PPD Project Planning & Design

Key standards

Climate zones (IECC)

Sub-classifications: A (moist), B (dry), C (marine)

Envelope U-factor prescriptive (commercial Zone 5)

Glazing performance

SHGC targets:

• Cold climate: 0.40-0.55 (capture winter solar)
• Hot climate: 0.25 or lower (block sun)
• Mixed: 0.25-0.40

Vapor retarder placement

Air barrier

Required by IECC and ASHRAE 90.1. Continuous around envelope. Testing:

• Blower door (residential)
• Whole-building pressurization (commercial)

Air leakage often bigger moisture issue than vapor diffusion.

Continuous Insulation (ci)

Required by IECC in many zones. Outboard of studs eliminates thermal bridging (which reduces effective R-value 30-50%).

Beam depth estimates

Column sizing

Tributary area × load = axial demand
Office typical: ~70 psf total (DL + LL)

• W-shape: select from tables based on axial + slenderness
• HSS: efficient compression, cleaner appearance
• Concrete: reinforced or post-tensioned

Foundation systems

Frost line depth (foundations below)

Soil bearing capacity (allowable)

Loads (typical)

Lateral systems

Higher R = lower seismic force = more deformation expected.

Seismic base shear

V ≈ Cs × W

• W = building weight
• Cs depends on site class, spectral acceleration, period, R, Ie
• Heavier buildings get more seismic force

System types

Cooling tonnage rules of thumb

Air change rates (ASHRAE 62.1)

Energy recovery (ERV/HRV)

• ERV: sensible + latent (humidity) transfer
• HRV: sensible only
• 50-75% effectiveness typical
• Required by ASHRAE 90.1 above certain airflow thresholds

Economizer

• Free cooling using outside air when conditions favorable
• ASHRAE 90.1 requires above certain capacity
• Climate-dependent value (huge in temperate zones)

DCV (Demand-Controlled Ventilation)

CO2-based airflow modulation. Energy savings in spaces with variable occupancy (conference rooms, classrooms, assembly).

Service sizing (residential)

Commercial service

Sized per NEC Article 220 load calc:

• Lighting (per LPD × area + factors)
• Receptacles (180 VA per outlet, but factors apply)
• HVAC (largest motor + 100% other motors)
• Specific loads (kitchens, elevators, etc.)
• Demand factors per use type

Voltage systems

Branch circuit standards

• 15 A: lighting, general outlets
• 20 A: kitchens, bathrooms (GFCI required), commercial general
• 30 A: dryers, water heaters
• 50 A: ranges, EV chargers

Panel locations

• Accessible (NEC 240.24)
• 30" wide × 36" deep clearance (working space)
• Not in bathrooms, closets with combustibles
• Headroom 6'-6" minimum

Conduit & wire

• EMT (electrical metallic tubing): light commercial, exposed
• RMC/IMC (rigid): hazardous, industrial, exterior
• PVC: underground, wet locations
• AC/MC cable (armored): commercial, accessible

Grounding & bonding

Critical for safety. NEC Article 250:

• Service ground rod or building grounding electrode system
• Equipment grounding conductor through all branch circuits
• Bonding jumpers at metallic systems

Emergency power

Water supply sizing

• Water Supply Fixture Units (WSFU) per IPC table
• Pressure: 40-80 psi typical from utility (50-60 ideal)
• Friction loss + elevation + fixture demand
• Main 3/4"-1" residential typical; commercial sized per WSFU

Drainage Fixture Units (DFU)

Pipe sizing — drainage

Venting

• Every fixture trap requires vent
• Vent termination 6" above flood level rim of fixtures (general)
• Vent extension 12" above roof in cold climate (frost closure)
• Combined drain/vent allowed for some fixtures (wet venting)

Hot water

• Storage tank vs tankless vs heat pump
• Recirculation for distant fixtures (energy code may require if length exceeds threshold)
• 120°F at fixtures (scald prevention); 140°F at tank (Legionella prevention)
• Mixing valves for showers/lavatories

Fixture counts (IBC/IPC)

Group B (office, sprinklered):

• Lavatories: 1 per 40 occupants
• WCs: 1 per 25 for first 50, then 1 per 50
• Drinking fountains: 1 per 100 occupants (or bottle filler)

Group A-2 (restaurant):

• Higher density requirements
• Per occupant load × 1/75 (M+F separate)

Code references

• IPC (International Plumbing Code) — most jurisdictions
• UPC (Uniform Plumbing Code) — Western states
• NFPA 99 healthcare-specific
• ANSI/ASHRAE 188 (Legionellosis prevention)

Low-slope (commercial) systems

Slopes

• Low-slope: ≤2:12 (typically 1/4" per foot minimum drainage)
• Steep-slope: >2:12 (shingles, tiles, metal)

Drainage requirements

• Primary: handles design storm (often 100-year)
• Overflow: backup; scuppers or secondary drains 2"+ above primary
• Critical: ponding water can collapse roof

Insulation placement

• Above deck (most common low-slope): no thermal bridging, cool roof
• Below deck (attic): cheaper but thermal bridging through joists
• Mass timber/exposed structure: insulation above deck

Cool roof (LEED, energy codes)

• SRI ≥29 (low-sloped) or ≥39 (steep) per LEED v4.1
• White TPO/PVC easily exceeds (SRI 80+)
• Reduces heat island, building cooling load

Green roof

• Extensive: 3-6" media, lightweight (10-35 psf wet), sedums
• Intensive: 8"+ media, heavy (80-150+ psf wet), rooftop gardens
• Stormwater retention, biodiversity, insulation, longer membrane life

Photovoltaic

• BIPV (Building Integrated PV): replaces membrane
• Rack-mounted: above existing roof
• Adds load (5-8 psf typical)
• Structural review required

Flashing detailing

• Step flashing at vertical surfaces
• Counterflashing over base flashing
• Pipe boots (pre-fabricated)
• Drains: 2-piece with clamping ring
• Coordination with parapet, walls, equipment

Daylight Factor (DF)

Ratio of interior to exterior illuminance under overcast sky:

• 2% adequate for general office task
• 5%+ preferred
• Toplighting (skylights, monitors) gives more uniform DF
• Sidelighting usable to ~2× ceiling height from window

Glazing performance metrics

SHGC targets by climate

Low-e coatings

• Hard coat (pyrolytic): durable, can face outside
• Soft coat (sputtered): better performance, must be in insulating air space
• Spectrally selective: high VT, low SHGC

Shading strategies

• Overhangs (south): depth ≈ 50% of glazing height (temperate)
• Vertical fins (east/west): low-angle sun harder to control
• Exterior shades (blinds, screens): most effective at blocking solar before glass
• Interior shades: less effective (heat already inside) but glare control

Light shelves

• Horizontal element on interior of south windows
• Bounces light deeper into space (off ceiling)
• Reduces glare near window, increases daylight at back
• Combined with proper ceiling reflectance (>70%)

Daylight harvesting controls

• Photosensors dim electric lights based on daylight available
• Required by ASHRAE 90.1 in daylit zones
• 25-50% lighting energy savings

Glare control

• Discomfort glare: subjective, distracting
• Disability glare: prevents seeing task
• Mitigation: blinds, fritted/screened glass, exterior shading, indirect lighting

Hurricane glazing (HVHZ zones)

• ASTM E1996 + E1886 test standards
• Laminated glass + anchored frame as system
• Required: Miami-Dade, Broward, coastal FL
• Alternative: shutters per code

Sound metrics

STC ratings (typical)

IIC ratings (floor-ceiling)

Detail matters

• Penetrations: outlets back-to-back, plumbing, ducts destroy STC
• Doors: STC of weakest element governs (door usually ≪ wall)
• Ceiling continuation: walls to deck (not just to ceiling) for true STC
• Flanking: sound around or through adjacent assemblies

Absorption (interior acoustics)

• NRC 0.0-1.0 (1.0 = total absorption)
• Acoustic ceiling tiles: NRC 0.65-0.95
• Carpet: NRC 0.20-0.55
• Hard surfaces: NRC 0.00-0.05

Reverberation Time (RT)

Time for sound to decay 60 dB:

• Speech intelligibility: 0.5-1.0 sec
• Music concert hall: 1.5-2.0 sec
• Cathedral: 4-6+ sec
• Calculated: RT60 = 0.049 × V ÷ (Σ Sα) [V volume, S surface area, α absorption]

Background noise (NC/RC)

• Private office: NC 30-35
• Open office: NC 35-40
• Library reading: NC 30-35
• Hospital exam: NC 30-35
• Classroom: NC 30 (ANSI standard)
• Auditorium: NC 20-25

ANSI standard S12.60 (classrooms)

• Background noise ≤35 dBA
• RT ≤0.6 sec (small) or 0.7 sec (large)
• Critical for speech intelligibility, especially for hearing-impaired

Sprinkler standards

NFPA 13 IBC trade-offs unlocked

• Area increases (200% under §506.3)
• Height increases (+20 ft + 1 story per §504)
• Travel distance increased (e.g., B 200 → 300 ft)
• Reduced fire ratings (e.g., 1-hr corridors → 0-hr in many cases)
• Dead-end corridors increased (B 20 → 50 ft)

Sprinkler hazard classifications

Sprinkler systems

• Wet pipe (most common): water in pipes ready to flow
• Dry pipe (freeze risk): air in pipes, water at valve
• Pre-action (sensitive areas): requires two events to activate
• Deluge (high hazard): all heads open, manual trigger

Standpipes (NFPA 14)

Required for buildings above 30 ft above lowest fire dept access (varies).

Fire alarm (NFPA 72)

• Initiating devices: manual pull, smoke detector, heat detector, water flow
• Notification appliances: horn/strobe, voice evacuation, visual for hearing-impaired
• Control panel: monitors, supervises, signals
• Power: AC + 24-hr battery backup
• Voice evacuation required: Group A 1000+ occupants, high-rises, certain occupancies

Fire-rated assemblies

• Walls: per UL design (e.g., UL U419 for 1-hr GWB)
• Doors: per NFPA 80 (e.g., 90-min in 2-hr wall)
• Penetrations: firestopping per ASTM E814/UL 1479
• Glazing: fire-protective vs fire-resistive (different criteria)

Smoke control

• Smoke barriers: contain smoke (I-2 every 22,500 SF max)
• Smoke partitions: less stringent than barriers
• Pressurization: stair pressurization in high-rise
• Smoke exhaust: atria, malls

Elevator types

Capacity & sizing

Elevator banking (population analysis)

Handling Capacity (HC) = passengers carried in 5 min ÷ population × 100

• Office target: 12-15%
• Hospital target: 8-10%
• Residential target: 5-8%

Average Interval (AI) = waiting time between cars

• Office: 25-35 seconds acceptable
• Premium: <25 seconds

Shaft & machine room

• MRL: no machine room, hoist machine in shaft
• Traditional: machine room above (overhead) or below (basement)
• Shaft sized per car capacity + clearances
• Pit depth per code (5-10+ ft, varies)
• Overhead clearance above top floor

Code compliance

• ASME A17.1: Safety Code for Elevators and Escalators
• ADA: accessible: 80" car min, controls 15-48" reach, audible signals
• Fire service operation: Phase I (recall), Phase II (firefighter operation)
• Emergency power: required for high-rise (one car at a time)

Escalators

• 24-30" tread width (typical commercial)
• 30° incline (typical)
• 100-120 fpm typical
• Sized for peak flow
• Two-direction common; one-direction in lower-volume

Lifts & dumbwaiters

• Wheelchair lifts: ADA accessible vertical transport (short distances)
• Platform lifts: industrial/freight
• Dumbwaiters: materials only, not occupied
• Some loophole avoidance in code (compliance check required)

Shallow foundations

Deep foundations

Pile capacity

• End bearing: load transferred to dense layer or rock
• Friction: load transferred through skin friction along shaft
• Combination: most piles in practice

Soil bearing capacity (allowable)

Settlement

• Immediate (granular): rapid
• Consolidation (clays): slow, months to years
• Total vs differential: differential more damaging
• Typical max: 1" total, 1/2" differential for typical building

Frost depth (foundation minimum)

Expansive vs collapsible soils

• Expansive (clay): swells with water, shrinks dry — foundations heave
  • Mitigation: deep foundations bypassing zone, moisture control, structurally elevated slabs
• Collapsible (silt, loess): collapses when wetted — settlement
  • Mitigation: pre-wetting/compaction, deep foundations

Lateral earth pressure

• At-rest, active, passive pressures
• Hydrostatic when below water table (drains critical)
• Surcharge from adjacent loads
• Designed by geotech + structural
• Drainage essential to prevent buildup

Waterproofing

• Membrane (sheet or fluid-applied)
• Drainage board (protects membrane)
• Perimeter drain (pipe in gravel to daylight or sump)
• Sump pump for low water level
• Vapor retarder on interior face

Foundation drainage

• Footing drains: perimeter pipe in gravel
• Slope to daylight or sump
• Filter fabric to prevent clogging
• Critical for basement spaces

Lateral force-resisting systems

Seismic base shear

V ≈ Cs × W

• W = effective seismic weight
• Cs = seismic response coefficient (per ASCE 7)
• Heavier buildings = more seismic force
• Lighter (steel, wood, mass timber) = less

Cs depends on

• Spectral acceleration (site location, mapped values)
• Site class (soil type — A rock to F poor)
• Period (T) of building
• R factor (system ductility)
• Importance factor (Ie — Risk Category)

Risk Category & Ie

Drift limits

• Typical 0.020 × story height (ordinary)
• 0.015 × h for hospitals, schools (Risk III/IV)
• 0.010 × h for some systems
• Story drift check separate from strength check

Diaphragms

• Rigid (concrete, well-attached steel deck): distributes load to walls by stiffness
• Flexible (untopped metal deck, wood): distributes by tributary area
• Semi-rigid: in between (most common, requires more analysis)

Soft story

A weak/soft level (often ground floor with parking or retail). Concentrates demand. Causes catastrophic collapse in earthquakes (Northridge 1994 examples). Need careful detailing or alternative configuration.

Wind vs seismic

Both lateral, but different characteristics:

• Wind: steady + gust, predictable distribution, high-rises governed
• Seismic: short-duration impulses, distributed per mass, low-rises often governed
• Building designed for worst case at each story

P-delta effects

Secondary moments from gravity loads acting on laterally deflected building. Becomes significant in tall buildings and ductile systems. Code triggers analysis at stability ratio thresholds.

Hurricane / high-wind areas

• HVHZ (High Velocity Hurricane Zone): Miami-Dade, Broward, parts of FL
• Special impact-resistant glazing or shutters
• Stricter component testing (ASTM E1996, E1886)
• Roof to wall to foundation continuous load path

Typical uniform live loads (psf)

Light loads (≤ 60 psf)

Medium loads (60-100 psf)

Heavy loads (100-150+ psf)

Roof live loads

• Ordinary flat roof: 20 psf (reduces with tributary area)
• Snow load: per ASCE 7 ground snow map + modifiers
• Heavier roof live load required for green roofs (load varies)

Key metrics

DA (Daylight Autonomy)

• % of occupied hours daylight alone provides target illuminance (typically 300 lux)
• Target: DA300 ≥ 50% for primary occupied spaces

sDA (Spatial Daylight Autonomy)

• % of floor area meeting DA threshold
• LEED v4.1: sDA300/50% ≥ 55% for 1 point; ≥75% for 3 points

ASE (Annual Sunlight Exposure)

• % of area exposed to direct sun >1000 lux for >250 hours/yr
• Target: ASE1000,250 ≤ 10% to prevent glare/overheating

Daylight Factor (DF)

• Static metric: indoor/outdoor illuminance ratio
• DF >2% generally desirable

Strategies by orientation (N. Hemisphere)

North glazing

• Even, diffuse light
• No direct sun → no glare
• Best for art galleries, design studios
• Largest openings possible

South glazing

• Brightest in winter (low sun)
• Predictable shading with horizontal overhangs
• Best controlled in passive solar design
• Overhang depth: (winter solar altitude angle) determines

East/West glazing

• HARDEST to control
• Low sun angles → horizontal overhangs ineffective
• Need vertical fins or external shades
• Minimize glazing where possible (especially West)

Window-to-Wall Ratio (WWR)

• Energy codes typically limit WWR to 30-40%
• High WWR good for daylight but bad for heat loss/gain
• Trade-off: glazing performance vs. quantity

Light shelves

• Horizontal element above eye level
• Reflects daylight onto ceiling, deeper into space
• Effective for ~2× shelf height in penetration
• Combine with proper overhang

Stall dimensions (typical)

Standard

• 9' × 18' standard space
• 8' × 18' compact (where allowed by code)
• 10' × 20' large/luxury

Accessible

• 8' × 18' space + 5' access aisle = car-accessible
• 8' × 18' space + 8' access aisle = van-accessible
• OR 11' × 18' + 5' aisle for van

Aisle widths (between rows)

Required spaces (ADA)

Garage clearances

• Headroom: 7'-0\" min for standard; 8'-2\" for van-accessible
• Drive aisle clearance: 14' typical for trucks/emergency
• Sloped floor for drainage: ¼\"/ft minimum
• Ramp slope: 6% max for vehicular; transitions at top/bottom

Sizing calculations

• Surface lot: ~350-400 SF per car (incl aisle)
• Single-floor garage: ~325 SF per car
• Multi-level garage: ~300 SF per car (more efficient)
• Underground garage: ~350 SF per car

Code minimums (zoning typically)

• Office: 1 space per 200-400 SF
• Retail: 1 per 250-300 SF
• Restaurant: 1 per 100-150 SF (or per seat)
• Residential: 1-2 per unit
• Hotel: 1 per room + employees

IECC Climate Zones (simplified)

Zone 1 — Very Hot (Miami, Honolulu)

• Cooling-dominated
• No heating typically required
• High humidity (Zone 1A)
• Strategies: shading, ventilation, reflective surfaces

Zone 2 — Hot (Houston, Phoenix)

• Cooling-dominated
• Hot humid (2A) or hot dry (2B)
• Strategies: shading, thermal mass (dry only), light colors

Zone 3 — Warm (Atlanta, LA, Dallas)

• Mixed cooling + some heating
• Most complex shading optimization
• Strategies: deep overhangs, cross-ventilation, modest insulation

Zone 4 — Mixed (Washington DC, Nashville)

• Significant heating AND cooling
• Hardest to optimize
• Strategies: balanced insulation, smart vapor management

Zone 5 — Cool (Chicago, Boston, Denver)

• Heating-dominated
• Strategies: high insulation, vapor retarder interior, solar gain in winter

Zone 6 — Cold (Minneapolis, Anchorage south)

• Strong heating dominance
• Strategies: very high insulation, triple-glazing, wind protection

Zone 7-8 — Very Cold / Subarctic

• Heating critical
• Strategies: super-insulation, minimal glazing, vestibules

Vapor retarder placement

• Zones 1-3: Exterior side (warm/humid outside)
• Zone 4: Vapor-open assemblies preferred; no vapor retarder
• Zones 5-8: Interior side (warm/humid inside)

Building orientation

• Long axis E-W generally optimal in most climates
• Maximizes north/south exposure (controllable)
• Minimizes east/west (uncontrollable)

Glass selection (SHGC, Solar Heat Gain Coefficient)

Beam depth (preliminary)

Typical span ranges

Lateral systems

• Moment frame: Open plan, less efficient
• Braced frame: Efficient, blocks bays
• Shear wall: Very efficient, blocks entirely
• Dual system: Moment + braced/shear

Foundations

Four control layers (priority order)

1. Water (bulk water) — sheds liquid
2. Air — must be CONTINUOUS
3. Vapor — warm side of insulation
4. Thermal — continuous, avoid bridging

Rain screen principle

Cladding + air cavity + air/vapor barrier (inboard)

• Cladding sheds most water
• Cavity drains incidental water
• Air/vapor barrier handles the rest
• Decouples water from air/vapor management

Vapor retarder placement

Curtain wall systems

Thermal bridging mitigation

• Continuous exterior insulation (best)
• Thermal breaks at slab edges, balconies
• Steel stud cavities: continuous insul. on top
• Aluminum framing: thermally broken

Cooling loads (rule of thumb)

1 ton = 12,000 BTU/hr

Duct velocities (commercial)

Sizing: A (sf) = Q (cfm) / V (fpm)

Electrical loads

Plumbing (Fixture Units)

HVAC system types

• VAV — variable air volume, constant temp
• CAV — constant air, variable temp
• DOAS — dedicated outdoor air system
• Chilled beam — radiant cooling + DOAS
• VRF — variable refrigerant flow

Three components

1. Exit Access — any point → exit
2. Exit — protected (stair enclosure, passageway, exterior door at grade)
3. Exit Discharge — exit → public way

Door swing

Swing in direction of egress when:

• Occupant load 50+
• Group H (any load)
• Horizontal exit
• Exit discharge (most cases)

Exit width sizing

Required width = Occupants × Factor

• Level egress (corridor, door): 0.2 in/occupant
• Stairs: 0.3 in/occupant
• Sprinklers reduce by ~80% (already in factors)

Minimum widths (most occupancies)

Travel distance (sprinklered)

Common path of travel (sprinklered)

Dead-end corridor (sprinklered)

Two exits required when:

• Occupant load >49 (most)
• Common path exceeded
• Travel distance to single exit exceeded
• Some occupancies require sooner (H, I)

Three or more exits

• 3 exits: 501-1000 occupants
• 4 exits: >1000 occupants

Reach ranges

Maneuvering clearances

• Turning space: 60" circle OR T-shape
• Pull-side door: 60" deep × 18" beyond latch
• Push-side door: 48" deep × 12" beyond latch (if closer + latch)
• Knee clearance: 27" h, 30" w, 11" deep
• Toe clearance: 9" h, 6" deep

Routes & ramps

• Running slope <1:20 (5%) = accessible walking surface
• >1:20 = RAMP (max 1:12 / 8.33%)
• Max ramp rise: 30" per run
• Cross slope: 1:48 (2.08%) max anywhere
• Min width: 36" (48" preferred)

Stairs (accessible egress)

• Tread: 11" min
• Riser: 4" min, 7" max
• Uniform throughout flight
• Closed risers (no open backs)
• Handrails: 34-38" both sides
• Handrail extensions: 12" top, 1 tread depth bottom

Toilets

• Accessible stall: 60" w × 56" d (wall-hung)
• WC centerline: 16-18" from wall
• Seat height: 17-19"
• Grab bars: rear 36" min, side 42" min
• Flush controls: open side
• Door: out-swing or large stall

Parking

Lateral systems

• Moment frame — rigid joints; open plan; less efficient
• Braced frame — diagonals; efficient; obstructs openings
• Shear wall — solid wall; very efficient; blocks openings
• Dual system — moment + braced/shear

Loads

• Dead — permanent (structure, finishes, MEP)
• Live — variable (occupants, furniture)
• Wind — lateral pressure; location, height, exposure
• Seismic — ground acceleration; zone + site class
• Snow — ground snow load + roof factors

Typical bay sizes

• Wood: 16-20 ft
• Light steel: 18-22 ft
• Steel deck/concrete: 30-40 ft
• Concrete flat slab: 25-30 ft
• Long-span: 60-120 ft

Four control layers

1. Water (bulk water) barrier
2. Air barrier — must be continuous
3. Vapor retarder — warm side of insulation
4. Thermal barrier — continuous to avoid bridging

Rain screen

Cladding + air cavity behind. Cladding sheds most water; air barrier (inside cavity) controls air/vapor. Decouples water management from air/vapor.

Thermal bridging

Conductive paths (steel studs, slab edges, balconies) bypass insulation — can drop effective R-value 40%+. Mitigate with continuous exterior insulation.

Three components

1. Exit Access — any point to an exit
2. Exit — protected (enclosed stair, exit passageway, exterior door)
3. Exit Discharge — from exit to public way

Key distances (sprinklered)

• Common path — typ. 75–100 ft
• Dead-end corridor — typ. 20–50 ft
• Travel distance — typ. 200–300 ft

Egress width

Occupant load × factor:

• Level egress (corridors, doors): 0.2 in/occupant
• Stairs: 0.3 in/occupant

When 2 exits required

• Most occupancies: occupant load >49 OR common path exceeded
• 3 exits: 501-1000 occupants
• 4 exits: >1000 occupants

Slope thresholds

• <1:20 (5%): Accessible walking surface
• >1:20: Ramp territory
• Max 1:12 (8.33%) running slope for ramps
• Max 30\" rise per ramp run before landing

Clearances

• Turning radius: 60\" diameter circle
• Knee clearance: 27\" h × 11\" deep
• Toe clearance: 9\" h × 6\" deep

Accessible parking

• 1-25 spaces: 1 accessible
• 26-50: 2 / 51-75: 3 / 76-100: 4
• 1 of every 6 accessible must be van-accessible