336-431-5852
aceavant@aceavant.com
5358 Poole Rd, Archdale, NC 27263
336-431-5852
aceavant@aceavant.com
5358 Poole Rd, Archdale, NC 27263
Sanitary sewer force main installation for site development and pump station discharge across North Carolina
We install force main sewer pipe from the pump station discharge through the full alignment to the gravity sewer connection point.
Force main pipe, fittings, and joints are installed to the pressure class required for the system operating pressure and surge conditions.
We install air release valves at high points along the force main where air pockets would accumulate and reduce flow capacity.
Force main connection to the gravity sewer is made at the design manhole with the drop connection or direct connection detail required by the receiving municipality.
The installed force main is hydrostatically pressure tested before trench backfill is completed and before the pump station is placed into service.
Force main installation is sequenced with pump station construction so the full system is ready for startup at the same time.
Trench excavation, pipe bedding, installation, and compacted backfill are part of our force main installation scope.
Force main installation handled alongside gravity sewer, pump stations, and wet utilities by the same crew and point of contact.
A force main sewer is a pressurized pipe that carries sewage pumped from a lift station or pump station to a point where it can discharge into a gravity sewer system or a treatment facility. Unlike gravity sewer, which flows downhill by gravity on a continuous slope, a force main operates under pressure and can convey sewage uphill, across flat ground, or over terrain that makes gravity flow impractical. Force mains are used when a site’s topography prevents the gravity sewer system from reaching the municipal connection without going too deep for practical excavation, or when the municipal connection point is at a higher elevation than the site being served.
Sewage from the collection system flows by gravity to the wet well of a pump station, where submersible pumps lift it into the force main under pressure. The force main carries the pressurized flow from the pump station discharge through the pipe alignment to the gravity sewer connection point, where it is discharged into a receiving manhole and continues to the treatment facility by gravity. The pump station cycles on and off based on the wet well level, pumping in intermittent cycles rather than continuous flow, which means the force main operates under varying pressure conditions that the pipe, fittings, and joints must be designed to handle.
Force main pipe material selection is driven by the operating pressure, surge pressure, soil conditions, and the specifications of the receiving municipality. The most common materials for sanitary sewer force main installation are PVC pressure pipe, ductile iron pipe, and HDPE pipe.
PVC pressure pipe is used for smaller diameter force mains operating at moderate pressures on typical commercial site development projects. It is available in pressure classes suited to the operating and surge pressures of most pump station force main applications and is the standard material for force mains that will be dedicated to a municipal sewer system.
Ductile iron pipe is used for larger diameter force mains, high-pressure applications, and installations in aggressive soil conditions or locations with high external loads from traffic or deep burial. It provides greater pressure capacity and impact resistance than PVC and is specified by many municipalities for force mains above a certain diameter or operating pressure.
HDPE pipe is used for force main installations involving directional drilling, river crossings, and other trenchless construction methods where the pipe needs to be pulled through a bored or drilled alignment. Its flexibility and leak-free fused joint system make it well suited to installations where open trench construction is not practical.
We review the force main alignment drawings and coordinate with the receiving municipality on material approval, inspection hold points, and pressure testing requirements before mobilizing.
Trench excavation is performed to the depth and width required for the pipe size, burial depth, and bedding specification. Force mains are often installed in the same trench corridor as other utilities, and we coordinate trench sequencing with water, storm, and gravity sewer installation to manage conflicts in shared corridors.
Force main pipe is installed in the trench to the alignment and depth shown on the civil drawings, with joints made to the pressure rating requirements of the pipe material. Thrust blocks are installed at bends, tees, and dead ends to resist the pressure forces that would otherwise displace fittings from the pipe alignment.
Air release valves are installed at high points along the force main alignment where air pockets would otherwise accumulate and reduce the effective flow area in the pipe. Air pockets in a force main reduce pump efficiency, cause pressure fluctuations, and can contribute to water hammer conditions that damage the pipe and fittings. We locate air release valve installations based on the force main profile and the high point locations identified in the civil design.
The downstream end of the force main is connected to the receiving gravity sewer manhole using the drop connection or direct connection detail required by the project design and the receiving municipality. The connection point and detail are critical because a force main discharging directly into a gravity manhole at high velocity can cause turbulence, odor, and corrosion in the receiving manhole if the connection is not made with the energy dissipation required by the design.
The installed force main is hydrostatically pressure tested to the test pressure and duration specified by the project engineer and the local sewer authority before trench backfill is completed. Any section that fails the pressure test is excavated, repaired, and retested before backfill proceeds.
After pressure testing is complete and the system passes inspection, the trench is backfilled in compacted lifts to the density required beneath road and paving surfaces and to the general backfill specification in non-paved areas.
The point where the force main discharges into the gravity sewer system is one of the most detail-sensitive connections in the sewer scope. The force main operates under pressure and discharges at a velocity that can cause significant turbulence and corrosion in the receiving manhole if the connection detail does not account for the energy in the discharge flow. Most municipal sewer authorities require a specific connection detail for force main to gravity sewer connections, typically involving a drop connection that dissipates flow energy before it enters the gravity pipe, or a tee connection with a baffle or deflector inside the manhole.
We coordinate the connection detail with the receiving municipality before installation, confirm that the manhole at the connection point is constructed to receive the force main discharge, and make the connection to the approved detail so the receiving gravity system handles the discharge without damage or odor problems after the pump station goes into service.
Air release valves are automatic valves installed at high points along the force main that allow accumulated air to escape from the pipe without allowing sewage to discharge at the surface. As the pump station cycles and flow velocity in the force main changes, air can become trapped at high points in the pipe profile. Trapped air reduces the cross-sectional area available for flow, increases head loss, and reduces pump efficiency. In severe cases, accumulated air can cause pressure surges when it is suddenly displaced by the liquid column behind it.
We install air release valves at the high point locations identified in the force main profile, in valve boxes or vaults that allow access for maintenance and inspection. Air release valve selection depends on the pipe diameter, operating pressure, and the volume of air that needs to be released at each high point location.
On most commercial development sites, gravity sewer and force main are used together. Gravity sewer handles the collection system where the site topography allows downhill flow to the municipal connection. Force main is used where the collection system needs to cross high ground, serve low areas that cannot drain to the gravity connection by gravity, or connect to a municipal system that is at a higher elevation than the site. The pump station is the mechanical component that connects the two systems, lifting sewage from the gravity collection point into the force main for conveyance to the gravity discharge point.
We install gravity sewer, force main, and pump stations as an integrated sewer scope, coordinating the three components so the full system is ready for startup and municipal acceptance at the same time.
Force main installation is typically sequenced with pump station construction so the two components are ready for connection and startup testing at the same time. Force main pipe can be installed ahead of pump station construction in most cases, with the pump station connection made when the wet well and discharge piping are ready. We coordinate force main installation with the gravity sewer and pump station schedule so the full sewer system is complete and tested before occupancy of the buildings it serves.
At project completion we provide pressure test records and as-built information on force main pipe location, depth, valve locations, and connection details as part of the project closeout documentation. We coordinate the final inspection with the receiving municipality and walk the installed system with the municipal inspector before dedication of the force main to public ownership.
A force main sewer is a pressurized pipe that carries sewage pumped from a lift station or pump station to a point where it discharges into a gravity sewer system or a treatment facility. It is used where gravity flow is not achievable based on the site topography and the location of the municipal sewer connection.
Gravity sewer flows downhill by gravity on a continuous slope without pumping. A force main operates under pressure from a pump station and can convey sewage uphill or across flat ground where gravity flow is not possible.
Common materials include PVC pressure pipe for smaller diameter moderate-pressure applications, ductile iron pipe for larger diameter and high-pressure installations, and HDPE pipe for directional drilling and trenchless installations. Material selection is based on the operating pressure, soil conditions, and municipal specifications.
Air accumulates at high points in the force main profile as flow velocity changes during pump cycling. Air release valves allow that air to escape without allowing sewage to discharge at the surface, maintaining full pipe flow capacity and preventing pressure surges caused by sudden air displacement.
Hydrostatic pressure testing is required before trench backfill is completed and before the pump station is placed into service. The test pressure and duration are specified by the project engineer and the receiving municipality.
The force main discharges into a receiving gravity sewer manhole using a drop connection or direct connection detail specified by the municipality. The connection detail is designed to dissipate the energy in the force main discharge before it enters the gravity pipe.
Yes. We self-perform gravity sewer, force main, and pump station construction as an integrated sewer scope coordinated with grading and other wet utilities by the same team.