All sewer systems require periodical sewer pipe cleaning and maintenance to prevent clogged sewer lines. Some sewer clogs may only be temporary stopping flow and letting water “weep” through solids or may create a sewer spill when the water backs up and spills at the lowest point into manholes, cleanouts or plumbing systems inside buildings.
Sewer Pipe Cleaning and Safety
A clogged sewer line is usually due to:
- Clogged sewer pipe not spilling with manhole holding water;
- Spilling but contained and ponding on its own;
- Relieving and spilling into waterways;
- Spilling into a structure;
- Large diameter pipe spilling requiring bypass.
To ensure safety, sewer clogs should be cleaned downstream by a dry manhole. Fatal accidents can occur using high pressure flushing machines in a full manhole. Extreme caution should be exercised when working on a blocked sewer line in a full manhole.
Blocked Sewer Line Procedures
Clearing a blocked sewer line can be difficult and slow, or quick and easy, depending on the situation.
Effective blocked sewer line cleaning is achieved by directing the nozzle over or into the debris. To minimize pipe damage keep the sewer nozzle moving at all times and do not leave the nozzle in one position for extended periods. The moment the clog has been removed the jetter hose rewind should be less than 1 ft./s to ensure effective sewer pipe cleaning.
Material removed from the blocked sewer should be inspected to ascertain if possible pipe damage exists. A sewer inspection using a camera should be run to see if there are any roots in the sewer line, physical damage, oil and grease deposits.
Risks Associated With Sewer Pipe Cleaning
The use of equipment with cutting blades to clear blockages and debris from drains and sewers carries the risk of breaking any gas lines and/or electrical cables that may be present in the drain or sewer. This places the workers performing the sewer drain cleaning as well as nearby persons at risk from potential gas leaks and electric shocks.
This risk is greatly reduced by using hydro jetters, which provides a more thorough cleaning and a less destructive cleaning method. Thus it is highly recommended to use hydro jetters for sewer pipe cleaning.
Before Going Ahead With Any Sewer Pipe Cleaning
In the US and Canada, call 811 to communicate with the Call Before You Dig program to establish the location of cables and pipes. Local governments and water authorities need to make sure that workers and sewer contractors are provided with up to date plans, maps and other information regarding the location of gas lines, electrical cables and any other utilities before starting any work.
When clearing a blocked sewer using a high pressure jet, always be alert to the risks of breaking a gas line or electrical cable.
Safe Work Procedure
It is recommended practice to take the following steps to minimise risks to the safety of workers and to the public. Ensure workers have received proper training through OSHA training online or other approved methods:
1 Lift manhole covers to determine the depth of drains and sewers and to minimise risk of gas build up if a breach occurs. Manholes should have approved site safety signs and barriers to alert passers by.
2 Determine the location and nature of blocked sewer line – tree roots, garbage or other debris. This may be done by a combination of visual inspection, use of a sewer inspection camera and the use of non destructive locators, such as hydro excavation methods and tools.
3 Determine if there are any gas lines or underground electrical cables in the vicinity of the blockage, by visually inspecting properties for gas meters and/or underground power cables, sourcing 811 (Call Before You Dig) information and using pipe/cable locators. Check both sides of the street.
4 If a gas line or cable is located crossing the drain or sewer in the immediate vicinity of the blocked sewer line, use a sewer inspection camera to confirm the presence of the line or cable in the drain or sewer, or if no camera is available, call the relevant utility company.
If a pipe or cable is found in the drain or sewer pipe, contact the relevant utility company immediately.
Do Not Attempt To Remove It.
If An Accident Occurs
If you break, or think you may have broken a gas line or electrical cable, you should immediately tend to the safety of yourself and other workers and members of the public in the area, and notify the appropriate authorities. It may be necessary to turn off the supply of gas and/or power to the area to prevent any additional risks from developing.
A lack of a proper sewer pipe cleaning schedule will ultimately result in clogged sewer pipes and pipe overflows. Cleaning crews must initiate a regular sewer pipe cleaning maintenance schedule to maintain public confidence.