early-phase-enabling-trades

# Early Phase Enabling Trades Expert-level guidance for sitework, excavation, demolition, environmental abatement, and underground utilities in commercial/institutional construction. This skill covers the critical first phases of construction that establish the foundation for all subsequent work. ## Quick Reference Tables ### OSHA Excavation Soil Classification | Type | Description | Max Allowable Slope | Cohesive Strength | |------|-------------|---------------------|-------------------| | **Type A** | Clay, silty clay, sandy clay, clay loam (ceite) | 3/4H:1V (53°) | 1.5 tsf or greater | | **Type B** | Angular gravel, silt, silt loam, sandy loam, previously disturbed soils | 1H:1V (45°) | 0.5-1.5 tsf | | **Type C** | Gravel, sand, loamy sand, submerged soil, unstable rock | 1.5H:1V (34°) | Less than 0.5 tsf | > **Reference:** [Trench Safety & OSHA Requirements](references/trench-safety-osha.md) ### Soil Classification Quick Reference (USCS) | Symbol | Description | Characteristics | |--------|-------------|-----------------| | **GW** | Well-graded gravel | Excellent drainage, high bearing | | **GP** | Poorly-graded gravel | Good drainage, moderate bearing | | **SW** | Well-graded sand | Good drainage, good bearing | | **SP** | Poorly-graded sand | Good drainage, lower bearing | | **SM** | Silty sand | Fair drainage, fair bearing | | **SC** | Clayey sand | Poor drainage, fair bearing | | **ML** | Silt | Poor drainage, low bearing | | **CL** | Lean clay | Poor drainage, fair bearing | | **CH** | Fat clay | Very poor drainage, variable bearing, expansive | | **OH/OL** | Organic soils | Not suitable for structural support | > **Reference:** [Geotechnical Fundamentals](references/geotechnical-fundamentals.md) ### Compaction Requirements by Application | Application | Minimum % Compaction | Test Method | Lift Thickness | |-------------|---------------------|-------------|----------------| | Structural fill under footings | 95-98% Modified Proctor | Nuclear density | 6-8" loose | | Building pad/slab subgrade | 95% Modified Proctor | Nuclear density | 8" loose | | Utility trench backfill (pipe zone) | 95% Standard Proctor | Nuclear density | 6" loose | | Utility trench backfill (above pipe) | 90-95% Standard Proctor | Nuclear density | 8-12" loose | | Pavement subgrade | 95% Modified Proctor | Nuclear density | 8" loose | | General site fill | 90% Standard Proctor | Nuclear density | 12" loose | > **Reference:** [Excavation & Earthwork](references/excavation-earthwork.md) ### Shrink and Swell Factors | Material | Shrink Factor | Swell Factor | Bank to Compacted | |----------|---------------|--------------|-------------------| | Clay | 0.90 | 1.30 | 0.90 | | Common earth | 0.90 | 1.25 | 0.90 | | Gravel | 0.92 | 1.12 | 1.05 | | Sand | 0.95 | 1.12 | 0.95 | | Rock (blasted) | 0.67 | 1.50 | Variable | > **Reference:** [Excavation & Earthwork](references/excavation-earthwork.md) ### Underground Utility Pipe Materials | Application | Common Materials | Typical Sizes | Key Considerations | |-------------|-----------------|---------------|-------------------| | Sanitary sewer | PVC (SDR 35), DIP, VCP | 4"-36" | SDR 35 to 15' depth; DIP for deeper | | Storm drainage | RCP, HDPE, PVC, CMP | 12"-96" | RCP for heavy loads; HDPE for flexibility | | Domestic water | DIP, PVC (C900), HDPE | 4"-16" | DIP most common; HDPE for HDD | | Fire water | DIP, cement-lined | 6"-12" | Typically ductile iron | | Gas (distribution) | PE, steel | 2"-6" | Yellow PE most common | | Electrical duct | PVC (Sch 40/80), HDPE | 2"-6" | Concrete encased in traffic areas | > **Reference:** [Sanitary & Storm](references/underground-utilities-sanitary-storm.md) | [Water & Fire](references/underground-utilities-water-fire.md) | [Dry Utilities](references/underground-utilities-dry.md) ### Dewatering System Selection | Groundwater Condition | Soil Type | Recommended System | Typical Depth | |----------------------|-----------|-------------------|---------------| | Low volume, shallow | Any | Open sumps | 0-6' | | Moderate volume | Sand, gravel | Wellpoints | 0-18' | | High volume, deep | Sand, gravel | Deep wells | 15-100'+ | | Fine soils, low perm | Silt, fine sand | Eductors | 0-60' | | Contaminated | Any | Contained system | Varies | > **Reference:** [Dewatering Systems](references/dewatering-systems.md) ### Shoring System Selection | Excavation Depth | Soil Conditions | Typical System | Design Responsibility | |------------------|-----------------|----------------|----------------------| | <5' | Type A soil | Open cut or box | Contractor | | 5-12' | Type B/C soil | Trench box/shield | Contractor | | 5-20' | Mixed conditions | Sheet piling | Engineer required | | 10-40' | Tight site, adjacent structures | Soldier pile & lagging | Engineer required | | 20'+ | High groundwater | Secant/tangent piles | Engineer required | | Variable | Permanent installation | Soil nail wall | Engineer required | > **Reference:** [Shoring & Excavation Support](references/shoring-excavation-support.md) ### APWA Utility Color Codes | Color | Utility Type | Examples | |-------|-------------|----------| | **Red** | Electric | Power lines, conduit, lighting | | **Yellow** | Gas/Oil/Steam | Natural gas, propane, petroleum | | **Orange** | Communication | Telephone, cable TV, fiber optic | | **Blue** | Water | Potable water, irrigation | | **Green** | Sewer/Drain | Sanitary sewer, storm drain | | **Purple** | Reclaimed water | Non-potable water | | **Pink** | Temporary survey | Survey marks, proposed excavation | | **White** | Proposed excavation | Dig area boundary | > **Reference:** [Utility Coordination & Locates](references/utility-coordination-locates.md) ### Asbestos-Containing Materials (Common Locations) | Material | Friability | Typical Location | Removal Method | |----------|------------|-----------------|----------------| | Pipe insulation | Friable | Mechanical rooms, ceilings | Full containment | | Spray-on fireproofing | Friable | Structural steel, decking | Full containment | | Acoustic ceiling tile | Non-friable | Ceilings throughout | Wet removal | | Floor tile (9x9, 12x12 VAT) | Non-friable | Throughout building | Wet removal | | Mastic/adhesive | Non-friable | Under flooring | Leave in place or removal | | Transite siding/panels | Non-friable | Exterior, mechanical rooms | Wet, intact removal | | Roofing felts | Non-friable | Roof systems | Wet removal | | Joint compound | Friable | Drywall joints | Full containment | | Boiler insulation | Friable | Mechanical rooms | Full containment | > **Reference:** [Asbestos Abatement](references/asbestos-abatement.md) ### Environmental Regulatory Framework | Regulation | Agency | Applies To | Key Requirements | |------------|--------|-----------|------------------| | NESHAP | EPA | Asbestos | 10-day notification, work practices | | OSHA 1926.1101 | OSHA | Asbestos (construction) | Worker protection, exposure limits | | OSHA 1926.62 | OSHA | Lead (construction) | Worker protection, medical monitoring | | RRP Rule | EPA | Lead paint renovation | Certified renovators, work practices | | TSCA | EPA | PCBs | Disposal requirements | | RCRA | EPA | Hazardous waste | Manifests, disposal | | NPDES | EPA/State | Stormwater | SWPPP, inspections, BMPs | > **Reference:** [Lead & Hazmat Abatement](references/lead-hazmat-abatement.md) | [Permits & Regulatory](references/permits-regulatory.md) ### Pipe Testing Requirements | Pipe Type | Test Method | Test Pressure/Duration | Acceptance Criteria | |-----------|-------------|----------------------|---------------------| | Sanitary PVC | Low-pressure air | 4.0 psi, 2 min minimum | No audible leaks | | Sanitary PVC | Mandrel (deflection) | 5% of ID | Pass without force | | Storm RCP | Exfiltration | 2' head above GW | <200 gal/inch-dia/mile/day | | Water main DIP | Hydrostatic | 150% working, 2 hrs | Max allowable leakage per AWWA | | Water main PVC | Hydrostatic | 150% working, 2 hrs | Max allowable leakage per AWWA | | Gas PE | Pressure test | 1.5x MAOP, 1 hr | No pressure drop | | Electrical duct | Mandrel | Per spec | Full pass-through | > **Reference:** [Testing & Inspections](references/testing-inspections.md) ### Erosion & Sediment Control BMPs | BMP Type | Application | Maintenance Frequency | Key Installation Requirements | |----------|-------------|----------------------|------------------------------| | Silt fence | Perimeter, slope bases | Weekly + after 0.5"+ rain | Trenched 6"+, posts 6' OC | | Inlet protection | Storm inlets | Weekly + after rain | Filter fabric or gravel | | Stabilized entrance | Site access points | Daily, add stone as needed | 50' min length, 6" stone | | Sediment basin | Large disturbed areas | After each storm event | Per SWPPP sizing | | Erosion blanket | Slopes >3:1 | Inspect weekly | Stapled per manufacturer | | Concrete washout | Mixer/pump cleaning | Weekly, dispose properly | Lined pit, 10' from drainage | > **Reference:** [Erosion & Sediment Control](references/erosion-sediment-control.md) ### Survey Layout Tolerances | Element | Horizontal Tolerance | Vertical Tolerance | Verification Method |