Description

• Excavation and backfill are used to prepare ground for site improvements, including building foundations and slabs, walking surfaces, perimeter and underfloor foundation drainage systems, and underground mechanical and electrical utilities.  
• Title 24 Code of Federal Regulations (CFR) Parts 50 and 58 (24 CFR Part 50 or 24 CFR Part 58) state that “All property proposed for use in HUD programs be free of hazardous materials, contamination, toxic chemicals and gasses, and radioactive substances, where a hazard could affect the health and safety of occupants or conflict with the intended utilization of the property.” As part of a National Environmental Policy Act (NEPA), State Environmental Quality Review Act (SEQRA) and/or City Environmental Quality Review (CEQR) environmental review, projects may be required to perform soil and site investigation to ensure that there are no new potential pathways for contamination as a result of a project.   

Baseline

• Details (site restoration, tree protection, erosion control, traffic control). 
• Drawings must indicate the locations of all utilities. 
• Material test reports must be performed in accordance with DOB requirements. 
• Trench and excavation walls must be supported by adequate sheeting and properly braced. 
• Surface water and subsurface or ground water must be prevented from flowing into excavations and from flooding project sites and surrounding areas. 
• Utilities must not be constructed or laid in a trench in the presence of water. All water must be removed from the trench prior to placing the line.  
• Before backfilling, all water distribution piping systems (including sewer, stormwater, steam, condensate carrier) must be hydrostatically tested and inspected. Similarly, gas piping, valves, fittings, support structures, anti-corrosion equipment and associated underground components must be inspected and tested before backfill is put in place. 
• All material for backfilling must have a moisture content and gradation suitable for attaining the required density, must be free from frost at the time of placement, and must be free from boulders. 
• Miscellaneous fill material removed from the trenches and excavations will not be considered as acceptable backfill material unless found acceptable and approved in writing. 
• In general, it is expected that material excavated from a trench must be used to backfill only the upper portion of the trench. Such material must not be used to backfill the lower portion of the trench. 
• Select granular fill material must be placed in the lower portion of the piping trenches. 
• Clean fill material must be used when there is a deficiency of acceptable backfill. 
• Cathodic protection must be installed for corrosion control of all buried metallic piping. 
• The trench for installation of electrical underground conduits and cables must be 24 inches deep minimum as is required by NEC. The bottom of the trench must be free of loose or projecting stones and debris. Backfill must be sand or screened earth free of stones and sharp objects. Backfill must be compacted to specified density to avoid settling. 
• Provide installation of Buried Utility Warning Tape above underground utilities. Tape’s color and lettering must be unaffected by moisture and other substances contained in the backfill material. 
• It is recommended that underground warning/marking tape be buried at a depth of 12 in (30 cm) or less below grade. 
• Underground conductors must be identified for the voltage and conditions under which they are installed. 
• When soil and site investigation is required as part of an environmental review, the project team would need to at a minimum provide a Phase I Environmental Site Assessment (Phase I ESA) which identifies potential or existing environmental contamination liabilities. Current standards for a Phase I is the American Society for Testing and Materials E1527-21 (ASTM E1527-21) but are subject to change. This Phase I ESA will be reviewed by NYCHA for concurrence.  
• If the result of the Phase I ESA indicates potential contamination or areas of concern, or NYCHA suggests, a Phase II Investigation Work Plan would be required to outline the proposed scope of work for soil, groundwater, and/or soil gas evaluation. This Phase II Investigation Work Plan should be accompanied by a Health and Safety Plan (HASP). These reports will be reviewed by NYCHA and potentially by NYC Department of Environmental Protection (DEP) for accuracy and concurrence.  
• Once the Phase II Investigation Work Plan and HASP are reviewed and approved by NYCHA and/or DEP, the investigation activities may take place. The results of the investigation should be summarized in a Phase II Environmental Site Assessment (Phase II ESA).  
• Depending on the result of the Phase II ESA, the project team should be prepared to put together a Remedial Action Plan (RAP) and Construction Health and Safety Plan (CHASP) that outlines what remedial measures that would likely be required to adequately mitigate the contamination. The Phase II ESA, RAP, and CHASP will all be subject to review and approval from NYCHA and/or DEP.  

Last Updated on March 10, 2025 at 2:29 pm

Downloads and Data

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Specifications

31 20 00 - Site Preparation, Excavation and Grading

31 22 00 - Earth Moving Excavation, Filling and Grading

31 30 00 - Earthwork

Details

L-DT_Soil Stabilization

L-DT_Stock Piling

L-DT_Subgrade 12

L-DT_Subgrade 24

L-DT_Subgrade Stabilization (12 Depth)

L-DT_Subgrade Stabilization (24 Depth)