336-431-5852
aceavant@aceavant.com
5358 Poole Rd, Archdale, NC 27263
336-431-5852
aceavant@aceavant.com
5358 Poole Rd, Archdale, NC 27263
Gravity sewer pipe, gravity sewer mains, and sanitary sewer system installation for site development across North Carolina
Gravity sewer pipe must be installed to precise grade and slope to flow correctly. We maintain grade control from first pipe to last manhole.
Pipe installation, manhole setting, service lateral installation, and trench backfill handled by our crew without subcontracting any part of the scope.
PVC, ductile iron, and reinforced concrete pipe selected based on cover depth, soil conditions, and municipal specifications.
Gravity sewer fittings, wye branches, and service lateral connections installed to the project specification and the receiving municipality’s standards.
Sewer main installation is sequenced with earthwork and other utilities so pipe goes in the ground at the right phase without conflicts with paving and base installation.
Installed pipe is tested before backfill is completed and before the system is submitted for municipal acceptance.
Precast manholes are set at the design locations, adjusted to finished grade, and connected to the pipe system as part of our gravity sewer scope.
Gravity sewer handled alongside force main, storm, and water by the same crew and point of contact.
A gravity sewer system is a sanitary sewer network that conveys wastewater from buildings and site facilities to a municipal connection or treatment facility using gravity flow, without mechanical pumping. Pipe is installed at a continuous downhill slope so wastewater flows by gravity from the high point of the collection system to the low point where it connects to the municipal main or a pump station that lifts it to the next gravity segment. Gravity sewer systems are the standard approach for sanitary sewer on commercial development sites where the site topography allows the pipe to be installed at the grade required for gravity flow without going too deep for practical excavation.
Gravity sanitary sewer design and construction is more tolerance-sensitive than most other underground utility installations. A water main that is installed a few tenths off grade still delivers water. A gravity sewer pipe installed at insufficient slope pools sewage, allows solids to accumulate, and eventually blocks the pipe. A pipe installed at too steep a slope allows liquid to run ahead of solids, which also leads to accumulation and blockage over time. The design slope is specified by the civil engineer based on the pipe diameter and the minimum and maximum velocity required to keep the pipe self-cleaning, and the installation has to match that slope within the tolerances the design and the receiving municipality require.
We install gravity sewer to the design grade using laser grade control and continuous checking throughout the installation, not spot checking at manholes and assuming the pipe in between is correct.
Pipe material for gravity sewer installation depends on the pipe diameter, burial depth, soil conditions, and the specifications of the receiving municipality. The most common materials for commercial gravity sewer installation are PVC pipe, ductile iron pipe, and reinforced concrete pipe.
PVC gravity sewer pipe is the standard material for gravity sanitary sewer on most commercial development projects. It is lightweight, corrosion resistant, and available in the SDR classifications required for different burial depths and external loads. It is the material most commonly specified for gravity sewer mains and laterals that will be dedicated to a municipal sewer system.
Ductile iron pipe is used for gravity sewer in locations where the external load from traffic or deep burial exceeds the capacity of PVC, or where the municipality requires ductile iron for specific installation conditions such as river crossings, casing pipe installations, or locations adjacent to water mains where additional corrosion resistance is required.
Reinforced concrete pipe is used for larger diameter gravity sewer mains where the pipe diameter and load requirements exceed the practical range of PVC. It is the standard material for trunk sewer mains and large collector sewers on major development projects.
Gravity sewer fittings include wye branches for service lateral connections, bends for direction changes, reducers for pipe size transitions, and end caps and plugs for future connections and system terminations. Pipe fittings for gravity sewer must be compatible with the pipe material and the jointing system being used, and must be installed with the same bedding and support requirements as the pipe itself. We install gravity sewer fittings as part of the pipe installation scope, selecting compatible fittings for each pipe material and installing them to the manufacturer’s requirements and the project specification.
Service lateral connections to the gravity sewer main are made using factory-installed wye branches or field-cut saddle connections, depending on the pipe material and the municipal requirements for lateral connection method. Lateral stubs are extended to the property line or the building location and capped for future connection before the trench is backfilled.
We review the civil sewer drawings and coordinate with the receiving municipality on inspection hold points, testing requirements, and material approval procedures before mobilizing.
Trench excavation is performed to the depth and width required for the pipe size, burial depth, and bedding thickness specified in the design. Gravity sewer trenches are often among the deepest utility excavations on a commercial site, and trench safety measures including shoring and sloping are applied based on the trench depth and soil conditions at each location.
Bedding material is placed and compacted in the trench bottom to provide uniform support along the full pipe barrel at the design grade. For gravity sewer, bedding accuracy is critical because the pipe grade is only as good as the bedding it sits on. We establish and maintain laser grade control throughout the bedding and pipe installation process.
Pipe is installed from the downstream end working upstream, with joints made according to the pipe manufacturer’s requirements. Each pipe section is checked for grade and alignment before the next section is installed, and any section that does not meet the grade tolerance is removed and reset before proceeding.
Precast manholes are set at the design locations, connected to the pipe system with flexible manhole boots, and adjusted to the finished grade elevation. Manhole frames and covers are set to finished grade after paving is complete.
Service laterals are connected to the main using wye branches or saddle connections and extended to the design terminus, with stubs capped and marked for future connection.
Installed pipe is mandrel tested to confirm it has not been deflected beyond the allowable tolerance, and leakage tested to confirm joints are watertight before trench backfill is completed and before the system is submitted for municipal acceptance.
After 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.
Gravity sewer and force main are the two primary sanitary sewer conveyance methods, and most commercial sewer systems use both in different parts of the site.
Gravity sewer flows downhill by gravity without pumping. It is the preferred system where the site topography allows pipe to be installed at the required slope without going too deep for practical excavation. Gravity systems have no mechanical components to maintain and are less expensive to operate over their service life than pumped systems.
Force main sewer is a pressurized pipe that carries sewage pumped from a lift station to a point where it can discharge into a gravity system or a treatment facility. Force mains are used where the site topography makes gravity flow impossible across part of the collection system, requiring a pump station to lift sewage over a high point or across flat ground. We install both gravity sewer and force main as part of an integrated sewer scope, coordinating the two systems with the pump station construction that connects them.
Gravity storm sewer and gravity sanitary sewer both use gravity flow, but they are separate systems with different pipe materials, design requirements, and regulatory standards. Storm sewer carries rainwater and surface runoff and is not required to be watertight, since storm pipe infiltration is less critical than sanitary sewer infiltration. Sanitary sewer must be watertight to prevent exfiltration of sewage into the surrounding soil and infiltration of groundwater into the sewer that adds hydraulic load to the treatment system. We install storm and sanitary sewer as separate scopes with the pipe materials, jointing methods, and testing requirements that apply to each system.
On a commercial development site, the gravity sewer main is the backbone of the sanitary collection system. Service laterals from each building connect to the main, which conveys the combined flow to the municipal connection or the pump station that lifts it to the next segment. Main sizing, slope, and alignment are specified by the civil engineer based on the anticipated flow from the development and the capacity of the receiving municipal system.
We install gravity sewer mains to the civil design, coordinating with the municipality on material approval, inspection scheduling, and the testing and acceptance procedures required before the system can be connected to the public sewer.
Gravity sewer installation is on the critical path of commercial site development because buildings cannot be occupied without a functioning sanitary sewer connection, and service laterals need to be in the ground before slab and foundation work covers the utility corridor. We work with the GC and civil engineer to phase gravity sewer installation within the overall site schedule, installing mains and laterals in each area before grading and paving advance over the utility corridor.
At project completion we provide mandrel test records, leakage test results, and as-built information on pipe location, depth, slope, and manhole locations 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 system to public ownership.
A gravity sewer system conveys wastewater from buildings to a municipal connection or treatment facility using gravity flow, with pipe installed at a continuous downhill slope that moves sewage without mechanical pumping.
Common materials include PVC for most commercial gravity sewer applications, ductile iron for high-load or special crossing conditions, and reinforced concrete for large diameter trunk mains. Material selection is based on the project design and municipal specifications.
Gravity sewer flows downhill by gravity without pumping. Force main is a pressurized pipe that carries sewage pumped from a lift station to a point where it can discharge into a gravity system. Most commercial sewer systems use both in different parts of the collection system.
Pipe slope determines the flow velocity in the sewer. Too little slope and the velocity is too slow to keep solids suspended, leading to accumulation and blockage. Too much slope and liquid outruns solids, also causing accumulation. The design slope is specified to keep velocity in the self-cleaning range for the pipe diameter.
Mandrel testing confirms the pipe has not been deflected beyond the allowable tolerance. Leakage testing confirms joints are watertight. Both are required before trench backfill is completed and before the system is submitted for municipal acceptance.
Yes. We self-perform gravity sewer, force main, water, and storm drainage installation as an integrated wet utilities scope coordinated with grading and earthwork by the same team.