationships of flows and pressures to the diameter of the pipe. These issues help determine what equipment to use for the project. This section addresses the efficiencies of various nozzle configurations, and differences in various nozzle applications (such as cleaning and penetrating). It also includes a matrix for selecting equipment appropriate to a specific job.
Cleaning and blockage removal. This section discusses cleaning and maintenance of sewer and storm lines as a process and offers guidelines to identify the best tools and techniques for each job (see the accompanying process diagram).
Information on flows, pressures and jet angles. This section explains the least understood area of sewer jetting: the relationship between flow (gpm) and pressure (psi) and how they affect sewer jetting. Areas covered include hose size and selection, jet angles and the selection of cleaning tools.
Equipment maintenance. Oper-ators are strongly advised to maintain recommended intervals for the maintenance, inspection, repair and replacement of key components. For example, high-pressure hose should be carefully monitored for nicks, cuts, and abrasions. Failure to inspect can lead to hose failure and serious injury or death.
General safety. This section outlines safety recommendations for equipment and personnel.
The Jetter Code of Practice can be purchased from NASSCO online at www.nassco.org or by contacting NASSCO operations manager Heather Myers at heather@nassco.org or calling 410/486-3500. The price is $50 for NASSCO members and $100 for non-members.
Michele Brier is public relations representative for NASSCO.
