AK General Contractor cheat sheet

Working capital = current assets − current liabilities; measures short-term ability to pay project costs.

Retainage receivable is an asset, not revenue; recognize it only when billed and collectible.

Straight-line depreciation = (cost − salvage value) ÷ useful life in years.

Break-even revenue = fixed overhead ÷ contribution margin ratio, where contribution margin ratio = (revenue − variable costs) ÷ revenue.

Over/under billing = earned revenue (costs incurred plus recognized profit) − billings to date; a positive value is underbilling.

Current ratio = current assets ÷ current liabilities; quick ratio excludes inventory and prepaid items.

Alaska has no state sales tax and no state personal income tax; do not add a state sales tax line to estimates.

Payroll burden percentage = (payroll taxes + insurance + benefits) ÷ base wages; apply to every labor hour in the bid.

Cash flow lag equals the gap between cash out for labor/materials and cash in from progress payments; fund it with working capital or a line of credit.

A written change order signed by the owner is required before performing work outside the contract scope; oral directives should be confirmed in writing.

Substantial completion starts warranty periods and often triggers release of retainage, subject to contract terms.

A lien claimant generally must record a lien within a statutory period after last furnishing labor or materials; the period is set by statute, not by the contract.

Pay-when-paid clauses shift timing risk to subcontractors; pay-if-paid clauses shift nonpayment risk and are treated differently by state law.

Alaska requires contractors to be licensed and to hold a residential contractors endorsement for residential work; an unlicensed contractor may be barred from collecting.

Alaska has a statutory contractor registration/licensing scheme and requires a surety bond as a condition of licensure; bond amounts vary by license category.

Notice of claim or notice of lien is typically a prerequisite to a lien; missing the notice can void the lien right.

Alaska's Little Miller Act governs bonds on state public works; the federal Miller Act governs federal projects, each with its own claim notice rules.

Differing site conditions clauses allow an equitable adjustment if conditions differ materially from those indicated in the contract documents.

Quantity takeoff: compute net quantities from dimensions, then add waste factors (commonly 5–10% for framing lumber, 3–5% for concrete).

Concrete volume = length × width × depth in consistent units; divide cubic feet by 27 for cubic yards.

Board feet = (thickness in inches × width in inches × length in feet) ÷ 12, per piece.

Masonry unit count = wall area ÷ (unit face area including mortar joint), then add breakage allowance.

Roof area = horizontal footprint area × roof slope factor; slope factor = square root of (rise² + run²) ÷ run.

Labor hours = quantity ÷ crew production rate; labor cost = hours × fully burdened hourly rate.

Bid price = direct costs + indirect costs + overhead + profit + contingency; express contingency as a percentage of direct cost.

Additive and deductive alternates are priced separately so the owner can select scope without re-bidding.

Unit price bids are used where quantities are uncertain; the unit price governs payment regardless of estimated quantity.

Critical path is the longest duration path through the network; its total float is zero, so any delay there delays completion.

Total float = late start − early start (equivalently late finish − early finish); free float is float before affecting a successor.

Crashing shortens duration by adding resources to critical activities; fast-tracking overlaps activities that were sequential, increasing risk.

A Gantt chart shows time on the horizontal axis and activities as bars; a network diagram shows logical dependencies.

Percent complete by cost = cost incurred to date ÷ total estimated cost at completion.

Estimate at completion (EAC) = budget at completion ÷ cost performance index, using earned value data.

Schedule variance = earned value − planned value; negative SV indicates work behind schedule.

Submittals, shop drawings, and long-lead material procurement belong on the schedule as predecessor activities.

Look-ahead schedules cover the next 2–6 weeks and identify constraints to remove before work starts.

Cut and fill volumes are computed by the average end area method or by prismoidal formula; net balance means cut equals fill.

Soil swell increases hauled volume above in-place bank volume; shrinkage reduces compacted fill volume relative to bank volume.

Compaction is specified as a percentage of maximum dry density from a standard or modified Proctor test at a specified moisture content.

Trench excavation requires sloping, benching, or shoring; the required protective system depends on soil classification and depth.

Footing depth must reach below the frost line; in much of Alaska frost depth is deep enough that frost-protected shallow foundations or insulated footings are used.

Perched water tables and seasonally frozen ground can require dewatering and frost-susceptible soil replacement before footings.

Excavation spoil must be kept back from the trench edge to reduce surcharge loading on trench walls.

Permafrost disturbance can cause thaw settlement; construction methods must preserve the thermal regime where permafrost is present.

Benchmarks and site control must be established and protected before mass excavation begins.

Concrete compressive strength is specified at 28 days; mix design targets that strength with a margin above the specified value.

Water-cement ratio controls strength and durability; lower w/c increases strength and reduces permeability.

Slump test measures workability; air content is measured to verify freeze-thaw durability, which matters in cold climates.

Formwork must be designed for lateral pressure of fresh concrete, which increases with placement rate and lower temperature.

Concrete must be protected from freezing until it reaches adequate strength; cold-weather practice requires heated enclosures or insulating blankets.

Masonry mortar joints are typically 3/8 inch; mortar type (M, S, N, O) governs compressive and bond strength.

Reinforcing steel must have specified cover over bars; cover depends on exposure condition and member type.

Structural steel connections are either bolted or welded; high-strength bolts are tensioned to a specified pretension.

Anchor bolts and embed plates must be set to template dimensions before concrete placement to avoid field correction.

Nominal lumber dimensions differ from actual: a 2x4 is 1-1/2 inches by 3-1/2 inches; a 2x10 is 1-1/2 inches by 9-1/4 inches.

Stud spacing is typically 16 or 24 inches on center; spacing and grade determine allowable span and load capacity.

Floor joist span is limited by species, grade, size, spacing, and deflection criteria (commonly L/360 for floors).

Headers over openings must be sized for the span and load; jack and king studs transfer load around openings.

Wall framing layout must align studs with sheathing edges and provide nailing for structural panels.

Wood must be protected from moisture; kiln-dried lumber shrinks after installation, so allowance for movement is required at joints.

Rough openings are framed larger than the finished unit to allow shimming and squaring during installation.

Subfloor panel thickness and edge support are set by span rating and joist spacing.

Finish carpentry tolerances are tighter than framing tolerances; verify wall plumb and square before trim installation.

Roof slope = rise ÷ run; a 4:12 slope rises 4 inches per 12 inches of horizontal run.

Slope factor for roof area = square root of (rise² + run²) ÷ run; use it to convert plan area to roof area.

Ice dam protection membrane is required at eaves in cold climates and must extend from the eave to a point inside the interior wall line.

A vapor retarder is placed on the warm side of insulation; in cold climates that is typically the interior side.

Ventilation must balance intake at the soffit and exhaust at or near the ridge; net free vent area is specified by code.

Roof underlayment requirements depend on slope; low-slope roofs require different membrane systems than steep-slope roofs.

Flashing is required at valleys, penetrations, walls, and roof-to-wall intersections to direct water out of the assembly.

Thermal bridging through framing reduces effective R-value; continuous exterior insulation reduces bridging.

Air leakage transports far more moisture than diffusion; air sealing precedes insulation in cold-climate assemblies.

Ohm's law: voltage = current × resistance; power in watts = volts × amps for resistive loads.

Circuit ampacity must not be less than the load; overcurrent protection is sized to protect the conductor, not the appliance.

Conductor sizing accounts for voltage drop over long runs; larger wire reduces drop for a given load.

GFCI protection is required in bathrooms, kitchens, outdoors, and other wet or damp locations; AFCI protects against arc faults.

Plumbing drain lines rely on gravity slope, commonly 1/4 inch per foot for pipes 3 inches and smaller.

Vent piping admits air behind a trap to prevent siphonage; every trap must be vented.

Water supply pressure and pipe sizing must satisfy fixture flow demand at the farthest fixture.

Heating load is calculated from envelope heat loss plus infiltration and ventilation loads; equipment is sized to the calculated load, not by rule of thumb.

Duct leakage and insulation affect system efficiency; ducts in unconditioned space must be sealed and insulated.

Fall protection is required when working at heights of 6 feet or more in construction, using guardrails, nets, or personal fall arrest.

Excavations 5 feet deep or more require a protective system unless the excavation is entirely in stable rock.

A competent person must inspect excavations daily and after rain or other events that could affect stability.

Scaffolds must be designed and loaded per the manufacturer and erected under the supervision of a qualified person; guardrails are required above 10 feet.

Hazard communication requires safety data sheets and labeling for chemicals on site.

Personal protective equipment is the last line of defense in the hierarchy of controls: elimination, substitution, engineering controls, administrative controls, then PPE.

Spill prevention and erosion control require silt fencing, containment, and proper disposal of wash water and fuels.

Asbestos and lead-containing materials require identification and regulated handling before demolition or renovation disturbs them.

Lockout/tagout procedures isolate hazardous energy before servicing or maintaining equipment.

Working capital = current assets − current liabilities; measures short-term ability to pay project costs.

Retainage receivable is an asset, not revenue; recognize it only when billed and collectible.

Straight-line depreciation = (cost − salvage value) ÷ useful life in years.

Break-even revenue = fixed overhead ÷ contribution margin ratio, where contribution margin ratio = (revenue − variable costs) ÷ revenue.

Over/under billing = earned revenue (costs incurred plus recognized profit) − billings to date; a positive value is underbilling.

Current ratio = current assets ÷ current liabilities; quick ratio excludes inventory and prepaid items.

Alaska has no state sales tax and no state personal income tax; do not add a state sales tax line to estimates.

Payroll burden percentage = (payroll taxes + insurance + benefits) ÷ base wages; apply to every labor hour in the bid.

Cash flow lag equals the gap between cash out for labor/materials and cash in from progress payments; fund it with working capital or a line of credit.

A written change order signed by the owner is required before performing work outside the contract scope; oral directives should be confirmed in writing.

Substantial completion starts warranty periods and often triggers release of retainage, subject to contract terms.

A lien claimant generally must record a lien within a statutory period after last furnishing labor or materials; the period is set by statute, not by the contract.

Pay-when-paid clauses shift timing risk to subcontractors; pay-if-paid clauses shift nonpayment risk and are treated differently by state law.

Alaska requires contractors to be licensed and to hold a residential contractors endorsement for residential work; an unlicensed contractor may be barred from collecting.

Alaska has a statutory contractor registration/licensing scheme and requires a surety bond as a condition of licensure; bond amounts vary by license category.

Notice of claim or notice of lien is typically a prerequisite to a lien; missing the notice can void the lien right.

Alaska's Little Miller Act governs bonds on state public works; the federal Miller Act governs federal projects, each with its own claim notice rules.

Differing site conditions clauses allow an equitable adjustment if conditions differ materially from those indicated in the contract documents.

Quantity takeoff: compute net quantities from dimensions, then add waste factors (commonly 5–10% for framing lumber, 3–5% for concrete).

Concrete volume = length × width × depth in consistent units; divide cubic feet by 27 for cubic yards.

Board feet = (thickness in inches × width in inches × length in feet) ÷ 12, per piece.

Masonry unit count = wall area ÷ (unit face area including mortar joint), then add breakage allowance.

Roof area = horizontal footprint area × roof slope factor; slope factor = square root of (rise² + run²) ÷ run.

Labor hours = quantity ÷ crew production rate; labor cost = hours × fully burdened hourly rate.

Bid price = direct costs + indirect costs + overhead + profit + contingency; express contingency as a percentage of direct cost.

Additive and deductive alternates are priced separately so the owner can select scope without re-bidding.

Unit price bids are used where quantities are uncertain; the unit price governs payment regardless of estimated quantity.

Critical path is the longest duration path through the network; its total float is zero, so any delay there delays completion.

Total float = late start − early start (equivalently late finish − early finish); free float is float before affecting a successor.

Crashing shortens duration by adding resources to critical activities; fast-tracking overlaps activities that were sequential, increasing risk.

A Gantt chart shows time on the horizontal axis and activities as bars; a network diagram shows logical dependencies.

Percent complete by cost = cost incurred to date ÷ total estimated cost at completion.

Estimate at completion (EAC) = budget at completion ÷ cost performance index, using earned value data.

Schedule variance = earned value − planned value; negative SV indicates work behind schedule.

Submittals, shop drawings, and long-lead material procurement belong on the schedule as predecessor activities.

Look-ahead schedules cover the next 2–6 weeks and identify constraints to remove before work starts.

Cut and fill volumes are computed by the average end area method or by prismoidal formula; net balance means cut equals fill.

Soil swell increases hauled volume above in-place bank volume; shrinkage reduces compacted fill volume relative to bank volume.

Compaction is specified as a percentage of maximum dry density from a standard or modified Proctor test at a specified moisture content.

Trench excavation requires sloping, benching, or shoring; the required protective system depends on soil classification and depth.

Footing depth must reach below the frost line; in much of Alaska frost depth is deep enough that frost-protected shallow foundations or insulated footings are used.

Perched water tables and seasonally frozen ground can require dewatering and frost-susceptible soil replacement before footings.

Excavation spoil must be kept back from the trench edge to reduce surcharge loading on trench walls.

Permafrost disturbance can cause thaw settlement; construction methods must preserve the thermal regime where permafrost is present.

Benchmarks and site control must be established and protected before mass excavation begins.

Concrete compressive strength is specified at 28 days; mix design targets that strength with a margin above the specified value.

Water-cement ratio controls strength and durability; lower w/c increases strength and reduces permeability.

Slump test measures workability; air content is measured to verify freeze-thaw durability, which matters in cold climates.

Formwork must be designed for lateral pressure of fresh concrete, which increases with placement rate and lower temperature.

Concrete must be protected from freezing until it reaches adequate strength; cold-weather practice requires heated enclosures or insulating blankets.

Masonry mortar joints are typically 3/8 inch; mortar type (M, S, N, O) governs compressive and bond strength.

Reinforcing steel must have specified cover over bars; cover depends on exposure condition and member type.

Structural steel connections are either bolted or welded; high-strength bolts are tensioned to a specified pretension.

Anchor bolts and embed plates must be set to template dimensions before concrete placement to avoid field correction.

Nominal lumber dimensions differ from actual: a 2x4 is 1-1/2 inches by 3-1/2 inches; a 2x10 is 1-1/2 inches by 9-1/4 inches.

Stud spacing is typically 16 or 24 inches on center; spacing and grade determine allowable span and load capacity.

Floor joist span is limited by species, grade, size, spacing, and deflection criteria (commonly L/360 for floors).

Headers over openings must be sized for the span and load; jack and king studs transfer load around openings.

Wall framing layout must align studs with sheathing edges and provide nailing for structural panels.

Wood must be protected from moisture; kiln-dried lumber shrinks after installation, so allowance for movement is required at joints.

Rough openings are framed larger than the finished unit to allow shimming and squaring during installation.

Subfloor panel thickness and edge support are set by span rating and joist spacing.

Finish carpentry tolerances are tighter than framing tolerances; verify wall plumb and square before trim installation.

Roof slope = rise ÷ run; a 4:12 slope rises 4 inches per 12 inches of horizontal run.

Slope factor for roof area = square root of (rise² + run²) ÷ run; use it to convert plan area to roof area.

Ice dam protection membrane is required at eaves in cold climates and must extend from the eave to a point inside the interior wall line.

A vapor retarder is placed on the warm side of insulation; in cold climates that is typically the interior side.

Ventilation must balance intake at the soffit and exhaust at or near the ridge; net free vent area is specified by code.

Roof underlayment requirements depend on slope; low-slope roofs require different membrane systems than steep-slope roofs.

Flashing is required at valleys, penetrations, walls, and roof-to-wall intersections to direct water out of the assembly.

Thermal bridging through framing reduces effective R-value; continuous exterior insulation reduces bridging.

Air leakage transports far more moisture than diffusion; air sealing precedes insulation in cold-climate assemblies.

Ohm's law: voltage = current × resistance; power in watts = volts × amps for resistive loads.

Circuit ampacity must not be less than the load; overcurrent protection is sized to protect the conductor, not the appliance.

Conductor sizing accounts for voltage drop over long runs; larger wire reduces drop for a given load.

GFCI protection is required in bathrooms, kitchens, outdoors, and other wet or damp locations; AFCI protects against arc faults.

Plumbing drain lines rely on gravity slope, commonly 1/4 inch per foot for pipes 3 inches and smaller.

Vent piping admits air behind a trap to prevent siphonage; every trap must be vented.

Water supply pressure and pipe sizing must satisfy fixture flow demand at the farthest fixture.

Heating load is calculated from envelope heat loss plus infiltration and ventilation loads; equipment is sized to the calculated load, not by rule of thumb.

Duct leakage and insulation affect system efficiency; ducts in unconditioned space must be sealed and insulated.

Fall protection is required when working at heights of 6 feet or more in construction, using guardrails, nets, or personal fall arrest.

Excavations 5 feet deep or more require a protective system unless the excavation is entirely in stable rock.

A competent person must inspect excavations daily and after rain or other events that could affect stability.

Scaffolds must be designed and loaded per the manufacturer and erected under the supervision of a qualified person; guardrails are required above 10 feet.

Hazard communication requires safety data sheets and labeling for chemicals on site.

Personal protective equipment is the last line of defense in the hierarchy of controls: elimination, substitution, engineering controls, administrative controls, then PPE.

Spill prevention and erosion control require silt fencing, containment, and proper disposal of wash water and fuels.

Asbestos and lead-containing materials require identification and regulated handling before demolition or renovation disturbs them.

Lockout/tagout procedures isolate hazardous energy before servicing or maintaining equipment.

Working capital = current assets − current liabilities; measures short-term ability to pay project costs.

Retainage receivable is an asset, not revenue; recognize it only when billed and collectible.

Straight-line depreciation = (cost − salvage value) ÷ useful life in years.

Break-even revenue = fixed overhead ÷ contribution margin ratio, where contribution margin ratio = (revenue − variable costs) ÷ revenue.

Over/under billing = earned revenue (costs incurred plus recognized profit) − billings to date; a positive value is underbilling.

Current ratio = current assets ÷ current liabilities; quick ratio excludes inventory and prepaid items.

Alaska has no state sales tax and no state personal income tax; do not add a state sales tax line to estimates.

Payroll burden percentage = (payroll taxes + insurance + benefits) ÷ base wages; apply to every labor hour in the bid.

Cash flow lag equals the gap between cash out for labor/materials and cash in from progress payments; fund it with working capital or a line of credit.

A written change order signed by the owner is required before performing work outside the contract scope; oral directives should be confirmed in writing.

Substantial completion starts warranty periods and often triggers release of retainage, subject to contract terms.

A lien claimant generally must record a lien within a statutory period after last furnishing labor or materials; the period is set by statute, not by the contract.

Pay-when-paid clauses shift timing risk to subcontractors; pay-if-paid clauses shift nonpayment risk and are treated differently by state law.

Alaska requires contractors to be licensed and to hold a residential contractors endorsement for residential work; an unlicensed contractor may be barred from collecting.

Alaska has a statutory contractor registration/licensing scheme and requires a surety bond as a condition of licensure; bond amounts vary by license category.

Notice of claim or notice of lien is typically a prerequisite to a lien; missing the notice can void the lien right.

Alaska's Little Miller Act governs bonds on state public works; the federal Miller Act governs federal projects, each with its own claim notice rules.

Differing site conditions clauses allow an equitable adjustment if conditions differ materially from those indicated in the contract documents.

Quantity takeoff: compute net quantities from dimensions, then add waste factors (commonly 5–10% for framing lumber, 3–5% for concrete).

Concrete volume = length × width × depth in consistent units; divide cubic feet by 27 for cubic yards.

Board feet = (thickness in inches × width in inches × length in feet) ÷ 12, per piece.

Masonry unit count = wall area ÷ (unit face area including mortar joint), then add breakage allowance.

Roof area = horizontal footprint area × roof slope factor; slope factor = square root of (rise² + run²) ÷ run.

Labor hours = quantity ÷ crew production rate; labor cost = hours × fully burdened hourly rate.

Bid price = direct costs + indirect costs + overhead + profit + contingency; express contingency as a percentage of direct cost.

Additive and deductive alternates are priced separately so the owner can select scope without re-bidding.

Unit price bids are used where quantities are uncertain; the unit price governs payment regardless of estimated quantity.

Critical path is the longest duration path through the network; its total float is zero, so any delay there delays completion.

Total float = late start − early start (equivalently late finish − early finish); free float is float before affecting a successor.

Crashing shortens duration by adding resources to critical activities; fast-tracking overlaps activities that were sequential, increasing risk.

A Gantt chart shows time on the horizontal axis and activities as bars; a network diagram shows logical dependencies.

Percent complete by cost = cost incurred to date ÷ total estimated cost at completion.

Estimate at completion (EAC) = budget at completion ÷ cost performance index, using earned value data.

Schedule variance = earned value − planned value; negative SV indicates work behind schedule.

Submittals, shop drawings, and long-lead material procurement belong on the schedule as predecessor activities.

Look-ahead schedules cover the next 2–6 weeks and identify constraints to remove before work starts.

Cut and fill volumes are computed by the average end area method or by prismoidal formula; net balance means cut equals fill.

Soil swell increases hauled volume above in-place bank volume; shrinkage reduces compacted fill volume relative to bank volume.

Compaction is specified as a percentage of maximum dry density from a standard or modified Proctor test at a specified moisture content.

Trench excavation requires sloping, benching, or shoring; the required protective system depends on soil classification and depth.

Footing depth must reach below the frost line; in much of Alaska frost depth is deep enough that frost-protected shallow foundations or insulated footings are used.

Perched water tables and seasonally frozen ground can require dewatering and frost-susceptible soil replacement before footings.

Excavation spoil must be kept back from the trench edge to reduce surcharge loading on trench walls.

Permafrost disturbance can cause thaw settlement; construction methods must preserve the thermal regime where permafrost is present.

Benchmarks and site control must be established and protected before mass excavation begins.

Concrete compressive strength is specified at 28 days; mix design targets that strength with a margin above the specified value.

Water-cement ratio controls strength and durability; lower w/c increases strength and reduces permeability.

Slump test measures workability; air content is measured to verify freeze-thaw durability, which matters in cold climates.

Formwork must be designed for lateral pressure of fresh concrete, which increases with placement rate and lower temperature.

Concrete must be protected from freezing until it reaches adequate strength; cold-weather practice requires heated enclosures or insulating blankets.

Masonry mortar joints are typically 3/8 inch; mortar type (M, S, N, O) governs compressive and bond strength.

Reinforcing steel must have specified cover over bars; cover depends on exposure condition and member type.

Structural steel connections are either bolted or welded; high-strength bolts are tensioned to a specified pretension.

Anchor bolts and embed plates must be set to template dimensions before concrete placement to avoid field correction.

Nominal lumber dimensions differ from actual: a 2x4 is 1-1/2 inches by 3-1/2 inches; a 2x10 is 1-1/2 inches by 9-1/4 inches.

Stud spacing is typically 16 or 24 inches on center; spacing and grade determine allowable span and load capacity.

Floor joist span is limited by species, grade, size, spacing, and deflection criteria (commonly L/360 for floors).

Headers over openings must be sized for the span and load; jack and king studs transfer load around openings.

Wall framing layout must align studs with sheathing edges and provide nailing for structural panels.

Wood must be protected from moisture; kiln-dried lumber shrinks after installation, so allowance for movement is required at joints.

Rough openings are framed larger than the finished unit to allow shimming and squaring during installation.

Subfloor panel thickness and edge support are set by span rating and joist spacing.

Finish carpentry tolerances are tighter than framing tolerances; verify wall plumb and square before trim installation.

Roof slope = rise ÷ run; a 4:12 slope rises 4 inches per 12 inches of horizontal run.

Slope factor for roof area = square root of (rise² + run²) ÷ run; use it to convert plan area to roof area.

Ice dam protection membrane is required at eaves in cold climates and must extend from the eave to a point inside the interior wall line.

A vapor retarder is placed on the warm side of insulation; in cold climates that is typically the interior side.

Ventilation must balance intake at the soffit and exhaust at or near the ridge; net free vent area is specified by code.

Roof underlayment requirements depend on slope; low-slope roofs require different membrane systems than steep-slope roofs.

Flashing is required at valleys, penetrations, walls, and roof-to-wall intersections to direct water out of the assembly.

Thermal bridging through framing reduces effective R-value; continuous exterior insulation reduces bridging.

Air leakage transports far more moisture than diffusion; air sealing precedes insulation in cold-climate assemblies.

Ohm's law: voltage = current × resistance; power in watts = volts × amps for resistive loads.

Circuit ampacity must not be less than the load; overcurrent protection is sized to protect the conductor, not the appliance.

Conductor sizing accounts for voltage drop over long runs; larger wire reduces drop for a given load.

GFCI protection is required in bathrooms, kitchens, outdoors, and other wet or damp locations; AFCI protects against arc faults.

Plumbing drain lines rely on gravity slope, commonly 1/4 inch per foot for pipes 3 inches and smaller.

Vent piping admits air behind a trap to prevent siphonage; every trap must be vented.

Water supply pressure and pipe sizing must satisfy fixture flow demand at the farthest fixture.

Heating load is calculated from envelope heat loss plus infiltration and ventilation loads; equipment is sized to the calculated load, not by rule of thumb.

Duct leakage and insulation affect system efficiency; ducts in unconditioned space must be sealed and insulated.

Fall protection is required when working at heights of 6 feet or more in construction, using guardrails, nets, or personal fall arrest.

Excavations 5 feet deep or more require a protective system unless the excavation is entirely in stable rock.

A competent person must inspect excavations daily and after rain or other events that could affect stability.

Scaffolds must be designed and loaded per the manufacturer and erected under the supervision of a qualified person; guardrails are required above 10 feet.

Hazard communication requires safety data sheets and labeling for chemicals on site.

Personal protective equipment is the last line of defense in the hierarchy of controls: elimination, substitution, engineering controls, administrative controls, then PPE.

Spill prevention and erosion control require silt fencing, containment, and proper disposal of wash water and fuels.

Asbestos and lead-containing materials require identification and regulated handling before demolition or renovation disturbs them.

Lockout/tagout procedures isolate hazardous energy before servicing or maintaining equipment.